U.S. patent application number 15/784675 was filed with the patent office on 2018-02-08 for system and method for deep vein thrombosis prevention and diagnosis.
The applicant listed for this patent is Zimmer Dental Ltd.. Invention is credited to Jacob Barak, Adi Dagan, Vitaly Rondel.
Application Number | 20180035902 15/784675 |
Document ID | / |
Family ID | 40229154 |
Filed Date | 2018-02-08 |
United States Patent
Application |
20180035902 |
Kind Code |
A1 |
Barak; Jacob ; et
al. |
February 8, 2018 |
SYSTEM AND METHOD FOR DEEP VEIN THROMBOSIS PREVENTION AND
DIAGNOSIS
Abstract
A system and method prevents and diagnoses deep vein thrombosis
in a body limb by providing a pressure sleeve having a plurality of
individually fillable cells, the pressure sleeve being configurable
to be placed around a body limb. A source fills each fillable cell
individually, and a pressure sensor measures a pressure in a
fillable cell. A controller establishes a fill sequence of each
individually fillable cell and a fill time for each individually
fillable cell. The controller causes a first individually fillable
cell of the pressure sleeve to be filled to a predetermined
pressure and causes the pressure of first individually fillable
cell of the pressure sleeve to be measured while a second
individually fillable cell of the pressure sleeve is filled. The
controller determines a presence of deep vein thrombosis in a body
limb having the pressure sleeve therearound based upon a measured
pressure change in the first individually fillable cell of the
pressure sleeve. The monitored pressure changes reflects the effect
of venous obstruction on naturally occurred venous flow
fluctuations like those caused by the respiratory cycle, and/or
artificially created fluctuations like those caused by inflation of
a second pressure cell. Relevant data can be collected during
routine system application for deep vein thrombosis prevention on a
24/7 basis. In the case deep vein thrombosis is suspected, a
controlled and more sophisticated study can be triggered using the
same system.
Inventors: |
Barak; Jacob; (Oranit,
IL) ; Dagan; Adi; (Zichron Yaakov, IL) ;
Rondel; Vitaly; (Hadera, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zimmer Dental Ltd. |
Rosh Haayin |
|
IL |
|
|
Family ID: |
40229154 |
Appl. No.: |
15/784675 |
Filed: |
October 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13759327 |
Feb 5, 2013 |
9788738 |
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15784675 |
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11924868 |
Oct 26, 2007 |
8597194 |
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13759327 |
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60863052 |
Oct 26, 2006 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/6828 20130101;
A61H 2201/165 20130101; A61H 9/0078 20130101; A61H 2205/10
20130101; A61H 2205/106 20130101; A61B 5/02007 20130101; A61B
5/02233 20130101; A61H 2201/5071 20130101; A61B 5/0285 20130101;
A61B 5/0225 20130101; A61B 5/02028 20130101; A61B 5/02133 20130101;
A61B 5/0205 20130101 |
International
Class: |
A61B 5/0285 20060101
A61B005/0285; A61B 5/02 20060101 A61B005/02; A61H 9/00 20060101
A61H009/00; A61B 5/00 20060101 A61B005/00; A61B 5/021 20060101
A61B005/021 |
Claims
1. A system for diagnosing and preventing, deep vein thrombosis in
a body limb, comprising: a compression system for applying external
pressure to a body limb; and a venous phasic flow monitoring system
to monitor a venous phasic flow in a body limb; said venous phasic
flow monitoring system determining a presence of deep vein
thrombosis in the body limb by detecting a change in a volume of
the body limb.
2. The system as claimed in claim 1, wherein said compression
system includes a non-pneumatic mechanical applicator to apply
non-pneumatic external pressure to the body limb, said
non-pneumatic mechanical applicator being configurable to be placed
around at least a portion of the body limb; said compression system
further including a mechanical device to cause said non-pneumatic
mechanical applicator to apply non-pneumatic external pressure to
the body limb.
3. The system as claimed in claim 2, wherein said non-pneumatic
mechanical applicator is a strap and said mechanical device pulls
said strap against the body limb to provide non-pneumatic external
pressure to the body limb.
4. The system as claimed in claim 2, wherein said venous phasic
flow monitoring system determining a presence of deep vein
thrombosis in the body limb having said non-pneumatic mechanical
applicator substantially therearound based upon detecting a change
in a strain being experienced by said non-pneumatic mechanical
applicator.
5. The system as claimed in claim 3, wherein said venous phasic
flow monitoring system determining a presence of deep vein
thrombosis in the body limb having said strap substantially
therearound based upon detecting a change in a strain being
experienced by said strap.
6. The system as claimed in claim 1, wherein said compression
system includes a pressure sleeve to apply external pressure to the
body limb, the pressure sleeve having a fillable cell and being
configurable to be placed around a body limb; said compression
system further including a source to fill the fillable cell.
7. The system as claimed in claim 6, wherein said source
pneumatically fills the fillable cell.
8. The system as claimed in claim 6, wherein said venous phasic
flow monitoring system determining a presence of deep vein
thrombosis in the body limb having said pressure sleeve therearound
based upon detecting a pressure change in said fillable cell.
9. The system as claimed in claim 6, wherein said pressure sleeve
includes a plurality of individually fillable cells and said source
fills each fillable cell individually.
10. The system as claimed in claim 9, wherein said source fills a
first individually fillable cell of said pressure sleeve to a
predetermined pressure; said source filling a second individually
fillable cell of said pressure sleeve while said venous phasic flow
monitoring system monitors a pressure change in the filled first
individually fillable cell of said pressure sleeve; said venous
phasic flow monitoring system determining a presence of deep vein
thrombosis in the body limb having said pressure sleeve therearound
based upon detecting a pressure change in the filled first
individually fillable cell of said pressure sleeve.
11. The system as claimed in claim 10, wherein said first
individually fillable cell of said pressure sleeve is proximal to
said second individually tillable cell of said pressure sleeve.
12. The system as claimed in claim 10, wherein said first
individually tillable cell of said pressure sleeve is distal to
said second individually tillable cell of said pressure sleeve.
13. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a presence of deep vein
thrombosis in a body limb having said pressure sleeve therearound
based upon increase in baseline pressure being measured by said
venous phasic flow monitoring system, the deep vein thrombosis
being located proximal to said first individually tillable
cell,
14. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a presence of deep vein
thrombosis in a body limb having said pressure sleeve therearound
based upon increase in baseline pressure in said first individually
tillable cell being measured by said venous phasic flow monitoring
system and an obliteration of a detection of venous phasic waves by
said first individually tillable cell, the deep vein thrombosis
being located proximal to said first individually tillable
cell.
15. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a probable deep vein thrombosis
is located in a body limb having said pressure sleeve therearound
based upon substantially no baseline pressure change being measured
by said venous phasic flow monitoring system, the probable deep
vein thrombosis being located distal to said first individually
fillable and proximal to said second individually tillable
cell.
16. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a probable deep vein thrombosis
is located in a body limb having said pressure sleeve therearound
based upon substantially no baseline pressure change being measured
by said venous phasic flow monitoring system and a detection of
venous phasic waves by said first individually fillable cell, the
probable deep vein thrombosis being located distal to said first
individually fillable and proximal to said second individually
fillable cell.
17. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a probable absence of deep vein
thrombosis in a body limb having said pressure sleeve therearound
based upon substantially no baseline pressure change being measured
by said venous phasic flow monitoring system.
18. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines a probable absence of deep vein
thrombosis in a body limb having said pressure sleeve therearound
based upon substantially no baseline pressure change being measured
by said venous phasic flow monitoring system and a detection of
venous phasic waves by said first individually fillable cell.
19. The system as claimed in claim 11, wherein said venous phasic
flow monitoring system determines post deep vein thrombosis
syndrome in a body limb having said pressure sleeve therearound
based upon increase in baseline pressure in said first individually
fillable cell being measured by said venous phasic flow monitoring
system and a detection of venous phasic waves equal to or greater
than normal venous phasic waves by said venous phasic flow
monitoring system, the deep vein thrombosis, causing a partial
obstruction, being located proximal to said first individually
fillable cell.
20. The system as claimed in claim 12, wherein said venous phasic
flow monitoring system determines a presence of deep vein
thrombosis in a body limb having said pressure sleeve therearound
based upon substantially no pressure change being measured by said
venous phasic flow monitoring system, the deep vein thrombosis
being located proximal to said second individually fillable cell.
Description
PRIORITY INFORMATION
[0001] This application claims priority from U.S. Provisional
Patent Application, Ser. No. 60/863,052, filed on Oct. 26, 2006.
The entire content of U.S. Provisional Patent Application,
60/863,052, filed on Oct. 26, 2006, is hereby incorporated by
reference.
BACKGROUND
[0002] Deep vein thrombosis is of extreme clinical importance as it
carries the short-term risk of pulmonary embolism and death and the
long term risk of chronic venous insufficiency, causing disabling
symptoms of swelling, chronic pain, and skin ulceration (post
thrombotic syndrome). Both pulmonary embolism and post-thrombotic
syndrome may develop after symptomatic or asymptomatic, proximal or
distal deep vein thrombosis events. Prevention of these short-term
and long-term sequelae is of great clinical, economic, medical, and
legal significance.
[0003] Due to the silent nature of deep vein thrombosis and
pulmonary embolism, prevention has been the conventional clinical
approach to avoid this disease. More specifically, prevention
protocols have been conventionally used with any high-risk patients
and especially with surgical patients. Conventional prevention
therapies include either chemoprophylaxis (anticoagulant drugs) or
mechanical (systems that enhance the venous return by compressing
the legs).
[0004] Despite great progress with these two modalities of
prevention in the recent years, conventional prevention therapies
pose a high failure rate and a significant risk to surgical
patients. Meta analysis studies showed that failure rate of the
most common anticoagulant drug, LMWH, is about 16% in patients
under going total hip replacement and 31% with patient undergoing
total knee replacement. Given such a high failure rate there is a
great need for routine screening to role out DVT in high risk
patients. The conventional prevention therapies do not address the
need to detect deep vein thrombosis in patients in which the
prophylaxis has failed. More specifically, deep vein thrombosis
screening is, conventionally, only done with patients who are
suffering from clinical symptoms, and only 5% of the deep vein
thrombosis patients have clinical manifestation.
[0005] Deep vein thrombosis can be conventionally diagnosed using
venography, an invasive and relatively high-risk method, or a
duplex scan. Both conventional diagnostic methods are expensive and
can be done only in the hospital settings by a skilled technician.
Thus, routine scanning for deep vein thrombosis with either duplex
or venography is not cost effective; and therefore, scanning is not
conventionally used.
[0006] Conventionally, once clinical symptoms are present (only
about 5% of the deep vein thrombosis patients show clinical signs
during the first 3-5 post operation days), a patient will go
through a duplex scan to confirm or rule out the presence of deep
vein thrombosis to allow for adequate treatment to be taken, There
are two major down sides to this conventional approach.
[0007] The first problem is as the scan can only be made in the
hospitals settings, the scans are done relatively a short time
after the operation, usually just before discharge (3-5 days after
the operation). However, many of the deep vein thrombosis
situations are either too small to be detected at this time or even
start manifestation later.
[0008] The second problem is that the current available scans are a
one time "snap shot" of the patient's situation and cannot provide
an understanding with respect to earlier or later situations.
Therefore, a positive scan can often time detect a fully developed
clot that could have been controlled if it was discovered earlier.
Alternatively, a negative scan could miss a small clot that is
about to develop, post discharge, into a significant clot.
[0009] With respect to the use of the anticoagulant drugs,
anticoagulant drugs expose the patient to the serious risk of
bleeding complications. For example, it is known that 2%-5% of the
patients using the anticoagulant drug, LMWH, for deep vein
thrombosis prevention in joint arthroplasties experience serious
bleeding complications.
[0010] In view of this serious side effect, since only about 50% of
the patients who are at risk for developing deep vein thrombosis
actually develop deep vein thrombosis, more than half of the
at-risk patients are subjected to a totally unnecessary risk of
bleeding due to the conventional widespread use of anticoagulant
drugs to prevent deep vein thrombosis.
