Title: Is it time to revisit tracheal intubation for Cesarean delivery?
Abstract: Significant progress has been achieved in obstetric anesthesia. Most notably, there has been a dramatic reduction in anesthesia-related maternal mortality. The Confidential Enquiries into Maternal Deaths in the United Kingdom was established in 1952, and in each of the first ten triennial reports, 30-50 deaths were attributed directly to anesthesia. In contrast, the last eight reports spanning 24 years included 41 direct anesthetic deaths, almost the same number that occurred over each three-year period in the earlier reports. A similar picture was also seen in North America. This reduction in anesthesia-related mortality is even more impressive considering the increasing number of anesthetics administered to parturients and the continuing rise in the rate of Cesarean delivery (CD) over the past 60 years. In the UK, it has been estimated that anesthesia for CD was more than 30 times safer in 2002 than in 1964. There are two main reasons for this remarkable success story. First, general anesthesia for CD has become much safer, and second, we have largely avoided general anesthesia by adopting neuraxial techniques as standard practice for the majority of CDs. The leading cause of death due to general anesthesia is related to airway management. Initially, aspiration of gastric contents was the major factor resulting in maternal mortality. A number of changes were introduced over several years to address this problem, including the technique of rapid sequence induction with cricoid pressure, avoidance of mask ventilation before tracheal intubation, and use of sodium citrate and H2 blockers. However, the requirement for tracheal intubation for CD in the 1960s introduced another problem, i.e., the emergence of failed tracheal intubation and inadequate oxygenation as factors leading to 34 maternal deaths in the UK over a nine-year period from 1976 to 1984. Such fatal events have since become unusual as a result of improved training, better monitoring with the use of oximetry and capnography, and improved airway management with the introduction of failed intubation drills and the increasing availability of airway rescue devices. The Laryngeal Mask Airway (LMA) is the main rescue device incorporated in failed tracheal intubation drills. Case reports and case series have highlighted its successful use after failed tracheal intubation in CDs. In 2001, Han reported the use of the LMA Classic in 1,067 parturients undergoing elective CD. More recently, Halaseh et al. described their experience using the LMA ProSeal (PLMA) in 3,000 women undergoing the same procedure. Both studies reported no cases of aspiration, but there was one case of regurgitation. In this issue of the Journal, Yao et al. add to this literature and report the use of the LMA Supreme (SLMA) in 700 Chinese parturients. They carefully selected low-risk patients for inclusion in their study. Women fasted for at least six hours for elective cases and four hours for urgent cases, and they were excluded if they had a potentially difficult airway, a body mass index (BMI) C 35 kg m, or gastroesophageal reflux. Two providers experienced in the use of the SLMA inserted the airway device in all patients following induction of anesthesia and muscle relaxation with rocuronium. Antacid prophylaxis was achieved with oral sodium citrate and ranitidine. Cricoid pressure was released after confirming adequate ventilation and inflation of the SLMA cuff. A pre-mounted orogastric tube was used to aspirate gastric contents after insertion of the SLMA and before A. S. Habib, MBBCh (&) Department of Anesthesiology, Duke University Medical Center, Box 3094, Durham, NC 27710, USA e-mail: [email protected]