U.S. patent application number 10/933190 was filed with the patent office on 2005-02-17 for ambient pressure control ventilation apparatus and method.
Invention is credited to Shusterman, Mark, Shusterman, Taly.
Application Number | 20050034727 10/933190 |
Document ID | / |
Family ID | 11073874 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050034727 |
Kind Code |
A1 |
Shusterman, Taly ; et
al. |
February 17, 2005 |
Ambient pressure control ventilation apparatus and method
Abstract
An ambient pressure control ventilation apparatus for mechanical
ventilation of a patient comprising a sealable chamber adapted to
accommodate a whole body of a patient, a pump fluidly connected to
the chamber adapted to alternatively compress and decompress a
ventilating gas within the chamber, a relief valve fluidly
connected to the chamber and a control unit adapted to control the
pump and the relief valve to facilitate a periodic regime of
alternating compression and decompression of the ventilating gas
within the chamber about a predetermined baseline.
Inventors: |
Shusterman, Taly; (Nahariya,
IL) ; Shusterman, Mark; (Nahariya, IL) |
Correspondence
Address: |
REED SMITH, LLP
ATTN: PATENT RECORDS DEPARTMENT
599 LEXINGTON AVENUE, 29TH FLOOR
NEW YORK
NY
10022-7650
US
|
Family ID: |
11073874 |
Appl. No.: |
10/933190 |
Filed: |
September 2, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10933190 |
Sep 2, 2004 |
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10220178 |
Aug 27, 2002 |
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6814076 |
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10220178 |
Aug 27, 2002 |
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PCT/IL01/00085 |
Jan 29, 2001 |
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Current U.S.
Class: |
128/205.26 |
Current CPC
Class: |
A61H 2031/025 20130101;
A61G 10/023 20130101; A61M 16/022 20170801; A61H 31/02
20130101 |
Class at
Publication: |
128/205.26 |
International
Class: |
A61M 016/00; A62B
007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 27, 2000 |
IL |
134742 |
Claims
1. An ambient pressure control ventilation apparatus for mechanical
ventilation of a patient comprising: a sealable chamber adapted to
accommodate a whole body of a patient, a pump fluidically connected
to said chamber adapted to alternatively compress and decompress a
ventilating gas within said chamber; a relief valve, fluidically
connected to said chamber; and a control unit adapted to control
said pump and said relief valve so as to facilitate a periodic
regime of alternating compression and decompression of said
ventilating gas within said chamber, about a predetermined
baseline.
2. The apparatus as claimed in claim 1, wherein said ventilating
gas is a mixture of air and oxygen.
3. The apparatus as claimed in claim 1, wherein said ventilating
gas is oxygen.
4. The apparatus as claimed in claim 1, said apparatus further
comprising at least one pressure sensor within said chamber, said
at least one pressure sensor communicating with said control unit
so as to allow said control unit to determine the pressure
condition within said chamber.
5. The apparatus as claimed in claim 4, wherein said control unit
is further adapted to prevent pressure drop within said chamber
below a predetermined oxygen partial pressure value.
6. The apparatus as claimed in claim 5, wherein said predetermined
pressure value is 0.25 atm.
7. The apparatus as claimed in claim 1, wherein said baseline
ranges between 0.5 atm. and 1.5 atm.
8. The apparatus as claimed in claim 1, wherein said control unit
is adapted to control said pump and said relief valve so as to
facilitate a periodic regime of alternating compression and
decompression of said ventilating gas within said chamber, about a
predetermined baseline, within a predetermined pressure range of
the baseline plus 170 mm Hg to the baseline minus 170 mm Hg.
9. The apparatus as claimed in claim 1, wherein said control unit
is adapted to control said pump and said relief valve so as to
facilitate a periodic regime of alternating compression and
decompression of said ventilating gas within said chamber, about a
predetermined baseline, within a predetermined pressure range of
between the ambient barometric pressure to the ambient barometric
pressure plus 175 mm Hg.
10. The apparatus as claimed in claim 1, wherein said chamber is
transportable.
11. The apparatus as claimed in claim 10, wherein said chamber is
provided with wheels for transportation.
12. The apparatus as claimed in claim 1, wherein said chamber is
essentially made of non-compliant transparent plastic material.
13. The apparatus as claimed in claim 1, wherein said chamber is
provided with a door adapted to allow quick bringing in and taking
out of a patient.
