Effects of hypothermia on short latency somatosensory evoked potentials in humans

Omkar N. Markand, Carroll Warren, Gunwant S. Mallik, Robert D. King, John W. Brown, Yousuf Mahomed

Research output: Contribution to journalArticle

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Short latency somatosensory evoked potentials (SSEPs) elicited by median nerve stimulation were monitored in 14 adult patients undergoing cardiac surgery under cardiopulmonary bypass and induced hypothermia. SSEPs were recorded at 1-2°C steps as the body temperature was lowered from 37°C to 20°C to determine temperature-dependent changes. Hypothermia produced increased latencies of the peaks of N10, P14 and N19 components, the prolongation was more severe for the later components so that N10-P14 and P14-N19 interpeak latencies were also prolonged. The temperature-latency relationship had a linear correlation. The magnitude of latency prolongation (msec) with 1°C decline in temperature was 0.61, 1.15, 1.56 for N10,P4 and N19 components, respectively, and 0.39 and 0.68 for interpeak latencies N10-P14 and P14-N19, respectively. The rise time and duration of the 3 SSEP components increased progressively with cooling. Cortically generated component, N19 was consistently recordable at a temperature above 26°C, usually disappearing between 20°C and 25°C. On the other hand, more peripherally generated components, N10 and P14, were more resistant to the effect of hypothermia; P14 was always elicitable at 21°C or above, whereas N10 persisted even below 20°C. The amplitude of SSEP components had a poor correlation with temperature; there was a slight tendency for N10 and P14 to increase and for N19 to decrease with declining temperature. Because incidental hypothermia is common in comatose and anesthetized patients, temperature-related changes must be taken into consideration during SSEP monitoring under these circumstances.

Original languageEnglish (US)
Pages (from-to)416-424
Number of pages9
JournalElectroencephalography and Clinical Neurophysiology/ Evoked Potentials
Issue number6
StatePublished - Jan 1 1990


  • (Human)
  • Hypothermia
  • Median nerve stimulation
  • Short latency somatosensory evoked potentials (SSEPs)

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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