In Australia approximately 6.1% of caesarean sections are undertaken under general anaesthesia with the most common reason being urgency of delivery when the mother or fetus is compromised. General anaesthesia with muscle paralysis remains an essential anaesthetic technique used for pregnant women delivering by caesarean section. This subset of patients consistently experiences higher rates of maternal morbidity and mortality compared to obstetric patients who are administered neuraxial anaesthesia.
The level of neuromuscular blockade is among the most important anaesthetic factors for both intubation and surgical delivery. Traditionally suxamethonium has been the muscle relaxant used for caesarean delivery performed under general anaesthestic. However, the newer combination of rocuronium and sugammadex for caesarean section has been shown to provide better surgical conditions for fetal delivery and faster surgical access. This results in safer delivery especially in technically more complicated caesarean section surgery. As the specialty of anaesthesia continues to encounter increasing rate of caesarean delivery and complexity of patients, it is critical for anaesthetists to continue to improve the quality and safety of anaesthesia for pregnant women requiring general anaesthesia.
The benefits of sugammadex have been demonstrated in several patient populations including the elderly, paediatrics and patients with impaired kidney function. However current pharmacokinetic models and dosing guidelines do not cater for the obstetric population. Pregnant patients may manifest markedly different pharmacokinetic parameters compared to non-pregnant patients. Without detailed knowledge of the pharmacokinetics of sugammadex in pregnancy, we risk inaccurate dosing with a potential for significant adverse patient outcomes.
The investigators will measure plasma levels of sugammadex in obstetric patients at the end of surgery to develop a pharmacokinetic model for a single bolus dose of sugammadex that will guide safe and effective dosing. These results will be used to inform clinical guidelines for the dosing of sugammadex in pregnant patients who have undergone elective or emergency GA Caesarean section at the Royal Brisbane and Women’s Hospital (RBWH). It will also provide evidence-based research to improve the high-quality anaesthetic care delivered to women requiring caesarean delivery under general anaesthetic.
Dr Anthony Hodge, Royal Brisbane and Women’s Hospital, Queensland.
The project was awarded $A19,999 through the ANZCA research grants program for 2022.