During heart lung pump the effect of ventilating lungs on postoperatively respiratory functions under open heart surgery

ABSTRACTDURING HEART LUNG PUMP THE EFFECT OF VENTILATINGLUNGS ON POSTOPERATIVELY RESPIRATORY FUNCTIONS UNDEROPEN HEART SURGERYAli G0RGU MD.Department of Anaesthesiology and Reanimation:expert thesisDirector of Thesis: Prof. Dr. Nursan TAHTACIJune 2007, 40 PageTo stop ventilation in aim to facilitate the surgical procedure during open cardiacsurgery will cause to collapse of the lungs and to occure more complications. Thereare many ventilation strategies to prevent these events. In our study we investigatedthe effects of the open lung concept (OLC) on hemodynamic parameters, pulmonaryshunts, gradient of alveolo-arterial oxygen partial pressure [P(A-a )O2] and levels ofnitric oxide in bronchoalveoler lavage and plasma.Thirty ASA I-III patients, 18-80 years old, have ejection fraction higher than %40and Euro score lower than 7 who were operated under cardiopulmonary pump due toelective coronary artery grafting or heart valve procedure are randomly divided into 2groups. Group I is selected as OLC group (ventilated during cardiopulmonary bypassprocedure) and group 2 as the control group.The patients were operated under standard general anesthesia. The patiens ofOLC group were inflated with a tidal volume of 100 ml, 30 frequency / min ,10cmH2O PEEP and the pump exit valves were arranged to be Paw=45 cm H2O for 1minute. Whereas, the control group patients were not ventilated duringcardiopulmonary bypass period.Hemodynamic data were recorded before, during and after cardiopulmonarypump period. Measurement of pulmonary shunt and P(A-a)O2 were performed atthese periods. In addition, measurement of BAL and plasma NO levels were alsoperformed before and after cardiopulmonary pump.No significant difference was observed between 2 groups with regard tohemodynamic parameters. Pulmonary shunt and P(A-a)O2 mesurements at thepostoperative 2th hour found to be significantly lower in OLC group. NO levelsmeasured in the BAL and plasma specimens of the OLC group were not changedafter cardiopulmonary bypass period.We believe that application of OLC during cardiopulmonary bypass process hasbeneficial effects with decrease atelectasis and pulmonary dysfunction decreasingpulmonary shunt and P(A-a)O2.Key words: Open lung concept, Cardiac surgery, Cardiac anesthesia,Cardiopulmonary bypass, NO