The Australasian Obstetric General Anaesthesia For Caesarean Section Survey
Michael J. Paech,1 Ornella Clavisi 2, Karen L. Scott 3 Nolan J. McDonnell3 and the ANZCA Trials Group
1 Pharmacology and Anaesthesiology Unit, School of Medicine and Pharmacology, University of Western Australia, Crawley, Australia; 2 The Australian and New Zealand College of Anaesthetists Trials Group, 3 Department of Anaesthesia and Pain Medicine, King Edward Memorial Hospital for Women, Subiaco, Western Australia
Purpose of Study
The study was designed to estimate the incidence of difficult intubation and awareness in an Australasian population of women having caesarean section under general anaesthesia. The secondary objective was to obtain demographic data about contemporary practices among this patient population.
Method
A prospective survey was conducted from June 1 2005 until Jan 15 2007 across 13 participating departments that provided obstetric anaesthesia services. Data collected included the circumstances and conduct of general anaesthesia and the occurrence of intraoperative incidents or adverse events. Post operative awareness interviews were conducted. Exploratory analysis was performed using Intercooled Stata 9.1.
Result
1070 case records (82% non elective caesarean sections) were analysed. Indications included patient request (23.5%) and failed regional technique (24.4%). A conventional rapid sequence induction was performed in 97.6% of cases, using thiopentone (84%), propofol (14.7%) and ketamine (1.3%). The initial laryngoscopic view was Grade 3 in 3.4% and Grade 4 in 0.6%. The incidence of difficult and failed intubation was 3.2% (95% CI 2.2 to 4.4) and 0.8% (95% CI 0.3 to 1.5 ) respectively. Of the 8 failed intubations, general anaesthesia was abandoned in 1 and the remaining 7 were maintained with a facemask (n=3), Proseal LMA (n=2) standard LMA (n=1) and Intubating LMA (n=1). There were 1 confirmed and 3 possible cases of aspiration. BIS or entropy monitoring was utilised in 32.2% of cases but was not utilised in the two cases (0.19%) of probable awareness detected.
Conclusion
Rapid sequence induction with thiopentone remains the standard approach to general anaesthesia for caesarean section. The incidence of failed intubation is higher than that previously reported and the incidence of awareness is lower.
References
1. Barnardo PD, Jenkins JG. Failed tracheal intubation in obstetrics: a 6-year review in a UK region. Anaesthesia 2000;55:685-694
2. Lyons G, Macdonald R. Awareness during caesarean section. Anaesthesia 1991;46:62-64
Time of Presentation
0830
