JPS586502B2 - Gaiatsujiyunkanenjiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an external pressure circulatory assist device of the type that uses an electrocardiogram to facilitate synchronization of heart beats and pressure pulses.

Atraumatic methods of helping blood circulation in patients are already known in the art.

According to Dennis, US Pat. No. 3,308,841, applying external pressure to the lower part of the body squeezes out more blood than the heart pumps in one heartbeat.

This squeezed blood is forced back into the aorta and the larger ductus arteriosus, thereby reducing the strain on the ventricles while maintaining good blood filling during ventricular expansion.

This general process is detailed in "Synchronized Circulatory Assist Method" by Bartwell et al., published in the Journal of the Canadian Medical Association, September 24, 1966, Vol. 95, pp. 652-664.

In general, the synchronous external pressure assistance method is clearer and superior to the existing contralateral pressure assistance method.

The reason is that in the latter case, cannulation of the aorta,
Problems include the use of special bodily blood processing equipment, the use of less useful techniques, and the need to provide anticoagulants to the patient.

Furthermore, the bleeding trauma and hemolysis created by special body pump devices limits the allowable assistance time and worsens the patient's condition.

Finally, such traumatic methods are not only time consuming, but can pose a very serious risk to many patients, increasing the risk factor when treating all patients.

Accordingly, one object of the present invention is to provide an improved external pressure circulatory aid device that is easily and safely applied and used by moderately skilled hospital personnel and those unfamiliar with such devices. be.

The above objects were achieved by creating an external pressure circulation assist device having one or more of the following advanced technologies.

A. Water Filling Device A water filling device is used to fill a bag surrounding the foot with an amount of water appropriate for a particular patient.

A suitable amount refers to a specific amount appropriate to the size and shape of the individual patient's foot.

It has also been determined that the patient's foot may change its effective size during processing due to patient movement in and out of the machine.

In other words, the water filling device not only fills water appropriately;
It is also used to automatically drain water from the bags that surround the feet.

It is also used to moderate water during treatment, thereby maintaining an effective hydraulic connection between the mechanical pressure inducing device described below and the patient's foot.

During a filling operation, a pressure sensor placed between the shell surrounding the bag and the bag itself detects the pressure within the bag.

When the filling pressure reaches a predetermined amount (usually about 25 mmHg), the filling operation is terminated by stopping the filling pump.

This filling action is normally performed by a reciprocating member in an upper position, ie in a position compressing the bag.

Once operation of the device begins, a level detector adjusted by the reciprocating member positions the reciprocating member at the top position of each upward stroke.

If this position is incorrect, water is pumped into and out of the bag until the reciprocating member is again in the correct position.

B. Mechanical pressurization device In order to obtain an appropriate pair of pulses, a bag encasing the foot applies positive pressure to the foot during diastole, and removes that pressure or applies negative pressure (e.g. -50 mmHg) to the foot during systole. It must be possible to create.

The amount of positive pressure applied is approximately 150 to 250 m at all times.
mHg.

It is most convenient to obtain this pressure difference by applying the reciprocating member to a fairly large surface of the tabi that encloses the liquid.

This reciprocating member is mounted under the bag for reciprocating vertical movement that adjusts the magnitude of the positive pressure.

The pressure in the bag increases as the reciprocating member rises relative to it and decreases to a minimum (usually about 25 mmHg) as the reciprocating member descends to a lower level (or to a minimum if negative pressure is used). becomes low.

). If the negative pressure capabilities of the present invention are used, the reciprocating member, the bag and the patient's body are partially evacuated into a bag that is evacuated to a negative pressure of, for example, 70 mm Hg below atmospheric pressure.
It covers you from the waist down.

The bag is preferably of flexible material and is held away from the foot by the rest of the device so that a low pressure zone of negative pressure is maintained.

The bag or suction bladder is snugly fitted to the patient's body with a waistband and sealed appropriately at the waist.

The device described above has a normal operating cycle ranging from -50 mmHg to +250 mmHg.

In operation, the pressure is cycled with lower pressures of the cycle coinciding with the systolic aspect of the heart's work and higher pressures coinciding with the heart's diastole.

A tabi, a comfortable single-chamber blanket, is placed around the patient's foot, and a rigid casing is used to encase both the foot and the mechanical pressure transmitting reciprocating member.

