U.S. patent application number 12/153423 was filed with the patent office on 2009-06-18 for methods and devices for sensing respiration and providing ventilation therapy.
This patent application is currently assigned to Breathe Technologies, Inc.. Invention is credited to Robert Bryan, Gregory Kapust, Michael Khenansho, Anthony Wondka.
Application Number | 20090156953 12/153423 |
Document ID | / |
Family ID | 40122176 |
Filed Date | 2009-06-18 |
United States Patent
Application |
20090156953 |
Kind Code |
A1 |
Wondka; Anthony ; et
al. |
June 18, 2009 |
Methods and devices for sensing respiration and providing
ventilation therapy
Abstract
Methods and systems are provided for intra-airway breath sensors
where intra-airway breath sensors are not located within a
ventilation gas delivery circuit, but are exposed to spontaneous
respiration airflow from a patient. Furthermore, methods and
systems of the present invention may be used to protect an
intra-airway breath sensor from contacting tissue or accumulating
debris that may impair abilities of the intra-airway breath
sensors.
Inventors: |
Wondka; Anthony; (Thousand
Oaks, CA) ; Kapust; Gregory; (San Ramon, CA) ;
Bryan; Robert; (San Ramon, CA) ; Khenansho;
Michael; (Modesto, CA) |
Correspondence
Address: |
PATTON BOGGS LLP
8484 WESTPARK DRIVE, SUITE 900
MCLEAN
VA
22102
US
|
Assignee: |
Breathe Technologies, Inc.
Fremont
CA
|
Family ID: |
40122176 |
Appl. No.: |
12/153423 |
Filed: |
May 19, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60924514 |
May 18, 2007 |
|
|
|
Current U.S.
Class: |
600/538 ;
128/204.21; 600/529 |
Current CPC
Class: |
A61M 2016/102 20130101;
A61B 5/085 20130101; A61M 16/0434 20130101; A61B 5/097 20130101;
A61M 2205/3375 20130101; A61M 16/042 20140204; A61M 2205/332
20130101; A61M 2230/65 20130101; A61M 16/0475 20140204; A61M
2205/3306 20130101; A61B 5/082 20130101; A61B 5/6853 20130101; A61B
5/6858 20130101; A61B 5/0878 20130101; A61M 2016/0027 20130101;
A61M 2016/003 20130101; A61M 16/0486 20140204; A61M 2230/43
20130101; A61M 16/0465 20130101; A61M 2016/0036 20130101; A61B
5/0873 20130101; A61M 16/0003 20140204; A61M 2016/0021 20130101;
A61M 16/0427 20140204 |
Class at
Publication: |
600/538 ;
600/529; 128/204.21 |
International
Class: |
A61B 5/087 20060101
A61B005/087; A61M 16/00 20060101 A61M016/00 |
Claims
1. A breath sensing and ventilation delivery apparatus comprising:
a catheter, one or more intra-airway breath sensors coupled to an
outer surface of the catheter, and an airflow permeable protector
with a proximal end adapted to be positioned outside a patient and
a distal end adapted to be placed in an airway of the patient,
wherein the airflow permeable protector at least partially
surrounds the catheter such that the airflow permeable protector
prevents the one or more intra-airway breath sensors from
contacting a tissue and reduces accumulation of debris on the one
or more intra-airway breath sensors.
2. The apparatus of claim 1, wherein the airflow permeable
protector is a tracheostomy tube cannula.
3. The apparatus of claim 2, wherein the cannula has one or more
fenestrations.
4. The apparatus of claim 2, wherein the cannula at least partially
surrounds the catheter forming an annular space between the cannula
and the catheter.
5. The apparatus of claim 1, wherein the airflow permeable
protector is a protective shield.
6. The apparatus of claim 5, wherein the protective shield is
selected from the group consisting of a shield tapered on at least
one end, a shield collapsible against an outer surface of the
ventilation catheter, stoma sleeve, and combinations thereof.
7. The apparatus of claim 1, wherein the one or more intra-airway
breath sensors are selected from the group consisting of thermal
sensors, pressure sensors, pressure sensing lumen, gas composition
sensors, flow sensors, ultrasonic sensors, resistivity sensors,
piezoelectric sensors, light emittance/reflectance sensors, and
combinations thereof.
8. A breath sensing and ventilation delivery apparatus comprising:
a ventilation catheter, a tracheostomy tube cannula with one or
more fenestrations, wherein the cannula at least partially
surrounds the ventilation catheter to create an annular space
between an inner diameter of the cannula and an outer diameter of
the ventilation catheter, and one or more intra-airway breath
sensors within the annular space between an inner diameter of the
cannula and an outer diameter of the ventilation catheter.
9. The apparatus of claim 8, wherein the ventilation catheter
extends beyond a distal portion of the cannula and into an
airway.
10. The apparatus of claim 8, further comprising a positioner for
positioning the ventilation catheter at a predetermined position
within the cannula.
11. The apparatus of claim 10, wherein the positioner is
basket-type device.
12. The apparatus of claim 10, wherein the positioner is a
deflector in a wall of the cannula.
13. The apparatus of claim 8, further comprising an anchor for
preventing movement of a distal tip of the ventilation
catheter.
14. The apparatus of claim 8, wherein the one or more fenestrations
are located in a position selected from the group consisting of a
superior side of the cannula, an inferior side of the cannula, a
lateral side of the outer cannula, and combinations thereof.
15. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are selected from the group consisting of thermal
sensors, pressure sensors, pressure sensing lumen, tubes with
sensing lumen, sensing subassemblies, gas composition sensors, flow
sensors, ultrasonic sensors, resistivity sensors, piezoelectric
sensors, light emittance/reflectance sensors, and combinations
thereof.
16. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are multiple elements placed in an array, wherein
one element is used as a reference signal.
17. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are coupled to the ventilation catheter.
18. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are coupled to the cannula.
19. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are de-coupled from the ventilation catheter and the
cannula.
20. The apparatus of claim 8, wherein the one or more intra-airway
breath sensors are a sensing lumen not in communication with a
ventilation catheter gas delivery circuit, wherein the sensing
lumen comprises a sensing element and a port positioned in the
annular space and wherein the sensing element is located external
to a body and communicating with the sensing lumen.
21. The apparatus of claim 8, wherein the ventilation catheter is
removable from the cannula.
22. The apparatus of claim 8, further comprising a seal between the
cannula and the ventilation catheter at a location proximal to the
one or more intra-airway breath sensors.
23. The apparatus of claim 8, wherein the ventilation catheter
comprises a moveable connection with the cannula.
24. A breath sensing and ventilation delivery apparatus comprising:
(a) a tubular member with a proximal end and a distal end, wherein
the proximal end is adapted to be positioned outside a patient and
the distal end is adapted to be positioned in an airway of the
patient, wherein the tubular member includes one or more
fenestrations, wherein spontaneous respiration by a patient passes
through the one or more fenestrations, (b) one or more intra-airway
breath sensors within a lumen of the tubular member, wherein a
distal end portion of the tubular member is positioned in the
airway such that the one or more intra-airway breath sensors are
located within the airway, and wherein the one or more intra-airway
breath sensors are exposed to the spontaneous respiration by the
patient while within the airway.
25. The apparatus of claim 24, wherein the one or more
fenestrations are located in a position selected from the group
consisting of a superior side of the tubular member, an inferior
side of the tubular member, a lateral side of the tubular member,
and combinations thereof.
26. The apparatus of claim 24, wherein the one or more intra-airway
breath sensors are selected from the group consisting of thermal
sensors, pressure sensors, pressure sensing lumen, tubes with
sensing lumen, sensing subassemblies, gas composition sensors, flow
sensors, ultrasonic sensors, resistivity sensors, piezoelectric
sensors, light emittance/reflectance sensors, and combinations
thereof.
27. A breath sensing and ventilation delivery apparatus comprising:
(a) a ventilation catheter for ventilation gas delivery including
at least one breath sensing lumen including a breath sensing lumen
port, (b) an airflow permeable protector at least partially
surrounding a portion of the catheter to protect the at least one
breath sensing lumen port, (c) a connection to connect the at least
one breath sensing lumen to an external sensor, and further wherein
the catheter is configured to be placed into an airway of the
patient to position the at least one breath sensing lumen port and
permeable protector in the airway, and wherein the at least on
breath sensing lumen port is protected by the airflow permable
protector but is exposed to spontaneous airflow in the airway.
28. The apparatus of claim 27, wherein the airflow permeable
protector comprises one or more fenestrations, which are located in
a position selected from the group consisting of a superior side of
the airflow permeable protector, an inferior side of the airflow
permeable protector, a lateral side of the airflow permeable
protector, and combinations thereof.
29. The apparatus of claim 27, wherein the external sensor is
selected from the group consisting of thermal sensors, gas
composition sensors, flow sensors, ultrasonic sensors, resistivity
sensors, piezoelectric sensors, light emittance/reflectance
sensors, and combinations thereof.
30. A breath sensing and ventilation catheter apparatus comprising:
a ventilation catheter for ventilation gas delivery, at least one
breath sensing lumen port positioned on an outside surface of the
ventilation catheter, an airflow permeable shield at least
partially surrounding the at least one breath sensing lumen port,
and wherein the airflow permeable shield prevents contact of the at
least one breath sensing lumen port with tissue and reduces
accumulation of debris on the at least one breath sensing lumen
port.
31. The apparatus of claim 30, wherein the airflow permeable shield
is a collapsible basket.
32. The apparatus of claim 30, wherein the airflow permeable shield
is a cone tapering from a proximal end to a distal end, and wherein
the cone further comprises one or more fenestrations.
33. The apparatus of claim 30, wherein the airflow permeable shield
is a cuff.
34. The apparatus of claim 30, wherein the airflow permeable shield
is a stoma sleeve.
35. The apparatus of claim 30, wherein the airflow permeable shield
is collapsible against an outer surface of the ventilation
catheter.
36. The apparatus of claim 30, wherein the at least one breath
sensing lumen port is connected to a sensor external to a patient,
the sensor selected from the group consisting of thermal sensors,
pressure sensors, gas composition sensors, flow sensors, ultrasonic
sensors, resistivity sensors, piezoelectric sensors, light
emittance/reflectance sensors, and combinations thereof.
