ORCID
Justin S. Brandt 0000-0002-3194-1087
Cande V. Ananth 0000-0002-0410-2595
Word count : 460
The obese parturient is at increased risk for numerous postoperative
complications, including surgical site infections (SSI). Several
promising strategies have emerged to reduce the risk of wound
complications, including appropriately dosed antibiotics, antiseptic
vaginal preparations, and prophylactic incisional negative pressure
wound therapy (iNPWT). The latter approach is an innovation that applies
negative pressure to a closed caesarean incision, redistributes lateral
tension, reduces edema, and protects the surgical site from external
infectious sources.
In this edition of the BJOG , Hyldig and colleagues (Prophylactic
negative pressure wound therapy in obese women undergoing caesarean
section: a commentary on new evidence that fuels the debate. BJOG 2021
xxx) have written a commentary about a recently published multicenter
randomized trial of obese women in the United States who underwent
caesarean delivery that compared iNPWT to standard wound dressings. The
trial, which included 1624 patients recruited from February 2017 through
November 2019, was prematurely stopped due to futility and concerns
about serious adverse events (SAE). The authors concluded that iNPWT
does not reduce the risk of SSI in obese women.
Hyldig and colleagues raise several methodological problems with the
trial. A primary concern was related to the conclusion of “no
difference” when the trial was powered as a superiority trial rather
than an equivalence trial. The rate of SSI was less than expected, and
Hyldig and colleagues argue this may have been a consequence of
ineffective study design. Patients were consented for study
participation when they were in labour, rather than before labour, which
likely precluded participation of the obese patients at highest risk for
SSI who could not be enrolled if/when an urgent indication for delivery
arose, such as cord prolapse or category 3 fetal heart rate tracing due
to abruption. The trial also reported higher than expected rates of SAE,
including skin blisters, but many of these events have been
characterised as mild events in other studies and may have been
prevented with proper administration of the negative pressure device.
They were concerned about another potential limitation of study design
that may have biased the study’s findings to the null. The iNPWT was
left in place during hospitalisation for a median of 4 days while the
iNPWT devices are designed for 7-days of continuous use.
Although Hyldig and colleagues have published extensively on the
potential benefits of iNPWT and may have a favorable bias towards this
intervention, their arguments are statistically sound and merit
attention. The published trial provides level 1 evidence, but the
study’s conclusions raise more questions. Indeed, the results of the
study should not dissuade the use of this intervention and, rather,
should motivate the performance of a properly designed and powered
superiority trial investigating the potential benefits of iNPWT to
reduce the risk of surgical site infections for obese women.