Anaesthesia
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Randomized Controlled Trial Comparative Study
LMA Supreme™ vs i-gel™--a comparison of insertion success in novices.
Two new supraglottic airway devices, the LMA Supreme™ (LMA) and the i-gel™, offer potential benefits when inserted by inexperienced operators. This study compared the insertion success rate and ventilation profile between the LMA Supreme and the i-gel when inserted by operators without previous airway management expertise. Following a short lecture and manikin training, airway novices were randomly allocated to insert either the LMA Supreme or the i-gel into 80 patients undergoing breast surgery. ⋯ Mean (SD) leak pressure (29 (8) vs 23 (11) cmH(2)O, p = 0.007) and expired tidal volume (PCV 17 cmH(2)O) (785 (198) vs 654 (91), p = 0.001) were significantly greater with the LMA Supreme than with the i-gel, respectively. More patients complained of pharyngolaryngeal pain with the LMA Supreme than with the i-gel (17/39 (44%) vs 8/41 (20%); p = 0.053). We found better first time success rate, fewer failures, and a better seal with the LMA Supreme compared with the i-gel, indicating that the LMA Supreme may be preferable for emergency airway use by novices.
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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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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.
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A caudal epidural injection was performed on a middle-aged woman for pain in her right foot. Although the procedure was uncomplicated and a good epidurogram was obtained, the patient went on to develop an orthostatic headache with generalised weakness and syncopal episodes that were treated successfully by epidural blood patching. We describe the aetiology, presentation and treatment of spontaneous intracranial hypotension and review the similarities with our patient's clinical presentation. We hypothesise as to how our intervention may have resulted in a dural tear.