Analysis of Daily Pressor Episodes using an Ambulatory Blood Pressure-Cardiac Output Monitor

54名男性大学生每5分钟使用24小时测量平均血压（MBP）、心输出量（CO）和外周血管阻力（PVR）。动态血压-心输出量监测仪。他们被要求使用活动日记每小时回顾检查三次血压发作。首先，39名受试者一次参加本研究的结果表明，MBP升高的血流动力学机制主要是由于交谈时CO升高和观看电视和电视游戏时PVR升高所致。这些结果与之前的实验室检测结果一致。其次，对参加两次监测的15名受试者在上述三次血压升高发作时的MBP反应性（=升压发作时的MBP /之前基线时的MBP）和血流动力学机制（=PVR反应性/CO反应性）的可重复性进行评估。交谈的相关系数为0.207，电视观看的相关系数为0.252，电视游戏的相关系数为0.304。后者分别为0.283、0.366、0.412。在以往的研究中，在严格控制实验设置的情况下，往往得到适度的相关性。第三，采用最大熵法（MEM）加最小二乘法（MemCalc <encircledR>）确定24小时的周期结构。39名受试者的MBP变化。差不多24小时。， 1.5小时。和1.8小时。分别提取整个、清醒和睡眠时段的MEM周期。计算得到MEM功率谱P (f) -1 /f^n的指数n分别为-1.077、-0.449和-0.421。因此，长期24小时。变异似乎是1/f的特征，而短期变异约为1.5小时。由于活动的多样性，类似于白噪音。

Fifty four undergraduate males were measured mean blood pressure (MBP), cardiac output (CO), and peripheral vascular resistance (PVR) every 5 min using a 24-hr. ambulatory blood pressure-cardiac output monitor. They were asked to check three pressor episodes every an hour retrospectively using an activity diary.First, results on the 39 subjects, who participated on the present study once, indicated that the hemodynamic mechanisms of MBP elevations were mainly those due to increases in CO for conversation and those in PVR for TV watching and TV game. These results were in consistent with the previous findings on laboratory syress testing. Second, reproducibility of MBP reactivity (=MBP during the pressor episode/MBP during the preceding baseline) and of the hemodynamic mechanisms (=PVR reactivity/CO reactivity) were assessed for the above-mentioned three pressor episodes using the 15 subjects who participated on the monitoring twice. Correlation coefficients were 0.207 for conversation, 0.252 for TV watching, and 0.304 for TV game for the former. They were 0.283,0.366, and 0.412 for the latter, respectively. The modest correlations have been often obtained in the previous study which strictly controlled the experimental settings. Third, maximum entropy method (MEM) plus least squares method (MemCalc <encircledR>) was applied in order to determine a periodic structure of the 24-hr. MBP variations using the 39 subjects. Nearly a 24-hr., a 1.5-hr., and a 1.8-hr. MEM periods were extracted for the whole, awake, and sleep periods, respectively. The exponent n of the MEM power spectrum P (f) - 1/f^n was calculated to be -1.077, -0.449, and -0.421, respectively. Accordingly, the long-term 24-hr. variation seemed to be 1/f characteristic, whereas the short-term variability of about 1.5 hr. resembled white noise due to a diversity of activities.