The feasibility of tracheal intubation without muscle relaxant after induction of anesthesia with target controlled propofol-remifentanil infusion

Objective To evaluate the feasibility of tracheal intubation without muscle relaxant after induction of anesthesia with propofol-remifentanil given by target controlled infusion (TCI) .Methods Twenty-eight ASA Ⅰ or Ⅱ patients of both sexes (15 males, 13 females) aged 18-67 yrs weighing 43-89 kg scheduled for elective operation under general anesthesia were studied. Midazolam 0.03 mg·kg-1 was given i. v. as premedication. Anesthesia was induced with propofol and remifentanil and both of them were given by TCI. The target effect site concentration of propofol was set at 3 μg·ml-1 and that of remifentanil at 4 ng·ml-1. BP, HR and bispectral index (BIS) were monitored during induction and intubation. The results of tracheal intubation were graded as satisfactory, average and poor baaed on intubation conditions and intubation response including easiness of ventilating the patients via face mask, jaw relaxation, easiness of inserting laryngoscope and visualization of larynx, the vocal cord position and patients response to intubation such as cough, limb movement and response to cuff inflation.Results HR and BP were significantly increased within 1 min after intubation as compared to the baseline values before intubation ( P 0.01) . There was no significant difference in BIS values before and after intubation (31±8 vs 35±14) . All patients were successfully intubated at first attempt, 71.5% patients developed slight cough when the endotracheal tube was passed through the vocal cords. Nineteen patients (67.9%) were graded as satisfactory, six patients as average and three patients as poor. Conclusion Induction of anesthesia with TCI of propofol at target effect site concentration of 3 μg·ml-1 and remifentanil at 4 ng·ml-1 might provide satisfactory intubation conditions without muscle relaxant.