Measurement of stroke volume from pulmonary artery pressure record in man

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.