The bladder is then filled with water until it is filled all around the foot and over the reciprocating member, such that the bladder is in contact with substantially the entire surface of the foot and is fully inflated at the ankle and hip ends. Ru.

From this point, the vertical reciprocating member of the reciprocating member
Apply a negative pressure cycle.

C. In order to control the pulsation of the pressurized waveform controller, the pressure applied to the patient's foot must be varied according to the desired waveform.

The device of the present invention has advantageous features whereby foot pressure is monitored and a feedback signal source is created which is directly compared to a signal representative of the waveform required for a particular patient.

The difference between the signal obtained from the actual waveform and the signal representing the desired waveform is called the "error signal."

This error signal is amplified and used to adjust an electric servo valve that regulates the flow of hydraulic fluid to a hydraulic cylinder that drives a vertically reciprocating member.

This flow is constantly adjusted in proportion to the error signal so that the transducer pressure waveform more closely resembles the desired waveform.

Paw pressure monitoring is conveniently performed by a water bladder measuring approximately 10 cm x 10 cm x 1.2 cm, which is placed between the shell surrounding the bladder and the bladder itself.

The water in this sensing bag is connected through a short tube to a pressure transducer that produces the desired electrical signal of the actual pressure waveform.

One advantage of this waveform control device is that it ensures that important characteristics of the desired waveform (e.g. duration, rise time, and fall time) are not compromised when applied to a patient's foot. .

This is despite variations in the hydraulic coupling between the reciprocating member and the foot caused by different patient-to-patient foot contours, sizes, and stiffnesses, and also due to deformation of the foot casing and dynamic stretching of the bladder during movement. achieved regardless.

Cardiac and pressure cycle phasing It has been found that when the heart experiences inappropriate timing of the onset of externally assisted pressure waves with respect to its beating cycle, deleterious physiological effects occur.

Furthermore, although this phenomenon is easily understood by the user, it is desirable for the user to avoid mistakes and to simplify the operation of the device by using a simple and accurate automatic phasing device.

In the present invention, a suitable visually monitored phasing control device is provided,
The arterial waveform is thereby displayed along with the ECG waveform on a multi-channel oscilloscope or other suitable display device.

Arterial pressure waveforms are measured at any convenient location in the body.

Typically, the most convenient location for an arterial wave pressure sensing device is the wrist.

ECG signals are often obtained by a detector placed directly on the torso near the heart.

In this application, it is important to know that it takes about 80 ms for the pressure wave guided to the thigh artery to reach the root of the aorta.

Continuous transmission from the root of the aorta to the wrist, where the arterial waveform is obtained as a standard, takes another 90 ms.

The important thing is that the artificially induced positive pressure wave is created in the legs well before diastole and that the pressure wave reaches the root of the aorta at the onset of diastole.

Therefore, the onset of the diastolic waveform seen at the wrist occurs a total of 170 ms after pressure is applied to the patient's foot.

That is, in the illustrative situation, 170 ms before the arterial waves, such as those seen at the wrist, indicate the onset of heart diastole.
and 80ms before the ECG signal indicates the start of cardiac diastole.
It is desirable to have the induced pressure wave initiated by a command signal that is timed to begin beforehand.

The onset of cardiac diastole occurs at the so-called "duplex notch" (described later), which approximates the end of the so-called "T wave," which is known to clearly indicate left ventricular relaxation and the end of cardiac contraction.
) is indicated by the arterial wave.

In this phasing device, the foot pressurization signal is used to brighten the ECG and the arterial traces that appear on the oscilloscope after this pressurization are displayed for 80 ms and 170 ms, respectively.

This device allows the user to adjust the delay time until the brightness enhancement signal of the ECG or arterial waveform is placed at the beginning of heart diastole.

In that regard, foot pressurization can be triggered in proper synchronization with the cardiac cycle.

It has been found particularly desirable to have a synchronizer that is more versatile, i.e., that is not subject to the expected fixed delay between an aortic event and an event previously detected at the detection site.

This is done by adjusting the synchronization of the controller and the external circulatory aid device, thereby achieving an optimal relationship between a certain aortic event (usually the "R" wave of the ECG curve) and the triggering of the circulatory aid pressure. The time is a visual mobile indicator that is moved during the setting of the time variable through a time range that can compensate for the time difference between the aortic phenomenon and its expression at any arterial wave detection location selected during the procedure. Accurately obtained by the device.

