RU224819U1 - Device for monitoring the parameters of the gas mixture of the extracorporeal circulation apparatus - Google Patents

Abstract

The proposed utility model relates to medicine, in particular to cardiovascular surgery, pathophysiology, perfusion, and can be used in extracorporeal circulation (EC) to monitor indicators: percentage concentration of carbon dioxide, end-expiratory partial tension of carbon dioxide (PETCO2), production carbon dioxide (VCO2), patient's basal metabolic rate (REE), volumetric flow rate of the gas mixture (Qv), oxygen consumption (VO2), concentration of anesthetics (sevorane, isoflurane, fluorotane). Obtaining this data in real time is a necessary condition for maintaining gas exchange and patient metabolism within physiological limits during cardiac surgery under extracorporeal circulation or extracorporeal membrane oxygenation (ECMO). The device consists of series-connected transparent backbone inches of a gas mixer and an anesthetic evaporator of the extracorporeal circulation apparatus, a volumetric flow sensor of the gas mixture and an anesthetic concentration sensor, a gas mixture filter, a unidirectional valve located in the inlet line of the gas mixture into the oxygenator of the EC apparatus. In the output line from the oxygenator, the following are connected in series: a carbon dioxide sensor, a temperature sensor, a line for removing the gas mixture from the oxygenator, an electronic computing module of the device connected via a cable to a gas volume flow sensor, an anesthetic concentration sensor, a carbon dioxide registration sensor, a gas temperature sensor, image block display, keyboard for data entry. The device is made with the possibility of sequential passage of the gas mixture from the gas mixer and the anesthetic evaporator of the extracorporeal circulation apparatus along the input line for supplying the gas mixture to the oxygenator of the extracorporeal circulation apparatus, through a volumetric flow sensor of the gas mixture, an anesthetic concentration sensor, made with the ability to record indicators in the direct flow of the gas mixture , through a filter of the gas mixture and a unidirectional valve into the oxygenator of the extracorporeal circulatory system, made with the possibility of gas exchange between the patient’s blood and the gas mixture, while the output line of the oxygenator of the extracorporeal circulatory system is made with the possibility of the gas mixture entering after the oxygenator, through a carbon dioxide sensor, with a transparent and a body permeable to the absorption spectrum of light waves of carbon dioxide, and a gas temperature sensor, in a metal case, one side located in the output line of the oxygenator of the extracorporeal circulation apparatus, and the other touching the temperature sensor, while the carbon dioxide sensor and the temperature sensor are in direct flow gas mixture, while the device is configured to transmit sensor data via a cable to the electronic computing module of the device containing a keyboard for entering patient data, procedure protocol, date and time, calibrating sensors for programming the limits of calculated indicators, while the device is configured to transfer of calculated data: percentage concentration of carbon dioxide, end-expiratory partial tension of carbon dioxide, carbon dioxide production, basal metabolism, volumetric flow rate of the gas mixture, oxygen consumption and concentration of anesthetics - sevorane, isoflurane, fluorotane, after processing the indicators in real time, transfer to image block display. As a result of the use of monitoring, the patient's gas exchange parameters are assessed in a direct gas flow, in real time, the device sensors are isolated from contact with biological material (viruses, bacteria), the calculated data is processed in the electronic computing module of the device with the possibility of transmission to the device display.

Description

The proposed utility model relates to medicine, namely to monitoring systems for a patient under conditions of extracorporeal circulation (EC), which controls the indicators of the gas mixture of the EC apparatus: the percentage concentration of carbon dioxide, end-expiratory partial tension of carbon dioxide (PETCO2), carbon dioxide production ( VCO2), patient's basal metabolic rate (REE), gas mixture volume flow (Qv), oxygen consumption (VO2), anesthetic concentrations (sevorane, isoflurane, fluorotane).

