心拍・血圧変動スペクトル解析を用いた自己血採血および輸液後の自律神経機能の評価

Abstract

Reducing vasovagal reactions (VVR) may have a beneficial impact on blood donor safety. The purpose of this study was to analyze the immediate response of autonomic activity during autologous blood donation (ABD). We investigated 30 patients who required preoperative ABD. To assess the respective contributory roles of the major reported variables (weight, gender, and donation status), spectral analysis of heart rate and systolic blood pressure variability was performed. Three phases were defined as follows: resting phase, after ABD, and after crystalloid or colloid infusion. Surface ECG and blood pressure were monitored continuously and R-R interval (RR) and systolic blood pressure (SBP) were analyzed. Discrete data with the modified head-up tilt (from supine to sitting position) test were analyzed using the MemCalc system. The power spectrum was integrated into two major components: a high frequency component (HF) from 0.15 to 0.40Hz and a low frequency component (LF) from 0.04 to 0.15Hz. HF is the specific index of cardiac parasympathetic tone (HF-RR). Further, the ratio of LF to HF (LF/HF-RR) was calculated as a marker of sympathetic activity. The low-frequency component of SBP (LF-SBP) is influenced by sympathetic activity of the peripheral arteries. Excluding the male group, HF-RR increased after ABD with sitting, indicating a shift in sympathovagal balance toward parasympathetic predominance. In females and first-time donors, LF-SBP was significantly increased after ABD. It is suggested that these groups have higher risk of VVR than other groups, given that transient sympathetic activation is reported as a primitive neurogenic shock reaction. After an infusion, parasympathetic predominance returned to the normal, and no significant differences were observed between the colloid solution and crystalloid solution groups. These results suggest that ABD carries a risk of VVR for all patients, especially females and first-time donors, and that infusion may be one of method of preventing VVR.