Background and Objectives: The pupillary pain index (PPI) allows the evaluation of intraoperative nociception by measuring pupillary reaction after a localized electrical stimulus. It was the objective of this observational cohort study to investigate the pupillary pain index (PPI) as a method to evaluate the fascia iliaca block (FIB) or adductor canal block (ACB) sensory areas during general anaesthesia in orthopaedic patients with lower-extremity joint replacement surgery. Materials and Methods: Orthopaedic patients undergoing hip or knee arthroplasty were included. After anaesthesia induction, patients received an ultrasound-guided single-shot FIB or ACB with 30 mL and 20 mL of 0.375% ropivacaine, respectively. Anaesthesia was maintained with isoflurane or propofol/remifentanil. The first PPI measurements were performed after anaesthesia induction and before block insertion, the second at the end of surgery. Pupillometry scores were evaluated in the area of the femoral or saphenous nerve (target) and C3 dermatome (control). Primary outcomes were differences between PPIs before and after peripheral block insertion as well as the relationship between PPIs and postoperative pain scores; secondary outcomes were the relationship between PPIs and opioid requirements after surgery. Results: PPI decreased significantly from the first to the second measurement (4.17 ± 2.7 vs. 1.6 ± 1.2, p < 0.001 for target; 4.46 ± 2.7 vs. 2.17 ± 2.1, p < 0.001 for control). Control and target measurements did not show significant differences. A linear regression analysis showed that early postoperative pain scores could be predicted with intraoperative piritramide with improved prediction after adding PPI scores, PCA opioids and surgery type. Forty-eight-hour pain scores at rest and in movement were correlated with intraoperative piritramide and control PPI after the PNB in movement and with second-postoperative-day opioids and target PPI scores before block insertion, respectively. Conclusions: While the effect of an FIB and ACB could not be shown with PPI postoperative pain scores due to a large effect of opioids, perioperative PPI was shown to be associated with postoperative pain. These results suggest that preoperative PPI may be used to predict postoperative pain.

中文翻译：

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瞳孔疼痛指数可预测全髋关节或全膝关节置换术患者的术后疼痛，但不能预测周围区域麻醉的影响：一项观察性研究

背景和目标：瞳孔疼痛指数 (PPI) 允许通过测量局部电刺激后的瞳孔反应来评估术中伤害感受。本观察性队列研究的目的是调查瞳孔疼痛指数 (PPI) 作为评估下肢关节骨科患者全身麻醉期间髂筋膜阻滞 (FIB) 或内收肌管阻滞 (ACB) 感觉区的方法置换手术。材料和方法：包括接受髋关节或膝关节置换术的骨科患者。麻醉诱导后，患者接受超声引导单次 FIB 或 ACB，分别使用 30 mL 和 20 mL 0.375% 罗哌卡因。使用异氟醚或丙泊酚/瑞芬太尼维持麻醉。第一次 PPI 测量是在麻醉诱导后和阻滞插入之前进行的，第二次是在手术结束时进行的。在股神经或隐神经（目标）和 C3 皮节（对照）区域评估瞳孔计分。主要结果是外周阻滞插入前后 PPI 之间的差异以及 PPI 与术后疼痛评分之间的关​​系；次要结果是 PPI 和手术后阿片类药物需求之间的关系。结果：从第一次测量到第二次测量，PPI 显着下降（目标为 4.17 ± 2.7 与 1.6 ± 1.2，p < 0.001；对照为 4.46 ± 2.7 与 2.17 ± 2.1，p < 0.001）。控制和目标测量没有显示显着差异。线性回归分析表明，术中吡曲酰胺可以预测术后早期疼痛评分，并在加入 PPI 评分、PCA 阿片类药物和手术类型后改善预测。静息和运动时 48 小时的疼痛评分分别与运动中 PNB 后的术中吡曲胺和对照 PPI 以及阻滞插入前术后第二天的阿片类药物和目标 PPI 评分相关。结论：虽然由于阿片类药物的巨大影响，FIB 和 ACB 的影响无法通过 PPI 术后疼痛评分显示，但围手术期 PPI 与术后疼痛相关。这些结果表明术前 PPI 可用于预测术后疼痛。静息和运动时 48 小时的疼痛评分分别与运动中 PNB 后的术中吡曲胺和对照 PPI 以及阻滞插入前术后第二天的阿片类药物和目标 PPI 评分相关。结论：虽然由于阿片类药物的巨大影响，FIB 和 ACB 的影响无法通过 PPI 术后疼痛评分显示，但围手术期 PPI 与术后疼痛相关。这些结果表明术前 PPI 可用于预测术后疼痛。静息和运动时 48 小时的疼痛评分分别与运动中 PNB 后的术中吡曲胺和对照 PPI 以及阻滞插入前术后第二天的阿片类药物和目标 PPI 评分相关。结论：虽然由于阿片类药物的巨大影响，FIB 和 ACB 的影响无法通过 PPI 术后疼痛评分显示，但围手术期 PPI 与术后疼痛相关。这些结果表明术前 PPI 可用于预测术后疼痛。由于阿片类药物的巨大影响，FIB 和 ACB 的影响无法通过 PPI 术后疼痛评分显示，但围手术期 PPI 显示与术后疼痛相关。这些结果表明术前 PPI 可用于预测术后疼痛。由于阿片类药物的巨大影响，FIB 和 ACB 的影响无法通过 PPI 术后疼痛评分显示，但围手术期 PPI 显示与术后疼痛相关。这些结果表明术前 PPI 可用于预测术后疼痛。