The potentially harmful effects of short-term mechanical ventilation during surgery have been examined in recent years. An optimal strategy for mechanical ventilation of patients during non-laparoscopic abdominal surgery must be devised. A total of 63 patients undergoing elective open abdominal surgery with more than 2 h of ventilation time were selected for this randomized, open-label, clinical study. They were divided into three ventilation groups: high volume of 9 ml/kg IBW (ideal body weight) with ZEEP (zero end-expiratory pressure); low volume of 7 ml/kg IBW with 8 cm H2O PEEP (positive end expiratory pressure); and low volume of 7 ml/kg IBW with 8 cm H2O PEEP and recruitment. Intraoperative PaO2/FiO2 ratio and pulmonary compliance and postoperative pulmonary function were measured. There were no significant differences in intraoperative PaO2/FiO2 ratio among the three groups (P=0.31). The pulmonary compliance of three groups showed different changes over time (group effect over time P=0.0006). There were no significant differences in FEV1 or FVC among the three groups (P=0.32 and 0.09, respectively), but both of these measurements showed different changes over time (group effect over time P<0.001). On the first postoperative day, the low volume with high PEEP and recruitment group had significantly higher FEV1 than the other two groups (mean ± SD): 1.52 ± 0.37 versus 0.95 ± 0.38 (P<0.001) and 1.52 ± 0.37 versus 0.95 ± 0.34 (P<0.001), respectively. Low tidal volume with PEEP and recruitment showed advantages in maintaining the pulmonary compliance and expediting the recovery of the 1(st) postoperative day's pulmonary function in patients undergoing non-laparoscopic abdominal surgery.
Keywords: PaO2/FIO2 ratio; Ventilation strategy; pulmonary compliance; pulmonary function.