What is a likely effect of a drop in temperature of the patient's legs during monitoring?

A drop in temperature in the patient's legs during monitoring can lead to physiological changes that affect the neurophysiological responses being measured, particularly the somatosensory evoked potentials (SSEPs). When the temperature decreases, it can cause a slowing of neural conduction because nerve conduction velocity is temperature-dependent.

As the temperature drops, the conduction velocity of neural fibers diminishes, which can lead to an increase in the time it takes for the SSEP waveforms to reach their respective peaks. This results in a prolongation of the peak latencies in the SSEP waveform. Thus, observing prolonged SSEP peak latencies is indicative of the negative impact that a decrease in temperature can have on the neural conduction within the monitored region.

In contrast to this, a decrease in amplitude of SSEP waveforms may occur, but the direct and more prominent initial effect observed is the delay in the peak latencies due to slowed conduction rather than an immediate change in amplitude. The L3S response and conduction velocity of the tibial nerve would also not demonstrate increases under reduced temperature conditions. This temperature dependence underscores the importance of maintaining normothermia during surgeries involving neurophysiological monitoring, as temperature can significantly impact the outcomes and interpretations of the evoked potentials