Best practice in obstetric general anaesthesia: an umbrella review of pharmacological strategies for induction of general anaesthesia.

Abstract

General anaesthesia for caesarean delivery carries specific maternal and neonatal risks. Drug choice, dose and timing during induction of general anaesthesia may influence maternal and neonatal physiology and outcomes. The objective of this umbrella review was to systematically identify, summarise and appraise evidence for pharmacological techniques for induction of general anaesthesia for caesarean delivery. Databases were searched for eligible studies, including meta-analyses, systematic reviews, randomised controlled trials not previously synthesised and relevant observational studies. Data extraction, methodological quality assessment and evaluation of evidence certainty were conducted. Interventions were grouped into four categories: induction opioids; induction hypnotics; drugs to obtund the pressor response to laryngoscopy; and neuromuscular blocking drugs. Seven meta-analyses, two systematic reviews, 26 randomised controlled trials and 15 observational studies were included. Moderate quality evidence indicated short-acting opioids offered maternal haemodynamic benefit without negative neonatal consequences. Low quality evidence indicated propofol was associated with equivalent early neonatal resuscitation requirements compared with thiopental, but with lower risk of maternal accidental awareness during general anaesthesia. Labetalol, dexmedetomidine, lidocaine and remifentanil attenuated maternal haemodynamic response to laryngoscopy, with minimal neonatal adverse effects. Rocuronium at dose of ≥ 1 mg.kg^-1 provided comparable tracheal intubation conditions to suxamethonium without affecting neonatal outcomes, based on moderate quality evidence. Current evidence supports the safety of short-acting opioids, propofol as the preferred induction drug and rocuronium as a suitable alternative to suxamethonium during induction of anaesthesia for caesarean delivery. Overall, the evidence base is constrained by exclusion of high-risk pregnancies and emergency cases, thus limiting generalisability.