14. The apparatus as claimed in claim 13, wherein said door can
also be opened and closed from within said chamber.
15. The apparatus as claimed in claim 1, wherein said chamber is
provided with a sealable opening adapted to allow quick access of a
nursing team to the airway and chest area of said patient.
16. The apparatus as claimed in claim 1, wherein a bed is provided
in said chamber for the patient to lie on.
17. The apparatus as claimed in claim 1, wherein said chamber is
provided with a communication block that is adapted to facilitate
linking of devices positioned within said chamber to said control
unit or other devices.
18. The apparatus as claimed in claim 17, wherein monitoring lines
from sensors placed in an endotracheal tube within the airway of
the patient are connected via said communication block to said
control unit.
19. The apparatus as claimed in claim 1, wherein a reserve oxygen
balloon is provided for emergency cases.
20. The apparatus as claimed in claim 1, wherein said chamber is
further provided with a highly compliant breathing bag that is
designed to be connected to the airway of the patient.
21. The apparatus as claimed in claim 1, wherein said pump is
electrically connected to the main electric supply.
22. The apparatus as claimed in claim 1, wherein a reserve battery
adapted to supply electricity to said pump is provided for cases of
emergency.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to mechanical ventilation
systems. More particularly, it relates to mechanical respiratory
assistance by ambient pressure control ventilation in a close
chamber.
BACKGROUND OF THE INVENTION
[0002] Assisted or artificial respiratory actions on patients are
often used in medical practice. Two types of ventilation methods
are generally used: positive pressure ventilation, when periodic
positive airway pressure is applied on patients airways and lungs,
and negative pressure ventilation (iron lungs) when the patient's
chest region is enclosed by an enclosure in which subatmospheric
pressure is applied periodically.
[0003] Those main traditional methods of mechanical respiratory
assistance such as positive airway pressure ventilation as well as
"iron-lungs" are known to have a lot of physiological adverse
effects, technical disadvantages and pitfalls. The main
disadvantages of positive pressure methods of ventilation stem from
the need to inflate the gas mixture into the patient's airway and
lungs with such a positive pressure that its range is comparable
with right and left heart ventricles filling pressures. This can
interfere with the venous blood return to the heart that may result
in hemodynamic deterioration, especially in patients that suffer
from hypovolemia, compromised cardiac function, lung and chest
problems and shock. Furthermore, patient's suffering from these
diseases are already in poor medical condition, and their body is
very likely not to withstand the strenuous procedure. Positive
pressure ventilation may also result in barotrauma of airway and
lungs with possible development of life threatening complications.
Long time exposure to positive pressure ventilation may result also
in the development of lung atelectasis and/or secondary infection,
which is directly related to the duration of the mechanical
positive pressure ventilation. Positive pressure ventilation also
requires the inflation of endotracheal tube balloon with such
pressures that on one hand, it establishes airway sealing, but on
the other hand it may result in severe damage to the tracheal
mucosa and tracheal wall, potentially leading to very dangerous
complications, such as tracheal wall and great mediastinal vessels
rupture.
[0004] Negative pressure ventilation, as opposed to positive
pressure ventilation, is free from problems related to venous
return and cardiovascular deterioration as well as barotrauma
development. There are problems that arise from the employment of
negative pressure ventilation. The need to accommodate the
patient's body in an enclosure requires the use of sealing means
that are very difficult to fit on the patient's neck, chest and
abdomen. It is especially difficult in pediatric population or in
uncooperative patients as well as during prolonged mechanical
ventilation. Negative pressure ventilators are very difficult to
use in weaning from mechanical ventilation.
[0005] Improvements of mechanical respiratory systems are known in
the art. An example of such system that encloses the chest region
is disclosed in U.S. Pat. No. 4,815,452 "VENTILATOR APPARATUS AND
FLUID CONTROL VALVE", filed in 1988 by Z. Hayek. One aspect of the
invention provides a patient enclosure for ventilator apparatus
comprising a base member and a liftable cover member which in an
operative position defines a patient receiving chamber having at
least one aperture in the cover member for accommodating a portion
of the patient's body, the or each such aperture in the cover
member being open along an edge of the cover member which overlies
the base member in the operative position and containing a seal
member for forming a substantially airtight seal in use between the
cover member and the patient's body and the base member, wherein
the seal member takes the form of a flexible curtain having a free
edge overlying the base member and means for tensioning a portion
of the curtain to cause the curtain to seal against the base member
and the patient's body.
