Background: Pain assessment is a challenge in critically ill patients, in particular those who are unable to express movements in reaction to noxious stimuli. The purpose of the study was to compare the pupillary response and skin conductance to pain stimulation in critically ill unconscious patients. Methods: This observational study included adult patients admitted to the intensive care unit (ICU) with acute brain injury (Glasgow Coma Scale < 9 with a motor response < 5) and/or requirements for deep level of sedation. Automated pupillometry (Algiscan, ID-MED, Marseille, France) was used to determine pupillary reflex dilation during tetanic stimulation. The maximum intensity of the stimulation value allowed the determination of a pupillary pain index score ranging from 1 (no nociception) to 9 (high nociception): a pupillary pain index (PPI) score of ≤4 was used to reflect adequate pain control. For skin conductance (SC), the number of SC peaks per second (NSCF) was collected concomitantly to tetanic stimulation. An NSCF of ≤0.07 peak/second was used to reflect adequate pain control. Results: Of the 51 included patients, there were 32 with brain injury and 19 receiving deep sedation. Mean PPI score was 5 (Interquartile Range= 2–7); a total of 28 (55%) patients showed inadequate control of the nociceptive stimulation according to the PPI assessment. Only 15 (29%) patients showed a detectable skin conductance, with NSCF values from 0.07 to 0.47/s. No correlation was found between skin conductance algesimeter (SCA)-derived variables and PPI score or pupillary dilation to pain. Conclusions: Detection of inadequate pain control might vary according to the method used to assess nociception in ICU patients. A poor agreement between quantitative pupillometry and skin conductance was observed.

中文翻译：

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危重无意识患者使用定量眼压法和皮肤电导法评估伤害感受的初步研究

背景：疼痛评估在重症患者中是一个挑战，特别是那些无法对有害刺激做出反应的患者。该研究的目的是比较重症昏迷患者的瞳孔反应和皮肤电导对疼痛刺激的影响。方法：这项观察性研究包括接受重症监护病房（ICU）急性脑损伤（格拉斯哥昏迷评分<9，运动反应<5）和/或需要深度镇静的成年患者。使用自动瞳孔测定法（Algiscan，ID-MED，马赛，法国）确定强直性刺激过程中瞳孔反射扩张。刺激值的最大强度可以确定从1（无伤害）到9（高伤害）的瞳孔疼痛指数：≤4的瞳孔疼痛指数（PPI）得分用于反映适当的疼痛控制。对于皮肤电导（SC），每秒伴随强直性刺激收集SC峰数（NSCF）。≤0.07峰值/秒的NSCF用于反映适当的疼痛控制。结果：在51名患者中，有32名脑损伤和19名接受了深度镇静。PPI平均得分为5（四分位间距= 2-7）；根据PPI评估，共有28名（55％）患者显示出对伤害性刺激的控制不足。仅15名（29％）患者表现出可检测到的皮肤电导，其NSCF值为0.07至0.47 / s。在皮肤电导测角计（SCA）衍生的变量与PPI评分或瞳孔扩张至疼痛之间未发现相关性。结论：根据ICU患者评估疼痛感受的方法，疼痛控制的检测可能会有所不同。观察到定量瞳孔测定法和皮肤电导之间的一致性差。