According to the accepted EASTA perfusion protocol 2019 [Alexander Wahba, Milan Milojevic, Christa Boer et al. 2019 EACTS/EACTA/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery. Eur J Cardiothorac Surg 2020 Feb 1; 57(2):210-251] blood gas monitoring is carried out once every 30 minutes.

If ventilation or blood circulation is impaired, irreversible changes occur in the body within 4 minutes (3.5). During an EC session, in the absence of continuous monitoring of gas exchange and metabolism indicators, indicators may go beyond physiological limits, while visually the operation of the EC apparatus does not change.

Continuous monitoring of the EC procedure or extracorporeal membrane oxygenation (ECMO) is possible with special devices: Terumo CDI, Euroset Loading, Spectrum Medical [Mirko Belliato, Antonella Degani, Antonino Buffa, Fabio Sciutti, A. et al. Brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation. Journal of Clinical Monitoring and Computing, (2017) P. 1027-1033; https://eurosets.com/products/cardiopulmonary/landing/; https://medtronic-cardiovascular.ru/upload/iblock/c47/Spectrum-Medical.pdf.; www.terumo-europe.com/en-emea/products/cdi%C2%AE-550-blood-parameter-monitoring-system], which provide real-time data on the patient's gas exchange and metabolic parameters. Their practical application is hampered by the high cost of imported equipment and consumables, and the limited operating time of consumables [www.terumo-europe.com/en-emea/products/cdi%C2%AE-550-blood-parameter-monitoring-system]. In the context of international sanctions, problems arise with the supply of equipment and components from foreign manufacturers, repairs and services.

The proposed EC monitoring device differs from the listed devices in that its operating principle is based on the analysis of the indicators of the gas mixture of the EC and ECMO device; calculations are carried out using the method of indirect calorimetry, by analogy with metabolographic devices that record the parameters of the gas mixture and calculate the gas exchange and metabolism of patients when breathing with the lungs during natural blood circulation [Shurygin I.A. Respiratory monitoring, oximetry, capnography, pulse oximetry. Binomial. 2000 (pp. 99-104); https://formed.ru/catalog/p/metabolograf_quark_rmr/]. The calculated parameters are also displayed on the monitor display in real time.

The proposed device (see Figure No. 1) consists of a gas volume flow sensor and an anesthetic concentration sensor (2), a gas mixture filter and a one-way valve (3), located in the inlet line supplying the gas mixture to the oxygenator (4).

The outlet line of the oxygenator of the apparatus (4) EC is connected in series with a carbon dioxide recording sensor, a gas temperature sensor (5), and a line for removing gases from the operating room (6).

All of the listed devices are connected in series with each other by a transparent line with a diameter of ¼ inch (10).

The electronic computing module of the device (7) is connected via a cable (9) to sensors (2.5), an image unit display (8), and a keyboard for data entry.

The operating diagram of the proposed utility model is presented in Figure No. 1:

1. Gas mixture mixer and anesthetic evaporator.

2. Gas volume flow sensor and anesthetic concentration sensor.

3. Gas mixture filter and one-way valve.

4. Oxygenator of the EC apparatus.

5. Carbon dioxide recording sensor and gas temperature sensor.

6. Exhaust gas removal line.

7. Electronic computing module of the device.

8. Image block display.

9. Cable.

10. Transparent gas mixture line with a diameter of ¼ inch.

Operating procedure of the EC monitoring device: from the gas mixer and anesthetic evaporator (sevorane, isoflurane, desflurane) of the EC apparatus (1), the gas mixture sequentially through a transparent gas line with a diameter of ¼ inch (10) enters the volumetric gas flow sensor and the anesthetic concentration sensor (2) , recording indicators in a direct gas flow. Next, the gas mixture follows through a filter designed to filter the gas mixture and protect the surface of the sensors from biological material (condensate containing bacteria, viruses), and a one-way valve (3), which prevents the reverse flow of gas through the mixer and sensors (2), their contamination with bacteria and viruses.

Unlike a side-stream gas monitoring system, where the gas flow is sampled for gas analysis and the set gas flow is reduced, in the forward gas flow there is no selection and change of the set gas flow.

