LV13151B - Method for evaluation of hemodynamic fluctuations in patients after heart surgery in artifical blood circulation conditions - Google Patents

Abstract

Invention pertains to the field of cardio surgery and particularly to a method for a monitoring haemodynamic fluctuations in patients after a heart surgery and during such surgery. The objective of the invention is an early and simultaneous evaluation of a volume of circulating blood and an effectiveness of work of a heart muscle in connection to an oxygen haemostasis in patients. The method provides for an insertion of additional catheter into a pulmonary artery through the right atrium having a secondary opening in it where a diluting solution is injected. An intrathoracal thermal volume - ITTV is determined. The catheter is connected to a monitor, it is calibrated and data concerning a content of gases in a mixed venous blood and a content of hemoglobin is input. A saturation of the mixed venous blood by oxygen is calculated (per cents). Further a monitoring of the content of oxygen (SvO2%) in the mixed venous blood is carried out continuously. Detecting the SvO2 lower than 50% and ITTV above 1400 units malfunction of the work of the heart muscle is established. Detecting the ITTV lower than 800 units and SvO2 lower than 50% the deficit of the volume of circulating blood is established.

Description

METHOD FOR EVALUATION OF HEMODYNAMIC VERSION IN PATIENTS AFTER HEART CIRCULATION IN ARTIFICIAL BLOOD CIRCUMSTANCES (MAR)

The invention relates to medicine, namely, cardiac surgery, and relates to hemodynamic oscillation and early diagnostic monitoring of a patient after heart surgery and during surgery.

During and after cardiac surgery, it is important to identify the cause of haemodynamic disorders early and concurrently, where underestimation can be complicated by death. In patients undergoing cardiac surgery under artificial circulatory conditions and during postoperative period, the abnormality may be due to ineffective functioning of the cardiac muscle or due to insufficient circulating blood volume. The pathogenetically directed therapy is different in both cases: either the catecholamines / inotropic agents are administered urgently or the liquid supplement is urgently used to provide volume replacement therapy (blood or blood substitute).

A known method for the assessment of hemodynamic oscillations in patients undergoing cardiac surgery under artificial blood flow (MAR), which measures the functions of left ventricular pumping and cardiac contraction. As these rates decline, myocardial insufficiency is diagnosed [1]. However, this method does not allow simultaneous detection of circulating blood volume insufficiency.

A known method of evaluating cardiovascular and hemodynamic oscillations in patients undergoing cardiac surgery under Artificial Circulation (MAR), which measures the relationship between isometric cardiac muscle contraction and isometric cardiac muscle relaxation duration. If this ratio is not greater than 0.75, then the occurrence of incomplete diastolic syndrome is determined, thus identifying early myocardial insufficiency and providing appropriate therapy [2]. However, this method does not allow simultaneous detection of circulating blood volume insufficiency.

A known method for the assessment of hemodynamic oscillations in patients undergoing cardiac surgery under Artificial Circulation (MAR) with continuous pulse contour analysis - PiCCO method [3, 4]. The procedure is as follows: a thermodilution catheter is inserted into the iliac artery and a central venous catheter is injected into a vein jugularis interna (right atrium and right heart). Prior to continuous cardiac output measurement, each patient undergoes system calibration to determine aortic elasticity and blood flow to the descending aorta. Calibration is performed as follows: Inject 10 ml of cold 0.9% NaCl solution at a temperature between 1 and 8 ° C. The patient's aortic wall elasticity and transit time of dilution fluid through the pulmonary circulation are determined. Cardiac output from each pulsation wave in the iliac artery, that is, changes in the temperature of the dilated fluid in the detected iliac arteries and the circulatory blood flow rate with subsequent intrathoracal thermal volume (ITTV) - the rate of dilution fluid flow through the pulmonary circulation. Together with the transpulmonary thermodilution curve plotted during calibration on the monitor, the ITTV (units) are automatically determined and the following values calculated:

ITTV = ITBV + EVLW, where

ITBV is the intrathoracic blood volume or intrathoracic blood volume (ml / m ² ); EVLW - volume of extra vascular lung vvater or extravascular lung water (ml / kg).

If the ITBV is 800-1200 ml / m ² , then it is within the allowable range, if the figure increases by 20%, then hemodynamic instability should be considered, which will worsen if intensive care measures are not applied.

