JPH04102035A - Pulmonary artery catheter for measuring pulmonary capillary pressure - Google Patents

Abstract

PURPOSE:To obtain data on a pulmonary capillary pressure which are accurate and excellent in reproducibility, by a method wherein after a balloon is inflated, the pressure of a pulmonary capillary system is measured through a first port, while the pressure of a pulmonary artery system is measured through a second port, and they are subjected to a comparative analysis. CONSTITUTION:Two pressure measuring systems by first and second ports 4 and 5 are opened to the air and a zero balance of the pressure measuring systems is secured. Subsequently, waveforms of pulmonary artery pressures of the ports 4 and 5 are displayed. Since the two ports 4 and 5 measure the same pressure when a balloon 3 is not inflated, an analytical computer executes correction of the sensitivity of two transducers so that the two waveforms of the pulmonary artery pressures be superposed automatically. In other words, the pressure waveform of a pulmonary capillary system after imperforation of a pulmonary artery by the port 4 and the pressure waveform of a pulmonary artery system after imperforation of the pulmonary artery by the port 5 are superposed. Because of the superposition of the two pressure waveforms, the pressure waveform from the port 4 dissociates from the pressure waveforms from the port 5 and lowers rapidly at the time of the imperforation of the pulmonary artery, and therefore the moment of the imperforation of the pulmonary artery can be detected accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pulmonary artery catheter for accurately measuring pulmonary capillary pressure (hereinafter also referred to as Pc).

More specifically, the present invention relates to pulmonary edema, adult respiratory distress syndrome,
The present invention relates to a pulmonary artery catheter for measuring pulmonary capillary pressure that can accurately and reproducibly measure pulmonary capillary pressure (Pc), which is extremely important as an index for patient management such as acute lung injury.

(Prior Art) Pulmonary capillary pressure (Pc) is the most important factor that moves water from protocapillaries to outside protocapillaries.

This means that if it becomes possible to accurately measure pulmonary capillary pressure (Pc) in the clinical setting, it will be possible to treat pathological conditions characterized by increased fluid in the lungs, such as acute lung injury, adult respiratory distress syndrome (ARDS), and pulmonary edema. This study shows that it is extremely useful in establishing indicators for diagnosis, evaluation, and treatment of cancer.

Pulmonary artery catheters are commonly used to obtain diagnostic information about the pulmonary artery system, and a particularly standard one is shown in FIG.

The conventional standard pulmonary artery catheter (1
') has a balloon (a) at the distal end of the catheter body (2') and a distal hole (b) for measuring pressure in the pulmonary artery system.

The balloon is essential for inserting the catheter from, for example, the right jugular vein, passing the blood flow through the right ventricle of the heart, and reaching the pulmonary artery. In addition, FIG. 3 shows one provided with a thermistor (C) for measuring cardiac output and a side hole (d) for measuring pressure in the right atrium and for injecting a drug solution.

The balloon (8) described above, the tip hole (b) for measuring the pressure of the pulmonary artery system, the thermistor (C), and the side hole (t) for measuring the pressure in the right atrium and injecting the drug solution, are connected to the catheter body (2'
It goes without saying that the catheter is connected to the operating system and measurement system outside the catheter body through the multi-chamber lumen inside the catheter body. In Figure 3, the balloon (a) is the hub for balloon inflation (a'), and the tip hole (b) is the hub for the tip hole (b) (b).
'), the thermistor (c) is the thermistor connector (C')
)It is connected to the.

FIG. 4 shows how the conventional pulmonary artery catheter (1') described above is used.

That is, in the conventional pulmonary artery catheter (1'), the balloon (a) is inflated so as to be carried by the blood flow, and the catheter is passed through the vena cava, from the right atrium to the right ventricle, while monitoring the pressure at the tip of the catheter, and is then inserted into the pulmonary artery. lead to. As it advances further, the inflated balloon (3) wedges into the pulmonary artery, and the pulmonary artery pressure waveform decreases. Once the catheter is positioned here and the balloon (a) is released from inflation, the original pulmonary artery pressure waveform can be obtained again.

FIG. 4 shows how the blood pressure in the pulmonary capillary system changes, particularly when blood flow is stopped from the pulmonary artery by balloon inflation of the catheter body.

