Predictors of surgical site skin infection and clinical outcome at caesarean section in the very severely obese: A retrospective cohort study

The Relationship between Body Mass Index and Operative Complications in Patients undergoing Immediate Postpartum Tubal Ligation

OBJECTIVE

 The objective of this study is to examine the relationship between body mass index (BMI) and complications for patients undergoing postpartum permanent contraception.

STUDY DESIGN

 Retrospective cohort study of patients aged 18 or older who had a vaginal delivery at an academic hospital between 2011 and 2016 and underwent a postpartum tubal ligation during the delivery admission. There were three comparative groups: nonobese (BMI ≤ 29 kg/m2), obese (BMI 30-39 kg/m2), and morbidly obese BMI (≥40 kg/m2). The outcome of interest was composite operative complications which included any occurrence of an intraoperative, postoperative, or anesthesia complication.

RESULTS

 A total of 921 patients were included for analysis. Average operative time was statistically longer for patients in the morbidly obese group (33 minutes) vs. the nonobese (25 minutes) and obese (29 minutes) groups (p < 0.0001). Composite complications were greater for the obese groups, but not statistically significant (5.1 vs. 6 vs. 16%, p = 0.06). Wound complications were significantly greater for the obese groups (0.8 vs. 1.5 vs. 5.5%, p = 0.01). A logistic regression model demonstrated that only operative time was predictive of operative complications.

CONCLUSION

 Overall complications of postpartum tubal complications are low; however, our study did demonstrate significantly longer operative time and wound complications for patients with obesity. The findings of our study indicate that postpartum permanent contraception can remain as an option for these patients. Further studies may help identify the best practices to decrease operative time and subsequent wound complications. This study contributes to the limited data regarding obesity and postpartum permanent contraception. We found increased operative time and wound complications for obese patients. Additional studies may identity best practices to decrease these complications. Given our findings of overall low operative complications, postpartum permanent contraception can remain an option for obese patients.

Challenges in timing and mode of delivery in morbidly obese women

Globally obesity is increasing especially in the reproductive age group. Pregnant women with obesity have higher complication and intervention rates. They are also at increased risk of stillbirth and intrapartum complications. Although organisations like NICE, RCOG, ACOG and WHO have published guidelines and recommendations on care of pregnant women with obesity the evidence from which Grade A recommendations can be made on timing and how to deliver is limited. The current advice is therefore to have discussions with the woman on risks to help her make an informed decision about timing, place, and mode of delivery. Obesity is an independent risk factor for pregnancy complications including diabetes, hypertension and macrosomia. In those with these complications, the timing of delivery is often influenced by the severity of the complication. As an independent factor, population based observational studies in obese women have shown an increase in the risk of stillbirth. This risk increases linearly with weight from overweight through to class II obesity, but then rises sharply in those with class III obesity by at least 10-fold beyond 42 weeks when compared to normal weight women. This risk of stillbirth is notably higher in obese women from 34 weeks onwards compared to normal weight women. One modifiable risk factor for stillbirth as shown from various cohorts of pregnant women is prolonged pregnancy. Research has linked obesity to prolonged pregnancy. Although the exact mechanism is yet unknown some have linked this to maternal dysregulation of the hypothalamic pituitary adrenal axis leading to hormonal imbalance delaying parturition. For these women the two dilemmas are when and how best to deliver. In this review, we examine the evidence and make recommendations on the timing and mode of delivery in women with obesity. For class I obese women there are no differences in outcome with regards to timing and mode of delivery when compared to lean weight women. However, for class II and III obesity, planned induction or caesarean sections may be associated with a lower perinatal morbidity and mortality although this may be associated with an increased in maternal morbidity especially in class III obesity. Studies have shown that delivery by 39 weeks is associated with lower perinatal mortality compared to delivering after in these women. On balance the evidence would favour planned delivery (induction or caesarean section) before 40 weeks of gestation. In the morbidly obese, apart from the standard lower transverse skin incision for CS, there is evidence that a supraumbilical transverse incision may reduce morbidity but is less cosmetic. Irrespective of the option adopted, it is important to discuss the pros and cons of each.

Closed incision negative pressure wound therapy versus standard dressings in obese women undergoing caesarean section: multicentre parallel group randomised controlled trial

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.

A Systematic Review and Meta-Analysis of Wound Complications after a Caesarean Section in Obese Women

(1) Background: Caesarean sections in obese patients are associated with an increased risk of surgical wound complications, including hematomas, seromas, abscesses, dehiscence, and surgical site infections. The aim of the present study is to perform a meta-analysis and systematic review of the current literature focusing on the strategies available to decrease wound complications in this population. (2) Methods: We reviewed the data available from the PubMed and the Science Direct databases concerning wound complications after caesarean sections in obese women. The following key words were used: “caesarean section”, “cesarean section”, “wound complication”, “wound morbidity”, and “wound infection”. A total of 540 papers were retrieved, 40 of which were selected for the final systematic review and whereas 21 articles provided data for meta-analysis. (3) Results: The conducted meta-analyses revealed that the use of prophylactic drainage does not increase the risk of wound complications in obese women after a caesarean sections (pooled OR = 1.32; 95% CI 0.64–2.70, p = 0.45) and that vertical skin incisions increase wound complications (pooled OR = 2.48; 95% CI 1.85–3.32, p < 0.01) in obese women, including extremely obese women. (4) Conclusions: Subcutaneous drainage does not reduce the risk of a wound complications, wound infections, and fever in obese women after caesarean sections. Negative prophylactic pressure wound therapy (NPWT) may reduce the risk of surgical site infections. The evidence of using a prophylactic dose of an antibiotic before the caesarean section is still lacking.

Maternal morbidity associated with skin incision type at cesarean delivery in obese patients: a systematic review

Aim:

To describe the relationship between cesarean skin incision type and postoperative wound complications (WCs) in obese pregnant patients.

Materials & methods:

MEDLINE (PubMed and OVID), Embase, Scopus, Web of Science Core Collection, Cochrane Library and ClinicalTrials.gov databases were used for publication search. Selection criteria consisted of articles studying pregnant patients with BMI ≥30 kg/m² undergoing cesarean delivery and assessing the effect of skin incision type on postoperative maternal outcomes.

Results:

Ten publications met criteria for a systematic review of a total of 2946 patients. The transverse skin incision was associated with a lower rate of WC compared with the vertical skin incision. The pooled risk ratio for WCs was 0.47 (95% CI: 0.37–0.58; p < 0.00001).

Conclusion:

Transverse skin incision may be preferable to vertical skin incision at cesarean delivery in pregnant patients with obesity as it may be associated with a lower rate of WCs.

PROSPERO registration ID: CRD42020151106

This systematic review describes the relationship between skin incision type and postoperative wound complications in obese patients following cesarean delivery. The study results suggest that transverse skin incisions may be preferable to vertical skin incisions in the obese obstetric population for the reduction of wound complications.