Tracheal intubation without the use of muscle relaxant in severe burn patients using propofol and varying doses of remifentanil

BACKGROUND: Severe burn patients often have a difficult airway. Tracheal intubation can be conducted safely in patients in a stable hemodynamic condition using a propofol in conjunction with remifentanil without employing muscle relaxant. However, no studies have been conducted to date to evaluate intubation of severe burn patients. Therefore, this study was conducted to evaluate the condition of tracheal intubation with propofol and varying doses of remifentanil without muscle relaxants in severe burn patients. METHODS: Eighty severe burn patients were divided into four groups at random. Anesthesia was intravenously induced by continuous infusion of propofol (4 microgram/ml of effect site concentration)and slowly injected remifentanil. Groups 1, 2, 3, and 4 received 1, 1.5, 2, and 2.5 microgram/kg of remifentanil, respectively. Ninety seconds after the administration of remifentanil, tracheal intubation was attempted. We used a scoring system in which jaw relaxation, the state when laryngoscopy was inserted, vocal cord opening, cough, limb movement, and difficulty with laryngoscopy were divided into < or = 2 (acceptable) or > or = 3 (not acceptable). In addition, the hemodynamic changes were measured at baseline, before intubation, and 1, 2, 3, 4, and 5 min after intubation. RESULTS: Clinically acceptable intubating conditions were observed in 35%, 40%, 55%, and 70% of the patients in groups 1-4, respectively. The mean arterial pressure and heart rate decreased immediately before intubation in all groups. One patient was treated for bradycardia however, no patients manifested hypotension. CONCLUSIONS: Propofol and slowly injected remifentanil (2.5 microgram/kg) without muscle relaxant can provide clinically acceptable intubating conditions and stable hemodynamic conditions in major burn patients. However, further studies should be conducted to evaluate the effects of increased doses of remifentanil.