Tracheal intubation without neuromuscular relaxants for thymectomy in myasthenic patients.

The purpose of the present study was to evaluate in detail the suitability of the combined use of fentanyl and propofol for endotracheal oral intubation without non-depolarizing muscle relaxants (NDMRs) for myasthenic patients. We evaluated orotracheal intubation, without using an NDMR, having induced anesthesia with 2 microg x kg(-1) fentanyl and 2.5 mg x kg(-1) propofol in myasthenic (Osserman's classification: I-IIb) and non-myasthenic patients. Using this technique, intubation was easily performed, the vocal cords remained opened, and any increase in blood pressure was satisfactorily suppressed in both myasthenic and non-myasthenic patients. In non-myasthenic patients, whose train-of-four ratio recorded immediately before intubation was 95-100%, a cough of moderate or severe intensity occurred. In myasthenic patients, no or only a slight cough occurred if the ratio was less than 75%, and a cough of moderate intensity occurred if the ratio was more than 90%. All of th coughing reflexes observed in myasthenic patients were considered to be clinically acceptable. The results indicate that the combined fentanyl and propofol technique, without NDMR, provides satisfactory intubatin conditions in myasthenic patients.