That is, FIG. 4 shows the state of blood pressure (mmHg) in the right atrium, right ventricle, pulmonary artery, pulmonary capillary, pulmonary vein, and left atrium.

As can be seen from Figure 4, the blood flow in the pulmonary artery stops due to the inflation of the balloon (a), and the subsequent change in blood pressure is the pressure waveform shown at the pulmonary artery → pulmonary capillary → pulmonary vein in Figure 4.
That is, the pressure waveform gradually decreases and finally reaches the minimum pressure in the left atrium. The minimum pressure in the left atrium is the pulmonary artery wedge pressure PCWP (Pu1m
On! ry capillar7 wedge pres
It is called ``sure''.

By observing changes in the pressure of the pulmonary capillary system (the occlusion pressure waveform in which the blood pressure gradually decreases in Fig. 4) using the conventional pulmonary artery catheter (1') described above, it is possible to determine whether the state of the pulmonary capillary system is normal. There is a possibility that it will be possible to detect whether there is an abnormality.

In that case, for example, the occlusion pressure waveform that gradually decreases after inflation of the balloon described above is fitted to a monoexponential function with a predetermined time (1) as a variable, and this is extrapolated to the time of occlusion (1 = O) to determine the pulmonary capillary blood flow. It can be regarded as pressure (Pc).

However, when attempting to determine pulmonary capillary pressure (Pc) using the approach described above, accurate determination of the moment of occlusion by the balloon is an important point. This is because, when attempting to determine Pc by extrapolating a single exponential function at the time of occlusion as described above, a 50% error in the value of Pc will occur if the determination at the moment of occlusion deviates by just 0.3 seconds. (Calculation based on normal lungs) Therefore, in diseased lungs, the degree of error is further increased, and the reliability and clinical value of the measurements are completely lost. To explain this point using Fig. 4, using a conventional pulmonary artery catheter and keeping in mind the pulmonary artery pressure waveform before occlusion, the method for determining the moment of occlusion as the point at which the waveform starts to change is as follows. It is very vague and imprecise for a reason. 1) Changes in pressure waveform due to occlusion are not necessarily sudden (especially during pulmonary artery diastole), 2) Pulmonary artery pressure itself does not necessarily repeat the previous heartbeat due to arrhythmia, and 3) Pulmonary blood flow due to balloon inflation changes in the pressure waveform near the point of occlusion due to catheter vibration or distal movement.

Therefore, this method cannot be an unreliable and clinically valuable indicator of Pc due to inaccurate determination of the moment of occlusion.

(Problems to be Solved by the Invention) The present invention solves the drawbacks of measuring pulmonary capillary pressure (Pc) using a pulmonary artery catheter having a balloon that occludes the pulmonary artery with the conventional tip portion described above. The present invention provides a pulmonary artery catheter for measuring pulmonary capillary pressure (Pc) that can obtain accurate and highly reproducible Pc data.

The present invention also provides a method for measuring Pc data using the pulmonary artery catheter for measuring Pc of the present invention.

[Structure of the invention]

(Means for Solving the Problems) To summarize the present invention, firstly, the present invention provides a pulmonary artery catheter having a balloon at the distal end portion which inflates to occlude the pulmonary artery. (I) A first port provided at the tip of the catheter to detect the pressure state of the capillary system; (I) A first port provided near the balloon to detect the pressure state of the pulmonary artery system after pulmonary artery occlusion due to balloon inflation; a second port; secondly, using the pulmonary capillary pressure measuring pulmonary artery catheter, (I) After inflation of the balloon, determining the pressure waveform of the pulmonary capillary system using the pressure measurement system of the first port; (Ii); After inflation of the balloon, determining the pressure waveform of the pulmonary artery system using the pressure measurement system of the second port; (IiD, Polymerizing the pressure waveforms of (I) and (Ii),
The moment when the two pressure waveforms dissociate is detected to determine the point of occlusion of the pulmonary artery by the balloon.The pressure waveform of the pulmonary capillary system detected by the first port after a predetermined time after the lateral occlusion of the pulmonary artery is expressed by the following monoexponential function ( 1) by curve fitting P (t) = A-exp (-
kl) + PCWP--(1) However, ^ indicates a parameter.

pcwp indicates the minimum value of the pressure waveform of the pulmonary capillary system measured by the first port after pulmonary artery occlusion.

