Correlation of Doppler derived velocity change with cardiac index

Doppler ultrasound may be used as a screen to determine the need for placement of a pulmonary artery catheter. We tested the utility of Doppler derived acceleration, in correlation with pulmonary artery catheter derived cardiac index, as a screen for pulmonary artery catheter placement in 40 trauma patients. We found the expected quadratic relationship between acceleration and cardiac index. We also found that acceleration less than 200 cm/s2 correlates well with cardiac index less than 3.0 liter/min/m2.