General anaesthesia for caesarean sections

Introduction General anaesthesia for caesarean sections (c-sections) is feared to be associated with high incidence of airway problems and so the majority of c-sections are performed under regional anaesthesia which decreases the experience of anaesthetists in general anaesthesia for such procedures.1–4 Therefore, young anaesthetists invariably face a lot of pressure when administering general anaesthesia to obstetric patients, especially in emergency conditions.2 Based on an 8-year experience of general anaesthesia for c-sections at Aziz Fatima Hospital, Faisalabad, Pakistan, our point of view on general anaesthesia for c-sections is slightly different from the current popular point of view on this subject. We believe that in the absence of additional risk, for example obesity, pregnancy alone does not significantly increase the risk of airway complications in obstetric patients. We report here our experience/observations about the incidence of regurgitation and failed intubation involving patients primarily scheduled for c-sections under general anaesthesia. Methods After the approval of an ethical committee of the Aziz Fatima Hospital, Faisalabad, Pakistan, of the protocol ‘GA for c-sections 1991–1999’ (Chairperson Dr Tariq Javid), a retrospective observational study was performed to determine the incidence of regurgitation and failed intubation during an 8-year period from 1991 to 1999 in parturients who received general anaesthesia for their c-sections. The patients who had general anaesthesia following a failed spinal block were excluded. Data were retrieved from a paper-based anaesthesia and postoperative record. During the 8 years, there was a consistent technique for induction of general anaesthesia for c-sections. Anaesthesia was managed by a team of four experienced anaesthetists consisting of a consultant and three staff grade professionals. Patients were given no antacid premedication. Anaesthesia was induced after draping the patient, and a surgeon was standing by ready to proceed immediately after tracheal intubation was achieved. The patient's head was stabilised on a sand bag in sniffing position and the body was placed in a slight reverse-Trendelenburg position. Each patient was given metclopramide 10 mg intravenously followed by preoxygenation for 3 min, a sleeping dose of thiopentone (4–6 mg kg−1 body weight) and suxamethonium (1.5 mg kg−1 body weight) to intubate the trachea. No cricoid pressure was applied and lungs were gently mask ventilated until full relaxation was achieved. No other device except a laryngoscope and a gum-elastic stylet was available for airway management. Occurrence of clinical and subclinical regurgitation was based on anaesthetist's direct observation and on perioperative clinical and radiological indicators in suspected patients. Patients who developed postoperative problems such as a cough, fever, and so on were investigated. Endotracheal intubation was assumed to have failed if general anaesthesia was maintained for a c-section without an intubation or general anaesthesia was terminated to consider an alternate form of anaesthesia for the c-section. Results A total of 2114 parturients received general anaesthesia of which 1018 were assessed as American Society of Anesthesiologists-I (ASA-I), 1004 ASA-IE, 66 ASA-II and 26 as ASA-IIE. Of the 2114 c-sections, 1030 (49%) were emergency procedures. Thirty (1.4%) patients were assessed having Mallampati-III grade. No study patient had any other major risk factor for regurgitation, for example morbid obesity, gastro-esophageal reflux or opioid labour analgesia. Other parturient-related characteristics are summarised in Table 1.Table 1: Parturient characteristicsNo incidence of clinical/subclinical regurgitation or a failed intubation in the study population was observed (0/2114). Eight (0.4%) patients complained of mild hoarseness immediately after recovery from anaesthesia and this was determined to be due to inadvertent laryngeal trauma during endotracheal intubation. Five (0.23%) patients presented with fever and rigors on the 2nd postoperative day. Three (0.14%) of those patients were diagnosed as having a urinary tract infection and two (0.09%) having bilateral basal atelectasis of lungs. Chest radiographs of those patients did not show any feature suggestive of pulmonary aspiration. Discussion Results of this study indicated that the incidence of airway complications related to general anaesthesia for c-sections in the study population was extremely low (0%). Djabatey and Barclay5 have reported a similar success with traditional rapid sequence induction technique of general anaesthesia in a series of 3430 low-risk c-sections involving experienced anaesthetists. In a recent study of 1095 c-sections involving anaesthetists of variable experience, McDonnell et al.4 reported the occurrence of regurgitation and a failed intubation in eight and four patients, respectively, and their reported incidence is similar to the one previously reported by many other investigators. In spite of limitations resulting from the retrospective and weak nature of the data, the results of this study are overall reassuring for anaesthetists. Our observations clearly indicate that in the absence of additional risk factors, parturients are not at any significant extra risk of regurgitation or failed intubation. Traditionally reported higher incidence of such complications may be due to compromised experience of anaesthetists and the application of cricoid pressure.6,7 Acknowledgement The author thanks Dr Tariq Javid and Mr. Bukhari in administration, and Mr. Sarfraz and M. Afzal in the operating department of Aziz Fatima Hospital, Faisalabad, Pakistan for their help in facilitating collection of data for this study. This study was completed without any external funding and the author has no conflict of interest associated with it.