[Intubation with propofol without neuromuscular blockade. Effect of premedication on fentanyl and lidocaine].

AIMS: Laryngotracheal reflexes, and possibilities of intubations following anaesthetic induction with propofol, with or without premedication and without neuromuscular blockade were evaluated. Hemodynamic parameters were also measured.

METHODS: Sixty ASA I-II patients were randomly allocated into 3 groups according to anaesthetic premedication. Group P: (placebo), 2 and 4 ml of saline 0.9%; group F, 4 micrograms/kg of fentanyl and 2 ml of saline 0.9%; group L, 4 micrograms/kg of fentanyl and 1.5 mg/kg of lidocaine 5%. Two point five mg/kg of propofol were administered and 45 seconds later intubation was attempted. Mandibular relaxation, visualization of the glottis, opening of the vocal chords, reflex reactions to laryngoscopy and intubation, time used, blood pressure and heart rate were evaluated.

RESULTS: Mandibular relaxation and visualization of the glottis were acceptable in all the patients. The aperture of the vocal chords was enough so as to carry out intubation in 65% (P), 100% (F) (p < 0.05) and 95% (L) (p < 0.05). Laryngeal reactivity significantly decreased (p < 0.001) from 40% (P) to 15% (F) and 10% (L). Tracheal reflexes decreased from 84.6% (P) to 55% (F) (p < 0.01) and 37% (L) (p < 0.001). Blood pressure and heart rate rose with intubation over the basal levels in group P and significantly decreased in groups F and L.

CONCLUSIONS: The use of propofol without neuromuscular blockade is inadequate for intubation since laryngotracheal reflexes are not suppressed. Besides, propofol does not prevent hemodynamic reactions. Premedication with fentanyl and/or lidocaine improves the responses not sufficiently to safely perform intubation.