[0011] Furthermore, as the conventional prophylaxis protocols are
extended beyond the acute care time (10-30 days with joints
arthroplasty patients), patients are being discharge with the risk
of developing deep vein thrombosis due to prevention failure, of
bleeding complications due to the continued use of anticoagulant
drugs beyond the acute care time, or of both developing deep vein
thrombosis and bleeding complications. It is noted that once the
patient has detected a post acute care time problem and seeks
clinical treatment, the situation is usually very serious or too
late.
[0012] Therefore, it is desirable to provide a device that will
detect, in real time and on a 24/7 basis, the possible formation of
deep vein thrombosis in patients in acute care and/or post acute
settings. Furthermore, it is desirable to provide a device that
will be able to prevent deep vein thrombosis, in real time and on a
24/7 basis, as well as detect the possible formation of deep vein
thrombosis. Moreover, it is desirable to provide a device that will
provide deep vein thrombosis screening for patients receiving
mechanical prophylaxis without any additional hardware.
[0013] Also, it is desirable to provide a device that will be able
to reduce the rates of symptomatic deep vein thrombosis and
pulmonary embolism by alerting the presence of an early formation
of deep vein thrombosis and triggering early initiation of
treatment. It is desirable to provide a device that can eliminate
the risk of unnecessary bleeding associated with the wide use of
anticoagulant by providing good prophylaxis capabilities together
with good diagnostic capabilities in case of prophylaxis failure
that together will eliminate the need to use anticoagulant drugs
for the same purpose. It is further desirable to provide a device
that will be able to protect against and detect deep vein
thrombosis when the patient is out of the hospital.
[0014] In addition, it is desirable to provide a device that will
be able to provide information on the progress of the condition and
its acuteness or healing instead of providing a snapshot of the
situation. Furthermore, it is desirable to provide a device that is
capable of following dynamic trends that have been developed along
treatment time axis and incorporate such dynamic trends into the
decision-making algorithm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The drawings are only for purposes of illustrating
embodiments and are not to be construed as limiting, wherein:
[0016] FIG. 1 is an illustration showing an exemplary embodiment of
a massage/diagnostic sleeve in use on the leg of a patient;
[0017] FIG. 2 is a schematic block diagram of an exemplary
embodiment of a pump unit;
[0018] FIG. 3 graphically illustrate relationships between femoral
venous flow and respiration; and
[0019] FIGS. 4 through 7 illustrate an example of valves' states
that enable alternate use of the pressure massage/diagnostic
sleeve's air-cells as recording cuffs or compression sites.
DETAILED DESCRIPTION
[0020] For a general understanding, reference is made to the
drawings, In the drawings, like reference have been used throughout
to designate identical or equivalent elements. It is also noted
that the various drawings may not have been drawn to scale and that
certain regions may have been purposely drawn disproportionately so
that the features and concepts could be properly illustrated.
[0021] In the following descriptions, the concepts will be
described with respect to use on a leg of an individual. However,
it is to be understood that the concepts are also extended to use
on any body limb such as an arm, a foot, a part of a leg, arm, or
foot, and may be used on two or more limbs simultaneously.
[0022] Moreover, although the concepts will be described in
conjunction with a portable pneumatic compression system console or
small pneumatic compression system console wherein the medium used
to provide compression is realized by pressurized air, the concepts
can be used with any compression system wherein the medium used to
provide compression can be realized by a liquid, fluid, gas, or any
other mechanical means,
[0023] The descriptions below relate to medical devices for
applying pressure to a region of a body surface. More particularly,
the descriptions below relate to medical devices that use a
pressure sleeve to apply pressure to a region of a body surface for
deep vein thrombosis therapeutic and diagnostic purposes.
[0024] Moreover, the descriptions below relate to systems for
applying compressive pressures against a patient's limb, as well
as, measuring venous phasic signals to enable the detection of deep
vein thrombosis wherein a miniaturized, portable, ambulant,
massage/diagnostic system may be utilized,
[0025] It is noted that the entire contents of U.S. patent
application Ser. Nos. 11/023,894 and 10/370,283 are hereby
incorporated by reference. The entire content of U.S. Pat. No.
7,063,676 is hereby incorporated by reference,
[0026] In FIG. 1, an exemplary embodiment of a pressure
massage/diagnostic sleeve 1 is illustrated. The pressure
massage/diagnostic sleeve 1 has an inner and outer surface composed
of a durable flexible material and is divided into a plurality of
cells 2 along its length arid each cell is connected to the control
unit 3 by a separate tube collectively labeled 4 in FIG. 1.
Sections of the pressure massage/diagnostic sleeve may be of
non-inflatable elastic material 5, for example around the knee and
ankle.
[0027] As illustrated in FIG. 1, each cell has a fluid inlet
opening 6 to which a hose 4 from the control unit 3 is attached.
The control unit 3 contains a compressor capable of compressing and
pumping ambient air into one or more selected cells in the pressure
massage/diagnostic sleeve via the hoses 4. It is noted that the
console may also include a compression system wherein the medium
used to provide compression can be realized by a liquid, fluid,
gas, or other mechanical means.
[0028] The control unit 3 allows a temporo-spatial regime of
inflation and deflation of the cells to be selected, e.g. a regime
which generates peristaltic contractions of the pressure
massage/diagnostic sleeve so as to force fluids inside the limb
towards the proximal end of the limb, or a regime which enhances
the flow of the venous blood in the limb.
[0029] The cells may be subdivided into a plurality of intra-cell
compartments 7. The intra-cell compartments 7 are formed, for
example, by welding the inner and outer shells of the pressure
massage/diagnostic sleeve along the boundaries of the intra-cell
compartments. The intra-cell compartments 7 in a given cell are
confluent due to openings 8 between adjacent intra-cell
compartments 7 so that all the intra-cell compartments 7 in the
cell are inflated or deflated essentially simultaneously.
[0030] FIG. 2 is a schematic block diagram of a pump unit 60. It
will be appreciated that the thick interconnecting lines represent
a pneumatic connection or multiple pneumatic connections, while the
thin interconnecting lines represent an electrical connection or
multiple electrical connections. The pump unit 60 may include an
independent source of energy, such as a rechargeable battery pack
67, which enables the pneumatic device operation without a fixed
connection to a main power outlet. The batteries can be bypassed
and the device is able to operate for longer times. and the
batteries can be recharged at the same time, while it is connected
to the main power supply with the aid of a charger.
