Comparison of Arterial Pressure Waveform Derived dp/dt Versus Transesophageal Echocardiogram Derived Left Ventricular dp/dt Max in the Intra-operative Setting

The Hypotension Prediction Index (HPI, Edwards LifeScience, Irvine, CA) software is a new technology that integrates selected dynamic cardiovascular measurements, using the arterial pressure waveform, to predict impending intra-operative hypotensive episodes. In addition, the monitor provides a calculated (dp/dtmax), determined from the radial arterial pressure waveform as a guide to optimal therapeutic interventions. A recent study has demonstrated significant correlation between radial arterial dp/dtmax values calculated with the HPI software to those calculated using echocardiography in patients with acute heart failure in the cardiac ICU setting, especially in those with higher systemic vascular resistance, lower cardiac output, and lower stroke volumes.

This study seeks to assess the strength of these correlations in the intra-operative setting in patients with normal and abnormal cardiac function. Corroboration of the reliability of this newer method of ascertaining Left ventricular contractility and quantifying the correlations in different settings will allow for more accurate and efficient clinical utilization of dp/dtmax in a larger number of clinical settings.