37. A method for breath sensing and ventilation comprising:
inserting at least one intra-airway breath sensor into a tubular
guide positioned with a proximal end adapted to be outside of the
patient and a distal end adapted to be inside an airway of a
patient, wherein the at least one intra-airway breath sensor is not
located within a ventilator gas flow, and wherein the at least one
intra-airway breath sensor is shielded from contacting tissue and
from accumulating debris by the tubular guide.
38. The method of claim 37, wherein the tubular guide is a
tracheostomy tube cannula.
39. The method of claim 38, wherein the cannula at least partially
surrounds a ventilation catheter for providing the ventilator gas
flow, wherein the cannula forms an annular space between the
cannula and the ventilation catheter.
40. The method of claim 39, wherein the at least one intra-airway
breath sensor is within the annular space.
41. The method of claim 38, wherein the cannula has one or more
fenestrations.
42. The method of claim 37, wherein the tubular guide is a
protective shield.
43. The method of claim 42, wherein the protective shield is
selected from the group consisting of a shield tapered on at least
one end, a shield collapsible against an outer surface of the
ventilation catheter, stoma sleeve, and combinations thereof.
44. The method of claim 37, wherein the at least one intra-airway
breath sensor is selected from the group consisting of thermal
sensors, pressure sensors, pressure sensing lumen, gas composition
sensors, flow sensors, ultrasonic sensors, resistivity sensors,
piezoelectric sensors, light emittance/reflectance sensors, and
combinations thereof.
45. A method for breath sensing and ventilation comprising:
inserting at least one intra-airway breath sensor in a path of a
patient's airway airflow, but not within a ventilation gas delivery
circuit, monitoring the patient's airway airflow with the at least
one intra-airway breath sensor, operating at least one ventilation
gas sensor within a ventilation gas delivery circuit, and
monitoring the ventilator gas delivery with the at least one
ventilation gas sensor simultaneous with monitoring the patient's
airway airflow with the at least one intra-airway breath
sensor.
46. The method of claim 45, wherein the at least one intra-airway
breath sensor is coupled to a ventilation catheter.
47. The method of claim 45, wherein the at least one intra-airway
breath sensor is at least partially surrounded by a protector.
48. The method of claim 47, wherein the protector is a tracheostomy
tube cannula.
49. The method of claim 48, wherein the cannula comprises one or
more fenestrations.
50. The method of claim 47, wherein the protector is an airflow
permeable shield.
51. The method of claim 50, wherein the airflow permeable shield is
selected from the group consisting of a basket, a cone, a cuff, a
grouping of wires or filaments, a shield tapered on at least one
end, a shield collapsible against an outer surface of the
ventilation catheter, stoma sleeve, and combinations thereof.
52. The method of claim 45, wherein the at least one intra-airway
breath sensor is selected from the group consisting of thermal
sensors, pressure sensors, pressure sensing lumen, gas composition
sensors, flow sensors, ultrasonic sensors, resistivity sensors,
piezoelectric sensors, light emittance/reflectance sensors, and
combinations thereof.
53. An apparatus for breath sensing and ventilation comprising: a
ventilation catheter for supplying ventilation gas to a patient via
a ventilation gas delivery channel in the catheter, a sensing
conduit not in communication with the ventilation catheter gas
delivery circuit, an opening in the sensing conduit for sensing
respiration of the patient through the sensing conduit when the
opening is positioned within an airway, and a sensing element
communicating with the sensing conduit for sensing respiration of
the patient, wherein the sensing element is located external to the
patient, and a protector at least partially surrounding the
ventilation catheter and sensing conduit opening.
54. The apparatus of claim 53, wherein the protector is a
tracheostomy tube cannula.
55. The apparatus of claim 54, wherein the cannula comprises one or
more fenestrations.
56. The apparatus of claim 55, wherein the sensing element is
selected from the group consisting of: a pressure sensor, a flow
sensor, a thermal sensor, or an ultrasonic sensor.
57. The apparatus of claim 56, wherein the protector is selected
from the group consisting of a basket, a cone, a cuff, a grouping
of wires or filaments, a shield tapered on at least one end, a
shield collapsible against an outer surface of the ventilation
catheter, stoma sleeve, and combinations thereof.
58. A breath sensing and ventilation delivery apparatus comprising:
a ventilation catheter, a tracheostomy tube cannula, wherein the
tube cannula at least partially surrounds the ventilation catheter
to create an annular space between an inner diameter of the cannula
and an outer diameter of the ventilation catheter, and one or more
intra-airway breath sensors within the annular space between an
inner diameter of the cannula and an outer diameter of the
ventilation catheter.
59. The apparatus of claim 58, wherein the one or more intra-airway
breath sensors are coupled to the ventilation catheter.
60. The apparatus of claim 58, wherein the one or more intra-airway
breath sensors are coupled to the cannula.
61. The apparatus of claim 58, wherein the one or more intra-airway
breath sensors are de-coupled from the ventilation catheter and the
outer cannula.
62. The apparatus of claim 58, wherein the at least one
intra-airway breath sensor is selected from the group consisting of
thermal sensors, pressure sensors, pressure sensing lumen, gas
composition sensors, flow sensors, ultrasonic sensors, resistivity
sensors, piezoelectric sensors, light emittance/reflectance
sensors, and combinations thereof.
63. A breath sensing and ventilation delivery apparatus comprising:
(a) a ventilation catheter including a ventilation gas delivery
channel and a breath sensing lumen, wherein the breath sensing
lumen includes a sensing port, and wherein the ventilation catheter
is configured to be placed into the lumen of a tracheostomy tube
such that the ventilation catheter is at least partially surrounded
by the tracheostomy tube to prevent the sensing port from
contacting the tracheal wall; and (b) a breath sensor external to
the patient communicating with the breath sensing lumen.
64. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the external breath sensor is a pressure sensor.
65. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the ventilation gas delivery channel is connected to a
flow or pressure sensor external to the patient.
66. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the tracheostomy tube is a cannula of a dual cannula
tracheostomy tube.
67. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the tracheostomy tube is a single cannula tube.
68. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the ventilation catheter has a locking connector to
connect to the tracheostomy tube
69. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the tracheostomy tube has a fenestration positioned in
the airway.
70. A breath sensing and ventilation delivery apparatus as in claim
63, wherein the ventilation catheter has a centering feature to
prevent the sensing port from touching the inner wall of the
tracheostomy tube.
71. A breath sensing and ventilation delivery apparatus as in claim
63 wherein the sensing port is positioned at a distance away from
the distal end of the ventilation catheter.
72. A breath sensing and ventilation delivery apparatus comprising:
(a) a ventilation catheter including (i) a ventilation gas delivery
channel, (ii) a breath sensing lumen including a sensing port,
(iii) an airflow permeable shield at least partially surrounding
the sensing port; (b) a breath sensor placed external to the
patient communicating with the breath sensing lumen, wherein the
catheter is configured to be placed into an airway of a patient
such that the sensing port and at least a portion of the airflow
permeable shield is positioned in the airway of the patient such
that the airflow permeable shield prevents the sensing port from
contacting the airway wall, and such that the sensing port is
exposed to airflow in the airway.
73. A breath sensing and ventilation delivery apparatus as in claim
72 wherein the external breath sensor is a pressure sensor.
74. A breath sensing and ventilation delivery apparatus as in claim
72 wherein the ventilation gas delivery channel is connected to a
flow or pressure sensor external to the patient.
75. A breath sensing and ventilation delivery apparatus as in claim
72 wherein the sensing port is positioned at a distance away from
the distal end of the ventilation catheter.
76. A breath sensing and ventilation delivery apparatus as in claim
72 wherein the ventilation catheter is configured to be placed in
through a stoma guide.
77. A breath sensing and ventilation delivery apparatus as in claim
72 wherein the airflow permeable shield is collapsible.
78. A method for breath sensing and ventilation delivery
comprising: inserting a one end of a ventilation catheter into a
tracheostomy tube of a patient, wherein the ventilation catheter
includes a gas delivery channel, and a breath sensing lumen and a
breath sensing lumen port, and connecting at a second end of the
ventilation catheter the gas delivery channel to a ventilation gas
source and the breath sensing lumen to a breath sensor element.
79. A method as in claim 78, wherein step of connecting includes
connecting to the external breath sensor that is a pressure
sensor.
80. A method as in claim 78, wherein the step of connecting
includes connecting the ventilation gas delivery channel to a flow
or pressure sensor external to the patient.
81. A method as in claim 78, further comprising the step of
connecting the ventilation catheter having a locking connector to
the tracheostomy tube.
82. A method as in claim 78, further comprising the step of
positioning a fenestration in the tracheostomy tube in the
airway.
83. A method as in claim 78, further comprising the step of
centering the ventilation catheter using a centering feature on the
ventilation catheter to prevent the sensing port from touching the
inner wall of the tracheostomy tube.
84. A method as in claim 78, further comprising the step of
positioning the sensing port at a distance away from the distal end
of the ventilation catheter.
85. A method for breath sensing and ventilation delivery
comprising: inserting a one end of a ventilation catheter through a
stoma and into an airway of a patient, wherein the ventilation
catheter includes a gas delivery channel a breath sensing lumen and
a breath sensing lumen port, and a protective shield at least
partially surrounding the catheter section inserted into the airway
to prevent the sensing lumen port from contacting the airway wall,
and connecting, at a second end of the ventilation catheter, the
gas delivery channel to a ventilation gas source and the breath
sensing lumen to a breath sensor element.
86. A method as in claim 85, wherein the step of connecting
includes connecting to the external breath sensor is a pressure
sensor.
87. A method as in claim 85, wherein the step of connecting
includes connecting the ventilation gas delivery channel to a flow
or pressure sensor external to the patient.
88. A method as in claim 85, further comprising the step of
positioning the sensing port at a distance away from the distal end
of the ventilation catheter.
89. A method as in claim 85, further comprising the step of
positioning the ventilation catheter through a stoma guide.
90. A method as in claim 85, wherein the step of inserting includes
inserting the airflow permeable shield that is collapsible.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 60/924,514, filed May 18, 2007, the disclosure
of which is hereby incorporated by reference in its entirety. This
application further incorporates by reference in their entireties:
U.S. Non-Provisional patent application Ser. No. 10/771,803 (U.S.
Printed Publication 2005/0034721), filed Feb. 4, 2004, U.S.
Non-Provisional patent application Ser. No. 10/870,849 (U.S.
Printed Publication 2005/0005936), filed Jun. 17, 2004, U.S.
