Effects of pulmonary static inflation with different pressures on postoperative lung function in patients undergoing cardiac valve replacement with cardiopulmonary bypass

Abstract

Objective To evaluate the effects of pulmonary static inflation with different pressures on postoperative lung function in patients undergoing cardiac valve replacement with cardiopulmonary bypass (CPB).Methods Sixty ASA Ⅱ or Ⅲ patients,aged 26-70 yr,weighing 47-78 kg,undergoing elective cardiac valve replacement with CPB,were randomly divided into 2 groups (n =30 each):pulmonary static inflation with 5 cm H2O group (group L) and with 10 cm H2O group (group H).In L and H groups,pulmonary static inflation was performed with the pressure maintained at 5 and 10 cm H2O,respectively,after stopping mechanical ventilation during CPB.Arterial blood samples were taken before skin incision and at 1,3 and 6 h after termination of CPB for blood gas analysis.The alveolar-arterial oxygen pressure difference (D(A-a)O2),respiratory index (RI) and oxy.genation index (OI) were calculated.The indwelling time of endotracheal tube after operation and duration of ICU stay were recorded.Results Compared with group L,D(A-a)O2 and RI were significantly decreased and OI was increased at 1,3 and 6 h after termination of CPB,the incidence of OI less than 300 mm Hg was decreased (P ＜ 0.05),and no significant change was found in the indwelling time of endotracheal tube after operation and duration of ICU stay in H group (P ＞ 0.05).Collusion Pulmonary static inflation with 10 cm H2O can better improve postoperative pulmonary diffusion function than with 5 cm H2O in patients undergoing cardiac valve replacement with CPB. Key words: Pressure; Extracorporeal circulation; Respiratory function tests; Pulmonary static inflation