US3533408A - Extra-corporeal blood circulation - Google Patents

Description

United States Patent i 13,s33,40s

[72} Inventor Jean-Marc Paoli 16 Traverse de Pomeques Le Chateau, Marseille, France [21] Appl. No. 539,261 [22] Filed March 30, 1966 [45] Patented Oct. 13, 1970 [32] Priority March 31, 1965 [33] France [31 20,948

Pat. 1,451,277

[54] EXTRA-CORPOREAL BLOOD CIRCULATION 5 Claims, 8 Drawing Figs.

[52] U.S.Cl 128/214, 23/2585 [51] 1nt.Cl A61m 5/00 [50] Field ofSearch 128/214, 214.2, 1 H-L Digest: 23/2585: l37/(lnquired): l03/(lnquired) [56] References Cited UNITED STATES PATENTS 2,927,582 3/1960 Berkman et al 23/2585 3,142,296 7/1964 Love 23/2585 OTHER REFERENCES Surgery, vol. 45 #2 2/59. pp. 288-291 (Dickson et a1.) l28/H-L. Dig.

Murphy-Amer. Soc. Art. Inter. Organs, 1961, vol. 7 pp. 361-68, l28/H-L. Dig.

Primary E.talniner-Dalt0n L. Truluck Attorney-William Anthony Drucker ABSTRACT: In an extra-corporeal blood circulating system synchronised with the cardiac cycle, an electronic unit including a multitrack electrocardiograph receiving an R wave from a patient and converting said wave into a QRS output signal; an arterial line and a venous line, a return reservoir connected to said lines; a continuous delivery pump con nected in said arterial line; a shunt connecting said arterial line to said reservoir for branching off said pump at the moment of cardiac systole, a valve for opening and closing said shunt; a control system for governing said valve, said control system including a piston means responsive to said output signal to pinch or release said shunt in synchronism therewith.

OXYGENATING DEV/CE Patented Oct. 13, 1970 3,533,408

r 1 23:: E SORT/N6 v ECG osczuosco I 23 'j' i:

TACHYMET Y Y A i 24 e m MONITOR/N6 E D SIGNAL OSCILLOSCOPE I l I g 3/ g 27 MAGNETIC PACE MAKER RECORDER JEn/v-mm FQOL/ EXTRA-CORPOREAL BLOOD CIRCULATION This invention relates to an apparatus for extra-corporeal blood circulation in synchronism with the cardiac cycle.

It is known that any extra-corporeal circulation of the blood (hereinafter abbreviated to E.C.C.), carried out, for example, before or during or after a surgical operation, comprises an apparatus which includes:

an arterial return path or arterial line;

a venous return route or venous line;

an intermediate circuit between these two (with a reservoir or oxygen appliance); and

a pump for arterial injection.

Arterial injection is generally carried out in a continuous manner. When such injection is used it may add its pressure to that of the blood pumped by the heart, and may thereby cause such discomfort to the patient that it cannot be endured very long.

To avoid such discomfort it is present practice to use blood pumps operating for short periods of time and triggered by an electrocardiograph during the diastolic phase of the cardiac cycle.

However, such pumps operate with a certain time lag which increases with the flow, and tends to limit the flow. They also inject rapidly a predetermined volume of blood, which in the case of variations of the cardiac cycle, may be too large or too small.

To remedy this, the object of the present invention is to provide a continuous-flow blood pump which is only branched off, at the moment of the cardiac systole (cardiac contraction) by a shunt connecting the arterial line to the intermediatecircuit, e.g. to the return reservoir; this shunt includes a valve the opening and closing of which is controlled, at suitable moments and after predetermined durations, by an electric unit which utilizes the QRS signal of an electrocardiograph apparatus, thus itself regulating the moments and durations'of arterial pipe 16 connecting the patients artery to the pipes 13 the opening and closing actions, or enabling them-to be regulated, in accordance with the desired result.

