不同浓度异丙酚作为**麻醉剂对瞳孔直径的影响：随机试验

背景：全身麻醉下的瞳孔测量监测是基于瞳孔直径变化可反映所提供的镇痛是否满足伤害性手术刺激疼痛强度这一假设。要准确解释瞳孔测量学数据，就必须清楚地确定在每个特定催眠状态下，未受刺激的瞳孔直径的预期基线是多少。阿片类药物以剂量依赖的方式减小瞳孔直径。相比之下，催眠药对瞳孔直径的影响尚未可知。我们的目的是探讨异丙酚的预测效应点浓度(CET)在1-3µg/mL范围内与瞳孔直径之间的潜在关系。

方法：患者随机接受异丙酚靶控输注，预计CET为1、2或3µg/mL(分别为P1、P2和P3组)。在随机分组的CET中，稳态输注异丙酚10分钟后进行瞳孔直径测量。研究过程中未进行任何刺激。连续记录心率和脑电双频指数(BIS)。

结果：共纳入40例全麻患者：P1组有13例，P2组有14例，P3组有13例。P1组平均瞳孔直径为5.7 mm(1 Mm)，P2组平均瞳孔直径为4.8 mm(1.3 mm)，P3组平均瞳孔直径为3.3 mm(0.8 mm)。异丙酚对瞳孔直径有剂量依赖性影响(线性回归R2=0.45，P<0.001)。瞳孔直径与BIS值呈正相关(Spearman r=0.75[95%CI 0.5 4，−0.87]，P<0.0 0 1)。

结论：在1~3µg/mL的预测CET范围内，异丙酚对瞳孔直径有剂量依赖性影响。在此浓度范围内，BIS与瞳孔直径呈正相关。异丙酚对瞳孔直径皮质下的影响与其对大脑皮层的影响有关。评估瞳孔直径作为伤害性-抗伤害性平衡指标的研究应该在具有标准深度催眠的患者中进行。

文献来源：Sabourdin N, Meniolle F, Chemam S, et al. Effect of Different Concentrations of Propofol Used as a Sole Anesthetic on Pupillary Diameter: A Randomized Trial.[J].Anesth Analg 2020,131:510-517.

Effect of Different Concentrations of Propofol Used as a Sole Anesthetic on Pupillary Diameter: A Randomized Trial

Abstract

BACKGROUND: Pupillometry monitoring under general anesthesia is based on the assumption that pupillary diameter variations reflect the adequacy of the provided analgesia to the intensity of the nociceptive surgical stimulus. The accurate interpretation of pupillometric data requires establishing clearly what the expected baseline unstimulated pupillary diameter at each specific level of hypnosis is. Opioids decrease pupillary diameter in a dose-dependent fashion. In contrast, the effects of hypnotic drugs on pupillary diameter are not well known. Our aim was to describe the potential relationship between propofol predicted effect-site concentrations (Cets) ranging from 1 to 3 µg/mL and pupillary diameter.

METHODS: Patients were randomized to receive propofol by target-controlled infusion at a predicted Cet of 1, 2, or 3 µg/mL (groups P1, P2, and P3, respectively). Pupillary diameter measurements were performed after 10 minutes of steady-state propofol infusion at the randomized Cet. No stimulation was performed during the study. Heart rate and bispectral index (BIS) were continuously recorded.

RESULTS: Forty patients were included: (13, 14, and 13 in groups P1, P2, and P3, respectively). Mean pupillary diameter was 5.7 mm (1 mm) in group P1, 4.8 mm (1.3 mm) in group P2, and 3.3 mm (0.8 mm) in group P3. Propofol had a dose-dependent effect on pupillary diameter (linear regression R2 = 0.45, P < .001). Pupillary diameter was positively correlated with the BIS (Spearman r = 0.75 [95% confidence interval (CI), 0.54 to −0.87] P < .001).

CONCLUSIONS: From 1 to 3 µg/mL of predicted Cet, propofol has a dose-dependent effect on pupillary diameter. Within this concentrations range, there is a positive correlation between BIS and pupillary diameter. The subcortical effect of propofol on pupillary diameter is correlated to its effect on the cortex. Studies assessing pupillary diameter as a marker of the nociception–antinociception balance should be performed in patients with a standardized depth of hypnosis.