Non-Provisional patent application Ser. No. 11/523,519, filed Sep.
20, 2006 and U.S. Non-Provisional patent application Ser. No.
11/523,518, filed Sep. 20, 2006.
FIELD OF THE INVENTION
[0002] The present invention relates to ventilation therapy for
persons suffering from respiratory impairment and breathing
disorders, such as chronic obstructive pulmonary disease (COPD),
pulmonary fibrosis, acute respiratory distress syndrome (ARDS),
neuromuscular impairment, sleep apnea and/or other related
conditions. More specifically, the present invention relates to
accurately and reliably measuring a patient's respiratory pattern
using breath sensing, including providing methods, systems and
apparatus to protect breath sensors.
BACKGROUND OF THE INVENTION
[0003] There are two general types of control systems for
conventional ventilators. A first type is delivery of gas to a
patient based on a frequency selected by the clinician. The
frequency selected delivery is independent of patient activity.
This control system is used when the patient is non-alert, sedated,
unresponsive or paralyzed. In this type of system the ventilator is
breathing for the patient. A second type of control system is
delivery of gas to the patient in response to an inspiratory effort
created by the patient. This type of ventilation helps the patient
breathe. There are also ventilators and modes of ventilation that
combine the two types of control systems.
[0004] In the case of a control system that responds to patient
breathing effort, breath effort sensors are required to detect
inspiration. In basic conventional systems, the breath sensors
detect the start of inspiration using a pressure or flow sensor.
The inspiratory effort sensor is located somewhere in the path of
ventilation gas delivered by a ventilation gas delivery circuit. A
ventilation gas delivery circuit is generally defined as the path
of respiration gas delivered by a ventilator. The inspiratory
effort sensor may be either inside the ventilator, or in the tubing
between the ventilator and the patient, including at the patient
end of the tubing. Various attempts have been made to place the
inspiratory effort sensor(s) inside the patient, or externally
attached to the patient to improve breath effort detection and/or
improve response time of the ventilator gas delivery.
[0005] Pressure or flow sensors within the ventilation gas delivery
circuit have successfully been used to detect the start of
inspiration to trigger the ventilator to deliver gas to the
patient. However, when there is a need or desire to measure the
entire respiratory curve in addition to start of inspiration,
sensors within the ventilation gas delivery circuit produce
inadequate results because the gas being delivered by the
ventilator also moves past the sensor. Thus, the sensor no longer
measures the patient's respiration, but rather the gas delivered
through the ventilation gas circuit. In a closed ventilation
system, the ventilator activity approximates the overall lung
activity, hence this positioning of sensors may be adequate. In an
open ventilation system, or in ventilation systems that augment a
patient's spontaneous breathing, sensors within the ventilation gas
delivery circuit are inadequate in measuring the entire respiratory
curve.
[0006] Sensors not within the ventilator gas delivery circuit have
the ability to measure the entire respiration activity. For
example, chest impedance sensors can be used to measure the entire
respiratory curve of a patient and to use that signal to control
the ventilator and synchronize the ventilator to the patient's
breathing. Although an improvement, this approach has the
disadvantage that the chest impedance signal is prone to drift,
noise and artifacts caused by patient motion and abdominal
movement. In another technology, neural activity related to the
respiratory drive is used to measure the respiration of a patient.
However, this has the disadvantage that it is invasive and requires
electrodes typically placed in the esophagus to detect the neural
activity.
[0007] U.S. Non-Provisional patent application Ser. No. 10/870,849
(U.S. Printed Publication 2005/0034721), which is incorporated by
reference in its entirety above, describes a new form of breath
sensing with sensors not within a ventilation gas delivery circuit.
The sensors may be located in the airway of a patient, for example,
in the patient's trachea, but not within the ventilation gas
delivery circuit. In this manner, the gas delivery from the
ventilator may not dominate the sensor measurements. This
intra-airway sensor may measure naturally inspired gas flow of the
patient, naturally exhaled gas flow of the patient, and the effect
of the ventilator gas delivery on lung volumes. The sensor may not
measure gas flowing in the ventilator delivery circuit as in
conventional systems. This breath sensing method may then measure,
not just the start of inspiration, but the entire respiratory
pattern of the patient. This may be advantageous to optimize the
synchrony of the ventilator to the patient's natural breath
pattern, so that the patient is comfortable. Also, if the goal is
to provide therapy during different portions of the respiratory
curve, such as during the middle of inspiration, or during a
particular part of the expiratory phase, then this method may be
used to accurately measure the entire respiratory curve. This new
breath sensing technology, however, may not be simple or obvious to
reduce to practice. Sensors within the airway of the patient are
prone to problems stemming from tissue interaction,
patient-to-patient variability, variability within a given patient
over time, and a variable physiological environment that can not be
controlled. For example, debris in the airway may collect on the
sensors and may cause signal artifacts and disrupt the sensors'
ability to accurately and reliably measure the entire breath curve.
Or, the sensor could come into contact with the tracheal wall,
which may disrupt the sensors' signal. Alternatively, tracheal
movement during breathing can affect the signal.
[0008] Need exists for improved breath sensing systems and methods
for ensuring reliable and accurate breath measurements.
SUMMARY OF THE INVENTION
[0009] The present invention may be directed to methods and systems
for intra-airway breath sensors, especially those sensors not
within a ventilation gas delivery circuit, but exposed to a
patient's spontaneous respiration airflow. The present invention is
an improvement over existing breath sensing techniques. Further,
apparatus and methods for shielding and protecting the intra-airway
sensors from disruptions such as contacting tissue or accumulating
debris are provided.
[0010] One aspect of the invention is directed to a breath sensing
and ventilation delivery apparatus comprising: a catheter, one or
more intra-airway breath sensors coupled to an outer surface of the
catheter, and an airflow permeable protector with a proximal end
adapted to be positioned outside a patient and a distal end adapted
to be placed in an airway of the patient, wherein the airflow
permeable protector at least partially surrounds the catheter such
that the airflow permeable protector prevents the one or more
intra-airway breath sensors from contacting a tissue and reduces
accumulation of debris on the one or more intra-airway breath
sensors. The airflow permeable protector may be a tracheostomy tube
cannula. The cannula may have one or more fenestrations. The
cannula may at least partially surround the catheter forming an
annular space between the cannula and the catheter. The airflow
permeable protector may be a protective shield. The protective
shield may be selected from the group consisting of a shield
tapered on at least one end, a shield collapsible against an outer
surface of the ventilation catheter, stoma sleeve, and combinations
thereof. The one or more intra-airway breath sensors may be
selected from the group consisting of thermal sensors, pressure
sensors, pressure sensing lumen, gas composition sensors, flow
sensors, ultrasonic sensors, resistivity sensors, piezoelectric
sensors, light emittance/reflectance sensors, and combinations
thereof.
[0011] Another aspect of the invention is directed to a breath
sensing and ventilation delivery apparatus comprising: a
ventilation catheter, a tracheostomy tube cannula with one or more
fenestrations, wherein the cannula at least partially surrounds the
ventilation catheter to create an annular space between an inner
diameter of the cannula and an outer diameter of the ventilation
catheter, and one or more intra-airway breath sensors within the
annular space between an inner diameter of the cannula and an outer
diameter of the ventilation catheter. The ventilation catheter may
extend beyond a distal portion of the cannula and into an airway. A
positioner may be provided for positioning the ventilation catheter
at a predetermined position within the cannula. The positioner may
be a basket-type device. The positioner may be a deflector in a
wall of the cannula. An anchor may be provided for preventing
movement of a distal tip of the ventilation catheter. The one or
more fenestrations may be located in a position selected from the
group consisting of a superior side of the cannula, an inferior
side of the cannula, a lateral side of the outer cannula, and
combinations thereof. The one or more intra-airway breath sensors
may be selected from the group consisting of thermal sensors,
pressure sensors, pressure sensing lumen, tubes with sensing lumen,
sensing subassemblies, gas composition sensors, flow sensors,
ultrasonic sensors, resistivity sensors, piezoelectric sensors,
light emittance/reflectance sensors, and combinations thereof. The
one or more intra-airway breath sensors may be multiple elements
placed in an array, wherein one element is used as a reference
signal. The one or more intra-airway breath sensors may be coupled
to the ventilation catheter. The one or more intra-airway breath
sensors may be coupled to the cannula. The one or more intra-airway
breath sensors may be de-coupled from the ventilation catheter and
the cannula. The one or more intra-airway breath sensors may be a
sensing lumen not in communication with a ventilation catheter gas
delivery circuit, wherein the sensing lumen comprises a sensing
element and a port positioned in the annular space and wherein the
sensing element is located external to a body and communicating
with the sensing lumen. The ventilation catheter may be removable
from the cannula. A seal may be provided between the cannula and
the ventilation catheter at a location proximal to the one or more
intra-airway breath sensors. The ventilation catheter may comprise
a moveable connection with the cannula.
[0012] Another aspect of the invention includes breath sensing and
ventilation delivery apparatus comprising: (a) a tubular member
with a proximal end and a distal end, wherein the proximal end is
adapted to be positioned outside a patient and the distal end is
adapted to be positioned in an airway of the patient, wherein the
tubular member includes one or more fenestrations, wherein
spontaneous respiration by a patient passes through the one or more
fenestrations, (b) one or more intra-airway breath sensors within a
lumen of the tubular member, wherein a distal end portion of the
tubular member is positioned in the airway such that the one or
more intra-airway breath sensors are located within the airway, and
wherein the one or more intra-airway breath sensors are exposed to
the spontaneous respiration by the patient while within the airway.
The one or more fenestrations may be located in a position selected
from the group consisting of a superior side of the tubular member,
an inferior side of the tubular member, a lateral side of the
tubular member, and combinations thereof. The one or more
intra-airway breath sensors may be selected from the group
consisting of thermal sensors, pressure sensors, pressure sensing
lumen, tubes with sensing lumen, sensing subassemblies, gas
composition sensors, flow sensors, ultrasonic sensors, resistivity
sensors, piezoelectric sensors, light emittance/reflectance
sensors, and combinations thereof.