[0031] A source of compressed air, such as a compressor 64, is
powered by the batteries or the main electrical outlet, and
connected to the pressure massage/diagnostic sleeve or sleeves by
pneumatic conduits. A control unit 68 is adapted to receive inputs
from the operator and from pressure sensors 62 and 63.
[0032] The control unit serves to read and control the operation of
the compressor 64 and to control the cyclic inflating and deflating
of the pressure massage/diagnostic sleeve. The control unit also
controls the operation of solenoid valves 66, which receive and
distribute the flow to the different cells of the pressure
massage/diagnostic sleeve with the aid of a manifold 65, to enable
the sequential inflating and deflating of the multi-segmented
pressure massage/diagnostic sleeve's cells.
[0033] It is noted that the compressor 64 may be housed with the
control unit or may be housed separately. It is noted that pressure
sensors 62 and 63 may have individual pneumatic connections with
the manifold 65.
[0034] Alternatively, both the hardware and software can enable the
operation of the device from an external pressurized air and power
sources. In some hospitals, the source of pressurized air can be
the central source of pressure-regulated supply that has wall
outlets adjacent to the power outlets or that both the external
power and pump sources could be an integral part of the patient's
bed.
[0035] The use of miniaturized components like the compressor 64
and solenoid valves 66, together with the miniature accessories,
results in small power consumption that enables the operation of
the pneumatic device on batteries, while maintaining small
dimensions and lightweight of the operating unit. The use of a
pressure massage/diagnostic sleeve with a small-inflated volume can
also improve the obtained results of the operation unit for better
clinical operation and results.
[0036] The system applies cyclic sequential pressure on a body's
legs or arms. The cyclic sequential pressure is applied on the
treated parts of the body by inflating and deflating each cell of
the pressure massage/diagnostic sleeve at a predefined timing.
While being inflated, the multi-chambered segmented sleeve should
be encircling the part of leg to be treated. While the pressure
massage/diagnostic sleeve is inflated, a local pressure is applied
at the contact area between the pressure massage/diagnostic sleeve
and the body.
[0037] The control unit 68, which can be software based, controls
the operation of the compressor 64 and solenoid valves 66. The
control unit can be programmed to achieve any desired inflating,
deflating, and/or recording sequence and timing including delay
intervals, in accordance with clinical application.
[0038] As noted above, deep vein thrombosis can be detected using a
noninvasive and painless technique that enables the detection of
acute deep vein thrombosis, gives some basic idea on the location
of the pathological lesion (proximal/distal), and differentiates
acute deep vein thrombosis from chronic deep vein thrombosis. The
technique measures two variables. The first is the presence or
absence of obstruction in the deep venous system. The second is a
measurement of the collateral venous circulation. These variables
are indicated by the presence, absence, or size and configuration
of the naturally occurred, venous phasic flow waves (the "venous
phasic signal"). In other words, it requires knowledge of the state
of the venous phasic signals when it is determining the presence or
absence of an obstruction.
[0039] If there is an obstruction without venous phasic waves, the
process is acute. A sub-acute process is indicated by the presence
of obstruction with visible venous phasic waves. If there is
evidence of obstruction in the presence of larger than normal
venous phasic waves, the process is usually chronic.
[0040] The volume of the lower limb is directly affected by
respiration, Respiration has a neglect effect on the limb arterial
flow at rest; however, during inspiration (in diaphragmatic
respiration) there is a temporary reduction in limb venous return,
which temporarily increases the total volume of the leg. Expiration
has the opposite effect. This is illustrated in FIG. 3.
[0041] FIG. 3 demonstrates the average effects of ribcage or
diaphragm breathing patterns on femoral arterial inflow, mean
arterial pressure, and femoral venous outflow. Signals were
recorded during resting conditions in five healthy volunteers. A
minimum of 200 breaths were recorded per subject per condition,
Though there is no discernable effect of the breathing pattern on
arterial inflow, femoral venous return is facilitated during
ribcage inspiration and impeded during a diaphragmatic inspiration,
with these modulatory effects being reversed during the ensuing
expiratory phase of the breath.
[0042] As noted above, the knowledge of the state of the venous
phasic flow is required when it is determining the presence or
absence of an obstruction. The fact that respiration has direct
affect on leg volume means that by following periodic changes in
leg volume one can determine the state of the venous phasic flow.
The present invention employs one (or more) of inflatable cells of
a massage/diagnostic pressure sleeve as a recording cuff to measure
an increase or decrease in the volume of the lumen (limb or body
part within the inflatable cell) of the inflatable cell. The
increase or decrease in the volume of the lumen will produce a
similar change in the pressure of the captive air, which change can
be recorded with a suitable transducer (pressure sensor).
[0043] To better understand how the present invention diagnoses
deep vein thrombosis of the lower extremity the characteristics of
deep vein thrombosis of the lower extremity with respect to blood
flow will be described.
[0044] It is known that normal breathing produces a rhythmic
increase and decrease in the volume of blood in the lower extremity
of a normal patient, These changes (venous phasic waves) are
usually larger in amplitude when the patient lies on his left side
than those obtained when the patient is supine. It is further known
that acute deep venous thrombosis obliterates or significantly
reduces the size of the "venous phasic waves" in veins distal to
the obstruction.
[0045] It is noted that deep venous thrombosis interferes with the
normal outflow of blood from the lower extremities wherein the
outflow of blood from the lower extremities is in response to
rhythmic compression. If a recording cuff is placed proximal
(higher or closer to the heart than the site of compression is to
the heart) to the site of compression and a rise in the baseline of
the volume recorder, attached to the recording cuff, takes place,
it can be determined that a venous obstruction is proximal to the
recording cuff. For example, if the thigh tracing shows a stepwise
rise while the calf is being compressed, the level of obstruction
to the deep veins is located above the thigh cuff. In this
scenario, the recording cuff is detecting a momentary damming up of
blood (increase in blood volume) due to deep vein thrombosis
blocking the blood's from exiting the area; e.g., indicative of a
blockage.
