train-of-four
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train-of-four

train-of-four
,TOF
Patient care
In TOF, electrodes are placed on the patient's wrist, and the number of thumb twitches is counted. After the NMBA infusion is begun, thumb twitches are measured every 30 min for 2 hr to ensure the appropriate level of paralysis has been reached. The absence of contractions indicates that too much NMBA is being given; 1 to 2 twitches indicate the appropriate level of drug is being administered, and 3 to 4 twitches indicate the need to increase the infusion rate. Once the desired level is reached, response to peripheral nerve stimulation is measured every 4 hr.
Patients retain sensory nerve function and awareness of their surroundings, so analgesics and sedatives are usually administered concurrently. Whether TOF augments clinical assessment of neuromuscular blockade is controversial; it may be more useful with some neuromuscular blocking agents (e.g., vecuronium) than others.