[0013] Another aspect of the invention includes a breath sensing
and ventilation delivery apparatus comprising: (a) a ventilation
catheter for ventilation gas delivery including at least one breath
sensing lumen including a breath sensing lumen port, (b) an airflow
permeable protector at least partially surrounding a portion of the
catheter to protect the at least one breath sensing lumen port, (c)
a connection to connect the at least one breath sensing lumen to an
external sensor, and further wherein the catheter is configured to
be placed into an airway of the patient to position the at least
one breath sensing lumen port and permeable protector in the
airway, and wherein the at least on breath sensing lumen port is
protected by the airflow permable protector but is exposed to
spontaneous airflow in the airway. The airflow permeable protector
may comprises one or more fenestrations, which are located in a
position selected from the group consisting of a superior side of
the airflow permeable protector, an inferior side of the airflow
permeable protector, a lateral side of the airflow permeable
protector, and combinations thereof. The external sensor is
selected from the group consisting of thermal sensors, gas
composition sensors, flow sensors, ultrasonic sensors, resistivity
sensors, piezoelectric sensors, light emittance/reflectance
sensors, and combinations thereof.
[0014] Another aspect of the invention includes a breath sensing
and ventilation catheter apparatus comprising: a ventilation
catheter for ventilation gas delivery, at least one breath sensing
lumen port positioned on an outside surface of the ventilation
catheter, an airflow permeable shield at least partially
surrounding the at least one breath sensing lumen port, and wherein
the airflow permeable shield prevents contact of the at least one
breath sensing lumen port with tissue and reduces accumulation of
debris on the at least one breath sensing lumen port. The airflow
permeable shield may be a collapsible basket. The airflow permeable
shield may be a cone tapering from a proximal end to a distal end,
and wherein the cone further comprises one or more fenestrations.
The airflow permeable shield may be a cuff. The airflow permeable
shield may be a stoma sleeve. The airflow permeable shield may be
collapsible against an outer surface of the ventilation catheter.
The at least one breath sensing lumen port may be connected to a
sensor external to a patient, the sensor selected from the group
consisting of thermal sensors, pressure sensors, gas composition
sensors, flow sensors, ultrasonic sensors, resistivity sensors,
piezoelectric sensors, light emittance/reflectance sensors, and
combinations thereof.
[0015] Another aspect of the invention includes a method for breath
sensing and ventilation comprising: inserting at least one
intra-airway breath sensor into a tubular guide positioned with a
proximal end adapted to be outside of the patient and a distal end
adapted to be inside an airway of a patient, wherein the at least
one intra-airway breath sensor is not located within a ventilator
gas flow, and wherein the at least one intra-airway breath sensor
is shielded from contacting tissue and from accumulating debris by
the tubular guide. The tubular guide may be a tracheostomy tube
cannula. The cannula may at least partially surround a ventilation
catheter for providing the ventilator gas flow, wherein the cannula
forms an annular space between the cannula and the ventilation
catheter. The at least one intra-airway breath sensor may be within
the annular space. The cannula may have one or more fenestrations.
The tubular guide may be a protective shield. The protective shield
may be selected from the group consisting of a shield tapered on at
least one end, a shield collapsible against an outer surface of the
ventilation catheter, stoma sleeve, and combinations thereof. The
at least one intra-airway breath sensor may be selected from the
group consisting of thermal sensors, pressure sensors, pressure
sensing lumen, gas composition sensors, flow sensors, ultrasonic
sensors, resistivity sensors, piezoelectric sensors, light
emittance/reflectance sensors, and combinations thereof.
[0016] Another aspect of the invention relates to a method for
breath sensing and ventilation comprising: inserting at least one
intra-airway breath sensor in a path of a patient's airway airflow,
but not within a ventilation gas delivery circuit, monitoring the
patient's airway airflow with the at least one intra-airway breath
sensor, operating at least one ventilation gas sensor within a
ventilation gas delivery circuit, and monitoring the ventilator gas
delivery with the at least one ventilation gas sensor simultaneous
with monitoring the patient's airway airflow with the at least one
intra-airway breath sensor. The at least one intra-airway breath
sensor may be coupled to a ventilation catheter. The at least one
intra-airway breath sensor can be at least partially surrounded by
a protector. The protector may be a tracheostomy tube cannula. The
cannula may comprise one or more fenestrations. The protector may
be an airflow permeable shield. The airflow permeable shield may be
selected from the group consisting of a basket, a cone, a cuff, a
grouping of wires or filaments, a shield tapered on at least one
end, a shield collapsible against an outer surface of the
ventilation catheter, stoma sleeve, and combinations thereof. The
at least one intra-airway breath sensor may be selected from the
group consisting of thermal sensors, pressure sensors, pressure
sensing lumen, gas composition sensors, flow sensors, ultrasonic
sensors, resistivity sensors, piezoelectric sensors, light
emittance/reflectance sensors, and combinations thereof.
[0017] Another aspect of the invention relates to an apparatus for
breath sensing and ventilation comprising: a ventilation catheter
for supplying ventilation gas to a patient via a ventilation gas
delivery channel in the catheter, a sensing conduit not in
communication with the ventilation catheter gas delivery circuit,
an opening in the sensing conduit for sensing respiration of the
patient through the sensing conduit when the opening is positioned
within an airway, and a sensing element communicating with the
sensing conduit for sensing respiration of the patient, wherein the
sensing element is located external to the patient, and a protector
at least partially surrounding the ventilation catheter and sensing
conduit opening. The protector may be a tracheostomy tube cannula.
The cannula may comprise one or more fenestrations. The sensing
element may be selected from the group consisting of: a pressure
sensor, a flow sensor, a thermal sensor, or an ultrasonic sensor.
The protector may be selected from the group consisting of a
basket, a cone, a cuff, a grouping of wires or filaments, a shield
tapered on at least one end, a shield collapsible against an outer
surface of the ventilation catheter, stoma sleeve, and combinations
thereof.
[0018] Another aspect of the invention relates to a breath sensing
and ventilation delivery apparatus comprising: a ventilation
catheter, a tracheostomy tube cannula, wherein the tube cannula at
least partially surrounds the ventilation catheter to create an
annular space between an inner diameter of the cannula and an outer
diameter of the ventilation catheter, and one or more intra-airway
breath sensors within the annular space between an inner diameter
of the cannula and an outer diameter of the ventilation catheter.
The one or more intra-airway breath sensors may be coupled to the
ventilation catheter. The one or more intra-airway breath sensors
may be coupled to the cannula. The one or more intra-airway breath
sensors may be de-coupled from the ventilation catheter and the
outer cannula. The at least one intra-airway breath sensor may be
selected from the group consisting of thermal sensors, pressure
sensors, pressure sensing lumen, gas composition sensors, flow
sensors, ultrasonic sensors, resistivity sensors, piezoelectric
sensors, light emittance/reflectance sensors, and combinations
thereof.
[0019] Another aspect of the invention relates to a breath sensing
and ventilation delivery apparatus comprising: (a) a ventilation
catheter including a ventilation gas delivery channel and a breath
sensing lumen, wherein the breath sensing lumen includes a sensing
port, and wherein the ventilation catheter is configured to be
placed into the lumen of a tracheostomy tube such that the
ventilation catheter is at least partially surrounded by the
tracheostomy tube to prevent the sensing port from contacting the
tracheal wall; and (b) a breath sensor external to the patient
communicating with the breath sensing lumen. The external breath
sensor may be a pressure sensor. The ventilation gas delivery
channel may be connected to a flow or pressure sensor external to
the patient. The tracheostomy tube may be a cannula of a dual
cannula tracheostomy tube. The tracheostomy tube may be a single
cannula tube. The ventilation catheter may have a locking connector
to connect to the tracheostomy tube. The tracheostomy tube may have
a fenestration positioned in the airway. The ventilation catheter
may have a centering feature to prevent the sensing port from
touching the inner wall of the tracheostomy tube. The sensing port
may be positioned at a distance away from the distal end of the
ventilation catheter.
[0020] Another aspect of the invention is directed to a breath
sensing and ventilation delivery apparatus comprising: (a) a
ventilation catheter including (i) a ventilation gas delivery
channel, (ii) a breath sensing lumen including a sensing port,
(iii) an airflow permeable shield at least partially surrounding
the sensing port; (b) a breath sensor placed external to the
patient communicating with the breath sensing lumen, wherein the
catheter is configured to be placed into an airway of a patient
such that the sensing port and at least a portion of the airflow
permeable shield is positioned in the airway of the patient such
that the airflow permeable shield prevents the sensing port from
contacting the airway wall, and such that the sensing port is
exposed to airflow in the airway. The external breath sensor may be
a pressure sensor. The ventilation gas delivery channel may be
connected to a flow or pressure sensor external to the patient. The
sensing port may positioned at a distance away from the distal end
of the ventilation catheter. The ventilation catheter may be
configured to be placed in through a stoma guide. The airflow
permeable shield may be collapsible.
[0021] Another aspect relates to a method for breath sensing and
ventilation delivery comprising: inserting a one end of a
ventilation catheter into a tracheostomy tube of a patient, wherein
the ventilation catheter includes a gas delivery channel and a
breath sensing lumen and a breath sensing lumen port, and
connecting at a second end of the ventilation catheter the gas
delivery channel to a ventilation gas source and the breath sensing
lumen to a breath sensor element. The step of connecting may
include connecting to the external breath sensor that is a pressure
sensor. The step of connecting may include connecting the
ventilation gas delivery channel to a flow or pressure sensor
external to the patient. The ventilation catheter may have a
locking connector to the tracheostomy tube. The method may include
positioning a fenestration in the tracheostomy tube in the airway.
The method may include the step of centering the ventilation
catheter using a centering feature on the ventilation catheter to
prevent the sensing port from touching the inner wall of the
tracheostomy tube. The method may include the step of positioning
the sensing port at a distance away from the distal end of the
ventilation catheter.
[0022] Another aspect of the invention relates to a method for
breath sensing and ventilation delivery comprising: inserting a one
end of a ventilation catheter through a stoma and into an airway of
a patient, wherein the ventilation catheter includes a gas delivery
channel, a breath sensing lumen and a breath sensing lumen port,
and a protective shield at least partially surrounding the catheter
section inserted into the airway to prevent the sensing lumen port
from contacting the airway wall, and connecting, at a second end of
the ventilation catheter, the gas delivery channel to a ventilation
gas source and the breath sensing lumen to a breath sensor element.
The step of connecting may include connecting to the external
breath sensor is a pressure sensor. The step of connecting may
include connecting the ventilation gas delivery channel to a flow
or pressure sensor external to the patient. The method may include
step of positioning the sensing port at a distance away from the
distal end of the ventilation catheter. The method may include the
step of positioning the ventilation catheter through a stoma guide.