The visual marker is preferably electronic and is manually moved along the visible trace on the oscilloscope until the marker is placed at an easily recognized point on the curve (eg, indicating the onset of cardiac contraction).

D. Foot Wrapping Unit A new foot wrapping unit is used whose light weight and profile provide an effective casing for pressurizing the foot, yet can be conveniently and quickly applied to the patient.

E. Reciprocating Member Drive Mechanism A new mechanical ring arrangement is provided to couple the reciprocating member to the drive hydraulic cylinder, thereby providing suitable pressure displacement characteristics on the reciprocating member for pressurizing the bag, while at the same time providing a particularly Desirable dissipation of stress and improved control of pulsation cycles are obtained when the is operated at subatmospheric pressure.

From FIGS. 1 and 2, it can be seen that the leg 20 is a non-compressible liquid such as water 23.
It is placed in a blanket-like bag 22 filled with water.

The bladder 22 completely encloses the foot 20 and is slid into a durable casing 24 comprised of an upper shell 26 and a lower shell 28.

Immediately below the bag 22, a reciprocating member 30, also within the casing 24, is mounted for reciprocating vertical motion conveyed by a mechanical linkage 32.

This linkage is driven by a hydraulic cylinder, as best seen in Figure 5C.

Pressure sensitive transducer (detector) 34 (4th A
(see figure) is placed in the hydraulic passageway to the bag and is used to monitor the pressure inside it.

The special features of this transducer are explained below.

FIG. 2 shows how the enclosure 36 encloses the casing 24.

Enclosure 36 and casing 24 are cut open to indicate the relative position of reciprocating member 30.

The enclosure extends beyond the casing 24 and extends around the waist 3 of the patient 40.
It can be seen that it is designed to be slid into place at 8.

The suction pump 39 is constantly used to maintain a normal environment within the enclosure 36 at subatmospheric pressure.

There are some cyclic fading problems that are solved by the use of the present invention.

If pressure is applied to the patient's legs from above the bladder 22, such pressure will reach the heart and cause the ECG placed on the patient's chest to
By the time it synchronizes with your heartbeat, as monitored by the device,
It should normally take about 80 milliseconds (ms).

It takes another 90 ms for the pressure effects originating in the foot to reach the radial artery, where it is monitored by a detection device placed above it.

FIG. 3 is a diagram showing a graph of time phenomena related to the operation of the device.

In one trace, an ECG curve 402 is shown in real time relative to a normal heart cycle of 840 ms.

In this trace, the beginning of cardiac diastole is typically represented by the beginning of the curve's descent at 403.

This drop at 403 corresponds to the rise 40 of the foot pressure curve 404.
Occurs approximately 80ms after 5.

This means that the pressure waves induced by the device of the present invention are approximately 80
This is to ensure that it reaches the heart at the start of cardiac expansion after a time delay of ms.

Curve 407 is the curve of radial artery pressure measured at the lumbar region.

The onset of diastole in pressure curve 407 is represented by the so-called dicrotic notch 409, which occurs approximately 90 ms after the ECG signals diastole.

ECG curve 402 is characterized by having an R wave 415 and a T wave 420 (Figure 3A).

R waves 415 are also referred to as QRS.

The onset of cardiac contraction begins at 399, approximately 40 ms after the crest of the R wave 415 appears.

As can be seen with reference to Figure 3A, with respect to the ECG curve shown as channel 1, the one shown as channel 2 has a phase lag depending on the location of the measurement, such as the curves shown as 1 and 2.3, respectively. comes out.

These phase-delayed arterial waveforms form the so-called double beat notch 40.
9, which indicates the start of heart expansion.

For convenience, the device is typically triggered by detecting the R-wave 415 of the ECG.

From FIGS. 4A and 4B, one advantageous method of using the above-mentioned phenomena for fading and controlling a device is shown in a persistence diagram, which will be described in more detail below.

A transducer-type pressure detector 34 including a sensing bladder 35 is used to detect water pressure within the bladder 22.

If the pressure thus detected is less than 20 mm of mercury, the pressure level amplifier 46
8.

