April 2013

Reviews completed by Dr C Kearns, Consultant Anaesthetist, Council Member NASGBI


A national survey of anaesthetists (NAP5 Baseline) to estimate an annual incidence of accidental awareness during general anaesthesia in the UK.

Pandit JJ, Cook TM, Jonker WR, O’Sullivan E. Brit J Anaesth 2013;110:501-509

Editorial II: The incidence of intraoperative awareness in the UK: under the rate or under the radar?

Avidan MS, Mashour GA. Brit J Anaesth 2013;110:494-497

Anaesthetists in the UK should be proud of the National Audit Projects, the fifth of which is addressing accidental intraoperative awareness. Unusually, the results of this national survey to determine an estimate for the occurrence of accidental awareness have been published in both the BJA and Anaesthesia in the same month. The fact that all hospitals and 85% of consultants (7,125) responded to the survey augurs well for the forthcoming second phase of the audit.

The headlines are that the rate of accidental awareness among patients in the UK as recalled (sorry for pun) by anaesthetists is markedly lower than existing studies suggest. The authors of the paper and its accompanying editorial address why this might be.

The importance of all anaesthetists in the UK engaging in NAP5 cannot be overstated.

Postoperative Recovery with Bispectral Index versus Anaesthetic Concentration-guided Protocols.

Fritz BA, Rao P, Mashour GA et al. Anesthesiology 2013;118:1113-22

While avoidance of awareness under anaesthesia is the principal practical justification for BIS, neuroanaesthetists might be interested in its potential for controlling rapid emergence from anaesthesia, facilitating early clinical assessment.

This paper describes a post hoc analysis of nearly 3,000 patients within one American institution who were at high risk of awareness and had been enrolled in two multicentre awareness studies (B-Unaware and BAG-RECALL), comparing anaesthetic agent delivery determined by end tidal agent concentration with a BIS-guided (40-60) protocol.

5,884 patients were included in this study, but time to PACU (recovery) discharge readiness was measured in 2,949. No difference in time to discharge from PACU between the groups was found. A smaller subgroup (706) had their readiness for discharge from recovery determined by an Aldrete score of 9-10: again, no difference was found.

The authors (including an author of the editorial cited above re NAP5) acknowledge that their results contrast with Cochrane Database meta-analyses of efficacy trials. Of note was that the median BIS levels did not differ between the groups. The study also shows the difficulty entailed in secondary analysis of data collected over a protracted period and from different sources.



Neurogenic Pulmonary Edema in Patients with Nontraumatic Intracerebral Hemorrhage: Predictors and Association with Outcome

Junttila E, Ala-Kokko T,Ohtonen Pet al. Anesth and Analg 2013;116:855-61.

The diagnosis of neurogenic pulmonary oedema is common particularly following subarachnoid hemorrhage, but this group from Finland emphasizes the varied definitions of the condition in the literature, as well as the incomplete theories of causation, particularly involving inflammation.

This was a prospective observational study of 108 out of a total of 191 patients with nontraumatic intracranial hemorrhage (SAH + ICH + IVH) treated in a single ICU over a two-year period. NPE was defined by chest X-ray features, and the ratio between PaO2 and the inspired oxygen concentration, and was found to occur in 35% of patients following SAH and ICH. A battery of cardiac biomarkers and inflammatory mediators were measured in all but 14 patients.

The authors found that independent predictors of NPE in their small group of patients were high APACHE II score and higher IL-6 levels. The diagnosis of NPE was associated with a higher 1-year mortality, but not with a poorer 1-year functional outcome. The place of inflammation as an aetiological factor in NPE awaits further study.

Determination of Neurologic Prognosis and Clinical Decision Making in Adult Patients with Severe Traumatic Brain Injury: A Survey of Canadian Intensivists, Neurosurgeons and Neurologists.

Turgeon AF, Lauzier F, Burns KEA et al. Crit Care Med 2013;41:1087-1093

Accurate prediction of outcome following severe traumatic brain injury is problematic, not least because there is limited strong evidence to support the clinician in any discussion with family or relatives regarding withdrawal of treatment.

This carefully designed survey, which included scenario-based questions, was sent to 712 potential respondents across Canada and resulted in a response rate of 65% and an evaluable response rate of 65%, leaving 298 questionnaires to be analyzed.

Among the admittedly self-reporting respondents, there was wide variation in use and perceived usefulness of different prognostic indicators and tests, as well as clinically significant uncertainty in the determination of prognosis and variability in decisions made about withdrawal of treatment. There was also a gap between belief in the usefulness of potentially helpful ancillary tests (MRI, SSEPs etc), and their actual use by the respondents.

Prognosis in Severe Brain Injury.

Stevens R, Sutter R. Crit Care Med 2013;41:1104-1123

As if to continue the train of thought generated by the previous article, the same issue of the journal contains a ‘Concise Definitive Review’ addressing the prediction of neurological outcome in the resuscitation of brain injured patients. The problem of applying results of population databases such as IMPACT and CRASH to the individual patient is acknowledged, and the review addresses clinical, radiological, electrophysiological and biochemical (as well as genetic) markers and their relative potential use in determining a prognosis early in the clinical course.

By continuing to collect and pool as much data as possible, we may be able to gain more information to reduce the inherent subjectivity in our assessment of these patients.

Both publications address a hugely important area for all of us who look after severely brain injured patients, and it’s difficult to argue with the authors’ conclusion that improved and more consistent approaches to predicting outcome in these patients are urgently needed. This is expanded upon in an accompanying editorial: Probabilities, Predictors, and Self-Fulfilling Prophecies. Soreide E and Baardsen R. Crit Care Med 2013;41:1158-1160.



Ethicolegal aspects of organ donation.

Murphy P and Adams J. Contin Educ in Anaesth Crit Care Pain

first published online March 4 2013


This month, the aspiration of the Organ Donation Task Force to increase deceased organ donation in the UK by 50% over five years was achieved. This authoritative review gives an overview of the law in the UK relevant to organ donation, and a summary of national guidance that has been published to address many of the relevant ethical issues and concerns, particularly in relation to donation after circulatory death.