Anaesthesia
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Review Meta Analysis
Systematic review of the literature for the use of oesophageal Doppler monitor for fluid replacement in major abdominal surgery.
The use of intra-operative Doppler oesophageal probes provides continuous monitoring of cardiac output. This enables optimisation of intravascular volume and tissue perfusion in major abdominal surgery, which is thought to reduce postoperative complications and shorten hospital stay. Medline and EMBASE were searched using the standard methodology of the Cochrane collaboration for trials that compared oesophageal Doppler monitoring with conventional clinical parameters for fluid replacement in patients undergoing major elective abdominal surgery. ⋯ Overall, there were fewer complications and ICU admissions, and less requirement for inotropes in the intervention group. Return of normal gastro-intestinal function was also significantly faster in the intervention group. Oesophageal Doppler use for monitoring and optimisation of flow-related haemodynamic variables improves short-term outcome in patients undergoing major abdominal surgery.
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Review Meta Analysis
Dexmedetomidine and cardiac protection for non-cardiac surgery: a meta-analysis of randomised controlled trials.
We conducted a systematic review of the effects of dexmedetomidine on cardiac outcomes following non-cardiac surgery. We included prospective, randomised peri-operative studies of dexmedetomidine that reported mortality, cardiac morbidity or adverse drug events. A PubMed Central and EMBASE search was conducted up to July 2007. ⋯ Peri-operative hypotension (26%, OR 3.80, 95% CI 1.91-7.54, p = 0.0001) and bradycardia (17%, OR 5.45, 95% CI 2.98-9.95, p < 0.00001) were significantly increased. An anticholinergic did not reduce the incidence of bradycardia (p = 0.43). A randomised placebo-controlled trial of dexmedetomidine is warranted.
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The aim of this study was to determine the filtration performance of five commonly used paediatric breathing system filters following exposure to desflurane, isoflurane and sevoflurane. It has been suggested that oil may degrade the performance of filter material. Volatile anaesthetic vapours are organic and hence may affect the filtration performance of breathing system filters during anaesthesia. ⋯ The filtration performance of the filters was measured following exposure to desflurane, isoflurane and sevoflurane at 1 and 2 minimum alveolar concentration (MAC) for 1 and 4 h. Penetration of particles through the Clear-Therm Micro, Clear-Therm Mini and Humid-Vent Filter Pedi increased by between 2.4 and 2.8 times after exposure to desflurane at 2 MAC for 4 h compared to that through unexposed filters (p < 0.0001 for all three filters). Further investigation is required to determine whether this reduction in filtration performance by desflurane is clinically significant.
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The effect of flow on the filtration performance of six different types of filter intended for use in paediatric anaesthesia was measured by challenging the filters with sodium chloride particles at five different flows: 6, 10, 15, 20 and 30 l x min(-1). Twenty-five unused samples of each filter type were evaluated. The pressure drop across each filter was measured at the same flows as those used to measure penetration. ⋯ Allowing for the variation in pressure drop, the penetration of particles increased fairly linearly as flow increased for all six filter types. The increase in penetration per unit increase in flow varied from 0.11 to 0.82% per litre per minute. Over the range of flows studied, the increase in penetration with flow is fairly predictable.