Modification of a Transvalvular Microaxial Flow Pump for Instantaneous Determination of Native Cardiac Output and Volume.

• The Impella device does not have the capability of determining native cardiac output. • Admittance electrode technology can assess chamber volume and calculate cardiac output accurately. • A modified Impella device fitted with admittance electrodes is able to provide accurate, instantaneous native cardiac output data in various hemodynamic conditions. • The modified Impella provides simultaneous pressure-volume loop data that can be used for better understanding of real-time cardiac function in clinical situations. The current Impella cardiopulmonary (CP) pump, used for mechanical circulatory support in patients with cardiogenic shock (CS), cannot assess native cardiac output (CO) and left ventricular (LV) volumes. These data are valuable in facilitating device management and weaning. Admittance technology allows for accurate assessment of cardiac chamber volumes. This study tested the ability to engineer admittance electrodes onto an existing Impella CP pump to assess total and native CO as well as LV chamber volumes in an instantaneous manner. Impella CP pumps were fitted with 4 admittance electrodes and were placed in the LVs of adult swine (n = 9) that were subjected to 3 different hemodynamic conditions, including Impella CP speed adjustments, administration of escalating doses of dobutamine and microsphere injections into the left main artery to result in cardiac injury. CO, according to admittance electrodes, was calculated from LV volumes and heart rate. In addition, CO was calculated in each instance via thermodilution, continuous CO measurement, the Fick principle, and aortic velocity-time integral by means of echocardiography. Modified Impella CP pumps were placed in swine LVs successfully. CO, as determined by admittance electrodes, was similar by trend to other methods of CO assessment. It was corrected for pump speed to calculate native CO, and calculated LV chamber volumes trended as expected in each experimental protocol. We report, for the first time, that an Impella CP pump can be fitted with admittance electrodes and used to determine total and native CO in various hemodynamic situations. Transvalvular mechanical circulatory support devices such as the Impella CP do not have the ability to provide real-time information on native cardiac output (CO) and left ventricular (LV) volumes. This information is critical in device management and in weaning in patients with cardiogenic shock. We demonstrate, for the first time, that Impella CP pumps coupled with admittance electrodes are able to determine native CO and LV chamber volumes in multiple hemodynamic situations such as Impella pump speed adjustments, escalating dobutamine administration and cardiac injury from microsphere injection. A modified Impella cardiopulmonary pump with admittance electrodes and data output with real-time cardiac output and chamber volumes. The Impella-cardiopulmonary (CP) pump with admittance electrodes is able to provide real-time left ventricle (LV) chamber volumes, including stroke volume (SV). Using SV and heart rate, native cardiac output (CO) is calculated, with total CO calculated by the addition of pump flow. Pressure-volume data, obtainable by simultaneous LV pressure waveform, can be analyzed on a connected computer. The dashed line indicates future integration into Impella Controller, which could provide pump-weaning capabilities as native CO improves. [Display omitted] [ABSTRACT FROM AUTHOR]