During this low pressure signal situation, when the user presses the water fill switch 50
, a signal is sent by the AND gate 48 which operates the fill pump 52 through the pump control circuit 54 and simultaneously closes the multi-position solenoid valve 56.
is moved to its filling position, i.e. from conduit 58 to conduit 6.
The position is such that water flows to zero.

As a result, the water reaches a pressure of 20 mmHg at the pressure sensor 3.
4 into the bag 22 until it is detected by 4.

The signal from amplifier 46 then drops to AND gate 4
8 is closed.

Fill pump 52 is thereby deactivated and solenoid valve 56 is moved to the off position.

Using a similar device, pressure is detected by detector 62 and the water in bag 22 is drained.

In normal operating mode, the detected pressure is -15mmH
If the value of g is greater than the value of g, the signal is
sent to.

When the drain switch 66 is closed, the gate 64 sends a signal to the pump controller 68 and the drain pump.
69 , the solenoid valve 56 is moved to a discharge position, so as to allow water to flow from conduit 60 to conduit 70 .

Pump 69 evacuates until a pressure less than -15 mmHg is detected.

At that time, AND gate 64 no longer detects the desired signal by detector 62, pump 69 is stopped, and valve 56 returns to the off position.

The filling and emptying operations described above are generally used at the beginning and end of use and are not used as a continuous control device.

However, it is advantageous to be able to fill the bag with water up to a certain predetermined pressure by means of an automatic device without relying on discriminating means.

During operation of the device, the pressure within the sensing bag 34 is maintained at the desired level by adding or subtracting water to the bag as follows.

A position sensing transducer 76 is mounted above the hydraulically actuated rod cylinder arrangement 78.

Transducer 76 is adapted to produce an electrical signal output that is proportional to the linear position of device 78 at any given moment.

The normalized value of the position of the rod cylinder device 78 is:
It is obtained by feeding the signal from transducer 76 to level detector 80.

The normalized signal is therefore provided to level comparator 82.

The second input of comparator 82 is derived as follows.

The ECG signal from the patient being treated is sent to the ECG device 10.
2 to the trigger generator 84.

Trigger generator 84 is selected to recognize and respond to the so-called QRS or R wave of the ECG signal.

That is, as the QRS rise occurs periodically with each heartbeat, an output is triggered to the manually controlled variable delay device 86.

The purpose of variable delay device 86 is to transform the original signal from first trigger generator 84 into a second time-delayed signal that corresponds in real time to the onset of cardiac diastole.

This second signal enters a pressure sustaining signal generator 88.

The generator 88 receives a signal from the foot pressurization (detection bag 35
(such as that caused by the pressure of

The signal from this generator 88 is passed through a level strobe signal generator 89 to a level comparator 82.

The signal from generator 88 is also sent to waveform generator 90, which produces a waveform having an amplitude and frequency similar to that required for the foot pressurization sequence.

The standard waveform is 60ms rise and 250ms
It has a ladder shape with a flat upper part and a drop of 60ms.

The waveform from this generator 90 is sent to a waveform comparator 92,
Here it is continuously compared to the signal obtained from the actual bladder pressure wave received by the detector 34.

The output of comparator 92 is a so-called "error signal", that is, a signal representative of the quality and strength of the difference between the desired waveform signal from generator 90 and the actual waveform from detector 34.

The error signal is used to control a servo valve 94 through a servo amplifier 93, thereby controlling the liquid supply to the rod cylinder device 78, and thus the device 78.
control the movement of

As mentioned above, the level comparator 82 receives two signals, one being a periodic signal from the pressure sustaining signal generator 88 to the strobe signal generator 89, and the other being a periodic signal from the level detector 8.
It is a signal from 0.

Level comparator 82 compares the two signals, one representing the actual position of device 78 at a given time.

The other is a periodic signal from pressure sustaining signal generator 88 modified by level strobe signal generator 89, or a "strobe" signal.

This comparison is most useful when the reciprocating member 30 is at the top of its travel and pushing firmly against the bag 22.

When the level comparator 82 detects that the reciprocating member 30 is too high, the output is provided to a "one shot" (monostable multivibrator) 96.

This one shot 96 then turns on position solenoid valve 56 and fill pump 52 for a fill period of 0.5 seconds.

The 0.5 second fill period lasts for each cardiac cycle (i.e., each heartbeat) until the amount of water in the bladder 22 is sufficient such that the reciprocating member 30 is within the allowable displacement range at the top of its stroke. )
Continues inside.

