Arterielle Pulskonturanalyse zur Messung des Herzindex unter Veränderungen der Vorlast und der aortalen Impedanz

BACKGROUND: Cardiac index obtained by arterial pulse contour analysis (CI(PC)) demonstrated good agreement with arterial or pulmonary arterial thermodilution derived cardiac index (CI(TD), CI(PA)) in cardiac surgical or critically ill patients. However as the accuracy of pulse contour analysis during changes of the aortic impedance is unclear, we compared CI(PC), CI(TD) and CI(PA) during changes of preload and the aortic impedance as occurring during sternotomy.

PATIENTS AND METHODS: CI(PC) und CI(TD), were compared in 28 patients, (and CI(PA) in 6 patients) undergoing elective coronary artery bypass grafting, before and after sternotomy. The relative changes DeltaCI(PC) und DeltaCI(PC) were calculated.

RESULTS: Sternotomy resulted in a significant increase in CI in 25 out of 28 patients. Regression analysis was performed between CI(PC) and CI(TD) before and after sternotomy (r(2) = 0.87, p<0.0001, r(2) = 0.88, p<0.0001) as well as between CI(PC) and CI(PA), before and after sternotomy (r(2) = 0.85, p<0.0001, r(2) = 0.93, p<0.01) and between DeltaCI(PC) and DeltaCI(TD) (r(2) = 0.72, p<0.0001). Bland Altman-Analysis for determining bias (m) and precision (2SD) between CI(PC) and CI(TD) before and after sternotomy and between DeltaCI(PC) and DeltaCI(TD) resulted in m = -0.03 L/min/m(2), 2SD = -0.34 to 0.28 L/min/m(2), m = -0.06 L/min/m(2), 2SD = -0.45 to 0.33 L/min/m(2) and m = -0.02 L/min/m(2), SD = -0.47 to 0.44 L/min/m(2).

CONCLUSION: Pulse contour analysis derived CI(PC) accurately reflects thermodilution derived CI(TD) or CI(PA) during changes of preload and the aortic impedance as occurring during sternotomy.