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RU-2861552-C1 - METHOD AND SYSTEM FOR CARDIOPULMONARY BYPASS USING HYPODENSIVE OXYGENATION

RU2861552C1RU 2861552 C1RU2861552 C1RU 2861552C1RU-2861552-C1

Abstract

FIELD: medicine; medical engineering. SUBSTANCE: cardiopulmonary bypass system using a helium-oxygen mixture comprises a heart-lung machine (HLM) equipped with a roller pump. A medical gas mixer is connected to a central gas main with oxygen, contains a regulator for the percentage of oxygen in the gas mixture, a regulator for the volumetric flow rate of the gas mixture, and a pressure relief valve. An oxygenator is equipped with a polypropylene membrane and a heat exchanger connected to a temperature-regulating device, is connected to a first supply gas main connected to the medical gas mixer, a supply venous main connected via the roller pump of the HLM to a venous reservoir, and a discharge arterial main equipped with an arterial filter and a bubble sensor connected between the oxygenator and the arterial filter. A cylinder with compressed helium is connected by a second gas main to the gas mixer through a pressure reducer and is equipped with a means for regulating the pressure of the supplied helium from the cylinder to the second gas main, a pressure control sensor in the cylinder with compressed helium, and a pressure control sensor in the second gas main. An oxygen concentration sensor is placed in the first gas main. A flow sensor for the volumetric flow rate of helium is placed in the second gas main. A blood temperature sensor is placed on the discharge arterial main at the outlet of the oxygenator. A control unit is connected to the temperature-regulating device, a blood gas analyser, the means for regulating the pressure of the supplied helium from the cylinder to the second gas main, the pressure control sensor in the cylinder with compressed helium, the pressure control sensor in the second gas main, the oxygen concentration sensor placed in the first gas main, the flow sensor for the volumetric flow rate of helium placed in the second gas main, an oxygen pressure sensor of the central gas main, a patient's skin temperature sensor, an oropharyngeal temperature sensor, the blood temperature sensor, and the pressure relief valve of the second gas main, with the ability to maintain the amount of supplied helium in the gas mixture from 10 vol% to 15 vol% when recording microbubbles of size 0.65 cm 3 or more, increase the volumetric flow rate of the gas mixture at the oxygenator inlet by 1 litre per minute in the absence of a decrease in bubble size, and stop increasing the volumetric flow rate of the gas mixture when the partial pressure of carbon dioxide in the blood is 30 mmHg or less, and/or the partial pressure of oxygen in the blood is 150 mmHg or more. A method for cardiopulmonary bypass using a helium-oxygen mixture is disclosed. EFFECT: increasing the safety of the cardiopulmonary bypass procedure. 7 cl, 7 dwg, 6 tbl

Inventors

  • Ivanov Ivan Valerevich
  • ZHURAVEL SERGEJ VLADIMIROVICH
  • Vladimirov Vitalij Vasilevich
  • KOKOV LEONID SERGEEVICH
  • KAMBAROV SERGEJ YUREVICH
  • Sagirov Marat Anvarovich
  • Klychnikova Elena Valerevna
  • PETRIKOV SERGEJ SERGEEVICH

Dates

Publication Date
20260505
Application Date
20251004

Claims (20)

