Cold Sensation, Thermal Comfort and Autonomic Nervous Activity by Local Cold Compress

Abstract

冷罨法を安全・安楽かつ快適に行う方法を立案するための基礎データを得ることを目的に、臨床で局所の冷却を行う際に選択されやすい部位を冷却した場合の主観的な冷感・快適性および自律神経活動について検討した。健常な若年成人48 人（男性24 人、女性24 人）を便宜的抽出法で募集し、額、頸、掌のいずれか1 か所をそれぞれ10 分間、乾いたタオルを2 重に巻いた氷嚢を使用して順不同で冷却した。主観的な冷感・快適性はvisual analog scale で評価し、自律神経活動は心拍変動（low frequency / high frequency (LF/HF)）で検討した。冷感は皮膚温度の低下で強くなる有意な相関を示したが、個人差が大きかった。額は頸・掌よりも冷感が強い傾向にあったが、統計的有意差はなかった。快適性は額と掌で時間経過とともに低下したが、頸では有意な低下は見られなかった。快適性の強さには部位による有意な違いは見られなかった。自律神経活動では、頸の冷却でのみ、心拍数とLF/HF の低下が見られ、交感神経活動の相対的な低下が示唆された。以上の結果は、皮膚温度が冷感の指標になりうること、冷却時間に伴う快適性の変化は部位によって差があること、冷感・快適性いずれも個人差が大きく、冷罨法を行う場合には本人の温熱感覚と温熱快適性を確認しながら行うことが重要であることを示している。To obtain basic data for safe and comfortable cold compress procedures, we studied subjective cold and comfort sensations and autonomic nervous activities when cooling the forehead, neck or palm, which are likely to be selected for local cooling in clinical practice. Forty-eight healthy young adults (24 males and 24 females) were recruited by convenience sampling and cooled the forehead, neck, or palm for 10 minutes in random order. The cooling device was an ice bag wrapped in two layers of dry towel, and was prepared fresh for each participant. Subjective cold sensation and thermal comfort were evaluated by visual analog scale, and autonomic nervous activity was examined by heart rate variability (low frequency / high frequency (LF/HF)). Cold sensation showed a significant correlation with skin temperature, with large individual variations. The cold sensation of the forehead tended to be stronger than those of the neck and palm, although this was not statistically significant. Thermal comfort decreased with time on the forehead and palms, but not on the neck. No significant differences were found in the intensity of thermal comfort by site. As for autonomic nervous activity, the heart rate and LF/HF decreased only with neck cooling, suggesting a relative decrease in sympathetic activity. These results indicate that skin temperature can be an indicator of cold sensation, that changes in thermal comfort with cooling time vary depending on the cooling site, and that both cold sensation and thermal comfort vary greatly among individuals, making it important to evaluate the individual's thermal sensation and thermal comfort when applying a cold compress.departmental bulletin pape