Anaesthesia
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Randomized Controlled Trial
A randomised controlled trial of dexmedetomidine for suspension laryngoscopy.
We randomly allocated 80 patients to intravenous dexmedetomidine (0.25, 0.5, or 1 μg.kg(-1) ) or placebo 15 min before anaesthetic induction. Dexmedetomidine 0.5 and 1.0 μg.kg(-1) significantly reduced the mean (95% CI) propofol effect-site concentrations by 0.83 (0.63-1.03) μg.ml(-1) , p = 0.001 and 1.29 (1.12-1.46) μg.ml(-1) , p = 0.0003 at intubation, by 1.05 (0.85-1.25 μg.ml(-1) , p = 0.0006 and 1.33 (1.15-1.51) μg.ml(-1) , p = 0.0002 when surgery started, and by 0.59 (0.39-0.79) μg.ml(-1) , p = 0.030 and 0.72 (0.57-0.87) μg.ml(-1) , p = 0.004 on completion of surgery, respectively. ⋯ Bradycardia was treated after dexmedetomidine in six patients: five after 1.0 μg.kg(-1) ; and one after 0.25 μg.kg(-1). Single-dose dexmedetomidine can reduce anaesthetic requirements, with both desirable and undesirable haemodynamic effects.
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We prospectively compared two point-of-care haemoglobin concentration measuring devices with laboratory measurements to determine their accuracy in women undergoing caesarean section delivery. The two devices were the Masimo Rainbow SET(®) Radical -7™ pulse co-oximeter and the HemoCue(®) HB 201+, which is a cuvette-type system that uses photometry. Co-oximeter readings and HemoCue measurements were taken before and after surgery, and compared with laboratory measurements of haemoglobin concentration taken at the same time. ⋯ Limits of agreement for co-oximeter readings were -2.19 to 3.41 g.dl(-1) and for the HemoCue were -1.52 to 1.79 g.dl(-1). The bias (mean difference) for the co-oximeter was -0.61 g.dl(-1) (95% CI 0.36 to -0.86) and for the HemoCue was 0.13 g.dl(-1) (95% CI -0.015 to 0.28). [corrected] Overall, 110/274 (40%) co-oximeter readings were within 1 g.dl(-1) of laboratory values compared with 247/274 (90%) HemoCue measurements (p < 0.001 for difference). The co-oximeter gave lower readings and was less accurate than the HemoCue system when compared with laboratory measurements.
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Paediatric patients who require anticoagulation with therapeutic doses of low-molecular weight heparin are at risk of having a residual anticoagulant effect at the time of surgery, even if managed according to current peri-operative guidelines. Testing for residual effect is not currently recommended in such circumstances. ⋯ Subsequently, thromboelastography was also used to monitor haemostatic therapy, which consisted of protamine 2 mg.kg(-1) and 500 IU cryoprecipitate. Thromboelastography was used intra-operatively to allow rapid testing of coagulation status and guide therapy, thereby minimising use of blood products and reducing complications.
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Many clinicians consider severe aortic stenosis to be a contraindication to pulmonary artery catheterisation, except during open heart surgery with cardiopulmonary bypass. This is due to the perceived high risk of arrhythmia, although the true incidence of ventricular tachycardia and fibrillation remains unclear. ⋯ No episodes of ventricular tachycardia were recorded and there were also no arrhythmias during removal of the catheter. We have therefore concluded that pulmonary artery catheterisation in patients with severe aortic stenosis is not associated with a high incidence of ventricular fibrillation or tachycardia, allowing pulmonary artery pressure monitoring to be performed relatively safely in such patients.