Anaesthesia and intensive care
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The standard 0.5 to 1.0 mg dose of adrenaline used in cardiac resuscitation may be inadequate on the basis of theoretical and experimental evidence. Well designed clinical trials are indicated to test the hypothesis that higher doses of adrenaline could be more effective in specific subgroups of people experiencing cardiac arrest. ⋯ Other catecholamines such as noradrenaline may be more efficacious, as could be non-adrenergic vasopressors. Clinical studies are required, however, to evaluate these potential alternatives.
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Anaesth Intensive Care · Nov 1992
Randomized Controlled Trial Clinical TrialHigh-volume spinal anaesthesia. A dose-response study of bupivacaine 0.125%.
The clinical effects of high-volume spinal anaesthesia with bupivacaine 0.125% were studied in 30 patients presenting for postpartum sterilisation. Group A, B and C patients received 6, 8 and 10 ml of bupivacaine 0.125% respectively. Onset, duration and regression of sensory block and motor blockade, haemodynamic parameters and postoperative complications were studied. ⋯ Only one patient (Group A) developed a postdural puncture headache. In this study, high-volume spinal anaesthesia with bupivacaine 0.125% was found to be satisfactory for postpartum tubal ligation. The optimal volume of bupivacaine 0.125% was 8 ml.
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Anaesth Intensive Care · Nov 1992
A clinical evaluation of the Hemocue haemoglobinometer using capillary, venous and arterial samples.
The 'Hemocue' device for rapid estimation of haemoglobin concentration was evaluated in a clinical setting. Repeatable accuracy of capillary, venous and arterial samples was examined and then compared with standard laboratory venous haemoglobin estimates using a 'Coulter JT' analyser in 42 patients. The mean values for haemoglobin (g/l) and coefficient of variation were capillary 108.2 (8.0); venous 104.9 (2.2); arterial 105.9 (2.0); and laboratory venous 104.6 (1.3). ⋯ Peripheral skin temperature did not influence the accuracy of capillary samples. Hemocue estimations of venous samples were found to be as accurate as laboratory estimations. The lack of repeatable accuracy of capillary estimations was sufficiently large that their use cannot be recommended in clinical practice.
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Anaesth Intensive Care · Nov 1992
Comparative StudyDerived oxygen saturations are not clinically useful for the calculation of oxygen consumption.
In critically ill patients, oxygen consumption (VO2) and delivery (DO2) are used to determine optimal haemodynamic management and to grade severity of illness. VO2 may be measured by indirect calorimetry with metabolic gas monitoring systems or derived using the reverse Fick principle. Oxygen saturation (SaO2) may be measured directly by co-oximetry or derived by equations for incorporation into reverse Fick equations. ⋯ When SaO2 was calculated from three logarithmic equations and incorporated into the reverse Fick equations, calculated VO2's were significantly greater (P < 0.001) than those measured by indirect calorimetry. Correlation was poor and wide limits of agreement (-118 to +350 ml/min) were demonstrated. VO2 should ideally be measured by indirect calorimetry in the critically ill, or if reverse Fick is used, SaO2 should be measured by co-oximetry as the use of equations for clinical measurement of SaO2 is clinically suspect.