Effect of continuous positive pressure ventilation strategy during induction of general anesthesia on atelectasis after induction in obese patients / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of continuous positive airway pressure(CPAP) ventilation strategy during induction of general anesthesia on atelectasis after induction in obese patients.Methods:A total of 86 patients, aged 30-60 yr, with body mass index of 28-35 kg/m 2, of American Society of Anesthesiologists Physical Status classification Ⅱor Ⅲ, scheduled for elective cerebrovascular intervention under general anesthesia, were divided into 2 groups ( n=43 each) using a random number table method: CPAP group (group C) and routine group (group R). Group C received CPAP 5 cmH 2O-assisted ventilation after preoxygenation for spontaneous breathing and disappearance of spontaneous breathing. Chest CT scan and arterial blood gas analysis were performed after entering the operating room (T 1) and 5 min after endotracheal intubation (T 2) to calculate the percentage of atelectasis area and to record PaO 2. Dynamic lung compliance and plateau pressure were recorded at T 2. Mean minute ventilation under controlled breathing, P ETCO 2, and use of vasoactive drugs during induction were recorded. The occurrence of reflux and aspiration during mask ventilation was recorded. The development of pulmonary complications within 3 days after operation was recorded. Results:Compared with group R, the percentage of atelectasis area at T 2 was significantly decreased, PaO 2, dynamic lung compliance and plateau pressure were increased ( P<0.05), and no significant change was found in mean minute ventilation, P ETCO 2, requirement for vasoactive drugs and incidence of pulmonary complications in group C ( P>0.05). No reflux or aspiration was observed during mask ventilation. Conclusions:CPAP (5 cmH 2O) strategy during anesthesia induction can reduce the degree of atelectasis after induction in obese patients.