Tracheal intubation using alfentanil and no muscle relaxant: is the choice of hypnotic important?

Administration of alfentanil followed by propofol intravenously (IV) without neuromuscular blockade for induction of anesthesia provides adequate conditions for tracheal intubation. Other hypnotic drugs have not been thoroughly investigated in this regard. Accordingly, 140 ASA physical status I and II premedicated outpatients were randomly assigned to one of seven groups (n = 20/group). Patients in Groups I-VI received alfentanil 40 microg/kg followed by etomidate 0.3 mg/kg, propofol 2 mg/kg, or thiopental 4 mg/kg. One half of these patients (Groups II, IV, VI) also received lidocaine 1 mg/kg IV prior to the administration of the above drugs. Patients in group VII received d-tubocurarine 3 mg followed by thiopental 4 mg/kg and succinylcholine 1 mg/kg. Ninety seconds after induction, laryngoscopy and endotracheal intubation were attempted and graded. Patients in Group V (alfentanil/thiopental) were significantly (P < 0.05) more likely to have a clinically unacceptable response to intubation (55%) (e.g., vigorous coughing, purposeful movement, or requirement for succinylcholine to complete intubation) compared with patients who received propofol (35%) or etomidate (20%). Alfentanil/etomidate yielded intubation conditions comparable to those achieved with alfentanil/propofol and d-tubocurarine/thiopental/succinylcholine. Lidocaine appeared to improve intubating conditions, although this improvement did not reach statistical significance. The results suggest that healthy, premedicated patients with favorable airway anatomy who have received alfentanil 40 microg/kg can be reliably tracheally intubated 90 s after administration of propofol 2 mg/kg or etomidate 0.3 mg/kg.