红头发的人需要的麻醉剂量要多

专家们说，(除去发色以外)红头发的人也许还有一个使他们卓然于群的特征——敏锐的痛感。他们在一次麻醉学专家会议上说，天然红发的人需要的麻醉剂量要比其他发色的人多20%。这一意外发现不仅意味着红头发的人对痛楚更敏感，而且让人们对麻醉剂对人的作用有了更多的了解。“红发是第一个与麻醉剂量发生关联的可见人体特性或称显型，”肯塔基州路易斯维尔大学的埃德温-列姆博士在报告中说。“简单地说，在给定的刺激条件下，红头发的人会有更强的痛感，因此需要更多的麻醉剂来减轻痛苦。”列姆认为这一发现对负责在手术过程中监控患者状况的专科医生来说十分重要。“麻醉学的奥妙在于选择合适的剂量，”他说。“大多数麻醉剂的有效剂量和中毒剂量之间只有细微的差别。如果剂量不足，患者会在手术过程中醒来，而过多的麻醉剂会引起心肺并发症。”科学家们还不完全了解麻醉剂的作用机理，而这一发现为此提供了线索，因为红头发的人具有一种特定的遗传性变型。看来以后麻醉师在手术台上得先问一句：“染过头发没有？”
Midazolam causes less sedation in volunteers with red hair
[Le midazolam cause moins de sédation chez des volontaires aux cheveux roux]
Marlene V. Chua, MD, Kentaro Tsueda, MD and Anthony G. Doufas, MD PhD
From the Department of Anesthesiology and the Outcomes ResearchTM Institute, University of Louisville School of Medicine, Louisville, Kentucky, USA.

Address correspondence to: Dr. Kentaro Tsueda, Department of Anesthesiology, University of Louisville School of Medicine, Louisville, KY 40292, USA. Phone: 502-852-5851; Fax: 502-852-6056; E-mail: agdoufas@louisville.edu

Purpose: We studied sedation, cognition, and mood during midazolam infusion in volunteers with red and non-red (blond or brown) hair, to test the hypothesis that patients with red hair may require more drugs to attain desired levels of sedation.

Methods: Twenty red and 19 non-red hair subjects were studied in a randomized, placebo-controlled cross-over design. Subjects were studied during placebo and midazolam at 30 ng•mL-1 target effect site concentration. Sedation was assessed using the observer’s assessment of alertness/sedation (OAA/S) scale, the drowsiness visual analogue scale (VAS), and the bispectral index; cognition was assessed using the Repeatable Battery for Assessment of Neuropsychological Status; and mood was assessed using the bipolar form of the Profile of Mood States (POMS).

Results: Red hair volunteers showed significantly higher OAA/S (P < 0.01) and lower drowsiness VAS (P < 0.05) scores compared to non-red hair subjects during midazolam infusion. Visuospatial score was significantly higher in subjects with red compared to non-red hair during placebo and midazolam trials. Delayed memory score was significantly higher during midazolam infusion in subjects with red compared to non-red hair. There were no group differences in POMS during either trials.

Conclusion: Midazolam appears to cause significantly less sedation and cognitive impairment in red haired subjects.