The step of inserting may include inserting the airflow permeable
shield that is collapsible.
[0023] Additional features, advantages, and embodiments of the
invention are set forth or apparent from consideration of the
following detailed description, drawings and claims. Moreover, it
is to be understood that both the foregoing summary of the
invention and the following detailed description are exemplary and
intended to provide further explanation without limiting the scope
of the invention as claimed.
BRIEF DESCRIPTION OF THE INVENTION
[0024] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate preferred
embodiments of the invention and together with the detailed
description serve to explain the principles of the invention. In
the drawings:
[0025] FIG. 1a shows prior art for breath effort detection by using
breath sensors within a ventilator gas delivery circuit.
[0026] FIG. 1b shows optional prior art using an ultrasonic flow
meter.
[0027] FIG. 1c shows optional prior art using a rotameter flow
meter.
[0028] FIG. 1d is a graph illustrating a signal from the system of
FIG. 1a where the sensed pressure does not necessarily correspond
to respiration.
[0029] FIG. 2a shows prior art using chest impedance for breath
sensing and ventilator control.
[0030] FIG. 2b is a graph illustrating a drift in the impedance
signal of FIG. 2a caused by an environmental or stability
problem.
[0031] FIG. 3a shows prior art in which intra-airway breath sensors
are used for ventilator control and monitoring respiration
activity.
[0032] FIG. 3b is a graph illustrating a disruption of the sensor
signal of FIG. 3a caused by an environmental problem.
[0033] FIG. 4 shows a partial cross-sectional view of the overall
system of the invention including a ventilation catheter and a
fenestrated outer cannula and a breath sensor in the annular space,
and a ventilator.
[0034] FIG. 5 shows a partial cross-sectional view of the overall
system of the invention including a ventilation catheter, a
fenestrated outer cannula and a breath sensing lumen and sensing
port, and a sensor placed outside the patient in a ventilator
[0035] FIG. 6 shows a ventilation catheter and non-fenestrated
outer cannula with a breath sensor in the annular space.
[0036] FIG. 7 shows a ventilation catheter and an outer cannula
with a breath sensor part of the outer cannula.
[0037] FIG. 8 shows a ventilation catheter and an outer cannula
with a breath sensing lumen and port as part of the outer
cannula.
[0038] FIG. 9 shows a ventilation catheter and an outer cannula and
a separate sensor assembly placed in the space between the
ventilation catheter and outer cannula.
[0039] FIG. 10 shows a ventilation catheter and an outer cannula
and a separate sensing lumen assembly placed in the space between
the ventilation catheter and outer cannula.
[0040] FIG. 11 shows a ventilation catheter and an outer cannula
with an channel open to ambient between the catheter and cannula
and a sensor in the channel.
[0041] FIG. 12A shows a dual lumen trach tube with fenestrated
outer cannula.
[0042] FIG. 12B shows the outer cannula of FIG. 12A with the inner
cannula removed.
[0043] FIG. 12C is a cross section of a ventilation catheter placed
inside the fenestrated outer cannula of FIG. 12B where a sensing
element is positioned in an annular space.
[0044] FIG. 13 is a detailed view of an alternative, adjustable
ventilation catheter connector.
[0045] FIG. 14 is a partial cross section of a ventilation catheter
placed inside the fenestrated outer cannula of FIG. 12B where a
sensing lumen port is positioned in an annular space.
[0046] FIG. 15 shows a ventilation catheter with intra-airway
breath sensing protected inside a fenestrated single cannula
tracheostomy tube.
[0047] FIG. 16 is a cross section of a ventilation catheter with
intra-airway breath sensor protected inside a fenestrated outer
cannula with inferior and superior fenestration positions.
[0048] FIG. 17 shows a ventilation catheter with an outer cannula
with fenestrations on a lateral wall of the outer cannula.
[0049] FIG. 18A is a cross section of a ventilation catheter with
intra-airway breath sensors protected inside a fenestrated outer
cannula, with positioning and anchoring features for the
ventilation catheter.
[0050] FIG. 18B is an end view of the ventilation catheter shown in
FIG. 18A.
[0051] FIG. 19 shows a ventilation catheter with a fenestrated
outer cannula having a depression to create an annular gap between
the ventilation catheter and the fenestrated outer cannula.
[0052] FIG. 20A is a cross section of a ventilation catheter inside
a fenestrated outer cannula with a depression adjoining the
fenestration in a wall of the outer cannula to create an annular
gap between the ventilation catheter and the fenestrated outer
cannula.
[0053] FIG. 20B is a view of the device in FIG. 20A however with
the depression on the inferior side.
[0054] FIG. 21A is a cross section of a ventilation catheter inside
a fenestrated outer cannula with a protrusion in an inner wall of
the outer cannula to create an annular gap between the ventilation
catheter and the fenestrated outer cannula.
[0055] FIG. 21B is a view of the device in FIG. 21A however with
the depression on the inferior side.
[0056] FIG. 22 shows a ventilation catheter with intra-airway
breath sensors protected inside a minimally penetrating fenestrated
outer cannula.
[0057] FIG. 23 shows a ventilation catheter inserted through a
stoma sleeve where a sensor is protected by a stoma sleeve.
[0058] FIG. 24 shows a ventilation catheter with intra-airway
breath sensors protected by an air permeable shield that is
collapsible.
[0059] FIG. 25A shows a ventilation catheter with intra-airway
breath sensors protected by a permeable wire basket shield that may
be collapsible against a catheter shaft and may be expanded when in
use.
[0060] FIG. 25B is a cross sectional view of the ventilation
catheter shown in FIG. 10a.
[0061] FIG. 26 shows a ventilation catheter with intra-airway
breath sensors protected by a permeable conical shield that may be
foldable, collapsible against a catheter shaft, and may be expanded
when in use.
[0062] FIG. 27 shows a system layout of the system shown in FIG. 4,
with an additional ventilator gas delivery sensor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0063] FIG. 1a shows a prior art ventilator breath detection
triggering system where a pressure sensor is located within a
ventilation gas delivery circuit 21. A ventilator V may deliver
ventilation gas to a patient P through a ventilation gas delivery
circuit 21 and a ventilation tube 25. A ventilation circuit
pressure tap 22 may be located within the ventilation gas delivery
circuit 21. The ventilation circuit pressure tap 22 may sense
pressure in the ventilation gas delivery circuit 21. Thus, when the
patient P inspires, a negative pressure created in the lung L may
be transmitted to the trachea T, and the negative pressure may be
detected in the ventilation circuit pressure tap 22. The
ventilation circuit pressure tap 22 may be in communication with a
ventilator breath delivery control unit 20.
[0064] Alternatively, as shown in FIG. 1b, a flow sensor may be
used in place of the pressure sensor. The flow sensor may be an
ultrasonic flow sensor 30 or another type of flow sensor.
Alternatively, as shown in FIG. 1c, a rotameter flow sensor 32 may
be located within the ventilation gas delivery circuit 21 to detect
inspiration by the patient P, as shown in FIGS. 1a and 1b.
[0065] A signal representing the reading from the sensors 22, 30,
32 may be communicated to the ventilator breath delivery control
unit 20 in the ventilator V. The sensors 22, 30, 32 within the
ventilation gas delivery circuit 21 may measure the start of a
breath. After the ventilator breath delivery control unit 20
receives the signal, the ventilator V may be triggered to deliver a
mechanical breath to the patient P through the ventilation gas
delivery circuit 21. After the ventilator V is triggered, the
sensors 22, 30, 32 may measure activity of the ventilator V. The
sensors 20, 30, 32 may not accurately measure patient
breathing.
[0066] FIG. 1d shows the measurement of the patient's tracheal
pressure P(t) detected by the sensors 22, 30, 32 in comparison with
a tracing R of a patient's actual respiration. A patient's
inspiration 54 may be initially detected by the sensors 22, 30, 32
as a decrease in pressure from a patient inspiration pressure 50.
After triggering of the ventilator V, however, the sensors 22,
30,32 may only measure ventilator breath delivery pressure 52 and
not patient exhalation 56.
[0067] FIG. 2a shows a prior art ventilator triggering system where
the breath sensor is a chest impedance sensor. The breath sensor is
not located within a ventilation gas delivery system 21. A chest
impedance sensor may have the drawback that signals representing
patient breathing may be affected by motion of the patient P not
related to breathing. A chest impedance band 62 may be connected to
a ventilator V and corresponding ventilator breath delivery control
unit 20 by chest impedance wires 60.
[0068] FIG. 2b shows a respiration trace R of the patient P, which
may correspond to the patient's actual breathing for a certain
time, as compared to a flow of gas in a patient's trachea T as
shown in tracheal airflow tracing Q. A patient inspiration tracheal
flow curve 64 and a patient exhalation tracheal flow curve 66 may
be detected by the chest impedance band 62 as seen in a chest
impedance inspiration trace 74 and a chest impedance exhalation
trace 76, respectively. However, due to motion and patient position
and other factors, the chest impedance signal may have chest
impedance signal drift 78 or may have chest impedance signal noise
from patient motion 80.
[0069] FIG. 3a shows a prior art breath sensing system. An
intra-airway breath sensor 190 may be located in an airflow path of
a patient P in the patient's trachea T.
[0070] The intra-airway breath sensor 190 may be used to detect
spontaneous breathing by the patient P. To effectively measure
spontaneous breathing, the intra-airway breath sensor 190 is
preferably not located within a ventilation gas delivery circuit
21. For purposes of this disclosure, a sensor not located within
the ventilation gas delivery circuit 21 may be considered to be "in
parallel" to the ventilation gas delivery circuit 21. Sensors that
are located within the ventilation gas delivery circuit 21 may be
considered "in series" in relation to the ventilation gas delivery
circuit 21 for purposes of this disclosure. Sensors that are within
the ventilation gas delivery circuit 21 may not adequately measure
spontaneous breathing after the triggering of a ventilator V
because the sensor may then measure primarily the gas delivered by
the ventilator V and because the spontaneous breathing may move
substantially less air than the ventilator V. A benefit of not
having sensors in communication with the ventilator gas delivery
circuit is that the sensor may measure the entire spontaneous
breathing signal even after triggering the ventilator V because the
sensor would not be within the stream of gas supplied by the
ventilator V. Sensors outside of the ventilator gas delivery
circuit are not directly measuring gas delivered from the
ventilator V.
