In Reply:-Szmuk et al. question of an intermediate-acting muscle relaxant in a nonemergent situation. Our experience, from visiting many hospitals in the United States, is that it is common practice to administer succinylcholine intramuscularly to children before tracheal intubation, presumably to avoid giving excessive doses of inhaled anesthetics, and thereby avoiding hypotension. In light of recent concerns about succinylcholine's adverse effects, our technique offers clinicians an alternative.
Szmuk et al. argue that muscle relaxants with prolonged action “can put the patient at danger if a complication occurs”. If the ability to ventilate via facemask is compromised (and this can presumably be assessed before muscle relaxants are given, whether by the intravenous or intramuscular route), then both succinylcholine and nondepolarizing muscle relaxants might lead to the complications suggested by Szmuk et al.
Szmuk et al. then advocate that a possible indication for intramuscular rocuronium is to treat laryngospasm. In the absence of data examining the time course of rocuronium at the vocal cords, we stated previously that our “study provides no insight into the potential for treatment of laryngospasm with IM rocuronium.” A study to compare the time course of intramuscular rocuronium and succinylcholine at the vocal cords is in progress; pending the results of that study, we continue to advocate intramuscular administration of rocuronium only in nonemergent situations.
Finally, Szmuk et al. note the vigor of response to intramuscular injection of rocuronium in our lightly anesthetized patients and attribute it to local irritation specific to rocuronium. However, the magnitude of response that we observed does not differ from that observed by the senior author in patients enrolled in MAC studies. Although rocuronium may be a local irritant, our study provides no support for the conjecture by Szmuk et al.
Lynne M. Reynolds, M.D., Assistant Professor of Anesthesia; Dennis M. Fisher, M.D., Professor of Anesthesia and Pediatrics, University of California, San Francisco, California 94143–0648.
(Accepted for publication November 11, 1996.)