Deaths by horsekick in the Prussian army - and other ‘Never Events’ in large organisations

The purpose of this study was to use some statistical methods to assess if randomised controlled trials (RCTs) published by one particular author (Fujii) contained data of unusual consistency. I searched seven electronic databases, retrieving 168 RCTs published by this author between 1991 and July 2011. I extracted rates for categorical variables and means (SDs) for continuous variables, and compared these published distributions with distributions that would be expected by chance. The published distributions of 28/33 variables (85%) were inconsistent with the expected distributions, such that the likelihood of their occurring ranged from 1 in 25 to less than 1 in 1 000 000 000 000 000 000 000 000 000 000 000 (1 in 10(33)), equivalent to p values of 0.04 to < 1 × 10(-33) , respectively. In 141 human studies, 13/13 published continuous variable distributions were inconsistent with expected, their likelihoods being: weight < 1 in 10(33) ; age < 1 in 10(33) ; height < 1 in 10(33) ; last menstrual period 1 in 4.5 × 10(15) ; baseline blood pressure 1 in 4.2 × 10(5) ; gestational age 1 in 28; operation time < 1 in 10(33) ; anaesthetic time < 1 in 10(33) ; fentanyl dose 1 in 6.3 × 10(8) ; operative blood loss 1 in 5.6 × 10(9) ; propofol dose 1 in 7.7 × 10(7) ; paracetamol dose 1 in 4.4 × 10(2) ; uterus extrusion time 1 in 33. The published distributions of 7/11 categorical variables in these 141 studies were inconsistent with the expected, their likelihoods being: previous postoperative nausea and vomiting 1 in 2.5 × 10(6) ; motion sickness 1 in 1.0 × 10(4) ; male or female 1 in 140; antihypertensive drug 1 in 25; postoperative headache 1 in 7.1 × 10(10) ; postoperative dizziness 1 in 1.6 × 10(6) ; postoperative drowsiness 1 in 3.8 × 10(4) . Distributions for individual RCTs were inconsistent with the expected in 96/134 human studies by Fujii et al. that reported more than two continuous variables, their likelihood ranging from 1 in 22 to 1 in 140 000 000 000 (1 in 1.4 × 10(11)), compared with 12/139 RCTs by other authors. In 26 canine studies, the distributions of 8/9 continuous variables were inconsistent with the expected, their likelihoods being: right atrial pressure < 1 in 10(33) ; diaphragmatic stimulation (100 Hz) < 1 in 10(33) ; pulmonary artery occlusion pressure < 1 in 10(33) ; diaphragmatic stimulation (20 Hz) < 1 in 10(33) ; heart rate 1 in 6.3 × 10(10) ; mean pulmonary artery pressure 1 in 2.2 × 10(14) ; mean arterial pressure 1 in 6.3 × 10(7) ; cardiac output 1 in 110. Distributions were inconsistent with the expected in 21/24 individual canine studies that reported more than two continuous variables, their likelihood ranging from 1 in 345 to 1 in 51 000 000 000 000 (1 in 5.1 × 10(13)). Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

We 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.