EVLW is within the tolerable range of 4-7 ml / kg, and if this value rises to 20 ml / kg, a picture of pulmonary edema is observed.

This method is a prototype of the invention. A known method may indicate a circulating blood volume deficiency, but does not allow the detection of a possible cardiac muscle deficiency associated with oxygen homeostasis. Postoperative surgery may result in impaired circulating blood volume or ineffective functioning of the cardiac muscle, and may result in oxygen homeostasis.

In order to improve the patient's condition after cardiac surgery, it is desirable to know not only the circulating blood volume deficiency but also the inefficiency of cardiac muscle function. Knowing these parameters can improve the patient's myocardial strength and hemodynamics and correct it in a timely manner.

The object of the present invention is to determine the simultaneous and timely failure of circulating blood volume and the effectiveness of cardiac muscle function associated with oxygen homeostasis in a patient.

The stated goal is achieved by additionally introducing a pulmonary artery catheter into the pulmonary artery through the right atrium with the secondary opening in which a dilution solution with subsequent ITTV determination is inserted, the pulmonary artery catheter is connected to the monitor for calibration and input of mixed venous blood gas. composition and hemoglobin level in blood, determines% oxygen content of mixed venous blood with follow-up continuous oxygen monitoring in mixed venous blood SvO2%, and with SvO2 below 50% and ITTV values above 1400 units, determines poor heart muscle performance but, if ITTV is less than 800 units and SvO2 is less than 50%, then hemodynamic insufficiency is caused by circulating blood volume deficiency

Methods of the invention.

Introduce pulmonary artery thermodilution catheters into the right part of the heart, namely through the right atrium to the site of clamping in the pulmonary artery. A thermodilution catheter is then inserted into the hip artery. Inject 10 ml of saline at 1-8 ° C into the right anterior chamber. After dilatation of the fluid temperature changes detected in the iliac artery, the blood circulation rate and the subsequent intrathoracal thermal volume (ITTV) are determined. The pulmonary artery catheter is connected to the monitor for calibration and data on mixed venous blood gas composition,% oxygen saturation, and blood hemoglobin. From this point on, continuous oxygen monitoring in mixed venous blood - SvO2% - begins.

The determination of SvO2 takes place in an automatic continuous mode and the calculation formula is as follows:

SvO2 = SaO2 - [VO2 / (Hgb χ 13,8) (CO)], where

VO2 - oxygen consumption, which is the amount of oxygen consumed by the organism and corresponding to the difference between the supplied [(CO) (CaO2) j and the consumed or returned oxygen of the organism [(CO) (CvO2) j;

SaO2 - oxygen saturation of arterial blood;

Hgb - actual hemoglobin.

Oxygen venous blood SvO2 fluctuations are a response to hemodynamic instability, include more information than CO fluctuations. The cause of hemodynamic instability can be predicted. Normal SvO2 - more than 50%. To predict and correct cardiac muscle strength, as well as concomitant blood volume insufficiency, a thermodilution catheter is inserted into the iliac artery and a pulmonary artery catheter (PAK) with an oxygen saturation sensor through the jugular vein exterior, with one opening remaining in the central vein. Defines the following parameters: SvO2, ITBV, EVLW, MAP, and calculates:

ITTV = ITBV + EVLW, where

ITBV is the intrathoracic blood volume or intrathoracic blood volume (ml / m ² );

EVLW - volume of extra vascular lung water or extravascular lung water (ml / kg).

If ITTV values are above 1400 units and SvO2 is less than 50%, heart failure is detected, but if ITTV is less than 800 units and SvO2 is less than 50%, circulating blood deficiency is detected. Insufficient cardiac muscle efficiency is confirmed by a decrease in mean arterial pressure (MAP) of up to 20 mm / Hg and to "0".

Clinical example.

Patient I.M., 56, post-aortic valve replacement (AVP), cardiac tamponade due to bleeding. Introduce pulmonary artery thermodilution catheters into the right part of the heart, namely through the right atrium to the site of clamping in the pulmonary artery. A thermodilution catheter is then inserted into the hip artery. 10 ml of saline are administered at 1-8 ° C into the right anterior chamber. After dilution fluid temperature changes in the detected iliac artery, blood flow velocity and subsequent intrathoracic thermal volume (ITTV) are determined. The pulmonary artery catheter is connected to the monitor for calibration and input of mixed venous blood gas composition,% oxygen saturation, and blood hemoglobin. From this point on, continuous oxygen monitoring in mixed venous blood - SvO2% - begins.

