Post-operative atelectasis - a randomised trial investigating a ventilatory strategy and low oxygen fraction during recovery

作者：Edmark L^*; Auner U; Lindback J; Enlund M; Hedenstierna G

来源：Acta Anaesthesiologica Scandinavica, 2014, 58(6): 681-688.

DOI：10.1111/aas.12322

Background Atelectasis is common during and after general anaesthesia. We hypothesized that a ventilation strategy with a combination of 1) continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP) and 2) a reduced end-expiratory oxygen concentration during recovery would reduce post-operative atelectasis. Methods Sixty patients were randomized into two groups. During anaesthesia induction, inspiratory oxygen fraction (FIO2) was 1.0, and depending on weight, CPAP 6, 7 or 8cmH2O was applied in both groups via facemask. During maintenance of anaesthesia, a laryngeal mask airway (LMA) was used, and PEEP was 6-8cmH2O in both groups. Before removal of the LMA, FIO2 was set to 0.3 in the intervention group and 1.0 in the control group. Atelectasis was studied by computed tomography (CT) approximately 14min post-operatively. Results In one patient in the group given an FIO2 of 0.3 before removal of the LMA a CT scan could not be performed so the patient was excluded. The area of atelectasis was 5.5, 0-16.9cm2 (median and range), and 6.8, 0-27.5cm2 in the groups given FIO2 0.3 or FIO2 1.0 before removal of the LMA, a difference that was not statistically significant (P=0.48). Post-hoc analysis showed dependence of atelectasis on smoking (despite all were clinically lung healthy) and American Society of Anesthesiologists class (P=0.038 and 0.015, respectively). Conclusion Inducing anaesthesia with CPAP/PEEP and FIO2 1.0 and deliberately reducing FIO2 during recovery before removal of the LMA did not reduce post-operative atelectasis compared with FIO2 1.0 before removal of the LMA.

• 出版日期2014-7