[0006] Another enclosure for ventilation is disclosed in EP patent
No. 0379049 "CHEST ENCLOSURE FOR VENTILATORS" published in 1990 by
Z. Hayek. This chest enclosure is used for introducing assisted
ventilation for the lungs of a patient, when combined with an air
oscillator. The chest enclosure comprises a stiff but flexible
plastic tunnel member adapted to cover the chest, provided at its
upper and its lower end with an air-impermeable flexible cushion, a
band of flexible material extending from along the entire lateral
edges of the tunnel, said bands extending to behind the back of the
patient in an overlapping relationship, means being provided for
the attachment of the bands with each other, an air passageway
being provided into the enclosure for connection to an air
oscillator.
[0007] Ventilators of this type provide an apparatus in which at
least the patient's head protrudes from the enclosure. In order to
enable pressure changes in the enclosure, sealing the enclosure
from the surrounding is necessary. Sealing the enclosure promotes
problems and can also delay the commencing of assisted respiration,
which potentially may cause damage to the patient.
[0008] The use of a pressurized container in which the whole body
is enclosed was developed for blood oxygenation in premature
neonates. The method is disclosed in U.S. Pat. No. 5,582,574
"HYPERBARIC INCUBATION METHOD" filed in 1995 by F. S. Cramer. This
pressurized container is filled with pure oxygen. The apparatus,
and the method of treatment provided thereby, are able to deliver
oxygen to the blood of an enclosed premature neonate by means of
directly diffusing molecular oxygen through the unusually permeable
skin of such infants. Hyperbaric pressure, i.e., pressure
substantially above one atmosphere absolute (ATA), preferably at
least two ATA, is maintained in the container, which facilitates
the transcutaneous delivery of oxygen to the blood. Means are
included for protecting the eyes of the neonate and for performing
physiological ventilation of the lungs thereof. The provision of
normal tissue oxygen tensions facilitates the neurological
development of the infant, thereby enhancing its long-term quality
of life.
BRIEF DESCRIPTION OF THE INVENTION
[0009] It is a purpose of the present invention to provide new
ambient pressure control ventilation apparatus for mechanical
ventilation of a patient. The patient is placed inside a sealed
chamber wherein within that chamber periodic changes of pressure
are applied.
[0010] It is another purpose of the present invention to provide an
ambient pressure control ventilation apparatus for mechanical
ventilation applicable in cases were traditional mechanical
ventilation fails. These cases include among others patients with
hemodynamic deterioration such as hypovolemia, compromised cardiac
function, marginal cases of respiratory distress syndrome, chest,
airway and lung trauma and bleeding, and asthmatic attack.
[0011] Yet another purpose of the present invention is to provide
an ambient pressure control ventilation apparatus for home
ventilation which is safer for users and provide more comfort
conditions for patients suffering from chronic respiratory failure
who need negative or positive pressure ventilators for home use,
especially in pediatric and uncooperative populations.
[0012] Still another purpose of the present invention is to provide
an ambient pressure control ventilation apparatus for weaning from
mechanical ventilation.
[0013] It is another purpose of the present invention to provide an
ambient pressure control ventilation apparatus for patients with
chest, neck and abdomen deformity, scars, chronic infections, burns
etc., which make positive pressure ventilation difficult and
negative pressure ventilation impossible.
[0014] Yet another purpose of the present invention is to provide
an ambient pressure control ventilation apparatus for the treatment
of patients suffering from congestive heart failure. The
outpatient, home or intermittent overnight use of the novel
apparatus enables decreasing at least part of the patients
medication intake.
[0015] It is another purpose of the present invention to provide an
ambient pressure control ventilation apparatus for patients having
prophylactics of deep and superficial venous thrombosis that
enables elimination of anticoagulation treatment.
[0016] It is another purpose of the present invention to provide an
ambient pressure control ventilation apparatus for substitution of
intraortic balloon counterpulsation (IABC) device.
[0017] Another purpose of the present invention aims at providing
an ambient pressure control ventilation apparatus for substitution
of advanced closed cardiac massage devices (Cardiopump, Four-phase
Life-stick etc.).
