Grant G P, Graziano J H, Seaman C, Mansell A L
Am Rev Respir Dis. 1987 Jul;136(1):92-7. doi: 10.1164/ajrccm/136.1.92.
The cardiorespiratory response to exercise was examined in 13 patients, 12 to 22 yr of age, who were in stable condition while receiving regular transfusions for thalassemia major. Before transfusion (Hgb, 10.8 g/dl), the patients had reduced peak oxygen consumption for body weight (by 25%, p less than 0.002) in comparison with 20 age- and sex-matched control subjects (Hgb, 13.8 g/dl). The ventilatory equivalent for carbon dioxide was significantly reduced at all work rates, and end-tidal PCO2 was abnormally high (46.3 versus 40.7 mm Hg, p less than 0.001), but ventilatory reserve, as estimated from pulmonary function tests, was normal. Both heart rate and cardiac output (as estimated by the indirect Fick method) were abnormally high during exercise; at an oxygen consumption of 19 ml/min/kg, heart rate was 13% higher (p less than 0.01) and, at 16 ml/min/kg, cardiac output was 28% higher (p less than 0.001) in the patients than in the control subjects. Nine patients were retested 3 to 8 days after transfusion (Hgb, 13.0 g/dl, p50, 26.4 mm Hg). Neither ventilatory nor circulatory abnormalities improved significantly. In patients 12 to 22 yr of age in stable condition with thalassemia major, we conclude: cardiac output, estimated by the CO2 rebreathing method, is high and arteriovenous O2 extraction is low during exercise; the high cardiac output during exercise is associated with hypoventilation; the high cardiac output is independent of short-term changes in hemoglobin concentration associated with transfusion.
对13例年龄在12至22岁、因重型地中海贫血接受定期输血且病情稳定的患者进行了运动时心肺反应的检查。在输血前（血红蛋白，10.8 g/dl），与20名年龄和性别匹配的对照受试者（血红蛋白，13.8 g/dl）相比，这些患者按体重计算的峰值耗氧量降低（降低25%，p<0.002）。在所有工作负荷下，二氧化碳通气当量均显著降低，呼气末PCO2异常升高（46.3对40.7 mmHg，p<0.001），但根据肺功能测试估算的通气储备正常。运动期间心率和心输出量（通过间接菲克法估算）均异常升高；在耗氧量为19 ml/min/kg时，患者的心率比对照受试者高13%（p<0.01），在耗氧量为16 ml/min/kg时，患者的心输出量比对照受试者高28%（p<0.001）。9名患者在输血后3至8天（血红蛋白，13.0 g/dl，P50，26.4 mmHg）接受了重新测试。通气和循环异常均未显著改善。对于年龄在12至22岁、病情稳定的重型地中海贫血患者，我们得出以下结论：通过二氧化碳重呼吸法估算的心输出量在运动期间较高，动静脉氧摄取较低；运动期间的心输出量高与通气不足有关；心输出量高与输血相关的血红蛋白浓度短期变化无关。
