End-diastolic volume versus pulmonary artery wedge pressure in evaluating cardiac preload in trauma patients

To evaluate the relative accuracy of right ventricular end-diastolic volume index (RVEDVI) and pulmonary artery wedge pressure (PAWP) for determining cardiac preload.

A modified pulmonary artery catheter was used to determine RVEDVI, PAWP, and CI 238 times in 32 trauma patients.

The initial mean values included cardiac index (CI) = 3.4 +/- 1.3 L/min/m2, PAWP = 14.8 +/- 6.6 mm Hg, and RVEDVI = 99 +/- 40 mL/m2. Cardiac index correlated better with RVEDVI (r = 0.6440; p < 0.001) than with PAWP (r = 0.1068) or CVP (r = 0.1604). In 84 studies in 19 patients, the PAWP was high (19+ mm Hg) in spite of an RVEDVI that was low (< 90 mL/m2) in 22 (26%) or mid-range (90-140 mL/m2) in 49 (58%) of these. In addition, in 12 studies a high RVEDVI (> 140 mL/m2) existed with a relatively low PAWP (< 12 mm Hg). Thus, in 83 (35%) of the studies, PAWP provided information different from the RVEDVI. Of 65 instances in which preload was increased, CI "responded" (> or = 20%) in 26 (40%). The incidence of a response was not affected by the PAWP; however, responses with a RVEDVI of < 90, 90-140, or > 140 mL/m2 were 64%, 27%, and 0 (p < 0.001).

The RVEDVI more accurately predicted preload recruitable increases in CI than did the PAWP.