BACKGROUND During general anaesthesia, most patients develop atelectasis, which promotes postoperative pulmonary complications. RCTs that investigated perioperative lung protection have failed to reduce postoperative pulmonary complications consistently. Ultrasound imaging could help confirm the effects of different protective ventilatory strategies, but this has not been tested in trials. The objective of this study was to use ultrasonography to evaluate whether lung-protective ventilation measures reduce perioperative atelectasis. METHODS We conducted a prospective, randomised patient- and assessor-blinded controlled trial in women undergoing open gynaecological surgery. Subjects were randomised to either lung protection or zero end-expiratory pressure (ZEEP; with no recruitment manoeuvres [RMs]). Lung protection entailed PEEP (7 cm H2O) and RMs every 30 min. Lung ultrasonography was undertaken at five predefined time points. The primary outcome was the difference in lung ultrasonography score (LUS) between groups before emergence; a lower LUS indicates better lung aeration. RESULTS We recruited 45 women (34-85 yr old). Women randomised to lung protection had lower mean (standard deviation) LUS before emergence (6.1 [3.7]), compared with women randomised to ZEEP (11.7 [3.9]; 95% confidence interval for the difference between group means [-7.9 to -3.2]; P<0.0001). This difference did not persist after extubation, with similar mean LUSs in women who had received intraoperative lung protection (7.0 [4.1]), compared with women randomised to receive ZEEP (7.7 [3.1]). CONCLUSIONS As assessed by lung ultrasonography, intraoperative PEEP/RMs decreased aeration loss during general anaesthesia. However, similar degrees of aeration loss were observed after tracheal extubation regardless of intraoperative ventilatory strategy. CLINICAL TRIAL REGISTRATION NCT02055807.

中文翻译：

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通过超声检查评估，在开放式妇科手术过程中，呼气末正压/招募操作相对于呼气末正压为零的效果对肺不张的影响：一项随机对照试验。

背景技术在全身麻醉期间，大多数患者发展为肺不张，从而促进术后肺部并发症。研究围手术期肺保护的RCT未能始终如一地减少术后肺部并发症。超声成像可以帮助确认不同的保护性通气策略的效果，但尚未在试验中进行测试。这项研究的目的是使用超声检查来评估肺保护通气措施是否可以减少围手术期肺不张。方法我们对接受开放式妇科手术的妇女进行了一项前瞻性，随机，患者和评估者双盲对照研究。受试者被随机分配到肺保护或呼气末压力为零（ZEEP；无招募动作[RM]）。肺部保护需要每30分钟进行PEEP（7 cm H2O）和RMs。在五个预定的时间点进行了肺部超声检查。主要结局是出现前两组之间的肺超声检查得分（LUS）的差异。较低的LUS表示肺通气更好。结果我们招募了45名女性（34-85岁）。随机分组接受肺保护的女性在出院前的LUS平均值（标准差）较低（6.1 [3.7]），而随机分组进行ZEEP的女性（11.7 [3.9]；组均数间差异的置信区间为95％[-7.9至-3.2] ]； P <0.0001）。拔管后这种差异并没有持续，接受术中肺保护的女性的平均LUSs（7.0 [4.1]）与随机接受ZEEP的女性（7.7 [3.1]）相似。结论如经肺部超声检查所评估，术中PEEP / RMs减少了全身麻醉期间的通气损失。但是，无论术中采用何种通气策略，气管拔管后的通气程度均相似。临床试验注册NCT02055807。