チルト台を用いた起立負荷時の自覚的症状と循環動態に関する研究

起立負荷時における気分不良の有無と体循環,脳循環との関係について検討することを目的とし,電動チルト台を用いて起立負荷を行った.対象者は20代の自律神経疾患を有さない健常女性12名とし,起立負荷によって気分不良を示さなかった群を正常群とし,示した群を気分不良群とした.電動tilt tableを0°→ 30°→ 45°→ 60°→ 0°と変化させ,各段階を約3分ずつ保持した.その際,平均動脈血圧(MBP),心拍出量,心拍数,1回拍出量,総末梢血管抵抗,腓腹筋内側頭部のTotal Hb,中大脳動脈の平均血流速度(FV)と末梢血管抵抗(PI)を測定し,気分不良尺度を10段階評価でもって記録した.その結果,正常群は起立負荷に伴いFVは低下を示したが,MBP,PIに著変はなく,気分不良群はMBPの上昇に対してPIは減少し,FVはほぼ変化はみられなかった.一般的にめまいなどの気分不良症状は脳血流量の減少により生じるとされていたが,今回の結果では気分不良には脳血流量の増加による脳細動脈へのストレスなどが考えられた.

This study aimed at considering the relation between subjective symptoms and the circulation of healthy women during orthostatic stress using a tilt table. From 12 healthy women in there twenties who don't have autonomic nervous disorders, two groups were formed: 1) a normal group which didn't feel ill during orthostatic stress, and 2) a FI group which feel ill during orthostatic stress. An electric tilt table was changed from 0°→30°→45°→60°→0°, and each stage was held for about 3 minutes. Mean artery blood pressure (MBP), cardiac output, heart rate, stroke volume, total peripheral resistance and total hemoglobin at the part of interior gastrocnemius (Total Hb), flow velocity (FV) and peripheral resistance (PI) of the middle cerebral artery (MCA) were measured. The scale of poor feeling was also recorded by10 stage evaluations. Consequently, although the normal group showed an FV fall with orthostatic stress,there were no significant changes in MBP and PI. In the FI group, PI decreased but FV didn't show muchchange with the rise of MBP. According to this result, the stress to the arteriola caused not by a fall but anincrease in the cerebral blood flows etc. seems thus to have been the source of the feeling.