Medical Student Research Forum Posters

The contractility of the left ventricle (LV) is an important characterization of cardiac function and is oftenmeasured through dP/dtmax, defined as the maximum rate of left ventricular pressure change during isovolumetriccontraction. It can also be summarized globally by measurement of the left ventricular ejection fraction. Directmeasurement of left ventricular pressure is difficult as it involves invasive catheter placement, but other methodsof measuring dP/dtmax have been developed, such as echocardiographic analysis of the mitral regurgitation jet.While more convenient and less invasive, this method still has many limitations given inherent variability. Morerecently, several studies have used arterial pressure waveform analysis as a new method of determining dP/dtmax.Though more invasive, this modality is highly applicable in an operating room setting because many patientsalready have arterial catheters placed. Current evidence in literature is conflicted in regards to the accuracy ofthis newer method. The Hypotension Prediction Index (HPI) software is a new technology that integratesselected dynamic cardiovascular measurements, using the arterial pressure waveform, to predict impendingintraoperative hypotensive episodes. In addition, the monitor provides a calculated dP/dtmax, determined from theradial arterial pressure waveform. A recent study has demonstrated significant correlation between radial arterialdP/dtmax values calculated with the HPI software to those calculated using echocardiography in patients with acuteheart failure in the cardiac ICU setting, especially in those with higher systemic vascular resistance, lower cardiacoutput, and lower stroke volumes. Our proposed study sought to assess the strength of correlation betweenarterial pressure waveform derived dP/dtmax and transesophageal echocardiographically (TEE) determineddP/dtmax. In addition, correlations between dP/dtmax and TEE-derived assessment of ejection fraction will provideguidance for relating this new parameter with other standard contractility assessments.