[0046] However, when a recording cuff is placed proximal to the
site of compression and the baseline of the volume recorder,
attached to the recording cuff, remains level, it can be determined
that compression has been applied to a normal extremity having no
impediment to venous outflow.
[0047] On the other hand, if a recording cuff is placed distal
(lower or further from the heart than the site of compression is to
the heart) to the site of compression and a fall in baseline of the
volume recorder, attached to the recording cuff, takes place, it
can be determined that compression has been applied to a normal
extremity having no impediment to venous outflow.
[0048] Moreover, if a recording cuff is placed distal to the site
of compression and no changes or very small changes in baseline of
the volume recorder, attached to the recording cuff, takes place,
it can be determined that deep vein thrombosis is located proximal
to the compression site.
[0049] It is further noted that monitoring changes in the amplitude
of the venous phasic waves over time can help identify deep vein
thrombosis formation at an early stage. A trend towards an
amplitude reduction in one leg as compared to the other leg, which
remains unchanged, may indicate an on-going deep vein thrombosis
process in the leg with the lower amplitude. A trend towards an
increase in venous phasic wave amplitude in one leg as compared to
the other leg, which remains unchanged, may indicate chronic deep
vein thrombosis with re-canalization.
[0050] FIGS. 4-7 illustrate an example of valves' states that
enable alternate use of the pressure massage/diagnostic sleeve's
air-cells as recording cuffs or compression sites. As illustrated
in FIG. 4, a programmable console system is configured to
illustrate a method of detecting deep vein thrombosis using a
pressure massage/diagnostic sleeve (not shown) comprising two or
more individually inflatable cells.
[0051] The system also includes a console 6150 containing a
compressor 6020 that generates pressurized air. A conduit 6070
conducts the flow of pressurized air away from the compressor 6020.
The console 6150 has a housing 6200 containing a processor 6190,
conduit 6070 and valves (6050a, 6050b, and 6050c). The compressor
6020 may be located within the housing 6200 of the console 6150 or
outside the housing of the console 6150.
[0052] The number of solenoid valves (6050a, 6050b, and 6050c) can
he equal to the number of cells in the pressure massage/diagnostic
sleeve and are positioned along the conduit 6070. Each valve
(6050a, 6050b, and 6050c) has an air inlet connected to an upstream
portion of the conduit 6070, a first air outlet connected to a
downstream portion of the conduit 6070, a second air outlet (6110a,
6110b, and 6110c) connected to an associated cell via a conduit
(6140a, 6140b, and 6140c), and a third air outlet connected to
conduit 6075. A one--way valve 6250 prevents the flow of air in the
conduit 6070 from flowing from the valves (6050a, 6050b, and 6050c)
towards the compressor 6020. Each valve can, individually, realize
various states. The state of each valve is controlled by control
signals from a processor 6190.
[0053] In a first state, a valve allows pressurized air to flow
between its inlet and the first outlet. In a second state, a valve
allows pressurized air to flow between its inlet and the first
outlet and the second outlet (6110a, 6110b, or 6110c). In a third
state, a valve allows pressurized air to flow between the second
outlet (6110a, 6110b, and 6110c) and the third outlet connected to
conduit 6075, In a fourth state, a valve allows the pressurized air
in the pressure massage/diagnostic sleeve, conduit 6070, and
conduit 6075 to be exhausted from the system.
[0054] As noted above, the processor 6190 controls the state of
each of the valves (6050a, 6050b, and 6050c) so as to execute a
predetermined temporo-spatial array of inflation/deflation of the
cells. For example, in the application of detecting deep vein
thrombosis, the cells are inflated individually so that one cell
can act as a recording cuff, while another cell can act as a
compression site.
[0055] As illustrated in FIG. 4, this can be accomplished by the
processor 6190 causing the valve 6050c to realize the second state
(pressurized air flowing between its inlet and the first outlet and
the second outlet 6110c), while the valves 6050a and 6050b realize
the first state (pressurized air flowing between its inlet and the
first outlet). Pressurized air flows in the conduit 6070 from the
compressor 6020 into the cell associated with conduit 6140c. The
processor 6190 monitors the air pressure in the conduit 6070 by
means of a pressure gauge 6030. When the pressure has reached a
predetermined pressure, the processor 6190 closes the valves
(6050a, 6050b, and 6050c).
[0056] Next, as illustrated in FIG. 5, the cell associated with
conduit 6140a is inflated by causing the valve 6050a to realize the
second state (pressurized air flowing between its inlet and the
first outlet and the second outlet 6110a). The cell associated with
conduit 6140b is not inflated because valve 6050b is closed. While
the cell associated with conduit 6'140a is being inflated, the cell
associated with conduit 6140a is causing pressure (compression) to
be applied to the limb, and the cell associated with conduit 6140c,
which was pre-inflated to a predetermined pressure, is
pneumatically connected to pressure sensor 6035 via valve 6050c
being in the third state. In this situation, the cell associated
with conduit 6140c is acting as a recording cuff, which
communicates lumen volume change via pressure changes that are
detected by the pressure sensor 6035.
[0057] The recording cuff (the cell associated with conduit 6140c)
is placed proximal to the site of compression (the cell associated
with conduit 6140a). If the recording cuff, via the pressure sensor
6035, causes a rise in the baseline of the volume recorder, it can
be determined that a venous obstruction is proximal to the
recording cuff (the cell associated with conduit 6140c). In this
scenario, the recording cuff is detecting a momentary damming up of
blood (increase in blood volume) due to deep vein thrombosis
blocking the blood's from exiting the area; e.g., indicative of a
blockage. However, if the recording cuff, via the pressure sensor
6035, causes the baseline of the volume recorder to remain level,
it can be determined that compression has been applied to a normal
extremity having no impediment to venous outflow.
[0058] As illustrated in FIG. 6, the processor 6190 causes the
valve 6050a to realize the second state (pressurized air flowing
between its inlet and the first outlet and the second outlet
6110a), while the valves 6050b and 6050c are closed. Pressurized
air flows in the conduit 6070 from the compressor 6020 into the
cell associated with conduit 6140a. The processor 6190 monitors the
air pressure in the conduit 6070 by means of a pressure gauge 6030.
