title: 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: summary of main findings and risk factors.
abstract: We present the main findings of the 5th National Audit Project (NAP5) on accidental awareness during general anaesthesia (AAGA). 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% confidence interval 1:16,700-23,450). However, there was considerable variation across subtypes of techniques or subspecialities. The incidence with neuromuscular block (NMB) was ~1:8200 (1:7030-9700), and without, it was ~1:135,900 (1:78,600-299,000). The cases of AAGA reported to NAP5 were overwhelmingly cases of unintended awareness during NMB. 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, NMB, 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, mostly 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 NMB. 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 NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.
authors.affiliation: Nuffield Department of Anaesthetics, Oxford University Hospitals NHS Trust, Oxford, UK jaideep.pandit@dpag.ox.ac.uk.
authors.forename: J J
authors.initials: JJ
authors.lastname: Pandit
authors.affiliation: Department of Psychology, School of Psychology and Cognition Institute, Plymouth University, Plymouth, UK.
authors.forename: J
authors.initials: J
authors.lastname: Andrade
authors.affiliation: Department of Anaesthesia, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: D G
authors.initials: DG
authors.lastname: Bogod
authors.affiliation: Member Royal College of Anaesthetists' Lay Committee, London, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Hitchman
authors.affiliation: Department of Anaesthesia, Intensive Care and Pain Medicine, Sligo Regional Hospital, Sligo, Ireland.
authors.forename: W R
authors.initials: WR
authors.lastname: Jonker
authors.affiliation: Department of Anaesthesia, Northwick Park Hospital, Harrow, Middlesex, UK.
authors.forename: N
authors.initials: N
authors.lastname: Lucas
authors.affiliation: Department of Anaesthesia, Papworth Hospital, Cambridge, UK.
authors.forename: J H
authors.initials: JH
authors.lastname: Mackay
authors.affiliation: Department of Anaesthesia, Royal Infirmary of Edinburgh, Edinburgh, UK.
authors.forename: A F
authors.initials: AF
authors.lastname: Nimmo
authors.affiliation: Bristol School of Anaesthesia, Bristol, UK.
authors.forename: K
authors.initials: K
authors.lastname: O'Connor
authors.affiliation: Department of Anaesthesia, St James Hospital, James Street, Dublin, Ireland.
authors.forename: E P
authors.initials: EP
authors.lastname: O'Sullivan
authors.affiliation: Adult Intensive Care Unit, Royal Brompton Hospital, London, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Paul
authors.affiliation: Department of Anaesthesia, Salford Royal Hospital, Salford, UK.
authors.forename: J H M G
authors.initials: JH
authors.lastname: Palmer
authors.affiliation: Department of Anaesthesia, Imperial College NHS Trust, London, UK.
authors.forename: F
authors.initials: F
authors.lastname: Plaat
authors.affiliation: Department of Neuroanaesthesia, National Hospital for Neurology and Neurosurgery, Queen Square, UK.
authors.forename: J J
authors.initials: JJ
authors.lastname: Radcliffe
authors.affiliation: Department of Anaesthesia, Great Ormond Street Hospital NHS Foundation Trust, London, UK.
authors.forename: M R J
authors.initials: MR
authors.lastname: Sury
authors.affiliation: Bradford Teaching Hospitals NHS Foundation Trust, Bradford, UK.
authors.forename: H E
authors.initials: HE
authors.lastname: Torevell
authors.affiliation: University of Leicester, Leicester, UK.
authors.forename: M
authors.initials: M
authors.lastname: Wang
authors.affiliation: Leicestershire Partnership NHS Trust, Leicester, UK.
authors.forename: J
authors.initials: J
authors.lastname: Hainsworth
authors.affiliation: Department of Anaesthesia and Intensive Care Medicine, Royal United Hospital, Bath, UK.
authors.forename: T M
authors.initials: TM
authors.lastname: Cook
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000762:Anesthesia Recovery Period; D000768:Anesthesia, General / Q000009:adverse effects* / Q000379:methods; D000771:Anesthesia, Intravenous / Q000706:statistics & numerical data; D000773:Anesthesia, Obstetrical / Q000009:adverse effects; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D016292:Procedural Sedation / Q000009:adverse effects / Q000523:psychology; D056805:Consciousness Monitors; D003422:Critical Care / Q000706:statistics & numerical data; D004351:Drug Resistance; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D015994:Incidence; D007223:Infant; D058926:Intraoperative Awareness / Q000453:epidemiology* / Q000628:therapy; D007494:Ireland / Q000453:epidemiology; D008297:Male; D019300:Medical Errors / Q000706:statistics & numerical data; D008875:Middle Aged; D019148:Neuromuscular Blockade; D009765:Obesity / Q000150:complications / Q000453:epidemiology; D010360:Patient Transfer; D011247:Pregnancy; D012307:Risk Factors; D013594:Syringes; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
keywords: National Audit Project; accidental awareness; awareness