Objective To determine the effectiveness of closed incision negative pressure wound therapy (NPWT) compared with standard dressings in preventing surgical site infection (SSI) in obese women undergoing caesarean section. Design Multicentre, pragmatic, randomised, controlled, parallel group, superiority trial. Setting Four Australian tertiary hospitals between October 2015 and November 2019. Participants Eligible women had a pre-pregnancy body mass index of 30 or greater and gave birth by elective or semi-urgent caesarean section. Intervention 2035 consenting women were randomised before the caesarean procedure to closed incision NPWT (n=1017) or standard dressing (n=1018). Allocation was concealed until skin closure. Main outcome measures The primary outcome was cumulative incidence of SSI. Secondary outcomes included depth of SSI (superficial, deep, or organ/body space), rates of wound complications (dehiscence, haematoma, seroma, bleeding, bruising), length of stay in hospital, and rates of dressing related adverse events. Women and clinicians were not masked, but the outcome assessors and statistician were blinded to treatment allocation. The pre-specified primary intention to treat analysis was based on a conservative assumption of no SSI for a minority of women (n=28) with missing outcome data. Post hoc sensitivity analyses included best case analysis and complete case analysis. Results In the primary intention to treat analysis, SSI occurred in 75 (7.4%) women treated with closed incision NPWT and in 99 (9.7%) women with a standard dressing (risk ratio 0.76, 95% confidence interval 0.57 to 1.01; P=0.06). Post hoc sensitivity analyses to explore the effect of missing data found the same direction of effect (closed incision NPWT reducing SSI), with statistical significance. Blistering occurred in 40/996 (4.0%) women who received closed incision NPWT and in 23/983 (2.3%) who received the standard dressing (risk ratio 1.72, 1.04 to 2.85; P=0.03). Conclusion Prophylactic closed incision NPWT for obese women after caesarean section resulted in a 24% reduction in the risk of SSI (3% reduction in absolute risk) compared with standard dressings. This difference was close to statistical significance, but it likely underestimates the effectiveness of closed incision NPWT in this population. The results of the conservative primary analysis, multivariable adjusted model, and post hoc sensitivity analysis need to be considered alongside the growing body of evidence of the benefit of closed incision NPWT and given the number of obese women undergoing caesarean section globally. The decision to use closed incision NPWT must also be weighed against the increases in skin blistering and economic considerations and should be based on shared decision making with patients. Trial registration ANZCTR identifier 12615000286549.

中文翻译：

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剖宫产肥胖妇女闭合切口负压伤口疗法与标准敷料的比较：多中心平行组随机对照试验

目的确定闭合切口负压伤口疗法（NPWT）与标准敷料相比在预防剖宫产肥胖女性中预防手术部位感染（SSI）的有效性。设计多中心，务实，随机，对照，平行小组，优越性试验。在2015年10月至2019年11月之间设置了四家澳大利亚三级医院。参与者符合条件的妇女的孕前体重指数为30或更高，并通过选择性或半紧急剖腹产术分娩。在剖腹产手术前，对2035名同意接受干预的女性进行随机分组，以采用封闭切口NPWT（n = 1017）或标准敷料（n = 1018）。隐藏分配直到皮肤闭合。主要结局指标主要结局指标是SSI的累积发生率。次要结果包括SSI的深度（浅表，深度，或器官/身体空间），伤口并发症发生率（裂开，血肿，血清肿，出血，淤青），住院时间以及与敷料相关的不良事件发生率。妇女和临床医生没有被遮盖，但是结果评估者和统计学家对治疗分配不知情。预先指定的主要治疗分析意图是基于保守的假设，即缺少结果数据的少数女性（n = 28）没有SSI。事后敏感性分析包括最佳案例分析和完整案例分析。结果在主要的治疗分析中，采用标准切口NPWT治疗的75例女性（7.4％）和标准敷料的99例女性（9.7％）发生SSI（风险比0.76，95％置信区间0.57至1.01； P = 0.06）。事后敏感性分析探讨了缺失数据的影响，发现了相同的作用方向（闭合切口NPWT减少了SSI），具有统计学意义。40/996（4.0％）接受闭合切口NPWT的妇女和23/983（2.3％）接受标准敷料的妇女发生水疱（风险比1.72，1.04至2.85； P = 0.03）。结论与标准敷料相比，剖宫产术后肥胖妇女的预防性闭合切口NPWT可使SSI风险降低24％（绝对风险降低3％）。这种差异接近统计学意义，但可能低估了该人群闭合切口NPWT的有效性。保守的主要分析结果，多变量调整后的模型，考虑到全球范围内接受剖腹产的肥胖女性的数量，越来越多的证据表明闭合切口NPWT的益处，需要考虑事后敏感性分析和事后敏感性分析。使用闭合切口NPWT的决定还必须权衡皮肤起泡和经济因素的增加，并且应基于与患者共同的决定。试用注册ANZCTR标识符12615000286549。