Abstract

Stroke volume was determined from the pulmonary artery pressure record by application of the pulse contour method. Pulmonary artery pressure records were obtained in 17 patients using a high fidelity catheter-tip pressure transducer and simultaneous measurements of cardiac output were obtained from indicator dilution curves. The formula used was SV = KP sa (i plus T s/Td) where Psa is the planimetered area beneath the systolic portion of the pulmonary artery pressure curve. Ts and Td are the durations of systole and diastole, and K is a constant. Stroke volume was altered by isometric handgrip exercise and/or pharmacological agents in 15 patients. Serial measurementswere made in 2 patients in acute pulmonary oedema after myocardial infarction. Comparison of a wide range of values of stroke volume by the pulse contour method with those obtained from dye dilution curves showed a good correlation (r plus 0.97, P smaller than 0.001) regression line y = 1.01 times - 0.47. Measurement of stroke volume from the pulmonary artery pressure contour is a technique of potential value in serial haemodynamic monitoring.