[0018] It is thus provided an ambient pressure control ventilation
apparatus for mechanical ventilation of a patient comprising:
[0019] a sealable chamber adapted to accommodate a whole body of a
patient,
[0020] a pump fluidically connected to said chamber adapted to
alternatively compress and decompress a ventilating gas within said
chamber;
[0021] a relief valve, fluidically connected to said chamber;
and
[0022] a control unit adapted to control said pump and said relief
valve so as to facilitate a periodic regime of alternating
compression and decompression of said ventilating gas within said
chamber, about a predetermined baseline.
[0023] Furthermore, in accordance to another preferred embodiment
of the present invention, said ventilating gas is a mixture of air
and oxygen.
[0024] Furthermore, in accordance to another preferred embodiment
of the present invention, said ventilating gas is oxygen.
[0025] Furthermore, in accordance to another preferred embodiment
of the present invention, said apparatus further comprising at
least one pressure sensor within said chamber, said at least one
pressure sensor communicating with said control unit so as to allow
said control unit to determine the pressure condition within said
chamber.
[0026] Furthermore, in accordance to another preferred embodiment
of the present invention, said control unit is further adapted to
prevent oxygen partial pressure drop within said chamber below a
predetermined pressure value.
[0027] Furthermore, in accordance to another preferred embodiment
of the present invention, said predetermined pressure value is 0.25
atm.
[0028] Furthermore, in accordance to another preferred embodiment
of the present invention, said baseline ranges between 0.5 atm. and
1.5 atm.
[0029] Furthermore, in accordance to another preferred embodiment
of the present invention, said control unit is adapted to control
said pump and said relief valve so as to facilitate a periodic
regime of alternating compression and decompression of said
ventilating gas within said chamber, about a predetermined
baseline, within a predetermined pressure range of the baseline
plus 170 mm Hg to the baseline minus 170 mm Hg.
[0030] Furthermore, in accordance to another preferred embodiment
of the present invention, said control unit is adapted to control
said pump and said relief valve so as to facilitate a periodic
regime of alternating compression and decompression of said
ventilating gas within said chamber, about a predetermined
baseline, within a predetermined pressure range of between the
ambient barometric pressure to the ambient barometric pressure plus
175 mm Hg.
[0031] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is transportable.
[0032] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is provided with wheels for
transportation.
[0033] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is essentially made of
non-compliant transparent plastic material.
[0034] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is provided with a door
adapted to allow quick bringing in and taking out of a patient.
[0035] Furthermore, in accordance to another preferred embodiment
of the present invention, said door can also be opened and closed
from within said chamber.
[0036] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is provided with a sealable
opening adapted to allow quick access of a nursing team to the
airway and chest area of said patient.
[0037] Furthermore, in accordance to another preferred embodiment
of the present invention, a bed is provided in said chamber for the
patient to lie on.
[0038] Furthermore, in accordance to another preferred embodiment
of the present invention, The apparatus as claimed in claim 1,
wherein said chamber is provided with a communication block that is
adapted to facilitate linking of devices positioned within said
chamber to said control unit or other devices.
[0039] Furthermore, in accordance to another preferred embodiment
of the present invention, monitoring lines from sensors placed in
an endotracheal tube within the airway of the patient are connected
via said communication block to said control unit.
[0040] Furthermore, in accordance to another preferred embodiment
of the present invention, a reserve oxygen balloon is provided for
emergency cases.
[0041] Furthermore, in accordance to another preferred embodiment
of the present invention, said chamber is further provided with a
highly compliant breathing bag that is designed to be connected to
the airway of the patient.
[0042] Furthermore, in accordance to another preferred embodiment
of the present invention, said pump is electrically connected to
the main electric supply.
[0043] Furthermore, in accordance to another preferred embodiment
of the present invention, a reserve battery adapted to supply
electricity to said pump is provided for cases of emergency.
[0044] Furthermore, in accordance to another preferred embodiment
of the present invention, there is provided an ambient pressure
control ventilation method for mechanical ventilation of a patient
comprising the following steps:
[0045] 1. providing a sealable chamber adapted to accommodate a
whole body of a patient;
[0046] 2. providing a pump fluidically connected to said chamber
adapted to alternatively compress and decompress a ventilating gas
within said chamber;
[0047] 3. providing a relief valve, fluidically connected to said
chamber;
[0048] 4. providing a control unit adapted to control said pump and
said relief valve so as to facilitate a periodic regime of
alternating compression and decompression of said ventilating gas
within said chamber, about a predetermined baseline;
[0049] 5. placing a whole body of a patient in said sealable
chamber; and
[0050] 6. providing a periodic regime of alternating compression
and decompression of a ventilating gas within said chamber, about a
predetermined baseline.
