Utility of impedance cardiography to improve physician estimation of hemodynamic parameters in the emergency department.

Emergency physicians must often make assessments of complex hemodynamic parameters. To assess the utility of impedance cardiography (ICG) in the emergency department, the authors examined treating physicians' abilities to assess stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR) by comparing the clinicians' estimates of these values to ICG measurements. Treating physicians were asked to estimate the SV, CO, and SVR of acutely ill patients as being low, normal, or high. ICG measurements of SV, CO, and SVR were also categorized as low, normal, or high. Physician estimates were compared with ICG measures for concordance. Changes of therapy initiated as a result of discordance between physician's estimates and ICG measurements were recorded. The treating physician assessments and ICG hemodynamic measurements were concordant in 62 of 101 (62%) cases for SV (kappa=0.068), in 53 of 101 (53%) cases for CO (p=0.125), and in 50 of 101 (50%) measurements for SVR (p=0.148). The low concordance suggests that treating physicians did not consistently estimate SV, CO, and SVR accurately. ICG provides noninvasive hemodynamic measurements of SV, CO, and SVR that offer clinical utility and potential value in the emergency department.