The determination of SvO2 occurs in automatic continuous mode. A thermodilution catheter is inserted into the iliac artery and a pulmonary artery catheter (PAK) is introduced into the pulmonary artery with an oxygen saturation sensor through the jugular vein exterior, with one opening remaining in the central vein. Defines the following parameters: SvO2, ITBV, EVLW, MAP, and calculates:

ITTV = ITBV + EVLW, where

ITBV is the intrathoracic blood volume or intrathoracic blood volume (ml / m ² );

EVLW - volume of extra vascular lung water or extravascular lung water (ml / kg).

day 1. postoperative, patient extubated, arterial tension 100/60 mm / Hg, cardiac output CO - 3.4 1 / min to 2.0 1 / min.

SvO2 decreased from 65% to 39%.

ITBV increased from 800 to 1527 mm / m ² while EVLW was stable from 7 to 10 ml / kg. Thus ITTV = ITBV + EVLW = 1527 ml / m ² + 10 ml / kg = 1537 units, which means ITTV above the upper limit of 1400 units.

In this case, SvO2 is less than 50% and ITTV greater than 1,400 units, indicating a lack of cardiac muscle efficiency. This was confirmed by a mean arterial pressure (MAP) drop to 40 mm / Hg and limited diuresis.

The patient underwent repeated surgery, catecholamines were added during surgery, and renal replacement therapy - volume reduction.

As a result, ITBV was reduced from 1527 to 847 ml / m ² , thus reducing ITTV from 1537 to 854 units, ie ITTV within the normal range (800-1200 units). At the same time, a rapid increase in SvO2 from 39% to 62% was observed, within the tinormal range.

The method of the invention allows patients to undergo cardiac surgery to detect early and simultaneous changes in cardiac performance and oxygen homeostasis following cardiac surgery, and to investigate the causes of these changes leading to cardiac muscle inefficiency, lack of oxygen delivery, or blood volume reduction. Finding out the instant cause allows for correct correction of changes during the initial phase and enables patient stabilization and survival.

References:

1. CejiHBaHeHKO B.T., 3aHHeTHHHOB E.M., Cnoco6 onpenejieHHfl MHOKapflHajītHOH HenocTaTOHHOCTH Jieeoro xejiynoHKa.

Patents RU 2128000, Cl 1999 A61B5 / 02

2. CejiHBaHeHKO B.T., ΗεφεποΒ Ε.Π., Cnocoč onpenejieHHH MHOKapHHaJIBHOH HenOCTaTOHHOCTH.

Patents RU 1806655, Al, 1993, A61B5 / 02

3. Kuzkov V.V., Kirov M.Ju., Nedashkovsky Ye.V., Volumetric monitoring in intensive care unit (ICU).

J. Anesthesiology and Intensive Care, 2003, No. 4, p. 67-73 (prototype).

4. PiCCO plus Operator's Manual and Product Information.

PULSION-Medical systems, 2002, pp.43-54 (prototype).

5. Patents RU 2140186, Cl, 1999, A61B5 / 02

6. Patents RU 2173090, Cl, 2001, A61B5 / 02

7. Patents RU 95113486, A, 1997, A61B5 / 02

Claims (1)

Formula of the Invention Hemodynamic oscillation evaluation method in patients undergoing cardiac surgery under artificial blood flow (MAR) with right catheter insertion into the right atrium and thermodilution catheter in the iliac artery and system calibration with 10 ml of saline at 1-8 ° C , after changes in the temperature of the dilated fluid in the iliac artery, the blood flow rate is determined to determine the intrathoracal thermal volume (ITTV), which is characterized by the introduction of a pulmonary artery catheter into the pulmonary artery through the right atrium with the secondary opening. a solution with subsequent ITTV determination, the pulmonary artery catheter is connected to the monitor for calibration and data on mixed venous blood gas composition and hemoglobin level to determine oxygen saturation of the mixed venous blood % of patients with continued continuous oxygen monitoring in mixed venous blood SvO2%, with a SvO2 score of less than 50% and ITTV values greater than 1400 units, are found to have inadequate cardiac muscle efficiency but less than 800 units ITTV and less than 50 SvO2 %, then a circulating blood volume deficit is detected.