The device can be connected to any surgical E.C.C. as a preoperatory measure, or at the end of the operation, or to afford medical treatment.

In the accompanying drawing,

FIG. I is a graph showing relative time periods and durations;

FIG. 2 is a graph showing a modification of the time periods and durations;

FIG. 3 is a diagram which shows the apparatus in actual use connected to a patient;

FIGS. 4 and 5 show two different modes of use of a shunt system in the device;

FIG. 6 shows schematically a preferred construction of shunt valve;

FIG 7 is a block diagram of an electronic control device;

FIG. 8 is a block diagram showing a monitoring system for the control device.

FIG. 3 shows the device of the invention, as applied to a patient prepared for a surgical operation such as open heart surgery, or during or after the latter. An electronic synchronizing unit 10 receives the R wave of the patient from an ECG or pace maker" (not shown) and converts it into a signal of which the duration is regulated as desired. This output signal is received by an electromechanical bypass control 11 for controlling the closing and opening of a valve 12 in a shunt pipe 13. The shunt 13 which short circuits the pump, thus rendering possible an arterial return", which is facilitated by gravity, towards the intermediate circuit, and hence towards a return reservoir; this shunt can be a tube of elastic material such as Tygon.

The valve 12 is mounted on said shunt pipe 13 and can be rapidly actuated for example by an electric solenoid valve as described in relation to FIG. 6, to compress the pipe I3. In FIG. 3 the valve 12 is shown open. The shunt pipe I3'leads to an oxygenating apparatus 14, which forms a return reservoir. In parallel with the shunt pipe 13 there is a continuousdelivery pump-l5 connected to the reservoir 14. A similar and 15. The valve 12' is mounted on the arterial pipe I6 before its confluence with the shunt pipe I3 in order to enable its return delivery to be reduced, if necessary, in synchronism with the shunt valve I2, during the shunting process; similarly, 1

other valves of the same type can be mounted at other points on the ECC circuit. A venous pipe 17 connects the apparatus 14 to a vein, and

in FIG. 3 is shown without any valve in it.

In FIG. 4 there is shown diastolic transfusion. The shunt 13 is closed by closing the valve I2, and the arterial pipe 16 isleft open at valve 12' (that part of the shunt 13 which follows the closure at 12 being shown in broken line).

In FIG. 5 there is shown systolic by-passing by the shunt pipe 13, and the two valves 12 and 12' are left open; it is thus possible to permit an arterial return to take place, through the pipe line 16, or to interrupt it, by operating the valve I2.

FIG. 6 shows, schematically, a form of control valve for the shunt'pipe 13 or for any other flexible pipe. The pipe l3is clamped diametrically between a fixed part 18 and a movable part 19, the latter being controlled by a piston 20 connected to a solenoid valve 21 which in its turn is controlled by an electric line 21 "from the control unit 11.

FIG. 7 shows the structure of the electronic synchronizing unit 10, which includes an ECG unit 22, and its connection to the control device I l for the valve 12 of the shunt pipe 13 and this diagram provides an explanation of the application of the systole-diastole selection circuit, and of the regulating system.

The electronic unit I0, which enables the opening otlthe shunt pipe 13 to be regulated at the exact moment when the systole of cardiac contraction takes place, also enables the satisfactory operation of the assembly used to be verified; this electronic unit analyses the electrocardiographic complex and enables pressure control to be effected, for the purpose of the aforementioned regulation.

