Anaesthesia
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Randomized Controlled Trial
Induction of general anaesthesia by effect-site target-controlled infusion of propofol: influence of pharmacokinetic model and ke0 value.
We studied the use of a new ke0 value (0.6 min(-1)) for the Marsh pharmacokinetic model for propofol. Speed of induction and side-effects produced were compared with three other target-controlled infusion systems. ⋯ The Schnider model in effect-site control produced induction times that were longer (298 (282-398 [58-513])s) than those observed with the Marsh model in blood control (p < 0.05), or either effect-site control mode (p < 0.001). There were no differences in the magnitude of blood pressure changes or frequency of apnoea between groups.
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In thalassaemic patients, multiple organ systems may be affected by the disease, blood transfusion, iron overload and chelating therapy. Patients may develop cardiomyopathy, pulmonary hypertension or heart failure requiring pre-operative echocardiography or cardiac catheterisation. Restrictive lung dysfunction is commonly encountered, especially in patients with splenomegaly. ⋯ Cardiovascular depression due to negative inotropic and vasodilating effects of general anaesthesia should be minimised. Neuraxial techniques may also be challenging due to spinal skeletal abnormalities and extramedullary haemopoiesis. A multidisciplinary pre-operative approach, clinical optimisation and a carefully planned strategy are mandatory.
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Pulse oximetry is widely accepted as essential monitoring for safe anaesthesia, yet is frequently unavailable in resource-limited settings. The Lifebox pulse oximeter, and associated management training programme, was delivered to 79 non-physician anaesthetists attending the 2011 Uganda Society of Anaesthesia Annual Conference. ⋯ Immediately following the course, the test score increased to 41 (38-43 [25-47]); p < 0.0001 and at the follow-up visit at 3-5 months it was 41 (39-44 [33-49]); p = 0.001 compared with immediate post-training test scores, and 75/79 (95%) oximeters were in routine clinical use. This method of introduction resulted in a high rate of uptake of oximeters into clinical practice and a demonstrable retention of knowledge in a resource-limited setting.
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Autonomic function tests require standardised test conditions. We compared testing under non-standardised and standardised conditions and investigated the agreement between heart and pulse rate variability in 30 subjects with diabetes mellitus. Deep breathing, Valsalva manoeuvre and quick standing tests showed non-standardised reproducibility intraclass correlations (95% CI) of 0.96 (0.82-0.99), 0.96 (0.81-0.99) and 0.75 (-0.98 to 0.94), respectively. ⋯ Reproducibility under standardised conditions was comparable. The mean difference (95% limits of agreement) between heart and pulse rate variability was 0.99 (0.80-1.22) for very low frequency, 1.03 (0.88-1.21) for low frequency and 1.35 (0.84-2.16) for high frequency, with a Spearman's correlation coefficient of 1.00, 0.99 and 0.98, respectively. We demonstrated a high agreement between heart and pulse rate variability and acceptable reproducibility with most autonomic function tests, heart and pulse rate variability.