The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors

Abstract

SummaryWe present the main findings of the 5th National Audit Project on accidental awareness during general anaesthesia. Incidences were estimated using reports of accidental awareness as the numerator, and a parallel national anaesthetic activity survey to provide denominator data. The incidence of certain/probable and possible accidental awareness cases was ~1:19 600 anaesthetics (95% CI 1:16 700–23 450). However, there was considerable variation across subtypes of techniques or subspecialties. The incidence with neuromuscular blockade was ~1:8200 (1:7030–9700), and without it was ~1:135 900 (1:78 600–299 000). The cases of accidental awareness during general anaesthesia reported to 5th National Audit Project were overwhelmingly cases of unintended awareness during neuromuscular blockade. The incidence of accidental awareness during caesarean section was ~1:670 (1:380–1300). Two thirds (82, 66%) of cases of accidental awareness experiences arose in the dynamic phases of anaesthesia, namely induction of and emergence from anaesthesia. During induction of anaesthesia, contributory factors included: use of thiopental; rapid sequence induction; obesity; difficult airway management; neuromuscular blockade; and interruptions of anaesthetic delivery during movement from anaesthetic room to theatre. During emergence from anaesthesia, residual paralysis was perceived by patients as accidental awareness, and commonly related to a failure to ensure full return of motor capacity. One third (43, 33%) of accidental awareness events arose during the maintenance phase of anaesthesia, most due to problems at induction or towards the end of anaesthesia. Factors increasing the risk of accidental awareness included: female sex; age (younger adults, but not children); obesity; anaesthetist seniority (junior trainees); previous awareness; out‐of‐hours operating; emergencies; type of surgery (obstetric, cardiac, thoracic); and use of neuromuscular blockade. The following factors were not risk factors for accidental awareness: ASA physical status; race; and use or omission of nitrous oxide. We recommend that an anaesthetic checklist, to be an integral part of the World Health Organization Safer Surgery checklist, is introduced as an aid to preventing accidental awareness. This paper is a shortened version describing the main findings from 5th National Audit Project – the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home#pt.

Recommendations for standards of monitoring during anaesthesia and recovery 2015 : Association of Anaesthetists of Great Britain and Ireland

“…If so, a detailed handover must be delivered to the incoming anaesthetist and this should be recorded in the anaesthetic record. A handover checklist is useful, and one example of this is the ‘ABCDE’ aide memoir suggested in the NAP5 report 13, 14, 15. When taking over care of a patient (including when returning after relief for a break), the incoming anaesthetist should conduct a check to ensure that all appropriate monitoring is in place with suitable alarm limits (see below).…”

The 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: protocol, methods and analysis of data

“…The results and analysis of AAGA reports are presented in accompanying papers [36,37]. This article presents only the results relating to the methodology itself.…”

Beware the Boojum: the NAP5 audit of accidental awareness during intended general anaesthesia

“…1). One of the most compelling concepts expressed by the investigators is that "it is clear that the sensation of paralysis is a novel one with capacity to cause great psychological harm, unless it is counteracted by general anaesthesia" [2]. Conversely, AAGA without paralysis seldom results in psychological distress.…”

“…Like its NAP predecessors, NAP5 has been an impressive logistical undertaking with prospectively obtained national data from the UK and Ireland over a period of a year. The results of the NAP5 audit have been summarised in three papers published in this edition of Anaesthesia [1][2][3] and simultaneously in the British Journal of Anaesthesia, with a summary of the Irish data also recently published [4] and the full report available online (see http:// www.nationalauditprojects.org.uk/ NAP5_home). This work certainly adds information to the body of knowledge about intra-operative awareness with postoperative recall, and contains the elements to forge a definitive approach to the problem of accidental awareness during intended general anaesthesia (AAGA; Fig.…”