‘Train of four’ is characteristically used in concern with (AIPG 2008)
|B||Non-depolarizing neuromuscular blockers|
|D||To check hemodynamic parameters|
Non-depolarizing neuromuscular blockers
a. The degree of neuromuscular blockade is monitored by applying various patterns of electrical stimulation. A twitch is a single pulse that is delivered from every 10 s (1-0.1 Hz). Increasing block results in decreased evoked response to stimulation.
b. Train-of-four stimulation devotes four successive 200 – μs stimuli in 2 s (2 Hz). The twitches in a train-of-four pattern progressively fade as relaxation increases. The ratio of the responses to the first and fourth twitches is a sensitive indicator of nondepolarizing muscle paralysis. Disappearance of the fourth twitch represents a 75% block, the third twitch an 80% block, and the second twitch a 90% block. Clinical relaxation usually requires 75-95% neuromuscular blockade.