Intubating conditions and haemodynamic changes following thiopentone or propofol for early tracheal intubation.

Intubating conditions and haemodynamic changes were studied 30 sec after a fixed induction dose of thiopentone or propofol in patients scheduled for elective surgery. The hypnotic agent was preceded by the administration of papaveretum 10 mg three minutes before induction and alcuronium 0.2 mg.kg-1 at induction. Ease of intubation was graded and the study conducted in a randomised double-blind fashion. In the thiopentone group (n = 30) intubation was very easy in 73% compared with 79% in the propofol group (n = 29). In two patients in the propofol group the tracheas were moderately difficult to intubate but there were no failed intubations in either group. No patients recalled the intubation period on subsequent postoperative questioning. The immediate post-induction average systolic pressure in the thiopentone group decreased by 0.7% (range 15.9% increase to 25.3% decrease) whilst the post-intubation systolic pressure increased by 6.3% (range - 31.5% increase to 24.2% decrease). In the propofol group there was a decrease in systolic pressure after induction (average 14.4%; range 15.5% increase to 41.4% decrease, P < 0.05) but the subsequent pressor response to intubation was markedly attenuated compared with baseline (average systolic pressure decreased 15.5% (range 22.4% increase to 42.7% decrease)). Following intubation and maintenance, ventilation with nitrous oxide 70% and halothane 1% the systolic pressure decreased markedly in both groups with a greater reduction in the propofol group (P < 0.05). Compared with baseline there were increases (P < 0.0001) in heart rate in both groups from induction of anaesthesia to the end of study.(ABSTRACT TRUNCATED AT 250 WORDS)