[0071] The intra-airway breath sensor 190 of FIG. 3a may not be in
communication with the ventilation gas delivery circuit 21. The
intra-airway breath sensor 190 may be mounted on an outside surface
of ventilation tube 25. The intra-airway breath sensor 190 may
measure spontaneous breathing and create a signal representing the
spontaneous breathing. The signal may be communicated to a
ventilator breath delivery control unit 20 within the ventilator V
by intra-airway breath sensing wires 92, wireless technology, RFID,
or other communications technology.
[0072] The positioning of the intra-airway breath sensor 190 within
the trachea T not in communication with a ventilator gas delivery
circuit 21 may be an improvement over conventional systems because
the intra-airway breath sensor 190 may be less prone to drift and
disturbance from environmental influences and patient movement. The
sensor may also be less invasive and obtrusive to the patient P,
and may be more convenient for a supervising clinician. The
intra-airway breath sensor 190 may be mounted on a portion 24 of a
ventilation tube 25 inserted into the airway of a patient P.
Additionally, when the ventilator V is triggered to deliver gas to
the patient P through the ventilation gas delivery circuit 21, a
measurement by the intra-airway breath sensor 190 may not be
dominated by action of the ventilator V and may continue to measure
spontaneous respiration of the patient P.
[0073] FIG. 3b shows a tracheal airflow trace Q compared with a
breath sensor signal tracing S. Patient inspiration tracheal flow
65 and patient exhalation tracheal flow 67 compare well with an
inspiration trace 75 and an expiration trace 77, respectively.
However, the intra-airway breath sensor 190 may be susceptible to
contacting tissue, such as a wall of the trachea T, or accumulation
of debris on a surface of the intra-airway breath sensor 190.
Contacting tissue and/or accumulation of debris may disrupt
measurement from the intra-airway breath sensor 190 as shown by an
intra-tracheal breath sensor signal attenuation from tissue contact
or debris 94. Protection of the efficacy and accuracy of the
intra-airway breath sensor 190 may be important to ensure proper
function of a ventilator gas delivery circuit 21.
[0074] FIG. 4 shows a system diagram of an embodiment of the
present invention. A ventilation catheter 27 may be placed inside
an outer tube 28, such as a tracheostomy tube, and a breath sensor
or sensors 90 may be placed in an annular space 46 between the
ventilation catheter 27 and the outer tube 28 for protection
against accumulation of debris and tracheal wall contact.
Typically, the system may be configured to facilitate at least part
of the patient's spontaneous breathing airflow to travel in the
annular space. The sensor signal may be transmitted to the
ventilator V to control the ventilator, which may be attached to
the ventilation catheter 27 with a gas delivery circuit 21. The
outer tube 28 may include fenestrations 100 so gas may flow easily
in and out of the annular space 46.
[0075] An intra-airway breath sensor 90 may be located in the
trachea T, nose, mouth, throat, bronchial or any other location
within the path of inhaled and exhaled air. Furthermore, it may be
appreciated that embodiments of the present invention may apply to
other physiological applications where a catheter is placed in any
luminal structure for sensing and therapy. It should be further
appreciated that with the appropriate modifications, embodiments of
the present invention may be reusable or disposable and may be
adapted for adult, pediatric or neonatal use.
[0076] The breath sensors in accordance with the principles of the
present invention may be thermal sensors, pressure sensors, sensing
lumens, gas composition sensors, flow sensors, ultrasonic sensors,
resistivity sensors, piezoelectric sensors, light
emittance/reflectance sensors, or any other sensor capable of
sensing respiration. The breath sensors may be a single sensing
element/transducer. Alternatively, the breath sensors may contain
multiple sensing elements/transducers for redundancy of signal
measurements. Additionally, the breath sensors may contain multiple
elements arranged in a sensing array such that at least one of the
multiple elements may be used as a reference signal. In the present
disclosure, a sensor may be referred to as either singular or
plural, however, all of the above configurations may apply.
[0077] Preferably, the breath sensors may be mounted on a portion
of a ventilation tube inserted into the airway of a patient P as
shown in FIG. 4 Alternatively, as shown in the system diagram in
FIG. 5, an external breath sensor 96 may be positioned outside the
body. The external breath sensor 96 may measure airflow or
breathing pressure occurring in the patient airway via a sensing
conduit or lumen 42. The sensing conduit or lumen 42 may have an
opening or sensing port 44 within a patient airway in the annular
space 46 between the ventilation tube 27 and the outer tube 28. The
conduit or lumen 42 may run from the opening 44 to an external
breath sensor, for example a sensor 96, located in the ventilator
V. The sensor 96 may communicate with a control unit 20 to control
a gas delivery device 142 to control the delivery of gas to the
patient.
[0078] Fenestrations 100 in the outer tube 28 may be provided as
shown in FIGS. 4 and 5 to facilitate spontaneously breathing
airflow travels in the annular space. Alternatively, as shown in
FIG. 6, the outer tube 28 can be without fenestrations, and the
sensor 90 may register the tracheal breathing pressures that are
occurring without requiring an open flow path through the outer
tube 28.
[0079] The breath sensor or external breath sensor and
corresponding sensing conduit may be coupled to a ventilation tube
as shown in FIGS. 4-6. Alternatively, the breath sensor or external
breath sensor and corresponding sensing conduit may be integrated
with other components of the present invention as described herein.
For example, a breath sensor 90 may be part of the inner wall of
the outer cannula 28, as shown in FIG. 7. The ventilation catheter
27, when inserted into the outer cannula 28, may form an electrical
connection with the sensor 90 so the sensor signal may be
transmitted to the ventilator with wiring 92.
[0080] Or, as shown in FIG. 8, a sensing lumen 42 and sensing lumen
port 44 can be coupled to the outer cannula 28. When the
ventilation catheter 27 is connected to the outer cannula 28, the
outer cannula sensing lumen 42 connects via a pneumatic female and
male connection 104, 103, respectively, to an external lumen 109
extending away from the patient to an external sensor (not shown),
for example, a sensor 96 located in the ventilator V as previously
shown in FIG. 5. In FIGS. 7 and 8, the sensor 90 or sensing lumen
42 and port 44 may be located on the superior side of the outer
tube 28, in which case fenestrations, if present, may be located on
lateral walls of the outer tube (described later). Alternatively,
the sensor 90 or sensing lumen 42 and port 44 shown in FIGS. 7 and
8 can be located on the inferior side of the outer tube 28, in
which case fenestrations may be located on the superior side of the
outer tube 28. Further, the sensor 90 or sensing lumen 42 and port
44 can be located on a lateral wall of the outer tube 28.
[0081] Alternatively, the breath sensor or external breath sensor
may be decoupled from the various components of the present
invention. For example, as shown in FIG. 9, a separate assembly 97
including the sensor 90 can be inserted into the annular space 46
between the ventilation catheter 27 and outer cannula 28. The
separate assembly 97 and sensor 90 can be inserted or retracted
using a handle 105.
[0082] Or, alternatively, as shown in FIG. 10, a separate assembly
98 comprising a sensing lumen 42 can be inserted into the annular
space 46 between the ventilation catheter 27 and the outer cannula
28, where the sensing lumen 42 connects via an external sensing
lumen 109 to sensor positioned outside the body, for example a
sensor 96 at the ventilator V as shown in FIG. 5. The separate
assembly 98 and sensing lumen 42 can be inserted and retracted
using a handle 106.
[0083] As described herein, various embodiment of protective
configurations, apparatuses and methods for breath sensors may be
provided to reduce tissue contact with the breath sensors and
accumulation of debris on the breath sensors. The breath sensor may
be at least partially surrounded by airflow-permeable coverings,
protectors or shields that allow spontaneous respiration to pass
through the airflow-permeable coverings and reach the breath
sensors. Thus, in accordance with the principles of the invention,
various embodiments and configurations described and shown are
contemplated and the specific embodiments and configurations are
not limiting.
[0084] FIG. 11 shows an alternative where the annular space 46
between the ventilation tube 27 and outer cannula 28 may
communicate with ambient air depicted by arrows 107. Some of the
spontaneous breathing airflow in the trachea T, indicated by arrow
150, may travel to and from ambient through the annular space 46.
The sensor 90 may be placed in the annular space 46 and may
register the breathing signal.
[0085] FIGS. 12A-12C show the sequence of operation and
configuration when using a dual cannula tracheostomy tube assembly
23 containing a tracheostomy tube inner cannula 110 and a
tracheostomy tube outer cannula 28. For purposes of this invention,
the terms ventilation catheter, ventilation tube, and related
expressions are used interchangeably. Similarly, the terms
tracheostomy tube, outer cannula, outer tube and related
expressions are used interchangeably. Various combinations of
elements in alternative embodiments may be combined together within
the scope of the present invention.
[0086] FIG. 12A shows the tracheostomy tube outer cannula 28
surrounding the tracheostomy tube inner cannula 110. The
tracheostomy tube outer cannula 28 may be disposed relative to the
tracheostomy tube inner cannula 110 such that an annular space 46
may exist between an inner surface of the tracheostomy tube outer
cannula 28 and an outer surface of the tracheostomy tube inner
cannula 110. The tracheostomy tube outer cannula 28 may have one or
more fenestrations 100 to allow airflow into the annular space 46.
As indicated by arrows 150, spontaneous respiration may pass
through the one or more fenestrations 100 into the annular space 46
and out an end 151 of the tracheostomy tube outer cannula 28.
Ventilation gas (arrow 152) from a ventilator may pass through the
tracheostomy tube inner cannula 110, out an end 153 of the
tracheostomy tube inner cannula 110 and into a patient airway.
Ventilation gas (arrow 152) and/or spontaneous respiration 150 may
also pass through tracheostomy tube inner cannula 110 and the
annular space 46, respectively, in the reverse direction.
Fenestrations 100 may permit flow of gas past the dual cannula
tracheostomy tube 23 to and from the upper airway. The
fenestrations 100 may also permit speech by allowing exhaled air
flow past vocal cords.
[0087] The dual cannula tracheostomy tube 23 may include a
tracheostomy tube neck flange 112 and/or a tracheostomy tube
ventilation circuit connector 111. The tracheostomy tube
ventilation circuit connector 111 may allow the dual cannula
tracheostomy tube 23 to be connected to various types of
ventilators. The dual cannula tracheostomy tube 23 configuration
may be used when it is preferred to have the option of removing the
ventilator and ventilation catheter and allowing the patient to
breathe through the outer cannula.