(■), extrapolate (1.0) the mono-exponential function (1) to the moment of pulmonary artery occlusion and obtain the pulmonary capillary pressure Pc by the following formula (2), Pcm A 1 PCWP... ... Old... (
2) A method for measuring pulmonary capillary pressure characterized by the following.

Hereinafter, the configuration of the present invention will be specifically explained.

Conventional pulmonary artery catheters, e.g. standard 5vu-Ga
As described above, when attempting to measure pulmonary capillary pressure (Pc) using an Nr catheter, it is not possible to obtain accurate and highly reproducible data.

That is, in the pulmonary artery → pulmonary capillary → pulmonary vein system, a gradually decreasing occlusion pressure waveform as shown in Fig. 4 is obtained due to pulmonary artery occlusion, and this is fitted to a monoexponential function with a predetermined time (1) as a variable. When attempting to calculate Pc from the initial conditions by extrapolating to l = Q, when the pulmonary artery is occluded (t =
It is difficult to set O), and in order to remove disturbances in the occlusion pressure waveform immediately after occlusion, the problem is what kind of occlusion pressure waveform after a predetermined time should be curve-fitted to a monoexponential function. .

In order to solve these problems, the present invention has a conventional balloon at its tip that inflates to occlude the pulmonary artery, and has a first port at the tip for detecting the pressure of the original capillary system after pulmonary artery occlusion. The main feature of this pulmonary artery catheter is that it is provided with a second port at the rear of the balloon for measuring pressure in the pulmonary artery system after pulmonary artery occlusion. More specifically, the first
In addition to the port, a second port is provided near the balloon, for example, near 1al+. Pressure measurement through the first and second ports may be performed using a pressure measurement lumen inside the catheter body, or by installing a semiconductor micro pressure transducer at the site. It is also typically used to measure cardiac output.
The right atrial port of the van-Ganr catheter may be transferred to the pulmonary artery to serve as a second port, or even triple lumens may be provided, one of which may be used as a second port.

In the present invention, the pulmonary artery catheter is configured as described above, and after inflating the balloon, the pressure in the pulmonary capillary system is measured through the first port, and the pressure in the pulmonary artery system is measured through the second port, and comparative analysis is performed. By doing so, the time (instantaneous) of the pulmonary artery can be accurately detected. This point will be explained in detail below.

In the present invention, for example, a pressure measurement system (blood pressure transducer, amplifier) using the first and second ports is connected to a pulmonary capillary pressure analysis computer consisting of a signal processing, arithmetic system, and a liquid crystal display to perform the necessary analysis. will be done. More specifically, in the case of the previous example, the two pressure measurement systems are opened to the atmosphere and the pressure measurement systems are zero-balanced. Next, the pulmonary artery pressure waveforms of the first and second ports are displayed, and since both ports measure the same pressure when the balloon is not inflated, the analysis computer corrects the sensitivity of the two transducers, and Automatically superimpose two pulmonary artery pressure waveforms. That is, the pressure waveform of the pulmonary capillary system after pulmonary artery occlusion caused by the first port and the pressure waveform of the pulmonary artery system after pulmonary artery occlusion caused by the second port are superimposed.

Due to the superposition of the two pressure waveforms, the pressure waveform from the first port dissociates (separates) from the pressure waveform from the second port at the time of pulmonary artery occlusion and rapidly decreases, making it difficult to accurately detect the moment of pulmonary artery occlusion. can.

FIG. 1 schematically shows the pulmonary artery catheter (1) for measuring pulmonary capillary pressure of the present invention described above. The catheter shown in Figure 1 (
1) includes a catheter main body (2) with an outer diameter of about 2 cm, a balloon (3) with an outer diameter of about 1 ann fixed to the distal end of the catheter main body (2), a first port (4) opened at the distal end, It consists of a second port (5) that opens into the catheter body at a distance of lan from the balloon. The flush line in FIG. 1 is for flowing physiological saline.

Note that FIG. 1 also shows that data from the pressure measurement system (measured by a pressure transducer) of the first port and the second port is taken into the pulmonary capillary pressure analysis computer. These pressure data may be imported into a computer using 2QOL, for example, and subjected to the processing and analysis described above.

