Rodrigues Maurício Nunes, Vanfraechem Jacques Henri-Paul, Farinatti Paulo de Tarso Veras
Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Arq Bras Cardiol. 2007 Jan;88(1):79-84. doi: 10.1590/s0066-782x2007000100013.
This study assessed the agreement between cardiac output (Q) measurements generated by two indirect methods and their applicability in 54 men and 77 women (aged 60-90).
The subjects performed a cardiopulmonary test with incremental to maximal exercise on a cycle-ergometer. "Q" was estimated based on oxygen uptake and on impedance cardiography at 50% and 100% of the maximal workload (Wmax) reached during the test. The limits of agreement and mean differences (biases) were estimated using the methodology proposed by Bland-Altman, whereas the relationship between the methods was analyzed by linear regression and intra-class correlation (ICC).
For the load equivalent do 50% of Wmax, the bias between the means of the two methods was -0.58 L x min-1 (6.3% smaller for the impedance measurement) and the limit of agreement was +/- 2.54 L x min-1 (24.7%). At 100% of Wmax, the bias was 1.03 L x min-1 (8.5% greater for the impedance measurement) with a limit of agreement of +/- 3.35 L x min-1 (27.6%). ICC values and the regression curves obtained between the methods were: Qimp=1.82+0.75Q VO2 (r(2)=0.765, p<0.001; ICC=0.727, p<0.01) at 50% Wmax; and Qimp=0.93+1.00Q VO2 (r(2)=0.755, p<0.001; ICC=0.796, p<0.01) at 100% Wmax.
These results suggest that there is a good agreement between the two methods for the measurement of Q during exercise in the elderly, which is compatible with the findings of similar studies with young subjects.
本研究评估了两种间接方法所测得的心输出量（Q）之间的一致性及其在54名男性和77名女性（年龄60 - 90岁）中的适用性。
受试者在自行车测力计上进行递增至最大运动量的心肺测试。根据测试中达到的最大工作量（Wmax）的50%和100%时的摄氧量和阻抗心动图来估算“Q”。使用布兰德 - 奥特曼提出的方法估算一致性界限和平均差异（偏差），而通过线性回归和组内相关系数（ICC）分析两种方法之间的关系。
对于相当于Wmax 50%的负荷，两种方法均值之间的偏差为 -0.58 L×min⁻¹（阻抗测量值小6.3%），一致性界限为±2.54 L×min⁻¹（24.7%）。在Wmax的100%时，偏差为1.03 L×min⁻¹（阻抗测量值大8.5%），一致性界限为±3.35 L×min⁻¹（27.6%）。两种方法之间获得的ICC值和回归曲线为：在50% Wmax时，Qimp = 1.82 + 0.75Q VO2（r² = 0.765，p < 0.001；ICC = 0.727，p < 0.01）；在100% Wmax时，Qimp = 0.93 + 1.00Q VO2（r² = 0.755，p < 0.001；ICC = 0.796，p < 0.01）。
这些结果表明，在老年人运动期间测量Q时，两种方法之间具有良好的一致性，这与针对年轻受试者的类似研究结果相符。
