Figure 13-2 Schematic representation of the onset of a neuromuscular block after administration of a nondepolarizing neuromuscular blocking agent at the arrow. Neuromuscular function is monitored with repetitive train-of-four (TOF) stimuli (four stimuli of 0.5-msec duration administered over a period of 2 seconds). Note the presence of fade in the response to TOF stimulation.