[0051] Furthermore, in accordance to another preferred embodiment
of the present invention, said ventilating gas is a mixture of
oxygen and air.
[0052] Furthermore, in accordance to another preferred embodiment
of the present invention, said baseline ranges between 0.5 atm. and
1.5 atm.
[0053] Furthermore, in accordance to another preferred embodiment
of the present invention, the periodic regime of alternating
compression and decompression of said ventilating gas within said
chamber alternates between said baseline plus 170 mm Hg to said
baseline minus 170 mm Hg.
[0054] Furthermore, in accordance to another preferred embodiment
of the present invention, the baseline is the ambient barometric
pressure.
[0055] Furthermore, in accordance to another preferred embodiment
of the present invention, the periodic regime of alternating
compression and decompression of said ventilating gas within said
chamber, alternates between the ambient barometric pressure to the
ambient barometric pressure plus 175 mm Hg.
[0056] Furthermore, in accordance to another preferred embodiment
of the present invention, the periodic regime of alternating
compression and decompression of said ventilating gas within said
chamber, alternates between the ambient barometric pressure minus
90 mm Hg to the ambient barometric pressure plus 90 mm Hg.
[0057] Furthermore, in accordance to another preferred embodiment
of the present invention, said method further comprises the step of
compressing into said chamber an additional volume of oxygen upon
an oxygen partial pressure drop below a predetermined value within
said chamber.
[0058] Finally, in accordance to another preferred embodiment of
the present invention, said predetermined value is 0.25 atm.
BRIEF DESCRIPTION OF THE FIGURES
[0059] In order to better understand the present invention, and
appreciate its practical applications, the following Figures are
provided and referenced hereafter. It should be noted that the
Figures are given as examples only and in no way limit the scope of
the invention as defined in the appending claims. Like components
are denoted by like reference numerals.
[0060] FIG. 1 illustrates an ambient pressure control ventilation
apparatus for mechanical respiratory assistance in accordance to a
preferred embodiment of the present invention.
[0061] FIG. 2 illustrates a simplified experimental model apparatus
that imitates lungs of a patient in a vacuum chamber, built
according to the principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION AND FIGURES
[0062] Boyle's law states that the volume of a certain amount of
gas is inversely proportional to the pressure, the temperature
remaining constant. The physiological application of
Boyle-Marriott's law describes the gas volume in the lungs of a
patient placed in a closed chamber, wherein periodic changes of
barometric pressure are applied. It is known that when the
barometric pressure varies in the range between 0.75 to 1.25
atmospheres in a sealed chamber, the temperature does not change
significantly, i.e., there is no change in temperature when using a
thermometer of 0.1.degree. C. accuracy.
[0063] A preferred embodiment for an ambient pressure control
ventilation apparatus of the present invention is based on the
physiological application of Boyle-Marriott's law. Reference is now
made to FIG. 1, which illustrates an ambient pressure control
ventilation apparatus for mechanical respiratory assistance. The
ambient pressure control ventilation apparatus comprises a
non-compliant chamber 5 that is preferably made of a transparent
plastic material (maybe with metal enforcement etc.) and may be
designed in any preferable shape according to the needs of the
patients and the local conditions, provided the patient's entire
body is enclosed within that chamber. Chamber 5 is equipped with at
least two doors capable of sealingly block gas from leaking in or
out of the chamber. The first door 19 is adapted to enable a quick
bringing in and taking out of the patient and the other door 9 is
adapted to allow quick access of the nursing team to the patient's
airway and chest area in case of emergency. In an ambient pressure
control ventilation apparatus designed for cooperative and
conscious patients, it is recommended to provide the patient with
the facility to open and close door 19 and control totally or
partially the physiological parameters of the apparatus from within
chamber 5. The volume of chamber 5 is adapted to be minimal but in
the same time is designed to be comfortable for the patient
according to his needs (i.e. if the patient requires laying down or
can be seated, etc.).