Next, the gas mixture enters the oxygenator of the EC apparatus (4), where gas exchange occurs, by analogy with the human lungs under physiological conditions. The gas mixture passing through the oxygenator is saturated with carbon dioxide and depleted in oxygen. Next, the gas mixture enters the outlet of the oxygenator, passes through a carbon dioxide sensor and a gas temperature sensor (5), located in special housings that isolate the surface of the sensors from contact with viruses and bacteria. The transparent body of the carbon dioxide sensor is transparent to the absorption spectrum of light waves of carbon dioxide. The temperature sensor is located in a metal case, located on one side in the output line circuit, the other touching the temperature sensor, which also prevents contact with bacteria and viruses. Carbon dioxide and temperature sensors are located in the direct flow of the gas mixture, and there is no selection or reduction of the specified gas flow. Next, the exhaust gas mixture is supplied to the gas removal line from the operating room (6).

Sensor data is transmitted via cable (9) to the electronic computing module (computer) of the device (7) for mathematical calculations according to a given program in real time and is received via cable (9) to the display of the image unit (8).

The information processing unit has a keyboard for entering date and time, calibrating sensors, patient data, entering procedure protocol data, programming the boundaries of calculated parameters, connected by a cable to the computer.

Monitoring of gas parameters during EC reflects the level of metabolic activity and gas exchange of the patient, a critical decrease in which leads to metabolic disorders, impaired oxygen delivery, elimination of carbon dioxide, the development of hypoxia and the occurrence of complications. Obtaining this data in real time - continuous monitoring of EC, is the best condition for effective monitoring of the patient in many critical situations. [Jonas R.A. / Per. from English / Ed. M.V. Boriskova. Surgical treatment of congenital heart defects, GEOTAR-Media., 2017; Lokshin L.S., Lurie G.O., etc. Artificial and auxiliary circulation in cardiovascular surgery, Practical manual. Moscow 1998 (pp. 136-138); Marco Ranucci, Giovanni Carboni, Mauro Cotza, Filip de Somer. Carbon dioxide production during cardiopulmonary bypass: pathophysiology, measure and clinical relevance. Perfusion 1-9. 2016].

Many potentially dangerous situations are detected with the help of respiratory gas monitoring at the earliest stages of development, providing the doctor with timely information for analysis and prompt correction of the developing critical condition [Shurygin I.A. Respiratory monitoring, oximetry, capnography, pulse oximetry. Binomial. 2000 (pp. 99-104)].

The functionality of the device for monitoring the parameters of the gas mixture of the EC apparatus was tested at the Federal State Budgetary Institution Research Institute of the Communist Party of the Soviet Union of the Siberian Branch of the Russian Academy of Medical Sciences in Kemerovo.

The technical result is the ability to monitor a patient during EC in real time, to correct gas exchange and metabolic parameters until critical values are reached; the health and life of the patient often depends on the efficiency of obtaining this data [Gravlee, Glenn P.; Davis, Richard F.; Stammers, Alfred H.; Ungerleider, Ross M. Cardiopulmonary Bypass: Principles and Practice. ©2008 (P. 56-57); Marco Ranucci, Giovanni Carboni, Mauro Cotza, Filip de Somer. Carbon dioxide production during cardiopulmonary bypass: pathophysiology, measure and clinical relevance. Perfusion 1-9. 2016].

The proposed device is more affordable in comparison with analogues, has a significant continuous operation time, requires less maintenance and calibration, and reduces the risk of transmitting bacterial and viral infections. The location of the sensors in the direct gas flow does not change the main gas flow and ensures accurate measurements. The absence of gas sampling pumps, switching devices and other elements containing moving components eliminates their wear and failure and increases the reliability of the device. The absence of sensors with electrochemical cells, which have a limited service life, typically 6 to 1000 hours, increases the service life of device components. It is important to remove the gas mixture by the exhaust gas removal system and the absence of anesthetic vapors in the operating room atmosphere.

