Larson M D, Sessler D I, Washington D E, Merrifield B R, Hynson J A, McGuire J
Department of Anesthesia, University of California, San Francisco 94143-0648.
Anesth Analg. 1993 May;76(5):1072-8. doi: 10.1213/00000539-199305000-00028.
We studied the effects of noxious stimuli on arterial blood pressure, heart rate, pupil size, and the pupillary light reflex in 13 volunteers anesthetized with either isoflurane or propofol. Those given isoflurane (n = 8) were anesthetized twice, in a randomly selected order, once at an end-tidal concentration of 0.8% and once at 1.2%. An intense noxious stimulus was provided by electrical stimulation applied to skin of the abdominal wall (65-70 mA, 100 Hz). Hemodynamic values and pupillary responses were recorded immediately before stimulation and at 15-60-s intervals during 8 subsequent min. In the volunteers given isoflurane (both concentrations), stimulation significantly increased pupil size (265 +/- 44%) and the amplitude of the light reflex (233 +/- 23%). In contrast, mean heart rate and systolic blood pressure increased only 19 +/- 7% and 13 +/- 7% after stimulation. Five additional volunteers were anesthetized twice with propofol (approximately 3 micrograms/mL plasma concentration) and 60% nitrous oxide. The same electrical stimulus was applied, and hemodynamic and pupillary measurements were obtained. During one propofol anesthetic, an esmolol infusion (100 micrograms.kg-1 x min-1) was started 10 min before stimulation to determine whether this agent would blunt the pupillary response. The pupillary light reflex increased more than 200% during both propofol anesthetics with or without esmolol; once again, heart rate and blood pressure changed little. We conclude that with these experimental conditions, the pupil is a more sensitive measure of noxious stimulation than the commonly used variables of arterial blood pressure and heart rate.
我们研究了有害刺激对13名接受异氟烷或丙泊酚麻醉的志愿者的动脉血压、心率、瞳孔大小及瞳孔对光反射的影响。接受异氟烷麻醉的8名志愿者（n = 8），以随机顺序接受两次麻醉，一次呼气末浓度为0.8%，一次为1.2%。通过对腹壁皮肤施加电刺激（65 - 70 mA，100 Hz）提供强烈的有害刺激。在刺激前及随后8分钟内每隔15 - 60秒记录血流动力学值和瞳孔反应。在接受异氟烷麻醉的志愿者（两种浓度）中，刺激显著增加了瞳孔大小（265±44%）和光反射幅度（233±23%）。相比之下，刺激后平均心率和收缩压仅分别增加了19±7%和13±7%。另外5名志愿者接受丙泊酚（血浆浓度约3微克/毫升）和60%氧化亚氮麻醉两次。施加相同的电刺激，并进行血流动力学和瞳孔测量。在一次丙泊酚麻醉期间，在刺激前10分钟开始输注艾司洛尔（100微克·千克⁻¹·分钟⁻¹），以确定该药物是否会减弱瞳孔反应。在使用或未使用艾司洛尔的丙泊酚麻醉期间，瞳孔对光反射均增加超过200%；心率和血压再次变化不大。我们得出结论，在这些实验条件下，与常用的动脉血压和心率变量相比，瞳孔是有害刺激更敏感的指标。