On the other hand, if a signal is received by the level comparator 82 indicating that the reciprocating member 30 is too low in its stroke, the evacuation pump 69 is activated by the "one shot" device 98.
is turned on for 1/2 second each cardiac cycle.

Water is then pumped out of the bag until the reciprocating member reaches the desired height in its stroke.

The general operation of this device is as described above.

Here's how to get your movements to properly synchronize with your heartbeat.

The signal from the arterial pressure detection device 99 is transmitted to the ECG device 102.
Dual trace oscilloscope 1 with signal from
01.

It is during the presence of the pressure command signal received from the pressure sustain signal generator 88 that the intensity of these signals increases.

90ms delay device 108 and 80ms delay device 110
, the pressure command signal appears in both waveforms in approximately exact time relationship with respect to the actual ECG and arterial pressure.

A delay device 86 is adapted to vary D1 as shown in FIG. 3 and is used to align the intensity increase signal with diastole as seen in an ECG or arterial trace;
The pressurization wave is thereby phased with the cardiac cycle.

The user of the device may also use a variable control device to vary the characteristics of the pressure sustaining signal generator 88 to sustain the pressure command signal required for a particular patient.

On the oscilloscope 101, this pressure sustaining signal is shown as a brightness increase 103 in the oscilloscope trace.

It is observed for waveform generator 90 that a typical generated wave always has a positive pressure period of about 250-300 ms total.

The rise and fall of pressure takes approximately 60ms, with the rise beginning approximately 80ms before cardiac diastole.

Generally, it is desirable to choose a period determining device that can maintain a positive pressure period of approximately 150-500 ms.

FIG. 4C is an alternative to FIG. 4B and illustrates an embodiment of the present invention for use with a particularly advantageous control system as described below.

The above-mentioned control device is based on the premise that a specific arterial detection part, such as the wrist, is selected in advance and operated optimally.
Its optimal operation is about 90ms from the normal ECG cycle.
This refers to the case where the phase is out of phase.

The aforementioned 90ms between ECG and wrist detection
To avoid the need for preselection of a given delay like
A device according to the invention is used.

The signal from the ECG device 102 is transmitted to a trigger generator 84;
It is fed through a delay device 86 and a pressure duration signal generator 88 to an 80 ms delay device 110 as previously described.

Output from delay device 110, that is, pressure duration time D4
is delayed from the R wave by a time D1 (carried by delay device 86) plus 80 ms.

This pulse is used to obtain an increase in brightness of the ECG curve (channel 1).

This pulse is also supplied to a variable delay device 112, which outputs a signal at times D1 and 8.
It is delayed from the R wave by the sum of 0ms and D2.

Here D2 is a variable delay created by variable delay device 112.

By the way, the trigger signal from the trigger generator 84 is 4
A 0 ms delay device 114 is provided, and the output of delay device 114 is provided to a variable delay device 116.

The output from variable delay device 116 is output to marker generator 118.
This marker generator 118 is supplied to D2 and 4.
A marker pulse is generated that is delayed from the R wave by the sum of 0 ms.

Here D2 is the variable delay delivered by variable delay device 116.

The signals from marker generator 118 and delay device 112 are
A pulse mixer 120 is fed and the combined signal is fed to the channel 2 trace of the oscilloscope (the channel representing the arterial waveform).

In operation, marker pip originating from the generator 118 and shown alternately as 414, 415, or 416 in FIG. is moved to the position where cardiac contraction begins.

This position is where the arterial trace begins to rise rapidly.

The marker pip can be moved using marker position controller 122 over a range equal to the D2 variable delay time provided simultaneously by delay devices 112 and 116.

As the marker pip is so moved, the brightness increasing trace produced by the pressure duration signal generator 88 and representing external pressure assistance (which may also be referred to as the second marker pip) is D1+40ms (=
D3) is delayed.

In use, the operator of the device first views the arterial trace 106 and adjusts the marker position control 122 to move the marker pip to a predetermined position indicating the onset of cardiac contraction.

This time is equal to the delay D2 provided by variable delay device 116 plus 40 ms.

Delay device 86 then applies a delay D1 by adjusting delay control 124 to bring the brightness increase trace into phase with double beat notch 409, thereby moving the brightness gain trace from the marker pip to FIG. 3A. So D3
Set the interval as shown.

