National Health and Medical Research Council Centre of Research Excellence in Wiser Wound Care, Menzies Health Institute, Griffith University, Gold Coast, Qld, Australia
Gold Coast University Hospital, Gold Coast Health, Southport, Qld, Australia.
BMJ. 2021 May 5;373:n893. doi: 10.1136/bmj.n893.
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.
Multicentre, pragmatic, randomised, controlled, parallel group, superiority trial.
Four Australian tertiary hospitals between October 2015 and November 2019.
Eligible women had a pre-pregnancy body mass index of 30 or greater and gave birth by elective or semi-urgent caesarean section.
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.
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.
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).
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.
ANZCTR identifier 12615000286549.
比较封闭式切口负压伤口疗法（NPWT）与标准敷料在预防肥胖女性剖宫产术部位感染（SSI）中的效果。
多中心、实用、随机、对照、平行组、优效性试验。
2015 年 10 月至 2019 年 11 月期间澳大利亚四家三级医院。
符合条件的女性在怀孕前的体重指数为 30 或以上，并通过择期或半紧急剖宫产分娩。
2035 名同意的女性在剖宫产前随机分为封闭式切口 NPWT 组（n=1017）或标准敷料组（n=1018）。直到皮肤闭合前才进行隐藏分配。
主要结局是 SSI 的累积发生率。次要结局包括 SSI 的深度（浅表、深部或器官/体腔）、伤口并发症的发生率（裂开、血肿、血清肿、出血、瘀伤）、住院时间和与敷料相关的不良事件的发生率。女性和临床医生未进行盲法，但结局评估者和统计师对治疗分配进行了盲法。预设的主要意向治疗分析基于对少数（n=28）缺失结局数据的女性没有 SSI 的保守假设。事后敏感性分析包括最佳情况分析和完全情况分析。
在主要意向治疗分析中，75 名（7.4%）接受封闭式切口 NPWT 治疗的女性和 99 名（9.7%）接受标准敷料治疗的女性发生 SSI（风险比 0.76，95%置信区间 0.57 至 1.01；P=0.06）。为探索缺失数据的影响而进行的事后敏感性分析发现了相同的效果方向（封闭式切口 NPWT 降低 SSI），具有统计学意义。在接受封闭式切口 NPWT 的 996 名女性中，有 40 名（4.0%）发生水疱，而在接受标准敷料的 983 名女性中，有 23 名（2.3%）发生水疱（风险比 1.72，1.04 至 2.85；P=0.03）。
与标准敷料相比，肥胖女性剖宫产术后预防性使用封闭式切口 NPWT 可降低 24%的 SSI 风险（绝对风险降低 3%）。这一差异接近统计学意义，但可能低估了在该人群中使用封闭式切口 NPWT 的效果。保守的主要分析、多变量调整模型和事后敏感性分析的结果需要与越来越多的封闭式切口 NPWT 益处的证据以及全球行剖宫产术的肥胖女性数量一并考虑。使用封闭式切口 NPWT 的决定必须考虑到皮肤水疱增加和经济因素的影响，并且应该根据与患者的共同决策来做出。
澳大利亚临床试验注册中心标识符 12615000286549。
