Post Caesarean Surgical Wound Infection in Obese Patients: An Open Prospective Cohort Study

Background:Studies have linked intra-abdominal hypertension (IAH) to postoperative infectious complications. Since IAH is a constant companion of obesity, it is logical to assume a causal connection between high incidences of wound infection in female obese patients to the level of postoperative intra-abdominal pressure (IAP). Objective:The primary aim of the study was to determine if wound infection in obese primigravidas is related to intra- abdominal pressure (IAP) after caesarean section. Secondary objective was to determine the type of bacterial contamination in placenta, lochia and surgical site. Materials and methods:Inclusion criteria were all primigravida women with term singleton pregnancy and delivery by caesarean section. A total of 313 patients were divided into four groups according to their BMI recorded before sixth week of pregnancy. Group I (n=90): BMI 18.5 - 24.9, Group II (n=137): BMI 25-29.9, Group III (n=49): BMI 30-39.9, Group IV (n=37) BMI ≥ 40 kg/m2. Postoperatively incision site was evaluated for oedema, flushing, scar tenderness, hyperthermia, purulent discharge, and suture line disruption. Discharge was sent for cytology. The presence of seroma and hematomas (non-infectious complications) was assessed by ultrasound in uterovesical fold, subaponeurotic and epiaponeurotic layer done on post operative three, five and seven days. Bacteriological studies were carried out on amniotic fluid, placenta, lochia and wound discharge. IAP was assessed by UnometerTM Abdo-PressureTM (Unomedical). Difference in abdominal pressure (Δ IAP) from baseline at 12, 24 and 72 hours was calculated. Results:Postoperative wound complications (including infectious and non-infectious) was seen in 56 (17.9 %) post caesarean patients. Epiaponeurotic seroma, subaponeurotic and epiaponeurotic hematoma, infected wound and bacterial contamination of postoperative wounds was statistically significant in obese patients (group III & group IV) compared to non obese group I (p < 0.05). The titer of cultured microorganisms increased with higher degree of obesity, but did not exceed 105 CFU/ml, cut off for infective wound. Postoperative IAP decreased with time in all groups. However IAP was statistically higher in Groups II, III and IV compared to Group I at all stages of the study. Conclusion: In the present study, wound infection occurred in 9.9% obese female following caesarean section. Long- persisting IAH in the postoperative period is a significant risk factor for post caesarean wound infection. Keywords: Obesity; C-section; Wound infection; Intra-abdominal pressure; Bacteriological test