[Comparison of hemodynamic effects of the laryngeal mask and the orotracheal tube].

This prospective study was designed to compare the haemodynamic response to insertion of either a laryngeal mask or an orotracheal tube. Twenty patients scheduled for orthopaedic surgery were randomly assigned to two groups : laryngeal mask group (n = 10) and orotracheal tube group (n = 10). Patients were premedicated with flunitrazepam (1 mg i.m.) and anaesthesia was induced with propofol (bolus of 2.5 mg.kg-1, followed by a continuous infusion of 10 mg.kg-1.h-1) and vecuronium (0.1 mg.kg-1). Heart rate and mean arterial pressure were assessed non-invasively before and after induction of anaesthesia and immediately after tube or laryngeal mask insertion. Orotracheal intubation elicited a significant increase in heart rate (92 +/- 16 vs 77 +/- 19 b.min-1, p < 0.05) and in mean arterial pressure (117 +/- 21 vs 85 +/- 16 mmHg, p < 0.05), whereas there was significant increase in heart rate (74 +/- 11 vs 72 +/- 12 b.min-1) and mean arterial pressure (86 +/- 8 vs 81 +/- 10 mmHg) after insertion of the laryngeal mask. In both groups, plasma catecholamine concentrations were not significantly modified after tube or laryngeal mask insertion. It is concluded that, under propofol anaesthesia, laryngeal mask insertion does not induce any significant haemodynamic response in ASA 1 patients. In the opposite, orotracheal intubation increases both heart rate and mean arterial pressure.

RCT Entities:   Population Interventions Outcomes