When using the device with an ECMO device, the connection diagram is not fundamentally different, the operating principle remains the same. A long continuous service life of the device can provide real-time ECMO monitoring for up to several months [Shurygin I.A. Respiratory monitoring, oximetry, capnography, pulse oximetry. Binom.2000 (pp. 99-104); Mirko Belliato, Antonella Degani, Antonino Buffa, Fabio Sciutti, A. et al. Brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation. Journal of Clinical Monitoring and Computing, (2017) P. 1027-1033; Marco Ranucci, Giovanni Carboni, Mauro Cotza, Filip de Somer. Carbon dioxide production during cardiopulmonary bypass: pathophysiology, measure and clinical relevance. Perfusion 1-9. 2016].

An example of the implementation of the proposed device.

Example 1.

Patient X., age 69 l, 72 kg, body S 1.69 m ² , with a diagnosis of coronary heart disease, angina pectoris, functional class 2. Stenosis of the anterior interventricular coronary artery. Diabetes mellitus type 2.

Under conditions of artificial circulation, coronary artery bypass surgery and revascularization of the above artery were performed. During extracorporeal circulation, indicators were recorded and calculated by indirect calorimetry: production of excreted carbon dioxide (VCO2), partial pressure of carbon dioxide (PETCO2), calculated VO2, with respiratory coefficient (RQ) = 0.85. The IR session was carried out without donor blood at low blood hematocrit levels of 20-22% (with a minimum recommended of 25%).

Analysis of metabolic parameters using indirect calorimetry revealed a decrease in IVO2 below normal (110 ml/m2/min), IVCO2 below 88 ml/ ^m2 /min, PetCO2 below 34 mmHg.

In this example, metabolism was assessed using the traditional direct method of monitoring acid-base balance, which did not reveal metabolic disorders at the stage of extracorporeal circulation, and no correction of the parameters of the EC apparatus was carried out. This led to metabolic disorders after the EC session, the need for intensive therapy in the intensive care unit for 2 days: extended mechanical ventilation, drug correction, infusion therapy.

The patient was transferred from the intensive care unit only on the 3rd day after surgery and was subsequently discharged from the hospital. Indicators for monitoring an EC session using indirect calorimetry are presented in Table No. 1. Note to table No. 1 - * indicators that are outside the physiological boundaries are marked.

Example 2.

Patient K., age 64 years, 74 kg, body S 1.71 m, diagnosed with coronary heart disease, angina pectoris, functional class 2. Diabetes mellitus type 2. Stenosis of the anterior interventricular artery, circumflex artery, branch of the obtuse margin. Under conditions of artificial circulation, coronary artery bypass grafting of the above arteries was performed.

During extracorporeal circulation, we were guided by real-time metabolic indicators, which were recorded at the inlet and outlet of the oxygenator using indirect calorimetry with the calculation of: released carbon dioxide (VCO2), partial pressure of carbon dioxide (PetCO2), oxygen consumption (VO2), VO2 indicator calculated, with a respiratory coefficient (RQ) of 0.85.

Despite low hematocrit values of 22% and a real-time decrease in IVO2, IVCO2, PetCO2, by changing the volumetric gas flow rate, the percentage of oxygen in the oxygenator of the EC apparatus, and by changing the characteristics of the EC apparatus, the VO2, VCO2, PetCO2 indicators were achieved within physiological limits. The postoperative period was smooth, on the 2nd day the patient was transferred from the intensive care unit and subsequently discharged from the hospital. Indicators for monitoring the EC session using the method of indirect calorimetry are presented in Table No. 2.

Note to table No. 2 - * indicators that are outside the physiological boundaries are marked.

Example 3.

Patient B., age 71 years, 72 kg, body S 1.82 m ² , with a diagnosis of coronary heart disease, angina pectoris, functional class 3. Stenosis of the coronary arteries: anterior interventricular, obtuse edge branch, diagonal branch.

