Train-of-Four Results and Observed Muscle Movement in Children During Continuous Neuromuscular Blockade

To gauge the level of paralysis in children, clinical observation may be more accurate than train-of-four.

Nondepolarizing neuromuscular blocking agents (NMBAs) have been used in intensive care units (ICUs) to augment medical treatment for many years.¹ Medications such as vecuronium or cisatracurium, which are commonly used for long-term chemical relaxation in ICUs, bind to postsynaptic acetylcholine receptors but do not activate them^1,2 (Figure 1).

After stimulation of a nerve, depolarization at the neuromuscular junction releases a flow of acetylcholine, which binds temporarily to the thousands of nicotinic receptors. The nicotinic receptors open sodium channels, which allow the stimulus to continue traveling through the muscle fibers and create a muscle contraction. Once each receptor has been activated, the acetylcholine is released and inactivated by acetyl-cholinesterase. Nondepolarizing NMBAs also bind temporarily to nicotinic receptors, blocking binding of acetylcholine there. Once 70% of the nicotinic receptors are filled...