Effect of hypothermia on somatosensory evoked potentials / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of hypothermia on somatosensory evoked potentials (SSEPs). Methods Thirteen ASA Ⅱ or Ⅲ patients aged 23-51 yr weighing 45-82 kg scheduled for cardiac surgery were enrolled in this study. Bilateral median nerve SSEPs (N9, N13, N20) were recorded after induction.The MAP, peak latency and amplitude of N9, N13 and N20 were recorded when the target temperature (36, 35,34, 33 ℃ ) was reached during the cooling and rewarming periods. The neurological dysfunction was recorded after operation. Results The peak latency was prolonged and MAP was decreased with the decrease in the body temperature during the cooling period, the peak latency was shortened with the increase in the body temperature during the rewarming period ( P ＜ 0.05), but no significant change in the amplitudes was found ( P ＞ 0.05). The regression equation of the interaction between the peak latency and body temperature was YN9= -0.558X + 28.994(r=-0.673), YN13 =-1.121X+53.242 (r= -0.702) , YN20 = -1.458X+72.036(r= -0.702) during the cooling period (P ＜ 0.05), and YN9 = - 0.505X + 27.313 ( r = - 0.634), YN13 = - 0.905X + 46.249(r= -0.619), YN20 = - 1.142X + 61.668 (r= -0.600) during the rewarming period (P ＜0.05). No neurological dysfunction was found in all the patients. Conclusion Hypothermia can prolong the peak latency of SSEP and does not alter the SSEP amplitude.