Next, the characteristics of the pressure waveform due to the first port, which have been verified through many cases, will be explained.

Immediately after pulmonary artery occlusion, the pressure waveform from the first port (see ■pressure waveform in Figure 2 below) rapidly decreases (rapidly decreasing phase)
Thereafter, the pressure gradually decreases toward the pulmonary artery wedge pressure (slow decline phase). The rapid drop phase early after occlusion corresponds to the release of blood from the occluded pulmonary artery to the pulmonary capillaries, and the influence of the balloon on the pressure waveform during this period cannot be ignored.

The time required for the rapid decline phase is 0.1 seconds to 0 depending on the case.
．． Although there is some variation between 2 seconds and 0.0 seconds in all cases.
It was confirmed that the process would be completed within 3 seconds.

On the other hand, the slow release phase corresponds to the slow release of blood from the pulmonary capillaries to the pulmonary veins.If we extrapolate the pressure changes during this slow release phase to the point of occlusion, we can find that the moment of occlusion Pulmonary capillary pressure (Pc) at can be determined.

In addition, a significant increase was observed in the pressure waveform from the second port in all cases (see pressure waveform in Figure 2 below) after balloon occlusion, which was due to a shift in pulmonary blood flow to non-occluded pulmonary vessels. This is due to a number of reasons. The fact that the pulmonary artery pressure in the proximal part of the balloon changes due to the occlusion mentioned above points out the contradiction in determining the point of occlusion based on the assumption that the pressure in the proximal part of the pulmonary artery does not change with the conventional pulmonary artery catheter. It is.

From the above, the pressure waveform after the time when the rapid decline is completed ((1), specifically ++=0.3 seconds, is curve-fitted to the monoexponential function (1), and the parameters (person, K) are Pc can be definitively determined by equation 2).

Note that pcwp of the single exponential function (1) is the minimum value of the pulmonary capillary system, that is, as shown in FIG. 4, it gradually decreases from the pulmonary veins to the left atrium, and is the minimum pressure indicated by the left atrium.

In the present invention, as described above, at the time of pulmonary artery occlusion (t =
O) can be determined accurately, and the pressure waveform can be calculated using a monoexponential function (1
) is determined accurately, the monoexponential aperture (
1) to l=o to obtain the target pulmonary capillary pressure (P
c) can be accurately determined.

FIG. 2 illustrates a method of superimposing the pressure data obtained by the pressure measurement systems of the first port and the second port with 1=0 to obtain the target pulmonary capillary pressure (Pc).

In FIG. 2, the pressure waveform (■) is detected at the second port after pulmonary artery occlusion, and the pressure waveform (2) is detected at the first port.

In addition, for example, the following function (composite exponential function) (3) is curve-fitted to the occlusion waveform in the entire interval after 1-0, and Pc is determined by the above formula (2) or the following formula (3). is also possible, apart from the complexity and reliability.

P(1)=^・exp (-kl) +B-exp (
-It) + PCWP'・-(3) (However, people, k
, B, l indicate parameters. 1〉k) Pcm
(1-ni/I)・^+PCWP・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・(4) (Example) (I) In addition to the first port shown in FIG. A pulmonary artery catheter with two ports was inserted through the right carotid artery in patients undergoing laparotomy or open heart surgery. The two ports were connected to a pressure measurement system with the same configuration (pressure transducer manufactured by Spectramerad), and it was examined whether the frequency characteristics of both ports matched and were appropriate. If the frequency characteristics of both ports were not appropriate, adjustments were made using a variable damping device to match the frequency characteristics of both ports.

Next, after the general anesthesia was stabilized, the pulmonary artery occlusion pressure waveform was repeatedly measured several times for 5 seconds under apnea and analyzed using an analyzer.

That is, the occlusion pressure waveform (■ in Fig. 2) after 03 seconds after pulmonary artery occlusion is curve-fitted to the monoexponential function (1),
Pc was determined by the above-mentioned relational expression (2) in which the parameter A-k was determined and then extrapolated to 1=0 to obtain the pulmonary capillary pressure (Pc).

(I) PC measurement data The average data shown in Table 1 below was determined depending on the case.

