Anaesthesia
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Review
B type natriuretic peptide--a diagnostic breakthrough in peri-operative cardiac risk assessment?
The B-type natriuretic peptides; B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, are increasing being used as biomarkers for the diagnosis, management and prognostication of cardiac failure, but their application in the peri-operative period is unclear. This review examines the current understanding of the role of B-type natriuretic peptides in both the operative and non-operative settings. ⋯ Using this as a background, the role of B-type natriuretic peptides in the prediction of peri-operative mortality and morbidity is examined and potential confounders, such as renal failure and body mass index, which may impact significantly on the utility of the biomarkers, are discussed. Clinical recommendations with regard to its use are made and a research agenda is proposed for future peri-operative studies.
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Randomized Controlled Trial
The impact of trained assistance on error rates in anaesthesia: a simulation-based randomised controlled trial.
Trained assistance for the anaesthetist appears likely to improve safety in anaesthesia. However, there are few objective data to support this assumption, and the requirement for a trained assistant is not universally enforced. We applied a simulation-based model developed in previous work to test the hypothesis that the presence of a trained assistant reduces error in anaesthesia. ⋯ The mean (SD) error rate per scenario was 4.75 (2.9). There were significantly fewer errors in the technician group than the nurse group (33 vs 62, p = 0.01) and this difference remained significant when errors were weighted for severity. This provides objective evidence supporting the requirement for trained assistance to the anaesthetist, and furthermore, demonstrates that a simulation-based model can provide rigorous evidence on safety interventions in anaesthesia.
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Randomized Controlled Trial Multicenter Study
Ondansetron has similar clinical efficacy against both nausea and vomiting.
Ondansetron is widely believed to prevent postoperative vomiting more effectively than nausea. We analysed data from 5161 patients undergoing general anaesthesia who were randomly stratified to receive a combination of six interventions, one of which was 4 mg ondansetron vs placebo. For the purpose of this study a 20% difference in the relative risks for the two outcomes was considered clinically relevant. ⋯ Vomiting was reduced from 17% (441/2585) to 11% (293/2576), corresponding to a relative risk of 0.67, or a relative risk reduction of 33%. The relative risks of 0.67 and 0.74 were clinically similar and the difference between them did not reach statistical significance. We thus conclude that ondansetron prevents postoperative nausea and postoperative vomiting equally well.
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Anaesthetists are legally obliged to obtain informed consent before performing regional analgesia in labour. A postal survey of consultant-led UK anaesthetic units was performed in September 2007 to assess practice regarding obtaining informed consent before inserting an epidural, and documentation of the risks discussed. ⋯ There was great variation between units regarding which risks women were informed about and the likely incidence of that risk. One hundred and twenty-three respondents out of 157 providing an epidural service (78%) supported a national standardised information card endorsed by the Obstetric Anaesthetists' Association, with all the benefits and risks stated, to be shown to all women before consenting to an epidural in labour.
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Threshold systolic arterial pressure alarms often use pre-operative values as a guide for intra-operative values. Recently, two systems (normalisation and principal component analysis) have been described that use the 'current' systolic arterial pressure and the change in systolic arterial pressure over a preceding time interval to generate an alarm based on units of standard deviation. ⋯ Systolic blood pressure data, collected from 10 patients (a total of 2177 min at 100 Hz), were cleaned and submitted to analysis using threshold alarms, normalisation and principal component analysis. With the threshold alarms set at 100 mmHg (low) and 140 mmHg (high), and a 5-min window, the alarms were activated for 557 min; using statistics-based thresholds the alarms were activated for 169 min (normalisation) and 155 min (principal component analysis), a reduction of approximately 70-72%.