Finally, D4 is set by adjusting the pressure duration signal generator 88 to the duration control device 126, and the pressure duration signal generator 88 is set to 411 in FIG. 3A.
, 412 and 413.

This allows the pressurization wave to be phased with the heart cycle.

As seen in FIGS. 5A-5C, the mechanical actuator 510 includes a reciprocating member 512 that is pivotally mounted at one end at 514 and connected to a mechanical linkage 516 at the other end.

This reciprocating member 512 is attached to the frame 522 of the machine at 52
Hydraulic cylinder 518 supported for pivoting at 0
operated by.

The other end of the cylinder 518 is also fixed to the operating shaft 528 of the link device 516 by a bolt 524 and a yoke 526.

The operating shaft 528 further includes two generally triangular cam bearings 5.
30.

Cam 530 is mounted for pivoting about axis 532.

Thus, when the plunger 534 of the hydraulic cylinder 518 applies a force to the operating shaft 528, the triangular cam is caused to rotate clockwise about the shaft 532.

This causes arm 538 of cam 530 to be lifted.

At the same time, lever arms 53 are mounted for pivotal rotation relative to cam bearings 530 on each side of reciprocating member 512.
9 is adapted to lift the reciprocating member 512.

The surface of reciprocating member 512 has been partially removed from FIG. 5A so that a diaphragm or bellows 541 can be seen attached between frame 522 and reciprocating member 512.

The lower portion of bellows 541 is attached to flange 544 seen in FIG. 5A.

Flange 544 is the top of bellows support structure 543 that is attached to bottom plate 546 and together with bellows 541 constitutes a device that occupies most of the volume between the bottom of bottom plate 546 and plate 512, thereby providing a linkage device. 516
A housing is constructed for the

A seal 547 is provided around the opening through which cylinder 518 passes through bellows mount 543.

An outlet for the gas leaving the bellows is provided by an exhaust passage 550.

In operation, member 512 pivots up about 514 as plunger 534 is caused to rest against operating rod 528, thereby causing triangular cam 530 to rotate clockwise.

Air is then drawn into the bellows 541 from the atmosphere.

Conversely, when the reciprocating member is pulled down by retraction of the plunger and the volume occupied by bellows 541 is compressed, air is expelled from exhaust passage 550.

Improved control is achieved with this method, especially when the equipment is operated at subatmospheric pressure, i.e., when the equipment is enclosed in a bag, such as that shown at 557 in Figure 1, where the vacuum is partially removed. It is.

Additionally, the linkage has also been found to be particularly advantageous because it minimizes stress on the inside of the foot housing 554, as seen in FIG.

In order to understand the advantages of the special construction of the linking arrangement shown here, reference should be made to the arrangement of FIGS. 5A, 5B and 1.

Of course, any significant deflection of foot unit housing 554 by bladder 552 must be avoided.

If housing 554 is not rigid, its expansion will make desirable control of the pulse cycle difficult or impossible.

As can be seen, the operation of the mechanical actuation unit is ideally such that it minimizes expansion forces on the housing 554.

For example, when the reciprocating member is directed upward by the action of a hydraulic cylinder and a mechanical linkage, a force 560 is applied to the reciprocating member mechanism itself and thus to the foot unit holding the mechanism.

With the mechanical actuation system of the present invention, the bottom plate 546 is much lighter because it can only withstand the tensile strength provided by vector 560 shown in FIG. 5B, for example.

These forces place the bottom plate 546 in tension, but do not subject it to any significant bending stress.

Additionally, when the two parts of the foot unit are held together by quick disconnect bolts screwed into rods 556 and 558 as shown in FIG. 6 and seen in FIG. 5B, the upper segment of the foot unit Any normal force that tries to separate the lower segment is caused by the rod 556
and is recorded as the tensile stress at 558.

Again, there is no moment attempting to impart vertical bending motion at points 564 or 566.

The foot portion of the housing 554 is adapted to dissipate stresses in its circular structure as a circular stress distribution, thereby substantially eliminating any strain due to said stresses.

As a result of the relative lack of bending moments and said force distribution in the structure of the invention, the housing unit can be made of much lighter materials than before.