[0064] Chamber 5 is mounted on a carrying vehicle 24 such as a
trolley and can be easily disengaged from the trolley. Carrying
vehicle 24 permits easy intrahospital transportation of the chamber
with the patient in it for usual needs such as transfer from a ward
to an ambulance, from room to room etc. Inside chamber 5, a
mattress 18 such as the one used on intensive care unit beds is
provided. Mattress 18 can be taken out of chamber 5 and placed
again inside the chamber using wheels 21.
[0065] A theoretical account is hereby provided, with respect to
the volumes and pressures in the lungs of a paralyzed patient
having an open airway that is placed in a closed chamber with
periodic changes in the barometric pressure inside that chamber. At
normal barometric pressure, the lungs are filled with gas having
the same pressure as the ambient pressure within the chamber. The
transpulmonary pressure is zero. The lung's volume is determined
only by the intrinsic properties of the lungs and chest. After an
increase in the barometric pressure in the chamber while the
airways remain open, the airway pressure and the ambient pressure
equalize following a certain period of time called airway time
constant, so that the transpulmonary pressure becomes zero again
and the lungs volume is the same as before. It is important to
notice that the mass of gas in the same volume increases
proportionally to the barometric pressure change, provided the
temperature is constant.
[0066] It is known that normal tidal volume in children and adults
is about 7 ml/Kg including 2-3 ml/kg of dead space. Normal
functional residual capacity (FRC) ranges from 27-30 ml/Kg in
newborns to 30 ml/Kg in adults, so that V.sub.insp divided by
V.sub.exp equals about 1.23. Thus, according to Boyle's law and
Klapeyron's formula, a pressure difference of about 0.23
atmospheres is required in order to introduce such mass of gas to
the lungs that is sufficient to sustain normal breathing
parameters. A pulmonary gas exchange is originated while
transpulmonary pressure and the range of airway, lungs and chest
movements in the method of the present invention is less than the
transpulmonary pressure and the range of airway, lungs and chest
movements in any prior art traditional method of ventilation. This
aspect was tested and proved on computerized model, an experimental
model and animal pilot study.
[0067] An intake tube 3 and an exhaust tube 15 equipped with
pressure relief valve 14 are provided, fluidically connected to
chamber 5. Relief valve 14 is fluidically connected to a
compression or decompression pump 2, or a pump capable of
performing both tasks. The intake and exhaust tubes ventilate
chamber 5 in a minimal flow rate that suffice the provision of
O.sub.2 and CO.sub.2 gradient formation according to the patient's
needs. Relief valve 14 may be digitally controlled in order to
create the necessary pressure changes in chamber 5. When relief
valve 14 is closed, and fresh gas flows through intake tube 3 into
chamber 5 (pumped in by pump 2), the pressure in the chamber rises,
and when valve 14 is open, the pressure in the chamber decreases.
If subatmospheric pressure is needed for patient ventilation, the
system is capable of performing withdrawal of gas from chamber 5,
by activating the pump to create subatmospheric pressure levels
within chamber 5, and upon opening valve 14 air is allowed to enter
the chamber through exhaust tube 15. The apparatus is designed in
such a way that permits the formation of a subatmospheric baseline
pressure and positive and negative periodic changes of the pressure
around this baseline. The baseline pressure and the pressure
changes are adapted to the clinical conditions as will be explained
further on.
[0068] It is important to notice that in any case in which
subatmospheric pressure levels are required according to the
clinical conditions of the patient, a control unit 1 does not allow
a drop in the partial pressure of oxygen inside chamber 5 so that
it is kept higher than 0.25 atm. To compensate on the decrease in
the barometric pressure in the chamber, pump 2 insufflate
additional volume of oxygen until the desired oxygen partial
pressure is achieved (in any case more that 0.25 atm., in
accordance with the current standards of anesthesia machines).
[0069] The principle validity of the ambient pressure control
ventilation apparatus is illustrated using a simplified model shown
in FIG. 2. Reference is now made to FIG. 2 illustrating a
simplified experimental model apparatus that imitates lungs of a
patient in a vacuum chamber, built according to the principles of
the present invention, with a bottle replacing the lungs of a
potential patient.