Under conditions of artificial circulation, coronary artery bypass surgery and revascularization of the above arteries were performed. During extracorporeal circulation, indicators were recorded at the inlet and outlet of the oxygenator using indirect calorimetry in real time with the calculation of: released carbon dioxide (VCO2), partial pressure of carbon dioxide (PetCO2), oxygen consumption (VO2), VO2 calculated, with RQ = 0.85.

The intraoperative and postoperative course was smooth, without complications. The patient was transferred from the intensive care unit the next day after surgery and subsequently discharged from the hospital. Indicators for monitoring an EC session using indirect calorimetry are presented in Table No. 3.

Example 4. ECMO.

Patient F., age 62 years, 74 kg, body S 1.82 m, with a diagnosis of coronary heart disease, progressive angina, type 2 diabetes mellitus. Stenosis of the anterior interventricular artery, branch of the obtuse margin, right coronary artery. The ECMO session time was 125 minutes.

Under venoarterial ECMO conditions, stenting of the above arteries was performed. During the ECMO session, metabolic indicators were monitored in real time using the indirect calorimetry method in real time and discretely, using the traditional method with monitoring of acid-base balance indicators with an interval of 30 minutes (see Table No. 4). Taking into account deviations of PETCO2 beyond the reference limits, correction of mechanical ventilation parameters was carried out to achieve physiological PETCO2 parameters. The remaining indicators, determined by indirect calorimetry, were within the reference values during the ECMO session. The ECMO session was performed without donor blood. The postoperative period was smooth; on the 4th day the patient was transferred from the intensive care unit and discharged from the hospital with recovery.

When performing ECMO, metabolic rates are lower than those indicated in example No. 1 [3, 6, 8], this is due to the preservation of one’s own blood circulation, ventilation of the lungs and partial elimination of CO2 by the lungs. To clarify the reference values of the IVO2, IVCO2 indices, it is necessary to conduct a study with a statistically significant sample. Indicators for monitoring an EC session using indirect calorimetry are presented in Table No. 4.

Note to table No. 4 - * indicators that are outside the physiological boundaries are marked.

Example 5. ECMO.

Patient N., age 80 years, weight 82 kg, body S 1.92 sq. m. Diagnosis: Coronary heart disease, progressive angina, type 2 diabetes mellitus. Stenosis of the anterior interventricular artery, circumflex artery, branch of the obtuse margin, right coronary artery. The ECMO session time was 148 minutes.

Under ECMO conditions, stenting of the above arteries was performed. Indicators determined by indirect calorimetry in real time during the ECMO session were within the reference values. The ECMO session was performed without donor blood. The postoperative period is smooth, hemodynamics are stable. Due to the patient's advanced age and asthenia, mechanical ventilation was required for 3 days, the patient was transferred from the intensive care unit on the 16th day, and was discharged with subsequent recovery.

When performing ECMO, metabolic rates are lower than those indicated in example No. 1, this is due to the preservation of one’s own blood circulation, ventilation of the lungs and partial elimination of CO2 by the lungs. To clarify the reference values of the IVO2, IVCO2 indices, it is necessary to conduct a study with a statistically significant sample.

Indicators for monitoring an EC session using indirect calorimetry are presented in Table No. 5.

Literature.

1. Jonas R.A. / Per. from English / Ed. M.V. Boriskova. Surgical treatment of congenital heart defects., GEOTAR-Media., 2017.

2. Zavertaylo L.L., Malkov O.A., Leiderman I.N. Metabolic monitoring technology and choice of nutritional support program for a critically ill patient "Intensive Care" N1 - 2007 (pp. 65-77).

3. Lokshin L.S., Lurie G.O., etc., Artificial and auxiliary circulation in cardiovascular surgery. Practical guide. Moscow 1998 (pp. 136-138).

