Anaesthesia
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The practice of checking the ability to mask ventilate before administering neuromuscular blocking drugs remains controversial. We prospectively evaluated the changes in the expired tidal volume during pressure-controlled ventilation (two-handed mask ventilation technique) as a surrogate marker to assess the ease of mask ventilation following administration of rocuronium. ⋯ The mean (SD) expired tidal volume before administration of rocuronium increased by 61 (13) ml at 2 min following onset of neuromuscular block (p < 0.001). This supports the concept that neuromuscular blockade induced by rocuronium facilitates mask ventilation.
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Echocardiography has been widely adopted as a diagnostic and monitoring tool in cardiac anaesthesia and critical care. There is considerable interest in how echocardiography could be used to benefit patients in other areas of anaesthesia and peri-operative practice. The first part of review examines the impact and utility of echocardiography, while this second part is concerned with the matter of training and accreditation. ⋯ Some of these, such as Focused Intensive Care Echocardiography in the UK, have been developed into structured accreditation processes with embedded supervision. Learning opportunities are now emerging for anaesthetists who wish to acquire echocardiography skills--these encompass clinical, simulation and online resources. Whilst the roll-out of echocardiography for more widespread use in peri-operative management is a long-term project, it is now an appropriate time to consider how this may be achieved.
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A relatively new minimally invasive cardiological procedure, called the MitraClip(™), does not require sternotomy and may have a number of advantages compared with open mitral valve surgery, but its acute impact on the pulmonary circulation and right ventricular function during general anaesthesia is unclear. We prospectively assessed the effects of the MitraClip procedure in 81 patients with or without pulmonary hypertension (defined as mean pulmonary artery pressure > 25 mmHg), who were anaesthetised using fentanyl (5 μg.kg(-1)), etomidate (0.2-0.3 mg.kg(-1)), rocuronium (0.5-0.6 mg.kg(-1)) and isoflurane. ⋯ Patients with pulmonary hypertension experienced a similar decrease in mean pulmonary artery pressure compared with those without, and they also had a slight reduction in mean (SD) pulmonary artery occlusion pressure (22 (6) down to 20 (6) mmHg, p = 0.044). We conclude that successful MitraClip treatment for mitral regurgitation acutely improves right ventricular performance by reducing right ventricular afterload, regardless of whether patients have pre-operative pulmonary hypertension.
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Thromboelastography is used for assessment of coagulation and to guide administration of blood products peri-operatively. There is currently no method of standardisation in the UK, nor an approved method of proving quality. We investigated the reproducibility of thromboelastography by testing whole blood with no coagulation abnormality in three phases. ⋯ Further examination of the results indicated less variation where analysis was performed on blood taken from the same kaolin vial compared with results from different vials. Our preliminary study indicates that R- and K-times may be highly variable, which we hypothesise may be due to variable mixing of blood and kaolin. We intend to repeat this study in the context of coagulopathy, where variability in results could potentially impact upon transfusion practice.
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Prevention of aortocaval compression is essential for effective cardiopulmonary resuscitation in late pregnancy. This can be achieved by either lateral maternal tilt or lateral uterine displacement. Results from a previous manikin study show that a firm foam-rubber wedge allowed successful chest compressions whilst providing stable and reliable lateral tilt. ⋯ The aim of this study was to compare the effectiveness of chest compressions in a manikin in the supine position vs lateral tilt using a foam-rubber wedge, both on the floor and on a typical patient bed. Overall, we found that compressions were easier to perform in the supine position (p = 0.007 (bed) and 0.048 (floor)), and with greater stability in the supine position on the floor (p = 0.011). The effectiveness of chest compressions was similar in both the supine/uterine displacement and the lateral tilt positions, suggesting that either method may be suitable for CPR.