Q:  69 year old male with previous stroke and dense right sided hemiplegia is admitted to ICU with severe pneumonia requiring intubation and ventilator at 100% FiO2 and high Positive End Expiratory Pressure (PEEP). Complete sedation and neuromuscular blockade is applied. Neuromuscular monitoring is applied with Train of Four (TOF). What one precaution should be taken in this patient?


Answer: Neuromuscular monitoring should not be performed/applied on a paralyzed limb.

In this case TOF should not be measure on right side of the body (with dense hemiplegia). In paralysed muscles, upregulation of acetylcholine receptors occurs after denervation resulting in resistance to nondepolarizing Neuro-Muscular-Blocking-Agents (NMBAs). It gives variable exaggeration of the train-of-four ratio. Consequently, the level of systemic neuromuscular block is usually underestimated if a paretic limb is monitored.


Reference:

1. Moningi S, Durga P, Mantha S, Ramachandra G. Train of four responses in paretic limbs. J Neurosurg Anesthesiol 2009; 21:334.