Abstract 12327: Intravenous Waveform Analysis Correlates With Volume Status in Resuscitation in In-Vivo Rat Model

Abstract

Introduction: Current volume status markers under-perform. Dynamic markers demonstrate improved outcomes in goal directed fluid therapy but maintain validity in a narrow range of clinical parameters. In addition, they assess volume responsiveness over total volume status. Repeated echo assessments may be infeasible. Hypothesis: Intravenous waveform analysis-derived F1 more closely models volume status than current markers in a rat resuscitation model. Methods: Seven Sprague Dawley rats were anesthetized and mechanically ventilated. Pressure transductions occurred via cannulation of the right femoral vein, left femoral artery and right internal jugular vein. Hemorrhage and resuscitation occurred via the left femoral vein. Heparinized rats were bled to 80% of the estimated blood volume (EBV) then resuscitated with their own whole blood in increments of 2% of the EBV until euvolemia was reached. Cardiac output (CO) and left ventricular end diastolic area (LVEDA) were calculated with echocardiography. Fast Fourier transform was performed on venous waveforms to obtain the heart rate linked F1 amplitude. Pearson’s correlation coefficients were compared using Fisher’s Z transformation. Mixed effects modeling goodness-of-fit was assessed with Akaike information criterion (AIC). Significance was set at p=.05. Results: F1 had the strongest correlation with volume status, r= .70, followed by CO, r=.55, LVEDA, r=.55, mean arterial pressure (MAP), r=.50, central venous pressure r= -.02, and pulse pressure variation (PPV), r=.01. When compared, F1 rho was significantly greater than that of all variables except CO and LVEDA, p=.09 and p=.07, respectively. In mixed effects regression, F1 displayed the most significant AIC, -274, followed by CO at -239. Conclusions: The novel marker F1 is strongly correlated with volume status during whole blood resuscitation. F1 may be superior to current markers for directing volume resuscitation therapy.