Timing of hemodynamic pressure measurements on derived hemodynamic parameters.

The purpose of this study was to examine the difference between hemodynamic pressures and parameters obtained pre- compared to post-thermodilution CO measurements. A repeated measures within subject design was conducted with a cardiac surgical cohort. Three measures of hemodynamic pressures and parameters were determined pre- and post-CO measurements (Set 1) and repeated in 30 minutes (Set 2). The sequence was duplicated in four hours (Sets 3 and 4). Hemodynamic pressures lower pre-CO were PAS at Sets 1 and 3, and SBP, DBP, and MAP at Set 3. Hemodynamic parameters lower pre-CO were PVRI at Set 1 and SVRI at Set 3. These pre-post CO differences did not vary by greater than 10%. As the CO injectate volume had minimal effect, hemodynamic pressures may be obtained pre- or post-CO to derive hemodynamic parameters.