  1. 1. An artificial circulation system using a helium-oxygen mixture, including an artificial circulation apparatus (AC) equipped with a roller pump;
  2. a medical gas mixer connected to a central gas line with oxygen, containing a regulator of the percentage of oxygen in the gas mixture, a regulator of the volumetric flow rate of the gas mixture and an excess pressure relief valve;
  3. an oxygenator equipped with a polypropylene membrane and a heat exchanger connected to a temperature control device, connected to a first supply gas line connected to a medical gas mixer, a supply venous line connected through a roller pump of the CPB apparatus to a venous reservoir, and an outflow arterial line equipped with an arterial filter and a bubble sensor connected between the oxygenator and the arterial filter; and a blood gas analyzer,
  4. characterized in that it additionally contains
  5. a cylinder with compressed helium, connected by a second gas line to a gas mixer through a pressure reducer, equipped with a means for regulating the pressure of helium supplied from the cylinder to the second gas line, a pressure control sensor in the cylinder with compressed helium, a pressure control sensor in the second gas line;
  6. an oxygen concentration sensor located in the first gas line;
  7. a flow-through helium volumetric flow sensor located in the second gas line;
  8. oxygen pressure sensor in the central gas line,
  9. temperature sensors for the patient's skin and oropharynx,
  10. a blood temperature sensor placed on the outflow arterial line at the outlet of the oxygenator, and
  11. a control unit connected to a temperature control device, a blood gas analyzer, a means for regulating the pressure of helium supplied from a cylinder to a second gas line, a pressure control sensor in a compressed helium cylinder, a pressure control sensor in a second gas line, an oxygen concentration sensor located in the first gas line, a flow-through helium volumetric flow rate sensor located in the second gas line, an oxygen pressure sensor of the central gas line, a patient skin temperature sensor, an oropharynx temperature sensor, a blood temperature sensor and an excess pressure relief valve of the second gas line, with the ability to maintain the amount of helium supplied in the gas mixture from 10 vol.% to 15 vol.% when registering microgas bubbles of 0.65 cm3 or more in size, an increase in the volumetric flow rate of the gas mixture at the oxygenator inlet by 1 l per minute in the absence of a decrease in the bubble sizes, and a cessation of an increase in the volumetric flow rate of the gas mixture at a partial pressure of carbon dioxide in the blood of 30 mm Hg. and below, and/or partial pressure of oxygen in the blood of 150 mmHg and above.
  12. 2. The system according to paragraph 1, characterized in that the pressure reducer is made mechanical or electrical with the ability to regulate the pressure in the range from 0 to 2.5 MPa in increments of 0.1 MPa.
  13. 3. The system according to paragraph 1, characterized in that the excess pressure relief valve, located in the second gas line, is equipped with a flow-through pressure indicator.
  14. 4. The system according to claim 1, characterized in that it contains a shunt with a three-way valve built into it for taking a blood sample, wherein one end of the shunt is connected to the supply venous line on the side of the entrance to the oxygenator, and the other end is connected to the outlet arterial line on the side of the exit from the oxygenator.
  15. 5. A method of artificial circulation using a helium-oxygen mixture, characterized in that
  16. oxygen and helium are supplied to the medical gas mixer under pressure from 0.4 to 0.6 MPa, after first equalizing the pressure of helium and oxygen in the gas lines with a deviation of no more than 5% and obtaining a gas mixture with a 10 vol.% helium fraction at the outlet of the mixer,
  17. a gas mixture is supplied to an oxygenator with a heat exchanger, the blood supplied to the oxygenator from a venous reservoir is first cooled, the temperature is monitored using oropharynx and/or skin temperature sensors and the temperature is maintained until the end of the stage of the operation performed using IR, then the blood is heated to no higher than 37°C,
  18. the volumetric rate of gas mixture supply to the oxygenator is set in accordance with the calculated volumetric rate of blood flow during artificial circulation, which is determined taking into account the anthropometric parameters of the patient,
  19. During cooling and heating of the patient, the size of microgas bubbles in the blood in the arterial line draining from the oxygenator is monitored,
  20. when micro gas bubbles of 0.065 cm3 or more in size are detected, the amount of helium supplied to the gas mixture is increased to 15 vol.%; if there is no reduction in the bubble size within 1 minute after increasing the percentage of helium in the gas mixture, an iterative increase in the volumetric flow rate of the gas mixture supplied to the oxygenator inlet is carried out by 1 l per min relative to the preset value,