As shown in FIG. 2, a rigid housing or casing 24 is used to enclose the bag and its mechanical pressurization device.

This casing must be as light as possible without compromising its stiffness.

As seen in FIG. 6, the leg casing 24 has one upper shell 131 and one lower shell 132.

The shell is conveniently made of a plastic material and internally reinforced with a hard, low density, organic resin foam, such as Polyurethane Home 134.

A particular advantage of casing 24 is that it is a quick connect and quick disconnect device.

A bolt connector 136, which is generally mounted between the foot chambers 135, consists of a bolt that is permanently located within the upper shell 131.

The bolt has a large head to facilitate quick connection by threading into the lower shell 132.

The latch connectors mounted along the outer peripheries of the lower and upper shells have pins 140 that are attached to pins 140 when the connector member 144 is moved downwardly.
0 and is placed over the connector member 142 such that once lowered it locks into the aperture 146 of the pin member 144 by lateral movement of the top shell.

Once this latching action is achieved, bolt 136
can be tightened and the operation can proceed.

Another important aspect of the invention is that it can combine a relatively simple structure with only one liquid bag, an upper casing member and a lower casing member, yet provides a device suitable for excellent pressure control. It is possible to do this.

This was achieved by providing one upper foot casing member 131 and one lower foot casing member 132, each having two truncated semi-conical foot receiving chambers 135.

These chambers are connected by a thinner band (see Figure 1), which allows one blanket-like bag to be wrapped around the patient's foot.

To avoid any significant deflection by the bag (e.g. deflection of more than about 1.5 mm at the midpoint of pressure), a triangular reinforcement is provided between the foot enveloping chamber and the casing member, connecting them together. It turned out that there was a need.

This method allows the reinforcement to be made from a lightweight plastic material, such as polyester reinforced with fiberglass.

The band surrounding the foot itself tends to withstand considerable deflection and deformation because its conical shape resists circularly distributed stresses.

The connector 136 of FIG.
is connected to the lower reinforcing portion 152.

The upper reinforcement portion is made of resin-type honeycomb material 154.

The necessary electrical and hydraulic connections are made through the enclosure 36 and casing 24, as required.

In an illustrative embodiment of the invention, the surface area of the reciprocating member is approximately 600 cm2 and its stroke is approximately 5 cm.

This device has a displacement capacity of approximately 3000 cm3, which is perfectly suited to the displacement requirements arising from the compressibility of the patient's foot, and when combined with a pressure wave monitoring and control device as described above, certain limited Grooving materials with expansive properties can be used.

Generally, the reciprocating member and its actuator will have a minimum of about 150
It should be chosen to have a discharge capacity of 0 cm3.

The vertical stroke of the reciprocating member is conveniently kept below about 9 cm to avoid excessive speeds and associated design control problems with mechanical and hydraulic inertia.

[Brief explanation of drawings]

FIG. 1 is a detailed sectional view of the device of the present invention for placement on a patient's foot; FIG. 2 is a plan view of the foot wrapping device cut open to show the position of the reciprocating member; FIG. 3 is a plan view of the device of the present invention; is a chart showing the relative timing of physiological events with respect to the explanation of
Figure 3A is similar to the curves that would appear on a two-channel oscilloscope, including the electrocardiogram curve and several alternative curves representing the heartbeat as expressed by pressure in the central aorta, radial artery, or fingers. FIG. 4A and FIG. 4B collectively constitute a connection diagram of a unique control device used in the external pressure circulation support device, and FIG. 4C shows a connection diagram of an alternative device to the device shown in FIG. 4B. Figure 5A
5B is a plan view of a mechanical actuator made in accordance with the present invention with the upper bearing portion removed to better show the components of the device, and FIG. 5B is shown in FIG. 5A with the device in the upward or extended position. FIG. 5C is a side elevation view of the device shown in FIG. 5B with the device in a retracted position, and FIG. 6 is a side elevation view of the device shown in FIG. FIG. 3 is a perspective view of the device for quick connection of the casing; 20...foot, 22...bag, 23...
...Water, 24...Casing, 26...
...Upper member, 28...Lower member, 30...
...Reciprocating member, 34...Detector, 36...
... Enclosure, 39... Suction pump.

