低体温对患者体感诱发电位的影响

Effect of hypothermia on sonmtosensory evoked potentials

目的 评价低体温对患者体感诱发电位（SSEP）的影响.方法 择期心脏手术患者13例,性别不限,年龄23～51岁,体重45～82 kg,ASA分级Ⅱ或Ⅲ级.麻醉诱导后测定双侧正中神经体感诱发电位：于Erb点和第2颈椎棘突分别放置臂丛和颈部记录电极,随后放置头皮电极,分别记录臂丛电位（N9）、颈髓电位（N13）和皮层电位（N20）的峰潜伏期和波幅.记录降温阶段和复温阶段达到目标体温（36、35、34、33 ℃）时的MAP、峰潜伏期和波幅.术后记录显性神经功能缺陷的发生情况.结果 降温阶段随体温降低,峰潜伏期延长,MAP降低（P＜0.05）,波幅差异无统计学意义（P＞0.05）;复温阶段随体温升高,峰潜伏期缩短（P＜0.05）,MAP和波幅差异无统计学意义（P＞0.05）;降温阶段峰潜伏期与体温呈负相关,相关系数分别为-0.673（N9）、-0.702（N13）、-0.702（N20）（P＜0.05）,以体温为自变量X,峰潜伏期为因变量Y,得到直线回归方程分别为：Y9=-0.558X＋28.994,YN13=-1.121X＋53.242,YN20=-1.458X＋72.036;复温阶段峰潜伏期与体温呈负相关,相关系数分别为-0.634（N9）、-0.619（N13）、-0.600（N20）（P＜0.05）,直线回归方程分别为：YN9=-0.505X＋27.313,YN13=-0.905X＋46.249,YN20=-1.142X＋61.668.所有患者术后均未发生神经系统功能缺陷.结论 低体温可延长SSEP峰潜伏期,对波辐无明显影响.

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.