[0070] A compliant transparent plastic bottle 50 was placed in a
transparent, noncompliance plastic chamber 51 that is connected to
a vacuum pump (not shown in the Figure) through tube 52. A vacuum
port 57 was connected to tube 52. Plastic bottle 50 was designed to
imitate the lungs of a patent Plastic bottle 50 was partially
filled with water 53 and tightly closed by hermetic cover 54
through which a standard endotracheal tube of compatible size 55
was inserted. Chamber 51 was also provided with an exhaust tube 56
having a valve 58 that can be periodically opened or closed. During
suctioning of chamber 51 and periodic opening of valve 58, the
desired barometric pressure changes in the internal space of
chamber 51 were established. During the experiment, the following
observations were made:
[0071] 1. During barometric pressure decrease, water 59 ejected
from bottle 50 through endotracheal tube 55 to chamber 51.
[0072] 2. During barometric pressure increase, gas bubbles 60 were
observed in water 53: air entered from chamber 51 to bottle 50
through endotracheal tube 55.
[0073] 3. There were no visible movements of the outer walls of
bottle 50 during the barometric pressure changes, although the
bottle was made of compliant plastic.
[0074] 4. The variations in pressure were conducted periodically,
in about 60 cycles per minute, and accordingly surges of water 59
from bottle 50 and bubbling of gas bubbles 60 in water 53 were
observed with similar rate.
[0075] 5. The experiment was performed using three different
bottles with marginally different compliance from extremely low
(glass bottle) to extremely high (very thin wall plastic bottle).
Standard lung imitator for check up of anesthesia and intensive
care machines was also used in this experiment. It is important to
notice that in all four experiments the same results were obtained
in spite of different compliance of the bottles and lung
imitator.
[0076] Returning to FIG. 1, chamber 5 is provided with a
communication block 8 that is designed to enable safe passage of
monitoring lines 4 from the patient's body and lines 6 from sensors
16 in the patien's airway 17 to control unit 1, or other devices.
Physiological and respiratory parameters of the patient's
ventilation according to current standards of intensive care unit
and anesthesia machines are collected using endotracheal tube
sensors 16 from an endotracheal tube 17 and from a patient's body
26.
[0077] Infusion bags 13 and infusion devices 12 are placed inside
chamber 5, each bag is connected through an infusion line 11 to
patient 26 lying on mattress 18.
[0078] The pressure in chamber 5 is measured by a pressure sensor,
in this embodiment, a pressure gauge 25 that is communicating with
control unit 1. Monitoring lines 4 and endotracheal tube sensors
lines 6 from within the chamber are linked through communication
block 8 to control unit 1, on which the collected parameters may be
displayed. Control unit 1 also collects data from pressure gauge 25
via lines 27 so that feedback control of the pressure can be
performed, too. Control unit 1 is electrically connected to pump 2
and to relief valve 14 and controls the actuation of the pump and
the valve (independently) in a predetermined manner, which is
expalined hereafter.
[0079] Pump 2 is provided with pipelines supplying air 28 and
oxygen 29. In regular operation conditions, a mixture of air and
oxygen is ventilated into the chamber. There are situations in
which a compansating amount of oxygn is needed. For example, to
compensate on a possible decrease in the barometric pressure in
chamber 5, pump 2 insufflate additional volume of oxygen as
explained before.
[0080] Pump 2 is electrically connected to an electric supplier 30.
For cases of electricity failure emergencies, a reserve battery 23
is provided in the vicinity of the chamber. Reserve battery 23 may
be mounted on carying vehicle 24. In addition, a reserve oxygen
tank 22 is mounted on carying vehicle 24 for emergency cases.
[0081] Highly compliant breathing bag such as Ambu bag 10 is
designed to be connected via standard connectors to the patient's
airway 17. Ambu bag 10 is designated for emergency patient's
assisted ventilation in cases of technical failure of the system.
The nursing team is capable to assist in the ventilation of the
patient through door 9. The second purpose of Ambu bag 10 is to
provide a possibility in which the ambient pressure control
ventilation of the patients lungs will be performed through the
Ambu bag while using much less pressure difference of the
relatively high compliance of the Ambu bag in comparisson with the
patient's chest and lung compliance. Additional oxygen line 7
connects pump 2 and Ambu bag 10.
[0082] The ambient pressure control ventilation apparatus has many
advantages over the traditional ventilation systems. The
application of an excessive pressure on the whole body instead of
only on the torso results in squeezing of the capacitance vessels,
increasing venous return, right ventricle filling and output that
results in increased pulmonary perfusion during the phase of
maximal pulmonary gas filling (maximal partial pressure of oxygen).
