British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Haemodynamic and catecholamine changes after induction of anaesthesia with either thiopentone or propofol with suxamethonium.
We have compared the haemodynamic and catecholamine responses to laryngoscopy and tracheal intubation in 43 patients after induction of anaesthesia with either thiopentone 5.1 (SD 0.9) mg kg-1 or propofol 2.2 (0.1) mg kg-1, each with suxamethonium and without opioid pretreatment. Heart rate increased significantly above baseline after induction and intubation in both groups, but there were no differences between groups. Arterial pressure increased significantly at 1 min after intubation in both groups and at 2 min in the thiopentone group only. ⋯ Plasma concentrations of adrenaline were significantly greater in the thiopentone group than in the propofol group at both 1 and 2 min after intubation. Plasma concentrations of noradrenaline showed no significant time-based within-group changes, but were significantly greater in the thiopentone group at 1 and 2 min after intubation. We conclude that doses of either thiopentone or propofol sufficient to obtund the eyelash reflex with suxamethonium 1 mg kg-1 alone do not adequately block the catecholamine and hypertensive responses to laryngoscopy and intubation in normal patients and although propofol suppressed increases in catecholamines to a greater extent than thiopentone, there were no clinical advantages.
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Comparative Study
Clinical validation of a radionuclide detector to measure ejection fraction in critically ill patients.
The use of a new non-imaging nuclear probe (Cardioscint) capable of continuous online monitoring of left ventricular function is described in critically ill patients undergoing mechanical ventilation. Ejection fraction, measured by the Cardioscint, was compared with that measured by echocardiography. ⋯ Examples of fluid loading and inotropic support showed comparable changes in stroke counts measured by the Cardioscint and stroke index measured by thermodilution. The Cardioscint is a practical bedside method for continuous or repeated measurement of ejection fraction and for assessing the response to therapeutic interventions in critically ill patients.
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We have studied plasma protein binding of alfentanil in 10 patients given a mean total dose of 949 micrograms kg-1 as the principal anaesthetic agent for coronary artery bypass grafting. The mean unbound fraction of plasma alfentanil increased from 0.09 to 0.16 after administration of heparin and to 0.26 after beginning cardiopulmonary bypass (CPB). ⋯ Within the first 1 min of CPB, total alfentanil concentration had decreased by more than the unbound concentration and the decrease observed in the latter disappeared rapidly. From induction of anaesthesia until awakening of the patient, plasma protein binding of alfentanil was related significantly (P = 0.0166) to the serum concentration of orosomucoid (alpha 1-acid glyco-protein).
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Comment Letter Comparative Study
Comparison of the Belscope with the Macintosh laryngoscope.