CHAPTER 55 Diana A. Racusin and Alex C. Vidaeff Department of Obstetrics and Gynecology, Division of Maternal‐Fetal Medicine, Baylor College of Medicine, Texas Children’s Hospital Pavilion for Women, Houston, TX, USA The rate of obesity has increased dramatically in the United States, presently with 20.5% of women being obese as they begin pregnancy [1]. Obesity is classified by WHO [2] as: An additional category of super‐morbid obesity (BMI >50) is sometimes used, especially since the number of women in this category has increased fivefold in the last two decades of the twentieth century [3]. Of all parturients, 4–6% have morbid obesity [1] and it has been estimated that 200 000 morbidly obese women give birth per year in the United States [4]. One of the consequences of prepregnancy obesity has been a greater risk of primary cesarean delivery, both scheduled and unplanned, even after controlling for social and medical risk factors [5]. Given the low rate of vaginal delivery after cesarean, repeat cesareans for these mothers are likely to occur at an increased rate as well. Elevated BMI has been reported to be associated with increased rates of failed trial of labor after cesarean delivery [6] (Hibbard). Cesarean delivery is the most common major surgical procedure in the United States, but women with BMI >35 have a double risk of cesarean delivery [7] and about 60% of women with BMI >50 undergo cesarean delivery [8]. This trend is present in spite of the physicians’ general preference to avoid cesarean delivery in obese women because of the added risk of morbidity with surgery. Obesity alone increases the likelihood of operative wound infections after cesarean delivery by fourfold. Other post‐cesarean complications with increased risk of occurrence in obese women, as noted in the Maternal‐Fetal Medicine Unit Cesarean Registry, were: wound opening (fivefold increase) and endometritis (26% increased risk) [9]. The rates of surgical site infections and wound disruption increase in parallel with the increase in subcutaneous thickness [10]. Surgical site infections affect not only the mother but also her support system and the healthcare system at large. A wound infection can add over $3000 to the total cost of medical care [11]. Caring for obese patients often requires modification of techniques and practices in order to improve care and safety. The United Kingdom National Collaborating Centre for Women’s and Children’s Health antenatal guidelines recognize obesity as one of the conditions for which additional care is required [12]. The skin incision type for obese women remains at the latitude of the surgeon, with limited clinical research data to guide the decision‐making. In general, the literature contrasts transverse incisions (suprapubic or supraumbilical) with midline vertical incisions (subumbilical, periumbilical, or supraumbilical). The level of evidence is very low, consisting of expert opinions, observational studies, or institutional standards of care. With low transverse incisions, the mainly theoretical concern is placement of the incision under the large panniculus in an area of low oxygen tension and increased microbial flora. On the other hand, a vertical incision is not without wound healing concerns because of longer incisions, higher opposition tension and a deeper subcutaneous layer involved. Opposing opinions have been expressed in the last century’s gynecological literature, with several authors recommending transverse incisions, both in the lower abdomen and above the umbilicus to enter the abdomen in non‐pregnant obese women [13, 14], whereas others advocated supraumbilical upper abdominal midline incisions for pelvic surgery in the morbidly obese patients [15]. The literature reports are also inconsistent when recommendations are made specifically for cesarean deliveries. Retrospective data in morbidly obese women undergoing cesarean delivery suggest either no difference in wound outcomes based on the type of skin incision [16], a significantly higher wound complications rate with vertical incisions compared with low transverse incisions [17], or just the opposite, lower wound complications rates with vertical incisions [18]. The operative time and blood loss may be lower with vertical incisions, but, on the other hand, they are more painful, delay the post‐operative mobilization and increase pulmonary complications in postpartum [19]. Supraumbilical vertical midline incisions may also require a higher‐level of spinal anesthesia and that in turn can cause difficulties with ventilation in an obese patient. A particular aspect related to cesarean delivery in obese women is that high vertical incisions or high transverse incisions are associated with up to an 18‐fold increased risk of corporeal, fundal and vertical hysterotomies because the incision often overlies the uterine fundus limiting the access to the lower uterine segment [16, 20–22]. Tixier et al., proponents of transverse incisions, recommend supra‐ versus subumbilical transverse incisions only in obese women with a voluminous panniculus, in “apron” position [23]. In a recent survey of the American College of Obstetricians and Gynecologists members, for morbidly obese women in nonemergency conditions, 84% of respondents preferred a Pfannenstiel incision and even in emergency conditions, 66% preferred the same type of incision [24]. A common practice when Pfannenstiel incision is employed is to elevate the panniculus using adherent tape. This should be done cautiously to avoid interference with ventilation due to increased intrathoracic pressure. Cephalad retraction of the panniculus can also worsen hypotension. Methods of concomitant cephalad and vertical suspension of the panniculus have been proposed to facilitate ventilation and oxygenation [25]. Two cases of fat necrosis within the abdominal panniculus have been reported following cesarean delivery with suprapubic transverse incisions in morbidly obese patients. The diagnosis was made three to four weeks after delivery and it was postulated that traumatic ischemia during retraction at surgery may have contributed [26]. Taken as a whole, the