When the pressure has reached a predetermined pressure, the
processor 6190 closes the valves (6050a, 6050b, and 6050c).
[0059] Next, as illustrated in FIG. 7, the cell associated with
conduit 6140a is pneumatically connected to pressure sensor 6035
via valve 6050a because the processor 6190 causes the valve 6050a
is realize the third state. While the cell associated with conduit
6140b is being inflated, the cell associated with conduit 6140b is
causing pressure (compression) to be applied to the limb. In this
situation, the cell associated with conduit 6140a is acting as a
recording cuff, which communicates lumen volume change via pressure
changes that are detected by the pressure sensor 6035.
[0060] The recording cuff (the cell associated with conduit 6140a)
is placed distal to the site of compression (the cell associated
with conduit 6140b). If the recording cuff, via the pressure sensor
6035, causes a fall in baseline of the volume recorder, it can be
determined that compression has been applied to a normal extremity
having no impediment to venous outflow. However, if the recording
cuff, via the pressure sensor 6035, causes no changes or very small
changes in the baseline of the volume recorder, it can be
determined that deep vein thrombosis is located proximal to the
compression site (the cell associated with conduit 6140b).
[0061] It is noted that the change in the pressure in the cells can
be controlled by integrally controlling the states of valves. The
change in pressure is determined by the mode of the programmable
console.
[0062] For example, in some medical conditions it is beneficial to
produce a fast inflation of the sleeve encompassing the body
surface because the velocity of venous flow or the increase in
local arterial flow is proportional to the rate at which the
pressure rises. In the prevention of deep vein thrombosis, it is
believed that this acceleration of venous flow reduces the risk of
pooling and clotting of blood in the deep veins and therefore the
rate of pressure rise is a critical variable of effectiveness in
the prevention of deep vein thrombosis.
[0063] In the examples discussed above, the massage/diagnostic
compression sleeve may be a calf sleeve having three air cells that
encircle the lower, middle, and upper calf parts.
[0064] The compression sleeve may include an inflatable cell having
at least two intra-cell compartments. The intra-cell compartments
are confluent, The inflatable cell may include inner and outer
shells of durable flexible material, the inner and outer shells
being bonded together to form a perimetric cell bond and being
further bonded together along compartmental bonds, The perimetric
cell bond includes upper and lower perimetric cell bonds. The
compartmental bonds partly extend between the upper and lower
perimetric cell bonds to allow for confluent airflow between
adjacent intra-cell compartments within the cell.
[0065] As noted above, the inflatable cell includes at least two
intra-cell compartments, the intra-cell compartments being
confluent to allow for confluent airflow between adjacent
intra-cell compartments within the cell, Adjacent intra-cell
compartments are spatially fixed relative to each other such that
upon inflation of the cell, the cell becomes circumferentially
constricted. The inflatable cell has a first circumference when the
intra-cell compartments are deflated and a second circumference
when the intra-cell compartments are inflated. The second
circumference is less than the first circumference so as to provide
for circumferential constriction. The second circumference may be
defined as a circumference passing through center points of each
contiguous inflated intra-cell compartment.
[0066] It is further noted that the inflatable cell has a first
intra-cell compartmental dimension value when the inflatable cell
is deflated and a second intra-cell compartmental dimension value
when the inflatable cell is inflated, the second intra-cell
compartmental dimension value being less than the first intra-cell
compartmental dimension value so as to provide for circumferential
constriction of the inflatable cell. The first intra-cell
compartmental dimension value may be a length between adjacent
compartmental bonds when the inflatable cell is deflated. The
second intra-cell compartmental dimension value may be a length
between the adjacent compartmental bonds when the inflatable cell
is inflated.
[0067] As explained above, the present invention controls the
states of the various valves and the individually addressable air
cells of a massage/diagnostic compression sleeve to sense small
changes in limb volume that relate to the venous phasic flow.
[0068] By allowing the individual air cells of the
massage/diagnostic compression sleeve to function alternately as
"recording cuffs" and "compressing cuffs," the present invention
can function as a simple diagnostic system.
[0069] Furthermore, if the present invention is utilized on a 24/7
basis, convenient long-term follow-up and serial tracings can be
realized. This automatically collected information can be used to
identify trends in venous phasic signals amplitude changes and limb
volume changes.
[0070] In the case of proximal obstruction (deep vein thrombosis),
the venous blood pool distal to the lesion increases with parallel
increase in limb volume. This increase in limb volume reduces the
time needed for full inflation of the activated air cell up to the
target pressure. Accordingly, assuming that the pump flow, air cell
volume, and target pressure all remained the same, a trend towards
decreased inflation time is suggestive of venous and/or lymphatic
obstruction.
[0071] In addition the present invention is capable of collecting
and analyzing trends in heart rate and respiratory rate at rest.
Though not specific, a trend towards increasing respiratory rate at
rest to >16/min and/or beat rate at rest to >100/min are
suggestive of a patient suffering from acute pulmonary
embolism.
[0072] It is noted that cross analysis, integrating all four
trends, may improve the ability to correctly diagnose ongoing
pathological process, the level of chronicity, and the extent of
the disease. Moreover, manually entered clinical data (such as
Wells score) can be integrated into the decision-making algorithm
to further increase the accuracy of the final diagnosis.
[0073] It is further noted that the information about venous phasic
signal amplitude, cell inflation time, respiratory rate, and heart
rate trends can be collected simultaneously by the present
invention when the present invention is in a standard "treatment
mode." The data can be collected while using single-cell sleeve or
sleeve composed of plurality of individually inflated cells. If the
present invention is in a "diagnostic mode," the full test can be
done automatically, assuming that the sleeve used is composed of at
least two individually inflatable cells. In the case of a single
cell sleeve, the diagnostic mode can be used separately on each of
the involved limbs, using the contra lateral limb sleeve as the
needed second inflatable cell.
[0074] The signal processing and the diagnostic decision-making can
be done using the processor of the present invention, or
alternatively, the raw data can be communicated to an external
processing device for final processing.