4. Mochalin D.N. Patient respiratory gas monitoring system RU 135 511 U1 A61B 5/0205 (2006.01) A61 B 5/145 (2006.01).

5. Schmidt R., Lang F., Heckmann M. Human physiology with the basics of pathophysiology. Knowledge Lab 2019 (pp. 329-338).

6. Shurygin I.A. Respiratory monitoring, oximetry, capnography, pulse oximetry. Binom.2000 (pp. 99-104).

7. Alexander Wahba, Milan Milojevic, Christa Boer et al. 2019 EACTS/EACTA/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery. Eur J Cardiothorac Surg 2020 Feb 1; 57(2):210-251.

8. Gravlee, Glenn P.; Davis, Richard F.; Stammers, Alfred H.; Ungerleider, Ross M. Cardiopulmonary Bypass: Principles and Practice. ©2008 (P. 56-57).

9. Mirko Belliato, Antonella Degani, Antonino Buffa, Fabio Sciutti, A. et al. Brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation. Journal of Clinical Monitoring and Computing, (2017) P.1027-1033.

10. https://eurosets.com/products/cardiopulmonary/landing/

11. https://formed.rU/catalog/p/metabolograf_quark_rmr/

12. https://medtronic-cardiovascular.ru/upload/iblock/c47/Spectrum-Medical.pdf.

13. Marco Ranucci, Giovanni Carboni, Mauro Cotza, Filip de Somer. Carbon dioxide production during cardiopulmonary bypass: pathophysiology, measure and clinical relevance. Perfusion 1-9. 2016.

14. www.terumo-europe.com/en-emea/products/cdi%C2%AE-550-blood-parameter-monitoring-system.

Claims (1)

A device for monitoring the indicators of the gas mixture of an extracorporeal circulation apparatus, consisting of interconnected by a transparent line with a diameter of inches of a gas mixer and an anesthetic evaporator of the extracorporeal circulation device, a gas volume flow sensor and an anesthetic concentration sensor, a gas mixture filter and a unidirectional valve located in the input line for supplying the gas mixture to the oxygenator of the extracorporeal circulation device, the output line of the oxygenator of the extracorporeal circulation device connected in series with the sensor carbon dioxide registration, gas temperature sensor, line for removing the gas mixture from the operating room, electronic computing module of the device connected via a cable to a volumetric gas flow sensor, anesthetic concentration sensor, carbon dioxide registration sensor, gas temperature sensor, image unit display, keyboard for input data, while the device is made with the possibility of sequential passage of the gas mixture from the gas mixer and the evaporator of anesthetics of the extracorporeal circulation device along the input line for supplying the gas mixture to the oxygenator of the extracorporeal circulation device, through a volumetric flow sensor of the gas mixture, an anesthetic concentration sensor, made with the ability to record indicators in direct flow of the gas mixture, through a filter of the gas mixture and a unidirectional valve into the oxygenator of the extracorporeal circulatory system, made with the possibility of gas exchange between the patient’s blood and the gas mixture, while the output line of the oxygenator of the extracorporeal circulatory system is made with the possibility of the gas mixture entering after the oxygenator, through a carbon dioxide sensor gas with a transparent and permeable body for the absorption spectrum of light waves of carbon dioxide, and a gas temperature sensor, in a metal case, located on one side in the output line of the oxygenator of the extracorporeal circulation device, and on the other touching the temperature sensor, while the carbon dioxide sensor and the temperature sensor are located in a direct flow of the gas mixture, while the device is configured to transmit sensor data via a cable to the electronic computing module of the device containing a keyboard for entering patient data, procedure protocol, date and time, calibrating sensors for programming the limits of calculated indicators, while the device made with the ability to transmit calculated data: percentage concentration of carbon dioxide, end-expiratory partial tension of carbon dioxide, carbon dioxide production, carbon dioxide production, basal metabolism, volumetric flow rate of the gas mixture, oxygen consumption and concentration of anesthetics - sevorane, isoflurane, fluorotane, after treatment indicators in real time on the image block display.