This fact may improve the ventilation/perfusion ratio. At the same
time, the barometric pressure (BP) elevation during the operation
of the ambient pressure control ventilation apparatus increases
PaO.sub.2 according to
PaO.sub.2=(BP-47)*FiO.sub.2--PaCO.sub.2/RQ.
[0083] The ambient pressure control ventilation apparatus, when
operated in regular conditions, can have impact on systemic
vascular resistance and on the heart rate that may result in
beneficial or, in extreme cases, detrimental effect. In cases of
hemodynamic deterioration (for example: patients with aortic or
mitral regurgitation) it is possible to manipulate the barometric
pressure gradient to be regulated from normal BP-90 mm Hg to normal
BP+90 mm Hg, for example, instead of normal BP to normal BP+175 mm
Hg in regular conditions. This also manipulates the functional
residual capacity and the upper and lower airway diameter and
dynamic resistance that may be decreased according to the decrease
of the ambient pressure. It is probable that in contrast to normal
breathing and traditional mechanical ventilation, the airways may
paradoxically expand during expiration, loosing part of the
resistance and/or the ability to intrinsic positive and expiratory
pressure (PEEP) formation.
[0084] Another advantage of the use of the ambient pressure control
ventilation apparatus is the minimal, if at all, increase of
transpulmonary and intrathoracic pressures. Accordingly, there is a
minimal, if at all, interference with blood drainage from the
brain, a possible implication during treatment of high intracranial
pressure.
[0085] It was mentioned that much less transpulmonary pressure is
needed during ambient pressure control ventilation in the apparatus
of the present invention. Therefore, this apparatus can have a
vital role in the treatment of bronchopleural fistulas, airway
trauma or in postoperative ventilation after airway surgery.
[0086] Traditional positive pressure ventilation is more difficult
when native lung and/or chest compliance decreases. In contrast
with positive pressure ventilation, the ambient pressure control
ventilation may be even more effective when native lung and/or
chest compliance decrease. Therefore, other possible applications
of the apparatus may include adult respiratory distress syndrome,
pneumonia, bronchial asthma (attack) or uncontrolled intrinsic PEEP
elevation (OR, ICU).
[0087] According to the ability of ambient pressure control
ventilation to squeeze superficial veins and to increase preload to
the right ventricle of the heart without medication and fluid
loading, the apparatus may be beneficial for patients suffering
from congestive heart failure.
[0088] In the same principle of superficial vascular squeezing,
ambient pressure control ventilation may substitute deep venous
thrombosis prophylaxis, so the need of anticoagulant treatment may
be partially or fully eliminated. As mentioned above, ambient
pressure control ventilation most probably has an impact on
systemic vascular resistance. Being applied to the whole body with
rate of patient's pulse, such pressurizing like ambient pressure
control ventilation synchronized with electrocardiogram tracing may
substitute intraortic balloon counterpulsation (IABC). In the last
case, inflation phase of ambient pressure control ventilation must
be synchronized with heart diastola, effectively simulating
physiologic events of IABC.
[0089] The ability of ambient pressure control ventilation to
interfere with venous blood flow through superficial veins and its
influence on systemic vascular resistance may open the way to
nonpharmacological intervention in right and left congestive heart
failures, and nonpharmacological DVT prophylaxis.
[0090] According to the basic principles of modern cardiopulmonary
resuscitation (CPR), whole-body squeezing obtained in ambient
pressure control ventilation may serve as more effective priming
technique than traditional and advanced methods of close cardiac
massage (Cardiopump and Four-phase Life-stick). In order to use the
ambient pressure control ventilation apparatus for this purpose,
closure of the endotracheal tube is synchronized with the pressure
elevation in the chamber in such a manner that permits optimal
cardiac priming. The pressure elevation is applied with the rate
that enables optimal combination of cardiac priming/output and
pulmonary gas exchange.
[0091] Moreover, application of ambient pressure control apparatus
synchronized with spontaneous heart activity via EKG or arterial
blood pressure curves, may serve as alternative cardiac noninvasive
assisting device that enables the use of the apparatus in a wide
range of acute and chronic heart failure cases.
[0092] It should be clear that the description of the embodiments
and attached Figures set forth in this specification serves only
for a better understanding of the invention, without limiting its
scope as covered by the following claims.
[0093] It should also be clear that a person skilled in the art,
after reading the present specification could make adjustments or
amendments to the attached Figures and above described embodiments
that would still be covered by the following claims.
* * * * *