This electronic unit includes Y a. The multitrack electrocardiographic apparatus 22 '(abbreviated to "ECG), with oscilloscopes 29 and 30 enabling the most suitable electrocardiographic track to be selected at any moment.

b. The cardiotachymeter 23 imparting a brief impulse at the moment when the QRS signal of the ECG occurs, upon reception of R waves from the patient;

c. The relay 24 by which this short impulse is converted into a rectangular impulse of which the duration can be regulated as desired and by which the shunt tap will be "controlled.

d. The relay 25 supplying a required advance in relation to the original QRS wave, at the moment when the shunt pipe valve opens, and capable of being coordinated with the frequency of the heart beats.

e. The pace maker 27 which takes over when no waves are received from the patient, and the relay 26 for actuating f. A filtering relay'(not shown).

g. Electronic manometers for arterial and venous observation (not shown). t

h. A second oscilloscope 30 for monitoring and regulation,

which enables any possible regulating actions to becarried out and on the screen of which the following are recorded: the ECG track retained; the signal of each relay; an arterial pressure track; a venous pressure track; and the signal relating to the opening or the closingof .the shunt tap; 1

i. an audiosignal; and j. a multitrack magnetic recorder. FIG. 8 provides an explanation of the visual monitoring system. f

For the systole-diastole selection circuit (FIG. 7) in the ECG unit 22 one of the ECG tracks is selected. a cardiotachymeter 23 takes the instantaneous impulses from the positive ECG deflections on this selected track; a relay 24 receiving the output of the cardiotachymeter 23 then effects a filtering operation, so that only a QRS impulse 11 remains and this is fed to a relay 25 which converts it into a rectangular impulse of duration 12". This is fed to a relay 26 of a pace maker 27 and simultaneously to the bypass control device ii' 'iiWlfic nBp'eE'sYhE s'h'um i3 au'rirgtra'szaba 12'.

For monitoring (FIG. 8):

Signals from the ECG 22 are fed to a sorting oscilloscope 29 receiving all the tracks, and from there any selected signal can be transferred to a monitor tube 30 showing for example one ECG track, one track for relay 24, one arterial pressure track, one track for relay 25, one venous pressure track, opening or closing signal of electromechanical selector 11-12. At the relay stage 24 there is regulation of the duration :1; at the relay stage 25, there is regulation of the duration 12 (time for which the shunt pipe 13 is open, and duration of systole), starting of the electromechanical control lIl2, regulation of venous return delivery" and of arterial return and regulation of the pump.

An audio signal is obtained from an audio unit 28; control oscilloscope 30: unit 31 is a multitrack magnetic recording system.

Referring to FIG. I, it is shown how, staning from a QRS signaL'there is obtained a long impulse 4 for the control of the shunt valve 12.

On the arterial pressure PA, the point PS indicates theclosing of the aortic sigmoid valvulae.

In the P.QRS-T complex, point P indicates the contraction of the auricles of the heart, QRS indicates the wave marking the commencement of the contraction of the ventricles. and T indicates the depolarization wave.

The original impulse I, which is short, and synchronous with QRS, is taken up by the the cardiotachymeter 23. If it is accompanied by a parasitic impulse 2 caused, for example, by T, filtering is applied during the period 4 and interrupts this parasitic impulse. At 5, the signal of the opening and closing relay occurs, the shunt pipe I3 being open during the hatched period 6, which can be increased in accordance with the arterial pressure curve PA. The arrow 7 indicates the instant of opening and the arrow 8 the instant of closing.

FIG. 2 shows an alternative version of part 5 of FIG. 1, the opening taking place with a certain advance (the arrow 9 indicating the opening, advanced in respect of the arrow 7 or the arrow QRS shown afterwards, with the hatched opening period 6 The apparatus is utilized as follows:

The signals of the ECG unit 22 are transmitted to its sorting oscilloscope 29, on which they can be compared in order to select the best track or signal. The QRS signal retained is analysed by the cardiotachymeter 23, after the regulation of the threshold in accordance with its amplitude. We thus obtain an impulse on the QRS signal.

