Effect Of Recruitment Maneuver For Lung Ventilation Function In Adult Patients Undergoing Cardiac Surgery During Cardiopulmonary Bypass

Objective: The aims of the study are to evaluate the effect of alveolar recruitmentstrategy (ARS) to improve the function of lung ventilation in adult patients undergoingcardiac surgery after cardiopulmonary bypass (CPB).Methods:38patients, aged45-60years old with ASA2-3degree according toAmerican Society of Anesthesiologists (ASA) and undergoing cardiac surgery via CPB,were randomly assigned to two groups, conventional mechanical ventilationgroup(Group A), alveolar recruitment strategy group(Group B). Group B started ARSimmediately after cardiopulmonary bypass stopped. All the selected patients werewithout cerebrovascular and neurological diseases or serious liver and kidneydysfunction before the operation. Anesthesia was induced with iv injection midazolam0.05-0.1mg/kg, fentanyl10ug/kg, etomidate0.2-0.3mg/kg, cisatracurium0.2mg/kg.Anesthesia maintained: After tracheal intubation,1%propofol6-8mg/kg/h werecontinuously injected with fentanyl20ug/kg injected before stenotomy for all thepatients. According to surgical procedure, two groups of patients were injected withmidazolam and cisatracurium. The blood samples were collected for blood gas analysisby radial artery, extracorporeal circulation machine respectively after trachealintubation(T1), after CPB stopped and before normal ventilation(T2),and at the end ofthe operation after close the chest. Radial artery blood oxygen saturation were measured,Oxygenation index（OI）, alveolar-arterial oxygen difference (PA-aO2) and Qs/Qt werecalculated. During and after operation, mean blood pressure, central venous pressure,heart rate and resusxitation were also observed. And record the respiratory index: FiO2,PIP, TV, PEEP, Respiratory rate.Results: Before CPB, at the time point of T1the difference of OI, PA-aO2andQs/Qt for the two patient groups was statistically insignificant(P>0.05); After CPB and alveolar recruitment strategy, oxygenation index(OI) of Group B was higher than that ofGroup A(P <0．05), but PA-aO2and intrapulmonary shunt volume(Qs／Qt) werelower(P<0．05) at the time point of T2,T3.Conclusion: Alveolar recruitment strategy (PIP of the highest peak pressure for40cmH2O, and PEEP of the highest peak pressure for20cmH2O) use for the adultpatients when undergoing cardiac surgery after cardiopulmonary bypass(CPB):1)in thegroup B, the patients’ oxygenation index (OI) increased significantly, PA-aO2andintrapulmonary shunt volume(Qs／Qt) were lower.2) the level of the pressure canimprove the lung function, and without any complications.3) give the operation afterCPB stopped immediately, the effect could been maintained at the end in the operationroom.Alveolar recruitment strategy’s pressure and timing of given can improve therespiratory function, attenuate lung injury, prevent cardiovascular adverse events.