Metra M, Raddino R, Dei Cas L, Visioli O
Cattedra di Cardiologia, Universita' di Brescia, Italy.
Am J Cardiol. 1990 May 1;65(16):1127-33. doi: 10.1016/0002-9149(90)90326-v.
To determine the clinical value of respiratory gas analysis during exercise, oxygen consumption (VO2) at peak exercise and at lactate and ventilatory threshold was assessed in 34 patients with chronic heart failure who underwent maximal exercise testing with expiratory gas monitoring and serial determinations of mixed venous lactate and hemodynamics by Swan-Ganz catheterization. A lactate threshold, defined as the point of abrupt increment of blood lactate, could be identified in every patient; the ventilatory threshold, detected on the basis of the respiratory changes, was found in 26 patients (77%). Lactate and ventilatory thresholds were significantly related to each other (r = 0.94; p less than 0.001) and to peak VO2 (r = 0.89; p less than 0.001 in both). Among the resting hemodynamic measurements, peak VO2 was significantly related only to total pulmonary resistances (r = -0.35). Among the parameters at maximal exercise, it was positively related to cardiac index, stroke work, stroke volume index and mean arterial pressure (r = 0.89, 0.74, 0.74 and 0.56, respectively) and inversely related to systemic vascular and total pulmonary resistances (r = -0.74 and -0.63). Using multivariate stepwise regression analysis only maximal cardiac index and, to a lesser degree, total pulmonary resistance were related to peak VO2. Similar correlations were found between the hemodynamics and the lactate and ventilatory threshold. Thus, peak VO2, lactate and ventilatory thresholds can be detected in most patients with chronic heart failure. These parameters are highly correlated to each other and bear similar relations to the hemodynamic response to exercise. The cardiac index is the main central hemodynamic determinant of exercise capacity.
为了确定运动期间呼吸气体分析的临床价值，对34例慢性心力衰竭患者进行了最大运动测试，通过呼气气体监测以及经Swan-Ganz导管测定混合静脉血乳酸和血流动力学，评估了运动峰值、乳酸阈值和通气阈值时的耗氧量（VO2）。每位患者均可确定乳酸阈值，即血乳酸突然增加的点；根据呼吸变化检测到通气阈值的患者有26例（77%）。乳酸阈值和通气阈值彼此显著相关（r = 0.94；p < 0.001），且与VO2峰值显著相关（两者r均 = 0.89；p < 0.001）。在静息血流动力学测量中，VO2峰值仅与总肺阻力显著相关（r = -0.35）。在最大运动时的参数中，它与心脏指数、每搏功、每搏量指数和平均动脉压呈正相关（r分别为0.89、0.74、0.74和0.56），与全身血管阻力和总肺阻力呈负相关（r分别为-0.74和-0.63）。使用多因素逐步回归分析，仅最大心脏指数以及在较小程度上总肺阻力与VO2峰值相关。在血流动力学与乳酸阈值和通气阈值之间发现了类似的相关性。因此，大多数慢性心力衰竭患者均可检测到VO2峰值、乳酸阈值和通气阈值。这些参数彼此高度相关，并且与运动时的血流动力学反应具有相似的关系。心脏指数是运动能力的主要中心血流动力学决定因素。
