Abstract 18: Ultrasound Estimation of Cardiac Output in a Swine Model of Cardiac Arrest: Implications for Assessing Post Cardiac Arrest Syndrome.
Background: Post cardiac arrest syndrome (PCAS) is a dynamic process of physiologic compromise requiring repeated measures of the hemodynamic response to treatment. Ultrasound (U/S) provides a safe modality to investigate the character and quality of blood flow during this critical period. However, few studies evaluate the agreement between U/S and traditional invasive measures of cardiac output (CO) under these conditions.
Objective: To report the correlation and agreement between U/S estimates of CO and stroke volume (SV) to traditional measures of CO with a pulmonary artery catheter (PAC) in an ischemic model of cardiac arrest.
Methods: Juvenile swine (32–40 kg) were instrumented with PAC used to measure CO via thermodilution. An ultrasound monitor was used to measure the velocity-time-integral across the aortic valve to estimate SV and CO. Selective coronary artery occlusion was performed to induce ischemic VF. CO estimates were obtained during the pre-arrest and post-arrest circulatory conditions. Comparisons were analyzed by linear regression and Bland-Altman plots of agreement.
Results: CARDIAC OUTPUT Mean Difference for CO = 0.092 L/min (CI −0.2, 0.4 (L/min), Agreement Limits [−1.8, 2.0 L/min] STROKE VOLUME Mean Difference, 3.6 mL (CI 0, 7.3(mL)), Limits of agreement [−18.9, 26.2 (mL)]
Conclusions: This study supports the use of U/S to non-invasively estimate SV and CO under ischemic arrest conditions. Strong correlations are observed between these measures and limits of agreement suggest a trend for U/S to slightly overestimate the CO at extreme conditions. Further study should proceed in the clinical environment to characterize the trend in cardiac physiology during early PCAS.
- © 2010 by American Heart Association, Inc.