But if positive deflections of the same amplitude (as shown at T, for example, FIG. 1) are received from the cardiographic system, filtering may be required. The first signal actuates the electronic relay 24 which interrupts the cardiotachymeter circuit for a period corresponding to the duration of the electrocardiographic complex following the original signal. It is thus the first signal that is transmitted (and not the subsequent signal, e.g. that emanating from T). At the end of this period, the relay 24 returns the cardiotachymeter 23 to the circuit, and the first signal of the following complex may set up an original impulse and block the cardiotachymeter. The satisfactory operation of this filtering system is verified on the screen on the monitoring oscilloscope 30. A synchronous visual signal is recorded below the electrocardiographic track and enables this period to be prolonged or shortened at any moment.

This original impulse. thus filtered, sets up an audiosignal, in unit 28, which enables the electrocardiographic rhythm to beconstantly monitored by ear and makes it possible to take immediate action in the event ofdisturbance.

The original impulse is transmitted tothe electronic relay 25 which converts it into an impulse whose duration can be regulated as desired; this duration must correspond to the time for which the valve 12 of the shunt pipe 13 is open, which time is steplessly variable, e.g. between zero and a quarter of a second or more. This impulse is verified on the monitoring oscilloscope 30 by a synchronous visual signal in the vicinity of the arterial pressure track". It is thus known at any moment whether the opening of the shunt valve 12 is being correctly controlled. In this case, the final order can be transmitted to the said shunt valve 12 and to the valve 12', if provided on the arterial line. It also causes a signal to be conveyed to the screen of the monitoring oscilloscope 30, so that the periods during which the valve has been actually operated can be accurately differentiated in the recordings.

The final regulating operations are carried out in accordance with the haemodynamic effects desired. They necessitate control of the commencement of the venous return (the degree of shutting of the valve being variable by an electrical or manual control means), of the systolic arterial return, and of the real injection delivery which depends on the output of the injection pump (ascertainable from the revolution-counter on its control panel), and of the through flow in the shunt pipe as determined by the frequency and duration of opening of valve control, and the flow cross section of the pipe.

After adjustment of the electronic unit, and with the ECC progressing under normal conditions, the shunt valve 12 is actuated, the relay 25 being closed and then progressively opened for oscilloscopic verification of the pressure curves so as to obtain the value which is desired from the haemodynamic point of view.

The apparatus enables the arterial and venous outputs to be distributed in such a way as to enable any one of the following to be obtained, according to the type of return selected:

1. A veno-arterial ECC with diastolic injection, the artery being closed during the systole, and the injection continuing to be branched by the shunt pipe (treatment of righthand cavities of heart, necessitating the use of a blood oxygenating apparatus);

an arterio-arterial ECC with diastolic injection, with an arterial return during the systole, the delivery of the pump being branched by the open shunt pipe, while during the diastole the injection is effected by closing the shunt pipe (for treatment of left cavities of heart, no blood oxygenating apparatus being necessary here); and

3. an ECC which is any combination of those indicated above, according to the relative size of the venous and arterial returns (mixed" or overall" heart treatment). 1

The invention offers a further advantage in that the opening of the shunt pipe enables ventricular ejections to be facilitated, this being partly effected in an open system at a low pressure since it is in communication with the return reservoir of the ECC. It thus provides a true cardiac treatment combining the advantages of a reduction of the work having to be performed by the heart, and administration of a diastolic transfusion.

I claim:

1. In an extra-corporeal blood circulating system synchronised with the cardiac cycle, an electronic unit including a multi-track electrocardiograph receiving an R wave from a patient and converting said wave into a QRS output signal; an arterial line and a venous line, a return reservoir connected to said lines: a continuous delivery pump connected in said arterial line; a shunt connecting said arterial line to said reservoir for branching off said pump at the moment of cardiac systole, a valve for opening and closing said shunt; a control system for governing said valve said control system including a piston means responsive to said output signal to control said shunt in synchronism therewith.

4. System according to claim 1, wherein said return reservoir consists of an oxygenating device.

5. System according to claim 1, having a second similar valve controlling said arterial line and means for controlling said second valve in synchronism or alternation with said first valve.

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