M. R. J. Sury

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

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.

5th National Audit Project (NAP5) on accidental awareness during general anaesthesia: patient experiences, human factors, sedation, consent, and medicolegal issues

The 5th National Audit Project (NAP5) of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland into accidental awareness during general anaesthesia (AAGA) yielded data related to psychological aspects from the patient, and the anaesthetist, perspectives; patients experiences ranged from isolated auditory or tactile sensations to complete awareness. A striking finding was that 75% of experiences were for <5 min, yet 51% of patients [95% confidence interval (CI) 43-60%] experienced distress and 41% (95% CI 33-50%) suffered longer term adverse effect. Distress and longer term harm occurred across the full range of experiences but were particularly likely when the patient experienced paralysis (with or without pain). The patients interpretation of what is happening at the time of the awareness seemed central to later impact; explanation and reassurance during suspected AAGA or at the time of report seemed beneficial. Quality of care before the event was judged good in 26%, poor in 39%, and mixed in 31%. Three-quarters of cases of AAGA (75%) were judged preventable. In 12%, AAGA care was judged good and the episode not preventable. The contributory and human factors in the genesis of the majority of cases of AAGA included medication, patient, and education/training. The findings have implications for national guidance, institutional organization, and individual practice. The incidence of accidental awareness during sedation (~1:15,000) was similar to that during general anaesthesia (~1:19,000). The project raises significant issues about information giving and consent for both sedation and anaesthesia. We propose a novel approach to describing sedation from the patients perspective which could be used in communication and consent. Eight (6%) of the patients had resorted to legal action (12, 11%, to formal complaint) at the time of reporting. NAP5 methodology provides a standardized template that might usefully inform the investigation of claims or serious incidents related to AAGA.

A comparison of the recovery characteristics of sevoflurane and halothane in children

The recovery characteristics of sevoflurane and halothane anaesthesia were compared in 40 children aged 6 months to 6 years undergoing day case surgery. The mean time taken to open eyes after surgery had ended was appreciably and significantly shorter after sevoflurane than after halothane (sevoflurane, mean time (SD) 7 min 52s (5 min 46s), halothane, mean time (SD) 15 min 50 s (9 min 2 s), t = 3.32, p = 0.002). The time taken to be ready, for discharge from the recovery unit to the ward was also significantly shorter after sevoflurane than after halothane (sevoflurane, mean time (SD) 12 min 46s (4 min 11 s), halothane, mean time (SD) 19 min 13 s (9 min 48 s), t = 2.7, p < 0.01). However, more children were in pain and given analgesia after sevoflurane (p < 0.01) and the mean time to reach the criteria for discharge home was similar in both groups (sevoflurane, mean time (SD) 2h 9 min (17 min), halothane, mean time (SD) 2h 4 min (8 min)). There were no major complications in either group.

A comparison of the induction characteristics of sevoflurane and halothane in children

The induction characteristics of sevoflurane and halothane were compared in 81 children aged 6 months to 6 years. The mean time taken to achieve loss of eyelash reflex was significantly shorter with sevoflurane than with halothane (sevoflurane, mean time (SD) 1 min 41 s (35 s), halothane, mean time (SD) 2 min 17 s (43 s), t = 4.11, p = <0.01). The mean time taken to complete induction (to achieve steady spontaneous ventilation and small pupils with central gaze) was also shorter in children induced with sevoflurane (sevoflurane, mean time (SD) 3 min 58 s (1 min 8 s), halothane, mean time (SD) 4 min 50 s, (1 min 27s), t = 2.29, p = 0.027). Effects on heart rate, blood pressure and oxygen saturation during induction were similar for both agents. There were no major complications during induction with either halothane or sevoflurane.

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

BACKGROUNDnAccidental awareness during general anaesthesia (AAGA) with recall is a potentially distressing complication of general anaesthesia that can lead to psychological harm. The 5th National Audit Project (NAP5) was designed to investigate the reported incidence, predisposing factors, causality, and impact of accidental awareness.nnnMETHODSnA nationwide network of local co-ordinators across all the UK and Irish public hospitals reported all new patient reports of accidental awareness to a central database, using a system of monthly anonymized reporting over a calendar year. The database collected the details of the reported event, anaesthetic and surgical technique, and any sequelae. These reports were categorized into main types by a multidisciplinary panel, using a formalized process of analysis.nnnRESULTSnThe main categories of accidental awareness were: certain or probable; possible; during sedation; on or from the intensive care unit; could not be determined; unlikely; drug errors; and statement only. The degree of evidence to support the categorization was also defined for each report. Patient experience and sequelae were categorized using current tools or modifications of such.nnnCONCLUSIONSnThe NAP5 methodology may be used to assess new reports of AAGA in a standardized manner, especially for the development of an ongoing database of case reporting. This paper is a shortened version describing the protocols, methods, and data analysis from NAP5--the full report can be found at http://www.nationalauditprojects.org.uk/NAP5_home.

Neurological sequelae in children after prolonged propofol infusion.

a one-way haemostasis valve. The interpleural space is identified using saline. The Touhy needle and attached haemostatic valve are connected to a 500 ml bag of normal saline and an infusion set with the valve open. As the patient breathes spontaneously at the end of operation, the Touhy needle is advanced over the superior aspect of the chosen rib with each inspiration. Identification of the interpleural space is distinct when the normal saline suddenly flows freely. The infusion is then stopped and the catheter passed through the one-way haemostatic valve. At no time during identification of the interpleural space or insertion of the catheter is air permitted entry to the interpleural space. This technique is safe, easy to learn, use and teach. It minimises the chance of pneumothorax. It also minimises the chance of misplaced catheters which have been reported [2], with associated failure of analgesia.

Disease coding for anaesthetic and peri-operative practice: an opportunity not to be missed.

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