van Dijk Nynke, de Bruin Ivar G J M, Gisolf Janneke, de Bruin-Bon H A C M Rianne, Linzer Mark, van Lieshout Johannes J, Wieling Wouter
Academic Medical Center, Dept. of Internal Medicine, PO Box 22660, 1100 DD Amsterdam, The Netherlands.
J Appl Physiol (1985). 2005 Feb;98(2):584-90. doi: 10.1152/japplphysiol.00738.2004. Epub 2004 Oct 8.
Physical maneuvers can be applied to abort or delay an impending vasovagal faint. These countermaneuvers would be more beneficial if applied as a preventive measure. We hypothesized that, in patients with recurrent vasovagal syncope, leg crossing produces a rise in cardiac output (CO) and thereby in blood pressure (BP) with an additional rise in BP by muscle tensing. We analyzed the age and gender effect on the BP response. To confirm that, during the maneuvers, Modelflow CO changes in proportion to actual CO, 10 healthy subjects performed the study protocol with CO evaluated simultaneously by Modelflow and by inert gas rebreathing. Changes in Modelflow CO were similar in direction and magnitude to inert gas rebreathing-determined CO changes. Eighty-eight patients diagnosed with vasovagal syncope applied leg crossing after a 5-min free-standing period. Fifty-four of these patients also applied tensing of leg and abdominal muscles. Leg crossing produced a significant rise in CO (+9.5%; P < 0.01) and thereby in mean arterial pressure (+3.3%; P < 0.01). Muscle tensing produced an additional increase in CO (+8.3%; P < 0.01) and mean arterial pressure (+7.8%; P < 0.01). The rise in BP during leg crossing was larger in the elderly.
可采用物理动作来中止或延迟即将发生的血管迷走性晕厥。如果作为预防措施应用，这些对抗动作可能会更有益。我们假设，在复发性血管迷走性晕厥患者中，交叉双腿会使心输出量（CO）增加，从而使血压（BP）升高，同时肌肉紧张会使血压进一步升高。我们分析了年龄和性别对血压反应的影响。为了证实动作过程中，Modelflow心输出量的变化与实际心输出量成比例，10名健康受试者按照研究方案进行操作，同时通过Modelflow和惰性气体再呼吸评估心输出量。Modelflow心输出量的变化在方向和幅度上与惰性气体再呼吸测定的心输出量变化相似。88名被诊断为血管迷走性晕厥的患者在站立5分钟后交叉双腿。其中54名患者还进行了腿部和腹部肌肉紧张动作。交叉双腿使心输出量显著增加（+9.5%；P<0.01），从而使平均动脉压升高（+3.3%；P<0.01）。肌肉紧张使心输出量进一步增加（+8.3%；P<0.01），平均动脉压升高（+7.8%；P<0.01）。交叉双腿时老年人的血压升高幅度更大。
