Cardiac arrest in obstetric patients receiving anaesthetic care: results from the 7th National Audit Project of the Royal College of Anaesthetists

Abstract

SummaryThe 7th National Audit Project (NAP7) of the Royal College of Anaesthetists studied peri‐operative cardiac arrest. Additional inclusion criteria for obstetric anaesthesia were: cardiac arrest associated with neuraxial block performed by an anaesthetist outside the operating theatre (labour epidural analgesia); and cardiac arrest associated with remifentanil patient‐controlled analgesia. There were 28 cases of cardiac arrest in obstetric patients, representing 3% of all cardiac arrests reported to NAP7, giving an incidence of 7.9 per 100,000 (95%CI 5.4–11.4 per 100,000). Obstetric patients were approximately four times less likely to have a cardiac arrest during anaesthesia care than patients having non‐obstetric surgery. The single leading cause of peri‐operative cardiac arrest in obstetric patients was haemorrhage, with underestimated severity and inadequate early resuscitation being contributory factors. When taken together, anaesthetic causes, high neuraxial block and bradyarrhythmia associated with spinal anaesthesia were the leading causes overall. Two patients had a cardiac arrest related to labour neuraxial analgesia. There were no cardiac arrests related to failed airway management or remifentanil patient‐controlled analgesia.

Preventing maternal cardiac arrest: how do we reach the next level of safety in obstetric anaesthesia?

“…Most cases of high neuraxial block in NAP7 occurred in the setting of an unrecognised spinal catheter or when performing a spinal anaesthetic for caesarean delivery after a failed epidural block [1]. This is similar to data from the USA [3], suggesting these are important areas for safety improvements.…”

“…The organisers of the 7th National Audit Project (NAP7) are to be applauded for adapting their methodology to include cardiac arrest in obstetric patients receiving anaesthetic care, whether in or outside the operating theatre. The report by Lucas et al allows scrutiny of peripartum anaesthetic care with the ambition of preventing these infrequent but harrowing events [1]. Indeed, anaesthetic management factors were considered the key cause of the majority (19/28) of the maternal cardiac arrests observed in NAP7, which is line with other work.…”

“…The risk of maternal cardiac arrest during general anaesthesia in NAP7 was estimated to be an order of magnitude greater than in those receiving regional anaesthesia (82 vs. 5.9 per 100,000) [1]. Even though much of this increased risk is inherent in the scenarios for which general anaesthesia is indicated, this still emphasises the importance of continued efforts to avoid general anaesthesia where reasonable.…”

“…Bradyarrhythmia preceded cardiac arrest in six cases reported to NAP7 [1]. The panel judged that the concurrent phenylephrine infusion contributed to this bradycardia in five of those patients who had received de novo spinal anaesthesia.…”

“…Even though much of this increased risk is inherent in the scenarios for which general anaesthesia is indicated, this still emphasises the importance of continued efforts to avoid general anaesthesia where reasonable. The key message for obstetric anaesthetists from both the NAP7 and CAPS studies [1,2] is that additional efforts are needed to improve the safety of regional anaesthesia. The majority (13/16) of the anaesthesia-related cardiac arrests in the CAPS study were associated with neuraxial anaesthesia: 10 due to ``total (de novo) spinal´´and three related to conversion of epidural analgesia to anaesthesia [2].…”