A reliable estimation of time since death can be important for the law enforcement authorities. The compound method encompassing supravital reactions such as the chemical excitability of the iris can be used to further narrow intervals estimated by temperature-based methods. Postmortem iris excitability was mostly assessed by parasympatholytic or parasympathomimetic substances. Little is known regarding sympathomimetic agents. The present study aims to describe the postmortem iris excitability using the sympathomimetic drug phenylephrine. Cadavers were included after body donors gave written informed consent during lifetime. Exclusion criteria were known eye disease, or a postmortem interval exceeding 26 hours. A pupillometer with a minimum measurement range of 0.5 mm was used to determine the horizontal pupil diameter before and 20 minutes after the application of phenylephrine. Increase in pupil diameter was labeled as positive reaction, unchanged pupil diameter was labeled as negative reaction, and decrease in pupil diameter was labeled as paradox reaction. 30 eyes from 16 cadavers (median age = 80.0; 9 males, 7 females) were examined. Initial pupil size was in median 3.5 mm (interquartile range [IQR]: 3.0–4.5 mm) and progressed to 4.0 mm (IQR: 3.5–5.0 mm) 20 minutes after drug instillation. The achieved pupil diameter difference comprised in median 0.5 mm (IQR: 0.0–1.0 mm). A positive reaction was observed in 21 cases. Negative reactions were observed in 5 cases and paradox reactions in 4 cases. Overall, there was a statistically significant difference in diameter between the initial and the reactive pupil ( = 0.0002). Although relatively rarely used, sympathomimetic drugs seem to be eligible for chemical postmortem iris excitability. Currently, assessment of postmortem iris excitability usually only involves parasympatholytic and parasympathomimetic agents. The findings of the present study give a hint that the application of a third agent with a sympathomimetic mechanism of action could provide additional information. Further studies assessing such a triple approach in the compound method in comparison with the current gold standard for estimation of time since death are mandatory to ensure reliable results.

中文翻译：

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死后拟交感虹膜兴奋性

可靠地估计死亡后的时间对于执法当局来说非常重要。涵盖超生命反应（例如虹膜的化学兴奋性）的复合方法可用于进一步缩小基于温度的方法估计的区间。死后虹膜兴奋性主要通过副交感神经或拟副交感神经物质来评估。关于拟交感神经药知之甚少。本研究旨在描述使用拟交感神经药物去氧肾上腺素的死后虹膜兴奋性。尸体捐赠者在生前签署书面知情同意书后，尸体就被纳入其中。排除标准是已知的眼部疾病，或尸检间隔超过 26 小时。使用最小测量范围为0.5mm的瞳孔计测定应用去氧肾上腺素之前和之后20分钟的水平瞳孔直径。瞳孔直径增大为阳性反应，瞳孔直径不变为阴性反应，瞳孔直径减小为悖论反应。对 16 具尸体（中位年龄 = 80.0；9 名男性，7 名女性）的 30 只眼睛进行了检查。初始瞳孔大小中位数为 3.5 毫米（四分位间距 [IQR]：3.0–4.5 毫米），滴注药物 20 分钟后瞳孔大小发展为 4.0 毫米（IQR：3.5–5.0 毫米）。达到的瞳孔直径差异中位数为 0.5 毫米（IQR：0.0–1.0 毫米）。21例呈阳性反应。阴性反应5例，矛盾反应4例。总体而言，初始瞳孔直径与反应瞳孔直径之间存在统计学显着差异 (= 0.0002)。虽然相对较少使用，但拟交感神经药物似乎适合化学死后虹膜兴奋。目前，死后虹膜兴奋性的评估通常仅涉及副交感神经药和拟副交感神经药。本研究的结果暗示，应用具有拟交感神经作用机制的第三种药物可以提供额外的信息。为了确保可靠的结果，必须进行进一步的研究，以评估复合方法中的这种三重方法与当前估计死亡时间的黄金标准的比较。