What is a potential result of decreasing body temperature in a surgical patient monitored with EPs?

Decreasing body temperature in a surgical patient monitored with evoked potentials (EPs) can lead to increasing latencies of somatosensory evoked potentials (SSEP) and brainstem auditory evoked responses (BAER). When body temperature decreases, it affects neural conduction velocity and synaptic transmission. As temperature drops, the physiological processes in the nervous system slow down, resulting in prolonged latencies for the evoked potentials.

For SSEP, the neural pathways that are stimulated show increased resistance to conduction, meaning that it takes longer for the nerve impulses to travel from the periphery to the cortex. Similarly, BAER, which measures the electrical activity along the auditory pathway in response to sound stimuli, can also exhibit increased latencies due to the impact of reduced temperature on auditory nerve function and processing speed in the brainstem.

Maintaining normothermia during surgery is crucial because these changes in latencies can affect both the interpretation of the monitoring data and decision-making intraoperatively. By contrast, while increased amplitude of SSEP cortical responses could hypothetically occur in certain scenarios, it is generally not associated with decreased temperature, nor would one expect no changes. Higher electrode impedances might occur, but this is not the primary concern when considering the effects