We thank Drs. Connelly and Abbot for their interesting comments on our case report.1They give us the opportunity to clarify the choice our anesthetic strategy in the current case.
Drs. Connelly and Abbot mention a number of cases reported in the 1970s in which life-threatening hyperkalemia induced by succinylcholine was observed in patients with denervation pathology. As emphasized in our letter, the use of succinylcholine in patients with postpoliomyelitis syndrome remains controversial because of the risk of fatal hyperkalemia observed in patients with pathology close to postpoliomyelitis syndrome. The molecular mechanism of succinylcholine-induced hyperkalemia has been nicely described by Martyn and Richtsfeld2and results primarily from motor endplate receptor up-regulation. This explains why the expected dangerous increase in serum potassium occurs over a very brief period of time, and why normal preoperative potassium levels have limited value in predicting the magnitude of potassium increase. In our case, preoperative blood potassium was 3.4 mm. Although we did not obtain a postoperative potassium determination, we did not observe any significant electrocardiographic modification, such as T-wave changes indicative of hyperkalemia, in the current case after succinylcholine injection.
Drs. Connelly and Abbott also discuss the choice of general versus regional anesthesia in our case. We agree that regional anesthesia has been successfully used in some cases of patients with postpoliomyelitis syndrome. However, we did not consider it as a first-choice strategy because the risk of exacerbating the motor deficit of the limbs due to a toxic action of local anesthetics on the motoneurons could not be excluded. Moreover, there was a lack of symptoms suggesting a diagnosis of postpolio-related central disorder. We disagree with Drs. Connelly and Abbott that the use of a nondepolarizing muscle relaxant for rapid sequence intubation always represents an effective and safe alternative to succinylcholine. None of the nondepolarizing muscle relaxants available to date have the same rapidity of onset and reversal of action as that exhibited by succinylcholine. This particular kinetic profile makes this agent preferable to any other nondepolarizing muscle relaxants to decrease the risk of inhalation of the gastric contents, as was particularly important here for cesarean delivery. We agree that careful titration (dose reduction) and monitoring of succinylcholine effects are necessary, which was performed in our case.
Finally, we did not state, as mentioned by Drs. Connelly and Abbot, that succinylcholine should be used in patients with postpoliomyelitis syndrome. From this case, we concluded that the anesthetic strategy must be chosen after an extensive risk–benefit discussion, and that succinylcholine may represent a possible alternative in such patients, pending careful titration and monitoring of its effects.
*Beaujon University Hospital, Assistance Publique des Hôpitaux de Paris, Clichy, France. firstname.lastname@example.org