Claims (1)

[Claims] 1. Device 22, 3 for pressurizing a part of a patient's body.
0.78; and a synchronizer for synchronizing the operation of said pressurization device 22, 30.78 on a portion of the human body with the cardiac cycle of the patient being treated; and for generating an arterial waveform signal representative of said cardiac cycle. a display device 10 for displaying and monitoring the arterial waveform signal showing the double beat notch portion 409 in the form of a visible trace;
1, wherein the synchronizer comprises: a visual trace 10 representative of the arterial waveform signal obtained from the patient;
A first marker is displayed on the display device 101 that displays 6.
Device 102, 84, 86, 110, 114, 112 providing pip 414 and second marker pip 411
, 116, 118, 120; adjusting the position of the first marker pip 414 relative to the visible trace 106 along the visible trace 106 and moving it to a characteristic and verifiable position of the arterial waveform; At the same time as adjusting the first marker pip 414, the second marker pip 411 is adjusted to the first marker pip 414.
a marker position control device 122 for moving the second marker pip 411 along the visible trace 106 a fixed distance away from the second marker pip 414; Delay control device 12
4, the marker position control device 122 and the delay control device 1
24 synchronizes the patient's cardiac cycle and the start of pressurization of the patient's body by adjusting the time between the two. 2. The apparatus of claim 1, wherein the apparatus for providing the first marker pip 414 comprises:
a device 102 for forming an ECG signal, a trigger generator 84 for generating a trigger signal with the ECG signal, a variable delay device 116 for delaying the trigger signal, a marker generator 118, and the first marker pip 414. a second marker, which is a signal representative of the onset of pressure applied to the patient by said pressurization device 22, 30.70;
Pulse mixer 120 for combining with pip 411 signal
A device comprising: 3. The apparatus of claim 2, wherein the variable delay device 116 measures the amount of time elapsed from the diastole phase in the patient's cardiac cycle to the time the diastole phase is recorded at the distal end of the patient's finger. Apparatus characterized in that it provides a delay time that is variable by a time difference that is at least equal to . 4. The apparatus of claim 1, wherein the marker position controller 122 controls the diastole phase of the patient's heart cycle to the time when the diastole phase is recorded at the distal end of the patient's finger. Apparatus according to claim 1, wherein said marker pip is adjusted over a portion of a waveform whose length is equal to the time at which said marker pip is adjusted. 5. An external pressure circulation support device for applying external pressure support to a patient's limbs in cyclic synchronization with the patient's heartbeat, comprising: a device for generating a pressure command signal; and a device for generating a pressure command signal; a device for transmitting pressure through a hydraulic cylinder to the limb via a pressurization device of a fluid-filled bladder surrounding the limb in response to a device for activating the heart; a display device for displaying and monitoring said arterial waveform signal in the form of a visible trace, and for generating an ideal pressure waveform. a device 90, a detector 34 for sensing the actual pressure waveform of the limb, a waveform comparator 92 for continuously comparing the ideal pressure waveform and the actual pressure waveform, and a signal from the comparator 92; a servo that responsively modifies the flow of fluid to the hydraulic cylinder 78, thereby transmitting pressure through the fluid-filled bladder 22 to the limb to more closely achieve the ideal pressure waveform at the limb; In an apparatus comprising: a device for providing marker pip 414 on a display device 101 for displaying a visible trace 106 representative of said arterial waveform obtained from a patient; Pressure sustain generator 8 for forming trace 411
8, adjusting the position of the marker pip 414 to a characteristic and recognizable shape of the arterial waveform, and simultaneously moving the marker pip 414 a certain distance away from the marker pip 414. The highlighted trace 41 along the visible trace 106
Marker position control device 1 that adjusts to move 1.
22, a variable delay device 86 for aligning the enhanced trace 411 with the double beat notch portion 409 on the visible trace 106, and a device 90 for causing the pressure duration generator 88 to generate the ideal pressure waveform. and controlling the patient's heartbeat to cyclically synchronize the command signal with the patient's heartbeat. 6. In the device according to claim 5, the ECG
a multi-channel oscilloscope 101 adapted to display a trace 104 and a trace 106 obtained from an arterial pressure sensor; and a device 88 for visibly displaying the relative durations of pressure command signals on said traces 104, 106. and a device 124 for adjusting the relative timing and duration of the pressure command signal, while visually adjusting the pressure command to a desired correlation to the ECG trace 104. 122.