Anaesthesia
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Although brain natriuretic peptide has been shown to be superior to the revised cardiac risk index for risk stratification of vascular surgical patients, it remains unknown whether it is superior to alternative dynamic risk predictors, such as other pre-operative biomarkers (C-reactive protein and troponins) or myocardial ischaemia monitoring. The aim of this prospective observational study was to determine the relative clinical utility of these risk predictors for the prediction of postoperative cardiac events in elective vascular surgical patients. ⋯ Both brain natriuretic peptide and troponin risk stratification significantly improved overall net reclassification (74.6% (95% CI 51.6%-97.5%) and 38.5% (95% CI 22.4-54.6%, respectively)); however, troponin stratification decreased the correct classification of patients with cardiac complications (-59%, p < 0.001). Pre-operative brain natriuretic peptide evaluation was the only clinically useful predictor of postoperative cardiac complications.
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Randomized Controlled Trial
Directly measured mucosal pressures produced by the i-gel™ and Laryngeal Mask Airway Supreme™ in paralysed anaesthetised patients.
The i-gel™ and LMA Supreme™ are extraglottic airway devices with non-inflatable and inflatable cuffs, respectively. We hypothesised that directly measured mucosal pressures would differ between these devices in anesthetised paralysed patients. Thirty patients were randomly allocated to receive one of these two devices. ⋯ Mucosal pressures were low and similar for both devices. The LMA Supreme mucosal pressures were higher in the hypopharynx than in the distal oropharynx (p = 0.04) and base of the tongue (p = 0.011). There were no pressure differences between the locations for the i-gel.
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Randomized Controlled Trial
The Shikani optical stylet as an alternative to the GlideScope® videolaryngoscope in simulated difficult intubations--a randomised controlled trial.
The GlideScope(®) videolaryngoscope is widely utilised in the management of the difficult airway. However, complications such as mucosal injury, palatal and tonsillar perforations have been reported with its use. The Shikani optical stylet has shown promise in aiding difficult intubations. ⋯ The mean (SD) time to intubation was 64 (37) s when using the GlideScope and 58 (26) s in the Shikani group (p = 0.48). A higher incidence of airway mucosal injury was noted in patients intubated with the GlideScope videolaryngoscope, compared with the Shikani optical stylet (5 vs 0, respectively, p = 0.05). This trial suggests that the Shikani optical stylet is a viable alternative to the GlideScope videolaryngoscope in the management of the difficult airway.
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The SHAM (Serious Harm and Morbidity) scale was developed to categorise the severity of potential complications of placebo control interventions in the context of local anaesthesia research. A convenience sample of 43 anaesthetists used the SHAM scale to grade ten published randomised controlled trials investigating local anaesthesia nerve blocks. The Fleiss κ statistic assessed agreement between these anaesthetists and probability of random agreement (Pr(e)) when using the SHAM scale; a κ > 0 shows concordance between assessors above random agreement. ⋯ There was moderate agreement between assessors in determining whether studies were low-risk (SHAM score 0-2) or high-risk (SHAM score 3-4) (κ 0.60 (95% CI 0.58-0.62), Pr(e) = 0.51). Compared with anaesthetists given clinical examples of interventions when applying the SHAM score, anaesthetists who were not given examples showed significantly less inter-individual agreement (κ 0.76 (95% CI 0.72-0.81), Pr(e) = 0.5 vs 0.45 (95% CI 0.41-0.49), Pr(e) = 0.52, p < 0.0001). These results suggest that the SHAM score can be successfully used to grade the severity of potential complications of placebo-controlled interventions in local anaesthesia research and represent a first step towards the score's validation.
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Comparative Study
A comparison of the Nexfin® and transcardiopulmonary thermodilution to estimate cardiac output during coronary artery surgery.
The newly introduced Nexfin(®) device allows analysis of the blood pressure trace produced by a non-invasive finger cuff. We compared the cardiac output derived from the Nexfin and PiCCO, using transcardiopulmonary thermodilution, during cardiac surgery. Forty patients with preserved left ventricular function undergoing elective coronary artery bypass graft surgery were studied after induction of general anaesthesia and until discharge to the intensive care unit. ⋯ Bland-Altman analysis demonstrated the mean bias of Nexfin to be -0.1 (95% limits of agreement -0.6 to +0.5, percentage error 23%) and -0.1 (-0.8 to +0.6, 26%) l.min(-1).m(-2), before and after cardiopulmonary bypass, respectively. After a passive leg-raise was performed, there was also good correlation between the two methods, both before (r(2) = 0.72, p < 0.001) and after (r(2) = 0.76, p < 0.001) cardiopulmonary bypass. We conclude that the Nexfin is a reliable method of measuring cardiac output during and after cardiac surgery.