We appreciate the opportunity to respond to the excellent comments made about our editorial. The situation of laryngospasm without previous intravenous access is difficult to tackle, and the fact that two very different suggestions were made in letters to the editor indicates that the answers are not easy. Drs. Weiss and Gerber propose the intraosseous route, and Dr. Warner suggests using intramuscular succinylcholine. As we have mentioned, all possible strategies to relieve laryngospasm should be considered. 1
The option retained by the individual practitioner will depend on experience and skill. However, we wish to point out that the intraosseous route involves more complications than the intravenous route, and its use should be limited to emergency situations. Extravasation, 2
compartment syndrome, 3
and osteomyelitis 4
have been reported. In fact, one of the references quoted by Drs. Weiss and Gerber suggests an inhalational induction with halothane and nitrous oxide with intramuscular pancuronium in a case of a child with difficult intravenous access instead of intraosseous infusion of drugs. 5
In this case, securing intraosseous access is probably better than intramuscular pancuronium, a drug whose dosage and time course is not known when administered via
this route. In emergency situations, the body of evidence suggests that if one chooses to administer intramuscular relaxants, succinylcholine is the best choice. The time course of blockade is faster than with rapacuronium, which is faster than rocuronium. Intramuscular pancuronium is probably even slower. Rapacuronium has recently been withdrawn. We fully agree with Dr. Warner that the potential benefits of succinylcholine (relief of laryngospasm) outweigh its risks in a hypoxic child. Contrary to nondepolarizing muscle relaxants, laryngeal muscles are particularly sensitive to succinylcholine. 6
It would be an error to remove succinylcholine from our armamentarium. However, we would like to stress again that both the intraosseous route and intramuscular succinylcholine are not substitutes for poor planning. An intravenous line should be inserted before the airway is manipulated and before surgery commences. Intravenous access management is analogous to airway management. If one becomes familiar with several airway devices, the last resort measure (cricothyroidotomy or tracheostomy) should be learned, but hardly ever used. Similarly, if one becomes proficient at accessing the venous system at several sites, intraosseous infusions and intramuscular succinylcholine are techniques to be learned, but hopefully used infrequently.
Joanne Guay, M.D., F.R.C.P.C.