[0075] To realize a test, a patient lies quietly in bed with the
lower extremities approximately 10 degrees below heart level. In
this example, the massage/diagnostic compression sleeve encompasses
the patient's calf. As noted above, the present invention is in a
"diagnostic mode." In the diagnostic mode, the present invention
may execute two operational algorithms: algorithm A and algorithm
B.
[0076] In algorithm A, an upper air cell records the response to
compression of the lower calf caused by quick inflation of the
lower air cell. In algorithm B, the upper and lower air cells are
recording the response to compression of the mid-calf caused by
quick inflation of the middle air cell. Typically, the sensing
cells are inflated to 15-20 mm Hg and the compressing cell to 100
mm Hg with pump acceleration.
[0077] In one embodiment, each run may be repeated three times and
each record cycle may last 35 seconds. Inflation cycles may be
activated sequentially in both legs so that a full set of tests for
both legs may take about 7 minutes.
[0078] With respect to a normal patient, during algorithm A, good
venous phasic waves should be detected by the upper air cell, and
lower calf compression does not cause an increase in baseline
pressure as detected by the upper cell, Moreover, with respect to a
normal patient, during algorithm B, good venous phasic waves should
be detected by the upper and the lower air cells, and mid-calf
compression causes good lower-calf emptying, which causes fall in
baseline pressure as detected in the lower air cell and. The
baseline at the upper air cell remains unchanged.
[0079] With respect to a patient having acute proximal deep vein
thrombosis, during algorithm A, there is an obliteration of venous
phasic waves in the upper-calf, as well as baseline elevation
secondary to lower-calf compression. Moreover, with respect to a
patient having acute proximal deep vein thrombosis, during
algorithm B, there is an obliteration of venous phasic waves in the
upper-calf, as well as baseline elevation secondary to mid-calf
compression. The lower air cell detects only minor decrease in
baseline pressure, if at all, with no venous phasic waves.
[0080] With respect to a patient having acute distal (mid-calf)
deep vein thrombosis, during algorithm A, there are good venous
phasic waves in the upper-calf, without baseline elevation
secondary to lower-calf compression. Moreover, with respect to a
patient having acute distal (mid-calf) deep vein thrombosis, during
algorithm B, there are good venous phasic waves in the upper calf
and absence of venous phasic waves in the lower calf. Compression
of the mid-calf has only minor effects on baseline pressures in
both the upper and lower air cells.
[0081] With respect to a patient having post deep vein thrombosis
syndrome (chronic obstruction with collateral circulation), during
algorithm A, there are larger than normal venous phasic waves in
the upper-calf, with baseline elevation secondary to lower-calf
compression. Moreover, with respect to a patient having post deep
vein thrombosis syndrome (chronic obstruction with collateral
circulation), during algorithm B, there are larger than normal
venous phasic waves, as well as baseline elevation secondary to
mid-calf compression in the upper air cell. The lower air cell
detects only minor decrease in baseline pressure, if at all, with
larger than normal venous phasic waves.
[0082] In summary, the described systems enable the addition of
diagnostic capabilities in addition to the compression therapy.
Moreover, the described systems can be utilized with other deep
vein thrombosis diagnostic approaches, Furthermore, the described
systems are directed to a compression system for applying
therapeutic pressure to a limb of a body and enabling diagnostic
capabilities that includes a pressure sleeve; a compression system
console, pneumatically connected to the pressure sleeve, having a
controller and compressor to provide controlled pressurized fluid
to the pressure sleeve.
[0083] The compression console system may be portable, battery
operated with a rechargeable battery. The compression system may
indicate an appropriate inflation and deflation sequence.
[0084] A system for diagnosing deep vein thrombosis in a body limb
may include a compression system for applying external pressure to
a body limb and a venous phasic flow monitoring system to monitor a
venous phasic flow in a body limb. The venous phasic flow
monitoring system determines a presence of deep vein thrombosis in
the body limb by detecting a change in a volume of the body limb.
The compression system may include a pressure sleeve to apply
external pressure to the body limb, the pressure sleeve having a
fillable cell and being configurable to be placed around a body
limb. The compression system may further include a source to fill
the fillable cell,
[0085] The source may pneumatically fill the fillable cell. The
venous phasic flow monitoring system may determine a presence of
deep vein thrombosis in the body limb having the pressure sleeve
therearound based upon detecting a pressure change in the fillable
cell. The pressure sleeve may include a plurality of individually
fillable cells and the source fills each fillable cell
individually. The source may fill a first individually fillable
cell of the pressure sleeve to a predetermined pressure. The source
may fill a second individually fillable cell of the pressure sleeve
while the venous phasic flow monitoring system monitors a pressure
change in the filled first individually fillable cell of the
pressure sleeve. The venous phasic flow monitoring system may
determine a presence of deep vein thrombosis in the body limb
having the pressure sleeve therearound based upon detecting a
pressure change in the filled first individually fillable cell of
the pressure sleeve.
[0086] The first individually fillable cell of the pressure sleeve
may be proximal to the second individually fillable cell of the
pressure sleeve. The first individually fillable cell of the
pressure sleeve may be distal to the second individually fillable
cell of the pressure sleeve.
[0087] The venous phasic flow monitoring system may determine a
presence of deep vein thrombosis in a body limb having the pressure
sleeve therearound based upon substantially no pressure change
being measured by the venous phasic flow monitoring system. The
venous phasic flow monitoring system may determine that the deep
vein thrombosis is located in a body limb having the pressure
sleeve therearound, distal to the second individually fillable
cell, based upon substantially no pressure change being measured by
the venous phasic flow monitoring system. The venous phasic flow
monitoring system may determine an absence of deep vein thrombosis
in a body limb having the pressure sleeve therearound based upon a
pressure decrease being measured by the pressure sensor. The venous
phasic flow monitoring system may determine a presence of deep vein
thrombosis in a body limb having the pressure sleeve therearound
based upon a pressure increase being measured by the venous phasic
flow monitoring system.