[0088] FIG. 12B shows an embodiment of the present invention with
the tracheostomy tube inner cannula 110 removed from the
tracheostomy tube outer cannula 28 which is left in position in the
patient airway.
[0089] FIG. 12C shows another variation of an inner cannula
ventilation catheter 26 substituted for the tracheostomy tube inner
cannula 110. The inner cannula ventilation catheter 26 may be
configured to be placed inside the tracheostomy tube outer cannula
28 for precise positioning of intra-airway breath sensors 90 in the
annular space 46 between the inner cannula ventilation catheter 26
and the tracheostomy tube outer cannula 28. For example, the
precise positioning may include obtaining the correct depth of
insertion of the breath sensors relative to the outer cannula
length, or the correct circumferential orientation of the sensors
in relationship to the outer cannula inner wall, as will be
explained later. Thus, the intra-airway breath sensors 90 may be
protected within the annular space 46 and may not be susceptible to
contacting tissue or accumulating debris. However, the intra-airway
breath sensors 90 may be in communication with the spontaneous
respiration 150 (shown in FIG. 12A) in the inspiratory and
expiratory direction and may detect and measure the breathing
pattern of the patient P.
[0090] A ventilation catheter seal and connector 116 may connect
the inner cannula ventilation catheter 26 to the tracheostomy tube
outer cannula 28 for sealing, security and positioning and a flange
115 facilitates insertion and removal of the ventilation catheter
26 from the outer cannula 28. The seal and connector may be, for
example, a friction fit seal/connector, a twist and lock
seal/connector, or a snap-fit seal/connector, a compressible gasket
such as silicone, a line-to-line fit between the mating parts, a
mating tapered interface, and/or a slight interference fit with one
soft material and an opposing hard material. The location of the
intra-airway breath sensors 90 may be anywhere inside the annular
space 46, however, preferably the intra-airway breath sensors 90
may be positioned at a location between the fenestrations 100 and
the end 151 of the tracheostomy tube outer cannula 28. If the
sensors are positioned too close to the distal end of the outer
cannula, the sensor may be prone to Venturi artifacts created by
gas flow exiting the ventilation catheter from the ventilator.
Hence location of the sensors at a distance from the outer cannula
opening is preferred.
[0091] Because the amount of airflow traveling through the annular
space may be only a portion of the total tracheal airflow, the
breath signal measured by the breath sensor may be a dampened
signal. However, this is deemed acceptable, since the measurement
accurately reflects flow or pressure, albeit not necessarily
reflective of the true amplitude.
[0092] In FIG. 12C, the inner cannula ventilation catheter 26 may
include rigidity to prevent unwanted flexure of the inner cannula
ventilation catheter 26 that may inadvertently cause the
intra-airway breath sensors 90 to contact the outer cannula inner
wall.
[0093] FIG. 13 shows an alternative connection mechanism where the
inner cannula ventilation catheter 26 may include a connector 116
and flange 115 assembly which includes an adjustable sliding seal
117 between the catheter shaft 118 and the connector/flange 116/115
assembly. The ventilation catheter connector/flange assembly
116/115 may be used to position a distal tip D of the inner cannula
ventilation catheter 26 and the intra-airway breath sensors 90 in a
desired position. The ventilation catheter connector/flange
assembly 116/115 may be configured such that it locks or self-locks
onto the catheter shaft 118 when not moving the inner cannula
ventilation catheter 26. For example, the ventilation catheter
connector/flange assembly 116/115 may use a detent system, a collet
system, a compression clip a spring-loaded push button, or a
locking pin. Alternatively, the position of the intra-airway breath
sensors 90 may be adjustable. For example the a sensor can be
advanced or retracted by moving a rod or wire as shown previously
in FIG. 10.
[0094] FIG. 14 shows a sensing lumen 42 extending from outside a
patient P at a proximal end and into an airway, such as a trachea
T. The sensing lumen 42 may have a distal end within the airway
with a sensing lumen port/opening 44 positioned in the annular
space 46. A sensor may be located outside of the patient P as shown
previously in FIG. 5, but may be in communication with the sensing
lumen 42, sensing lumen port/opening 44, and/or the airway. This
may be advantageous to reduce cost of the ventilation catheter or
to reduce the required size of the ventilation catheter.
[0095] In addition to the embodiments of FIGS. 12-14, other
ventilation catheter and tracheostomy tube combinations and
interconnections can be used.
[0096] FIG. 15 describes a ventilation catheter 31 adapted to be
inserted into a signal cannula tracheostomy tube 29. The
tracheostomy tube 29 may include one or more fenestrations 100 to
allow spontaneous respiration to pass between the ventilation
catheter 31 and the tracheostomy tube 29. One or more intra-airway
breath sensors 90 may be located within the tracheostomy tube 29,
or on the ventilation tube 31. The one or more intra-airway breath
sensors 90 may be protected within an annular space 46 as
previously described. The ventilation catheter 31 and tracheostomy
tube 29 may have one or more mating features as those described
previously to permit connecting the ventilation catheter 31 and the
tracheostomy tube 29. The one or more mating features may position
the one or more intra-airway breath sensors 90 in a desired
position.
[0097] The embodiment of FIG. 15 may also include a tracheostomy
tube neck flange 112, a ventilation catheter seal 116 and a
tracheostomy tube ventilation circuit connector 111. This
embodiment allows the ventilation catheter 31 to be removed and a
conventional ventilator and breathing circuit to be connected to
the 15 mm connector 111 of the single cannula tracheostomy tube 29,
for example, in the event conventional ventilation is required.
[0098] Embodiments of the present invention may include various
patterns and configurations of fenestrations to allow gas to pass
through a sensor protection device onto a sensor. Fenestrations may
be located at any location and some preferred locations and
configurations are described below. Gas permeable shields for
sensors may come in various shapes and numbers, but the gas
permeable shields preferably prevent tissue contact with the
sensors and/or accumulation of debris on the sensors. For purposes
of this invention, the superior direction refers to a position
facing an exit of a patient airway from a body of the patient, for
example, facing the upper airway. Additionally, the inferior
direction refers to a position facing away from the exit of a
patient airway from a body of the patient, for example, facing the
lower airway. A lateral direction refers to any direction that is
not superior or inferior. As discussed above, the fenestrations
and/or gas permeable shields may be disposed in any position. The
shape of fenestrations may be circular, oval, or any other
reasonable shape. The location and shape of the fenestrations can
be any combination of the above.
[0099] FIG. 16 shows an alternate embodiment of a ventilation
catheter 33 and outer cannula tracheostomy tube 34. The outer
cannula tracheostomy tube 34 may include one or more fenestrations
100 on a superior side of the tracheostomy tube 120 and/or one or
more fenestrations 101 an inferior side of the tracheostomy tube
122. One or more fenestrations 100, 101 on various surfaces of the
outer cannula tracheostomy tube 34 may decrease resistance to
inspired and expired gas flow through the outer cannula
tracheostomy tube 34. Furthermore, one or more fenestrations 100,
101 on various surfaces of the outer cannula tracheostomy tube 34
may provide redundancy for gas flow through the outer tracheostomy
tube 34 in the event that one or more fenestrations 100, 101 are
miss-aligned, blocked and/or obscured. FIG. 16 also describes an
connector/seal 119 that connects to the outer cannula 120.
[0100] FIG. 17 shows fenestrations 102 on a lateral sides 121 of
the outer cannula tracheostomy tube 34.
[0101] Proper positioning of the one or more intra-airway sensors
90 may be important for proper functioning of the breath sensing
and ventilator control system. Furthermore, it may be important for
the one or more intra-airway sensors 90 to remain in an original or
desired position over time. Configurations and methods for
positioning and stabilizing the one or more intra-airway sensors 90
may be provided.
[0102] FIG. 18A shows an embodiment in which a ventilation catheter
35 includes one or more ventilation catheter
stabilization/positioning anchors 130. The one or more ventilation
catheter stabilization/positioning anchors 130 may locate and hold
one or more intra-airway breath sensors 90 at a desired position
within an outer cannula 36. The one or more ventilation catheter
stabilization/positioning anchors 130 may help center the
ventilation catheter 35 in the outer cannula 36 so the one or more
intra-airway breath sensors 90 do not contact an inner wall 37 of
the outer cannula 36. The one or more ventilation catheter
stabilization/positioning anchors 130 may also prevent the
ventilation catheter 35 from whipping when pressurized gas is
delivered through the ventilation catheter 35. The one or more
ventilation catheter stabilization/positioning anchors 130 may be
positioned at one or multiple locations. For example, the one or
more ventilation catheter stabilization/positioning anchors 130 may
be positioned a location near the one or more intra-airway breath
sensors 90 to assure that the one or more intra-airway breath
sensors 90 are properly positioned in the annular space 46.
Alternatively, the one or more ventilation catheter
stabilization/positioning anchors 130 may be positioned a location
near a distal tip D of the ventilation catheter 35 to reduce
movement of the distal tip during gas delivery. A ventilation
catheter outer seal 114 is shown.
[0103] FIG. 18B is an end view of FIG. 18A. Other possible
configurations of the one or more ventilation catheter
stabilization/positioning anchors 130 are possible to locate the
one or more intra-airway breath sensors in a desired position
within the annular space 46. The anchors are for example
compressible filaments or wires, such as an elastomeric filament or
a shape memory alloy wire. The filaments or wires can be for
example a loop shape, or spokes, or a braid, or a woven basket. The
density of the anchor structure is very low offering little to no
airflow resistance, unless the anchor is proximal to the
fenestration, in which case the anchor can be resistive to airflow
since airflow is not needed in that zone for the breath sensors to
detect the breathing signal.
[0104] FIG. 19 shows a cannula deflector 40 for ensuring the one or
more intra-airway sensors 90 are exposed to air flowing within the
annular space 46. The cannula deflector 40 of FIG. 19 is shown in a
superior side of the outer cannula 38 for the purpose of spacing a
ventilation catheter 39 and sensor 90 away from the inner wall of
the outer cannula 38. The ventilation catheter 39 may be formed and
shaped into an arc radius that is larger than the arc radius of the
outer cannula 38. The cannula deflector 40 may deflect the
ventilation catheter 39 into a tighter radius. Therefore, exact
matching of the radius of the ventilation catheter 39 to the radius
of the outer cannula 38 during manufacturing may be unnecessary.