available data do not allow firm conclusions to be drawn. A randomized clinical trial is underway comparing low transverse and vertical skin incisions for cesarean delivery in morbidly obese women in terms of wound complications (registered at http://clinicaltrials.gov with the ID number NCT 018997376). It will probably be the first randomized trial on this topic. Even if different incisions may have different wound infection risks, the choice of incision should still be individualized because the panniculus is different in different obese patients and the umbilicus may be more or less displaced caudally. The incision choice should focus on adequate exposure for optimal fetal delivery through a low transverse hysterotomy. Intra‐operatively, long instrument trays may be necessary [27], as well as self‐retaining retractors, at the discretion of the surgeon. Self‐retaining retractors, purported to act as a form of barrier protection while also retracting wound edges, when studied in a randomized controlled trial in 301 obese women, did not decrease the rate of surgical site infection or wound disruption [10]. Regarding the skin closure method, a Cochrane review found no difference in wound infection between staple and subcuticular skin closure in the general obstetrical population without separate analysis for obese women [28]. Two randomized controlled trials in obese women undergoing cesarean delivery showed a reduced risk of post‐operative wound complications with subcuticular closure, however, when analyzed specifically for wound infection, there was no difference [29, 30]. Using subcutaneous drains has not been shown to be beneficial, whereas closure of the subcutaneous fat layer measuring >2 cm appeared to decrease surgical site infections [31]. Others, in an effort to decrease surgical site infections, have turned their attention to the preoperative skin preparation. A recent study has demonstrated lower rates of surgical site infections when using chlorhexidine – alcohol skin preparation versus iodine‐alcohol skin preparation [32]. The reduction in risk was not affected by the presence or absence of obesity. Antibiotic prophylaxis is a well‐accepted evidence‐based practice for all patients undergoing cesarean delivery and is of particular importance in obese women, playing a critical factor in the prevention of surgical site infections. As of 2010, it has been recommended to administer the antibiotics within one hour before the skin incision [33]. Cefazolin is the preferred agent because of its efficacy as a prophylactic agent and excellent safety record in pregnancy [34, 35]. Whether the current antibiotic recommendations are adequate to prevent surgical site infections after cesarean delivery in obese women is unclear. Increased adiposity is accompanied by reduced tissue drug penetration due to decreased vascularity within the tissue. Obesity is also associated with higher glomerular filtration rate for drugs as cefazolin, exclusively cleared by the kidneys. Therefore, BMI increase is associated with lower maternal cefazolin plasma and adipose tissue concentrations. Recent work based on emerging resistance patterns for cefazolin suggests that the old minimal inhibitory concentration (MIC) for Gram‐negative organisms of 4 μg cefazolin/g of maternal adipose tissue is insufficient and an MIC of 8 μg g−1 should be observed instead [36]. With the 2 g standard prophylactic cefazolin dose, the majority of obese patients will not achieve above 8 μg g−1 MIC concentrations within the adipose tissue, suggesting that the increased dose of 3 g cefazolin would be advisable [37]. For standard surgical procedures in patients weighing more than 120 kg, the American Society of Health‐System Pharmacists also recommends an increased dose of cefazolin (3 g versus the standard 2 g) for preoperative prophylaxis [38]. However, in a retrospective study of 335 obese women, the rate of surgical site infections was not reduced when 3 g cefazolin prophylaxis was used instead of 2 g prophylaxis [39]. In addition to the retrospective design, susceptible to undetected bias, the study may have also been underpowered. Moreover, cefazolin is a concentration‐independent antibiotic and factors other than peak concentration may be important for its bactericidal activity, such as the length of time above MIC. According to the 2007 Report on Confidential Enquiries into Maternal Death in the United Kingdom, 67% of deaths directly attributable to anesthesia occurred in obese parturients [40]. Obese pregnant women are at increased risk of failed intubation, aspiration, and nonfunctional epidural anesthesia [41]. In one study, the initial epidural catheter failed, increasing the need for replacement, in 42% of cases of morbid obesity compared to 6% in normal weight women [42]. It also results that obese women have increased odds of requiring general anesthesia, with its additional risks. The Royal College of Obstetricians and Gynecologists recommends antenatal anesthesiology consultation in cases of morbid obesity [4] and early third trimester may be the ideal time to do that. It is important to point out that, regardless of any potentially existing comorbidities, obesity presents an independent increased risk for mortality and morbidity from both surgery and anesthesia [43]. The obese pregnant women presenting to the labor and delivery unit have to be evaluated by an anesthesiologist early in admission, in order to identify those with difficult airway. Also, the placement of epidural analgesia should be considered early in the labor course, with subsequent low threshold to replace a poorly functioning epidural. Such measures may prevent the need for general anesthesia in an emergency. In preparation for surgery in morbidly obese patients, longer needles and ultrasound equipment to help with intravenous or arterial catheterization and even neuraxial block placement may prove useful [44]
Cesarean delivery in the obese parturient
Introduction
Clinical questions
Technical surgical aspects at cesarean delivery
Antibiotic prophylaxis
Anesthesia considerations
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
