[Reproductibility of the true measurement of blood volume, cardiac output, mean pulmonary circulation time and pulmonary blood volume by radiocardiography].

Radiocardiography provides a simple method of measurement of blood volume, cardiac output, mean pulmonary circulation time, and pulmonary blood volume. The use of a computer allows the results to produced immediately provided that the circulating blood volume is measured during the test anpd that the radiocardiographic tracing is analysed by an entirely automatic method. The reproducibity of the results given by this automatic method has been studied in 35 patients, two measurements being made at 20 minute intervals. The standard deviation of the percentage difference between consecutive measurements was 5.8% for the blood volume, 10.4% for the cardiac output, 8.8% for the mean pulmonary circulation time, and 9.7% for the pulmonary blood volume.