Nerve stimulation in the setting of pharmacologic blockade

I am writing in response to the article “Train-of-Four Results and Observed Muscle Movement in Children During Continuous Neuromuscular Blockade” (June 2008:30–38). It is absolutely erroneous that with 4 twitches present, the approximate percentage of receptors blocked is “0,” as shown in Table 2 (page 32). Neither reference cited by the author makes such a statement. Foster et al¹ state “three to four twitches corresponds to approximately 75% to 80% blockade.” Viby-Mogensen² states “when the fourth response reappears, neuromuscular blockade is usually 60 to 85%.” The appropriate interpretation of these statements is that even with 4 twitches apparent by either visual or tactile evaluation, the state of neuromuscular function remains substantially blocked. Viby-Mogensen also points out that even with 1 or 2 responses in the train-of-four (TOF) pattern, a patient “may move, buck, or cough.”

The intent of nerve stimulation in the setting of pharmacologic blockade is not...