External Negative Pressure Dressing System vs. Traditional Wound Dressing for Cesarean Section Incision in Obese Women.

Obesity, defined as body mass index (BMI, calculated as weight (kg)/ [height (m)] 2) of 30 or greater, is a common medical comorbidity of pregnancy affecting one third of reproductive-aged women. Maternal obesity is also a well-recognized risk factor for dysfunctional labor and cesarean delivery with a cesarean section rate of 33% in obese women with BMI of 30 or greater and 43% in women with BMIs of 40 or greater.

Obesity is an independent risk factor for post-operative surgical site infection. The risk of post-cesarean surgical site infection has been shown to double for every 5 unit increase in body mass index (BMI) above 30 kg/m , occurring in about 10% of obese women undergoing caesarean section despite prophylactic strategies (e.g. antibiotics).

This can be explained partly by a decreased blood flow in adipose tissue and an obesity‐associated inflammation causing vascular dysfunction, which results in a local hypoxic response. Hypoxia impairs oxidative bacterial killing and leads to an increased risk of surgical site infection.

Wound healing is a sequence of physiologic events that include inflammation, epithelialization, fibroplasia, and maturation. Failure of wound healing at the surgical site can lead to seroma, hematoma, wound dehiscence, incisional hernia and surgical site infection.

Surgical site infection SSI according to The Centers for Disease Control and Prevention is as an infection occurring within 30 days from the operative procedure in the part of the body where the surgery took place, where there is purulent drainage from incision, isolated organisms from the incision, dehiscence or deliberate opening by the surgeon when the patient has at least one sign or symptom of clinical infection: localized pain, edema, erythema, warmth and fever greater than 38 c (unless culture of incision is negative) or there is an abscess or other evidence of infection is found during examination of incision, reoperation, or pathologic or radiologic exam.

SSIs is divided into incisional SSI and organ/space SSI. Incisional SSI is further divided into superficial and deep incisional SSI. Superficial Incisional Surgical Site Infection involves skin or subcutaneous tissue cellulitis, seroma, hematoma, wound healing disruption, or dehiscence. Deep Incisional Surgical Site Infection involves deep soft tissues such as fascia or muscle within incision. Organ/Space Surgical Site Infection involves any part of the anatomy other than the incision. SSI is associated with a maternal mortality rate of up to 3%.

Wound complication, even if not accompanied by an infection, is a significant cause of postoperative morbidity following cesarean delivery. In addition to the increased cost of care, there is the inconvenience of therapy, increased postoperative pain and convalescence, as well as difficulty with activities of daily living.

It is logical to employ novel risk reducing approaches including negative pressure wound therapy at the time of surgery that may prevent wound complications and to ensure that there is a demonstrable benefit to their use for wound complication prophylaxis.

Negative pressure wound therapy (NPWT), also known as a vacuum assisted closure (VAC), involves the controlled application of sub-atmospheric pressure to the local wound environment, using a sealed wound dressing connected to a vacuum to promote healing by primary intention by reducing the risk of hematoma / seroma due to improved lymphatic drainage and reduces the risk of wound dehiscence by decreasing the lateral and shear stress on sutures and decreasing bacterial load and wound fluids and by increasing blood flow, oxygenation, angiogenesis, and epithelialization.