Sadeh J S, Miller A, Kukin M L
Division of Cardiology, Mount Sinai Medical Center, New York, NY 10029, USA.
Chest. 1997 May;111(5):1295-300. doi: 10.1378/chest.111.5.1295.
A simple, accurate, and noninvasive method of cardiac output measurement can be an extremely useful tool for the clinician and researcher. This study used the acetylene gas uptake technique to measure the absorption of acetylene into the pulmonary circulation during a constant exhalation, which is proportional to the pulmonary capillary blood flow and to the cardiac output, assuming no anatomic shunts. We compared cardiac output measured simultaneously by this and by the standard thermodilution (TD) technique in 21 patients in the ICU with a variety of medical and surgical conditions and a wide range of cardiac outputs. We also compared the two techniques in 19 ambulatory patients with a 2-h interval between the invasive and noninvasive test to assess variability over time. The two tests had an excellent correlation when done simultaneously with a correlation coefficient of 0.89 (p < 0.001). With a 2-h interval between the two tests, the correlation coefficient was 0.66 (p = 0.0018). Nine patients in the simultaneous group had cardiomyopathy. When they were excluded, the correlation coefficient increased to 0.96. Most of these patients had documented tricuspid regurgitation (TR), which may underlie the greater difference between acetylene uptake and TD values, with consistently higher TD values in these patients. This study confirms the correlation between the acetylene uptake and the standard invasive TD techniques in sick patients with various medical and surgical conditions and a wide range of cardiac outputs. Furthermore, we believe this would be a more accurate method for measuring cardiac output in patients with cardiomyopathy and TR because it is based only on pulmonary capillary blood flow.
一种简单、准确且无创的心输出量测量方法，对于临床医生和研究人员来说可能是一种极其有用的工具。本研究采用乙炔气体摄取技术，在持续呼气过程中测量乙炔进入肺循环的吸收量，假设不存在解剖分流，该吸收量与肺毛细血管血流量和心输出量成正比。我们在21名患有各种内科和外科疾病、心输出量范围广泛的重症监护病房（ICU）患者中，比较了用这种方法和标准热稀释（TD）技术同时测量的心输出量。我们还在19名门诊患者中比较了这两种技术，在有创和无创测试之间间隔2小时，以评估随时间的变异性。当同时进行这两种测试时，两者具有极好的相关性，相关系数为0.89（p<0.001）。当两次测试间隔2小时时，相关系数为0.66（p = 0.0018）。同时测试组中有9名患者患有心肌病。当将他们排除后，相关系数提高到了0.96。这些患者中的大多数都记录有三尖瓣反流（TR），这可能是乙炔摄取量和TD值之间差异较大的原因，这些患者的TD值一直较高。本研究证实了在患有各种内科和外科疾病、心输出量范围广泛的患病患者中，乙炔摄取量与标准有创TD技术之间的相关性。此外，我们认为这对于测量患有心肌病和TR的患者的心输出量将是一种更准确的方法，因为它仅基于肺毛细血管血流量。