(Margins below) From the data in Table 1, it is clear that abnormal increases in Pc (original capillary pressure) are closely related to pathological conditions in which pulmonary extravascular water content increases. Therefore, it is important to keep the original capillary pressure as low as possible for the treatment. Currently, pcwp, which is measured using a conventional pulmonary artery catheter, shows an abnormal increase in hexagenic pulmonary edema and is used as a useful index for its diagnosis and treatment. However, in acute lung injury and ARDS, which are more difficult to treat and have a high mortality rate, PCWP
takes a normal value and is completely useless as an indicator for evaluating the severity of the disease or for treatment. On the other hand, Pc (original capillary pressure) is the most direct factor that increases the amount of original water, shows an abnormal increase even in such pathological conditions, and can be said to be an extremely useful index clinically.

〔Effect of the invention〕

The pulmonary artery catheter for measuring pulmonary capillary pressure of the present invention can measure original capillary pressure accurately and with good reproducibility. Therefore, the catheter of the present invention is extremely useful in establishing indicators for diagnosis, evaluation, and treatment of pathological conditions characterized by increased moisture in the lungs, which is highly correlated with original capillary pressure.

[Brief explanation of drawings]

FIG. 1 schematically shows a pulmonary artery catheter for measuring pulmonary capillary pressure according to the present invention. FIG. 2 is a diagram illustrating a method for determining original capillary pressure (Pc) according to the present invention. FIG. 3 is a schematic diagram of a conventional standard pulmonary artery catheter. FIG. 4 is a schematic diagram showing pulmonary artery pressure waveforms at various locations detected using a conventional pulmonary artery catheter. 1... Pulmonary artery catheter for pulmonary capillary pressure measurement 2
... Catheter body 3 ... Balloon 4 ... First port 5 ... Second port Fig. 2

Claims (1)

[Scope of Claims] 1. A pulmonary artery catheter having a balloon at its distal end that, when inflated, occludes the pulmonary artery; (II) a second port provided in a region near the balloon to detect the pressure state of the pulmonary artery system after pulmonary artery occlusion due to balloon inflation; A pulmonary artery catheter for measuring pulmonary capillary pressure characterized by: 2. The pulmonary artery catheter for measuring pulmonary capillary pressure according to claim 1, wherein the second port provided near the balloon is provided at a desired distance from the balloon. 3. The pulmonary artery catheter for measuring pulmonary capillary pressure according to claim 2, wherein the second port provided near the balloon is provided at a distance of 1 cm from the balloon. 4. The pulmonary artery catheter for measuring pulmonary capillary pressure according to claim 1, wherein the first port and the second port are connected to a piezoelectric element. 5. The pulmonary artery catheter for pulmonary capillary pressure measurement according to claim 4, wherein the first port and the second port are semiconductor micro pressure transducers. 6. Using the pulmonary artery catheter for pulmonary capillary pressure measurement according to claim 1, (I) After inflation of the balloon, determining the pressure waveform of the pulmonary capillary system by the pressure measurement system of the first port; ( II), After the balloon is inflated, the pressure waveform of the pulmonary artery system is determined by the pressure measurement system of the second port. (III) The pressure waveforms of (I) and (II) are superimposed and the two pressure waveforms are dissociated. (IV) The pressure waveform of the pulmonary capillary system detected by the first port after a predetermined time after pulmonary artery occlusion is determined by the following monoexponential function (1).
curve fitting, p(t)=A・exp(-kt)+PCWP...
...(1) However, A and k indicate parameters. PCWP indicates the minimum value of the pressure waveform of the pulmonary capillary system measured by the first port after pulmonary artery occlusion. (V), by extrapolating the monoexponential function (1) to the moment of pulmonary artery occlusion (t=0), the pulmonary capillary pressure Pc is calculated by the following formula (2).
To find, Pc=A+PCWP・・・・・・・・・・・・・・・(
2) A method for measuring pulmonary capillary pressure, comprising: 7. The pressure waveform of the pulmonary capillary system detected by the first port after 0.3 seconds after pulmonary artery occlusion is calculated using the monoexponential function (1).
7. The method for measuring pulmonary capillary pressure according to claim 6, wherein the method comprises curve fitting.