Understanding Uncertainty

How good are you at understanding chance, risk, uncertainty and probability? The UK referendum on whether to leave or remain in the European Union has brought statistics, risk and uncertainty back into our everyday language. We have (re) learnt that statistics without context can be misleading, tolerance of an acceptable risk is opinion–based, and that both financial markets and individuals struggle to deal with uncertainty. This is emphasised in an excellent article, which makes the point that 50% of anaesthetists are actually worse than average at understanding risk. Anaesthesia has made a point of providing easy-to-understand, concise, educational articles in the last year, our statistically speaking series, and this will continue into next year. We plan to publish a series called ‘methodological madness’, in which we invite readers to write in and ask our statistical guru (Dr Choi from Hong Kong email: msmethodmatters@gmail.com) about what authors have got up to when designing their methods for studies. The main message is, we all need to understand more about statistics, probabilities and risks.

Airway management is the prime professional skill of the anaesthetist; research into this topic is widespread, and Anaesthesia receives many such submissions. In a study from Switzerland, Kleine-Brueggeney and colleagues compared the performance of the Bonfils™ and SensaScope™ rigid fibreoptic scopes in 200 patients with a simulated difficult airway. They note in their introduction that rigid scopes such as the two studied are relatively underused in anaesthesia despite being favoured in otolaryngology and respiratory medicine.  The authors simulated a difficult airway by applying a cervical collar to each patient such that mouth opening was limited to a mean of 23 mm. The patients were randomly allocated into two groups; the primary outcome of the study was overall success of intubation. In this, the overall success rates were high for both devices (88% for the Bonfils and 89% for the SensaScope (p = 0.83), although median intubation times were a little shorter with the SensaScope (34 vs. 45  seconds).

In an accompanying editorial, Ward and Irwin explore the ethical implications of airway research where the normal airways of routine patients are rendered ‘difficult’ for the purpose of evaluating the performance of new devices (or those using them). Notwithstanding the fact that there are many reasons for an airway being ‘difficult’, and the difficulty created by the methods commonly used in the research context may not reproduce all of them, there are also important questions to consider about the nature of risk and benefit in such studies.

As Ward and Irwin note, patients taking part in such studies do not themselves benefit from such participation; instead, the data may contribute to the common good of future patients in general. In this context, the possible harms implied by the intervention are thrown into sharper focus. The members of research ethics committees may lack the specialist knowledge of anaesthesia devices to allow them to make a fully informed judgement about the balance of benefits and harms. Here, the anaesthetist’s first duty is the responsibility of a physician to a patient, not a researcher to data. An innovative Consensus on Airway Research Ethics is proposed, and I have also added a note advising anyone conducting airway device evaluation studies that manuscripts will need to comply with the recommendations in the Consensus if they wish to be considered for publication in Anaesthesia.

Also on the theme of airway management, this report from the Netherlands details the development of an audit tool to identify prospectively all peri-operative adverse events during airway management over an 8 week period. Data were collected daily by  questionnaires from, and interviews with, anaesthesia trainees and anaesthetic department staff members. A total of 168 airway-related events were reported out of 2803 patients undergoing general anaesthesia. The incidence of severe airway management-related events was 24/2803 (0.86%). There were 12 (0.42%) unanticipated ICU admissions and two patients (0.07%) required a surgical airway. There was one (0.04%) death, one ‘cannot intubate cannot oxygenate’ (0.04%), one pulmonary aspiration of gastric contents (0.04%) and eight (0.29%) severe desaturations (defined as an oxygen saturation less than 50%). Whilst this survey is restricted to one hospital, the authors suggest that the methodology they used could easily be followed by others within their own departments of anaesthesia.

Finally, this being December and Christmas being just around the corner, we have published our first-ever Christmas special in the journal, CRAC-ON, as in why don’t you just CRAC ON and give the anaesthetic! CRAC ON stands for complete relinquishing of anaesthetic conscientiousness, optimisation and nuance. This special article is meant to be light-hearted and satirical, and I really enjoyed reading it. It is included as an extra article, and the rest of the journal contains as many serious articles as normal. I hope you enjoy it too, and would be interested in receiving your feedback. CRAC ON and have a good Christmas!

Andrew Klein

Editor-in-Chief

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