Khurana R K, Nicholas E M
Autonomic Reflex Laboratory, Union Memorial Hospital, Baltimore, Maryland 21218, USA.
Clin Auton Res. 1996 Dec;6(6):335-41. doi: 10.1007/BF02556304.
There is great variation between laboratories in the angle and duration of tilt used in the head-up tilt table test. We compared the hemodynamic response to three sequential randomized 20-min tilts of 60 degrees, 80 degrees and 90 degrees in 20 normal subjects. We studied 66 patients to determine the duration of tilt needed to document three types of orthostatic intolerance. Blood pressure and heart rate were monitored non-invasively. Thirty-nine patients with orthostatic hypotension of diverse causes and 17 patients with orthostatic tachycardia plus were tilted to 90 degrees for 10 min. Ten patients with vasovagal syncope were tilted to 90 degrees for 30 min. A multivariate analysis of variance performed to assess the hemodynamic responses to 60 degrees, 80 degrees and 90 degrees tilts did not show a statistically significant difference (F = 0.459). Logistic regression analyses revealed that the duration of tilt required to document orthostatic hypotension was 5 min (73% cases correctly identified), orthostatic tachycardia plus 10 min (86.5% cases correctly identified) and neurally mediated syncope 10 min (86.5% cases correctly identified). Tilt duration is a more important variable than tilt angle and the duration of the tilt should depend on the suspected cause of orthostatic intolerance.
在头直立倾斜试验中，不同实验室所采用的倾斜角度和持续时间存在很大差异。我们比较了20名正常受试者在依次进行的60度、80度和90度随机倾斜20分钟时的血流动力学反应。我们研究了66例患者，以确定记录三种类型直立不耐受所需的倾斜持续时间。通过无创方式监测血压和心率。39例各种原因引起的直立性低血压患者和17例直立性心动过速患者被倾斜至90度，持续10分钟。10例血管迷走性晕厥患者被倾斜至90度，持续30分钟。对60度、80度和90度倾斜时的血流动力学反应进行的多变量方差分析未显示出统计学上的显著差异（F = 0.459）。逻辑回归分析显示，记录直立性低血压所需的倾斜持续时间为5分钟（73%的病例正确识别），直立性心动过速为10分钟（86.5%的病例正确识别），神经介导性晕厥为10分钟（86.5%的病例正确识别）。倾斜持续时间是比倾斜角度更重要的变量，倾斜持续时间应取决于直立不耐受的疑似病因。