The cannula deflector 40 may be shaped atraumatically to avoid any
harsh contact should contact occur between the deflector and the
tissue. One or more fenestrations 100 may be positioned at various
locations on the outer cannula 38.
[0105] FIG. 20A shows a cannula deflector 40 in the outer cannula
38 adjoining a fenestration 100. One or more intra-airway breath
sensors 90 and/or a sensing lumen port may be positioned just
distal to the cannula deflector 40 and the fenestration 100. This
may be advantageous when the superior or inferior portion of the
cannula which extends into the tracheal lumen from the anterior
wall of the trachea, is relatively short and there is not enough
distance between the anterior wall and posterior wall of the
trachea for both s deflector and a fenestration if separated from
one another.
[0106] FIG. 21A shows a cannula deflector 40 that protrudes only
from an inner wall of the outer cannula 38. An outer diameter of
the outer cannula 38 may not be affected by the cannula deflector
40. This may be advantageous for insertion and removal of the outer
cannula 38 from an airway. The cannula deflector 40 may be near or
adjoining one or more fenestration 100 or may be separated from the
one or more fenestrations 100 by a predetermined distance.
Typically, the deflector and fenestration may have to be located
close together due to the limited space requirements imposed by the
tracheal diameter. The embodiments described in FIGS. 19, 20A and
21A may be especially applicable in cases in which a single cannula
tracheostomy tube is being used, since a tracheostomy tube inner
cannula is not placed into the tracheostomy tube. A tracheostomy
tube inner cannula, when used with a dual cannula tracheostomy
tube, is typically as large as possible to optimize gas delivery.
The deflector may require a smaller diameter tracheostomy tube
inner cannula contrary to common practice.
[0107] In addition to the location of the cannula deflector 40 and
the one or more intra-airway sensors 90 shown in FIGS. 19, 20A and
21A as a superior location, the cannula deflector 40 may be located
at other positions on the outer cannula 38. Other positions for the
cannula deflector 40 may be an inferior side 122 of the outer
cannula 38 as shown in FIGS. 20B and 21B and/or a lateral side 121
of the outer cannula 38 (not shown). Preferably, the one or more
intra-airway sensors 90 may be located on corresponding sides of
the ventilation catheter 39. For example, if the cannula deflector
40 is on the inferior side 122 of the outer cannula 38, the one or
more intra-airway breath sensors 90 may be located on an inferior
side of the ventilation catheter 39. Various positions and
combination may be used. The sensor 90 may be positioned at a
location away from the midline of the catheter 38 so that when
inserted, the sensor does not get damaged by rubbing on the
deflector.
[0108] FIG. 22 shows an embodiment of the present invention with a
short tracheostomy tube 49. An inner ventilation catheter 47 may
extend distally beyond a distal end 51 the short tracheostomy tube
49. The embodiment of FIG. 8a may be beneficial because the short
tracheostomy tube 49 may extend into an airway only as far as
necessary to prevent one or more intra-airway breath sensors 90
from contacting the tissue and/or and or reduce accumulation of
debris on the one or more intra-airway breath sensors. The
patient's airway, therefore, may be potentially more open to
spontaneous breathing. In addition, this configuration may
facilitate measuring a breathing signal that is closer to the true
signal, since there is less obstruction of spontaneous gas flow by
the device, for example less Venturi effects, turbulence and
dampening of the tracheal flow and pressure. An inner ventilation
catheter seal 113 is shown.
[0109] FIG. 23 shows an embodiment of the present invention where
the ventilation catheter 47 may be adapted to be placed in a stoma
sleeve 48. The stoma sleeve 48 may only marginally extend into the
airway. The marginal extension into the airway may provide enough
shielding for the one or more intra-airway breath sensors 90 to
prevent contact with tissue and/or reduce accumulation of debris.
The embodiment of FIG. 22 may be beneficial because the stoma
sleeve 48 may be of a relatively small diameter and, therefore,
less obtrusive to a patient P. Use of the stoma sleeve 48 may be
useful when the patient P is not at risk of requiring full support
ventilation because the stoma sleeve 48 typically does not include
a standard 15 mm connector required for connection to a
conventional ventilator. The stoma sleeve is preferably different
than a similar conventional device known as the Montgomery T-Tube,
because the stoma sleeve must be configured to create space between
the sleeve and the ventilation catheter to define an annular space
for the breath sensor. Also, the stoma sleeve is preferably
different than a similar conventional device known as a stoma stent
such as the Hood Stoma Stent, because the stoma stent does not
elongate into the tracheal airway. The stoma sleeve and main lumen
there through must elongate a distance into the tracheal lumen in
order to define the annular space or protective zone for the breath
sensors. Some patients may require the tracheostomy tube compatible
version, rather than the stoma sleeve version. For example, if a
patient requires other respiratory treatments and accessories on
occasion or is at risk of requiring conventional mechanical
ventilation, the 15 mm respiratory connector that is part of the
tracheostomy tube will facilitate attachment to other respiratory
treatments.
[0110] Other embodiments of the present invention may have
alternative or supplemental protection for the one or more
intra-airway breath sensors. For the purposes of this disclosure,
the terms protectors and shielding are used interchangeably.
Various forms of protection may be used interchangeably or
together. In the following exemplary embodiments, the outer cannula
or stoma sleeve may be replaced or used with alternative protection
devices. Preferably, protectors and/or shields may be airflow
permeable.
[0111] FIG. 24 shows a fenestrated shield 136 on a ventilation
catheter 27. The ventilation catheter 27 may be inserted into an
airway, such as a trachea T through a stoma tract 134 or other
similar opening. The ventilation catheter may preferably be
inserted directly through the stoma tract 134, but may be inserted
through a tracheostomy tube or other similar apparatus if needed. A
ventilation catheter neck flange 132 may provide positioning and
securing of the ventilation catheter 27. One or more intra-airway
breath sensors 90 may be mounted on the ventilation catheter 27.
The one or more intra-airway breath sensors may be protected by the
fenestrated shield 136.
[0112] The fenestrated shield 136 may be a basket-type device and
is permeable to airflow. The basket may be a woven or braided
filament or wire structure with one or both ends of the structure
attached to the ventilation catheter shaft. The structure has a
normally expanded dimension, but can be easily compressed into a
compressed dimension for insertion of the ventilation catheter 27
through the stoma 134.
[0113] FIG. 25A shows a basket type fenestrated shield 136 that may
be collapsed by a pull wire mechanism or stretch mechanism (not
shown) from a collapsed state C to an expanded state E and back.
The pull wire mechanism is attached to the proximal end of the
basket wire structure. Pulling on the wire in the proximal
direction elongates the structure proximally, such that the
structure diameter reduces or collapses. Therefore, the proximal
end of the basket wire structure is slideably attached to the
ventilation catheter shaft. The basket type fenestrated shield 136
may also be collapsed by temperature sensitive shape memory alloys
that respond to temperature change. The materials may be in a first
collapsed state at room temperature, but upon insertion into an
airway, the materials may enter a second expanded state based upon
the change in temperature from room temperature to the temperature
within the airway. The basket type fenestrated shield 136 may also
be tapered to facilitate insertion and removal of the ventilation
catheter 27 through the stoma. The wires of the basket may be very
resilient and pliable to facilitate insertion or removal without
requiring uncomfortable amounts of forces. FIG. 25B is an end view
of the device of FIG. 25A when in the expanded state. When the
basket type fenestrated shield 136 is in an expanded state E, the
basket type fenestrated shield 136 has a diameter larger than the
diameter of the ventilation catheter 27. However, when the basket
type fenestrated shield 136 is in a collapsed state C, the basket
type fenestrated shield 136 may have a diameter only marginally
larger than the diameter of the ventilation catheter 27. In the
collapsed state C, the basket type fenestrated shield 136 may
collapsed against an outer surface of the ventilation catheter
27.
[0114] The one or more intra-airway breath sensors 90 may be
disposed on the ventilation catheter 27. Preferably, the basket
type fenestrated shield 136 may at least partially surround the one
or more intra-airway breath sensors 90 when the basket type
fenestrated shield 136 is in an expanded state E. The one or more
intra-airway breath sensors 90 may prevent tissue contact and/or
may reduce accumulation of debris on the one or more intra-airway
breath sensors 90.
[0115] Alternatively, the protection device may be a cuff or any
other similar structure that is airflow permeable.
[0116] FIG. 26 shows an airflow permeable shield 138 that may be
conical and tapered to favor removal out of a stoma tract 134. The
airflow permeable shield 138 may be coupled to a ventilation
catheter 27 at a tapered end of the airflow permeable shield 138.
The airflow permeable shield 138 may be collapsible. To collapse
the airflow permeable shield 138 for insertion, the airflow
permeable shield 138 may be composed of shape-memory materials. The
airflow permeable shield 138 may be provided in a collapsed state C
and then may then expand to an expanded state E after insertion
into an airway by responding to body temperature. Alternatively,
the airflow permeable shield 138 may be folded by hand or machine
into the collapsed state C and then inserted into the airway and
then self-expand or manually or mechanically expand to the expanded
state E. The airflow permeable shield 138 may assume predetermined
conical protective shield folds 140 when collapsed. The airflow
permeable shield 138 may manually, mechanically or automatically
collapse prior to or during removal from the airway and stoma.
[0117] The airflow permeable shield 138 may include one or more
fenestrations 100. The one or more fenestrations 100 may be
lengthened to facilitate collapsing and expanding of the airflow
permeable shield 138. Alternatively, the airflow permeable shield
may be permeable to airflow without the one or more fenestrations
100.
[0118] The intra-airway breath sensors of various embodiments of
the present invention may be combined with breath sensors within
the ventilation gas delivery circuit so patient breathing and
ventilator activity may be monitored separately, but
simultaneously. For example as shown in FIG. 27, the intra-airway
breath sensor 90 as described in the above embodiments can be used
to measure the patient's breathing, and the effect the ventilator V
has on the patient's respiratory system, while a sensor 108
measuring the output of the ventilator V in the gas delivery
circuit 21 is measuring the ventilator output.
[0119] Although the foregoing description is directed to the
preferred embodiments of the invention, it is noted that other
variations and modifications will be apparent to those skilled in
the art, and may be made without departing from the spirit or scope
of the invention. Moreover, features described in connection with
one embodiment of the invention may be used in conjunction with
other embodiments, even if not explicitly stated above.
* * * * *