Description

Field of technology to which the invention relates The invention relates to the field of medicine, namely anesthesiology and resuscitation, and can be used during cardiac surgery to eliminate microgas emboli from the extracorporeal circuit at the oxygenator level and to increase the rate of patient warming during artificial circulation. State of the art Surgical interventions on the heart and major vessels require replacement of cardiac and pulmonary functions using a cardiopulmonary bypass (CPB). The use of CPB involves direct contact of blood with air, including mixing of blood and air in the venous reservoir. This causes the formation of microgas bubbles and emboli in the lumen of the extracorporeal circuit during CPB operation. Furthermore, high-volume, prolonged cardiac surgeries require hypothermia, which increases the rate of bubble formation, negatively impacting patient outcomes. Patient rewarming is an essential and inevitable component of the procedure, carrying additional risks of microgas embolism and cerebral edema. Therefore, cardiovascular surgery under CPB is often associated with neurological complications caused by microgas embolism, as well as increased duration of CPB when hypothermia is required, leading to increased risks of adverse outcomes. The prior art describes the use of membrane oxygenators, arterial filters installed at the oxygenator outlet, and means for monitoring the volume of gas bubbles and temperature in the extracorporeal circuit to prevent microgas embolism. Currently, an oxygen-air mixture is used to provide extracorporeal blood oxygenation during artificial circulation. However, the addition of air to dilute the oxygen adds nitrogen to the microgas bubbles, complicating their dissolution in the blood, preventing the use of an oxygenator to eliminate microgas emboli. Blood temperature at the oxygenator is regulated by the temperature of the heat-conducting fluid in the heat exchanger. However, the use of an oxygen-air mixture does not significantly affect the rate of temperature change. Therefore, the development of a method and system for reducing the volume of microgas emboli in the artificial circulation circuit with the ability to additionally influence the rate of change of the patient's body temperature is of current interest. The prior art discloses various methods and systems for eliminating microgas embolism during CPB. In particular, a method and system for artificial blood circulation using hypobaric oxygenation are known [US Patent No. 10335531 B2], wherein the elimination of microgas emboli is achieved by creating a vacuum in the gas pressure at the outlet of the oxygenator using a vacuum device. The system comprises a blood storage reservoir; a pump configured to supply pressure to the CPB system; an oxygen source including an oxygen pressure regulator; an oxygenator connected to the oxygen source pressure regulator via a purge gas inlet, wherein the purge gas inlet is configured to create a pressure below atmospheric; a vacuum regulator connected to the oxygenator via a purge gas outlet and configured to supply a pressure below atmospheric; a flow restrictor connected to the purge gas inlet and configured to provide a pressure differential from the oxygen source to the oxygenator; An arterial filter connected to the oxygenator's blood outlet and to the artificial blood circulation reservoir. In artificial blood circulation, subatmospheric pressure in the oxygenator is maintained using a vacuum regulator; oxygen is introduced into the oxygenator at subatmospheric pressure through a pressure regulator and a flow restrictor. However, the existing method and system rely on the use of a gas mixture containing air, requiring technical means to ensure and control the vacuum in the circuit during CPB. Furthermore, existing solutions carry the risk of damaging the oxygenator membrane due to possible membrane deformation by the vacuum device, do not allow for the temperature regulation process, and do not ensure the complete elimination of microgas emboli. The closest to the claimed invention are a method and system for recirculating medical gases [patent US 2006231098 A1], providing for the supply of a helium-oxygen mixture to a breathing circuit, including an oxygenator, using a recirculation system. The system includes: a constant-speed circulation pump for supplying gas to the main circuit and increasing the gas pressure from a lower pressure to a higher pressure, a pressure maintaining valve downstream of the pump and dividing the main circuit into a higher-pressure section and a lower-pressure section, means for measuring the concentration of at least one component of the recirculated medical gas mixture and generating a signal indicating said concentration, means for regulating the volume of the main circuit in the lower-pressure section to maintain a specified gas flow to the pump and generating a signal indicating said volume, means for releasing gas fr