Sun Xing-Guo, Hansen James E, Garatachea Nuria, Storer Thomas W, Wasserman Karlman
Division of Respiratory and Critical Care Physiology and Medicine, Research and Education Institute, Harbor-UCLA Medical Center, St. John's Cardiovascular Research Center, Torrance, California 90509, USA.
Am J Respir Crit Care Med. 2002 Dec 1;166(11):1443-8. doi: 10.1164/rccm.2202033.
When evaluating dyspnea in patients with heart or lung disease it is useful to measure the quantity of ventilation needed to eliminate metabolically produced CO2 (i.e., the ventilatory efficiency). Mathematically, the relationship between ventilation (VE) and CO2 output is determined by the arterial CO2 pressure and the physiologic dead space-tidal volume ratio. We decided to determine how age, sex, size, fitness, and the type of ergometer influenced ventilatory efficiency in normal subjects. Three methods were compared for expressing this relationship: (1) the VE versus CO2 output slope below the ventilatory compensation point, commonly used by cardiologists for estimating the severity of heart failure; (2) the VE/CO2 output ratio at the anaerobic threshold, commonly used by pulmonologists; and (3) the lowest VE/CO2 output ratio during exercise, the latter parameter not previously reported. We studied 474 healthy adults, between 17 and 78 years of age during incremental cycle and treadmill cardiopulmonary exercise tests at three test sites, correcting the total VE for the equipment dead space. The lowest VE/CO2 output ratio was insignificantly different from the ratio at the anaerobic threshold, less variable than that for the slope relationship, and unaffected by the site, ergometer, and gas exchange measurement systems. The regression equation for the lowest VE/CO2 output ratio was 27.94 + 0.108 x age + (0.97 = F, 0.0 = M) - 0.0376 x height, where age is in years and height is in centimeters. We conclude that the lowest VE/CO2 output ratio is the preferred noninvasive method to estimate ventilatory inefficiency.
在评估患有心脏或肺部疾病的患者的呼吸困难时，测量消除代谢产生的二氧化碳所需的通气量（即通气效率）是有用的。从数学角度来看，通气量（VE）与二氧化碳排出量之间的关系由动脉血二氧化碳分压和生理死腔-潮气量比值决定。我们决定确定年龄、性别、体型、健康状况和测力计类型如何影响正常受试者的通气效率。比较了三种表达这种关系的方法：（1）通气补偿点以下的VE与二氧化碳排出量斜率，心脏病专家常用此来评估心力衰竭的严重程度；（2）无氧阈值时的VE/二氧化碳排出量比值，肺病专家常用此；（3）运动期间最低的VE/二氧化碳排出量比值，这一参数此前未被报道。我们在三个测试地点对474名17至78岁的健康成年人进行了递增式自行车和跑步机心肺运动测试，对设备死腔进行校正后计算总VE。最低的VE/二氧化碳排出量比值与无氧阈值时的比值差异不显著，比斜率关系的比值变化更小，且不受测试地点、测力计和气体交换测量系统的影响。最低的VE/二氧化碳排出量比值的回归方程为27.94 + 0.108×年龄 +（0.97 = 女性，0.0 = 男性）- 0.0376×身高，其中年龄以岁为单位，身高以厘米为单位。我们得出结论，最低的VE/二氧化碳排出量比值是评估通气效率低下的首选非侵入性方法。