[0088] The venous phasic flow monitoring system may determine that
the deep vein thrombosis is located in a body limb having the
pressure sleeve therearound, proximal to the first individually
fillable cell, based upon a pressure increase being measured by the
venous phasic flow monitoring system. The venous phasic flow
monitoring system may determine an absence of deep vein thrombosis
in a body limb having the pressure sleeve therearound based upon
substantially no pressure change being measured by the venous
phasic flow monitoring system.
[0089] The compression system may change a fill time for one of the
plurality of individually fillable cells of the pressure sleeve
based upon the determination of the presence of deep vein
thrombosis in the body limb having the pressure sleeve therearound.
The venous phasic flow monitoring system may monitor a pressure in
the fillable cell to create a history of pressure values. The
venous phasic flow monitoring system may determine a presence of
deep vein thrombosis in the body limb having the pressure sleeve
therearound based upon the history of pressure values for the
fillable cell. The venous phasic flow monitoring system may monitor
a progression of a clot in the body limb having the pressure sleeve
therearound based upon the history of pressure values for the
finable cell. The venous phasic flow monitoring system may monitor
a dissolving of a clot in the body limb having the pressure sleeve
therearound based upon the history of pressure values for the
fillable cell.
[0090] The compression system may apply external pressure to a
second body limb using a second pressure sleeve. The venous phasic
flow monitoring system may monitor a venous phasic flow in the
second body limb. The venous phasic flow monitoring system may
determine a presence of deep vein thrombosis in the first body limb
having the pressure sleeve therearound based upon comparing a
detection of a pressure change in the fillable cell of the pressure
sleeve around the first body limb and a detection of a pressure
change in the fillable cell of the second pressure sleeve around
the second body limb.
[0091] The venous phasic flow monitoring system may detect cyclic
pressure changes within the fillable cell, the cyclic pressure
changes being in correlation with changes in the venous return of
the body limb caused by respiration. The venous phasic flow
monitoring system may determine a presence of deep vein thrombosis
based upon gradual deterioration or disappearance of the cyclic
pressure changes over a predetermined period of time.
[0092] A system for diagnosing and treating deep vein thrombosis in
a body limb may include a compression system for applying external
pressure to a body limb and a venous phasic flow monitoring system
to monitor a venous phasic flow in a body limb. The venous phasic
flow monitoring system may determine a presence of deep vein
thrombosis in the body limb by detecting a change in a volume of
the body limb. The compression system may change a characteristic
of an application of external pressure to the body limb based upon
the presence of deep vein thrombosis in the body limb.
[0093] A method for diagnosing deep vein thrombosis in a body limb
may apply external pressure to a body limb; monitor a venous phasic
flow in a body limb; and determine a presence of deep vein
thrombosis in the body limb by detecting a change in a volume of
the body limb. Furthermore, a method for diagnosing and treating
deep vein thrombosis in a body limb may apply external pressure to
a body limb; monitor a venous phasic flow in a body limb; determine
a presence of deep vein thrombosis in the body limb by detecting a
change in a volume of the body limb; and change a characteristic of
an application of external pressure to the body limb based upon the
presence of deep vein thrombosis in the body limb.
[0094] These various embodiments enable the online 24/7 monitoring
of the progression of deep vein thrombosis (creation or dissolving
of deep vein thrombosis) with the same device that is used online
24/7 for the prevention of deep vein thrombosis. More specifically,
the various embodiments utilize an online 24/7 monitoring of the
venous phasic flow by detecting small pressure changes in one cell
to determine deep vein thrombosis. The pressure changes are
indicative of the venous phasic flow.
[0095] Although the various embodiments have been described in
conjunction with pneumatic pressure (compression), the concepts can
be used with any system for applying external pressure to a body
limb. More specifically, the external pressure may be realized
through a conventional mechanical device which may include a
non-pneumatic mechanical applicator to apply non-pneumatic external
pressure to the body limb.
[0096] The non-pneumatic mechanical applicator can be configurable
to be placed around at least a portion of the body limb. An example
of a non-pneumatic mechanical applicator is a strap which is placed
around at least a portion of the body limb. The strap is then
pulled against the body limb by a mechanical device (such as a
motor with gears and/or cams) to as to apply external pressure to
the body limb. The mechanical device controls the application of
external pressure to the body limb. The external pressure may be
intermittent or constant.
[0097] The conventional non-pneumatic external pressure device may
include a strain gauge or other device to detect a change in a
strain being experienced by the non-pneumatic mechanical
applicator. The detection of a change in a strain being experienced
by the non-pneumatic mechanical applicator (detection of the venous
phasic flow in the body limb) enables the conventional
non-pneumatic external pressure device to determine a presence of
deep vein thrombosis in the body limb.
[0098] Although the various embodiments have been described in
conjunction with a portable compression system console or small
compression system console wherein the source of the pressurized
air is within the console, the concepts can be used with any
compression system wherein the source of pressurized air may be
without the console.
[0099] For example, it is contemplated that the source of the air
pressure for inflation of the pressure sleeves can be located in
the patients bed or be built into the wall of a room. This source
of pressurized air can be directly connected to the pressure
sleeves via proper air conduits (assuming that a pressure control
device that regulates or control the delivery of pressurized air to
the pressure sleeves is associated with the pressurized air source)
or can be connected to the pressure sleeves through a control
device or system that regulates or control the delivery of
pressurized air to the pressure sleeves of the present
invention.
[0100] In other words, a system is contemplated where the source of
pressurized air is integral with the pressure control device or a
system where the source of pressurized air is not integral with the
pressure control device.
[0101] Again as noted above, the concepts have been described with
respect to use on a leg of an individual. However, it is to be
understood that the concepts are also extended to use on any body
limb such as an arm, a foot, a part of a leg, arm, or foot, and may
be used on two or more limbs simultaneously. Moreover, although the
concepts have been described in conjunction with a portable
pneumatic compression system console or small pneumatic compression
system console wherein the medium used to provide compression is
realized by pressurized air, the concepts can be used with any
compression system wherein the medium used to provide compression
can be realized by a liquid, fluid, gas, or other mechanical
means.
[0102] While various examples and embodiments have been shown and
described, it will be appreciated by those skilled in the art that
the spirit and scope of the embodiments are not limited to the
specific description and drawings herein.
* * * * *