Real-time Doppler-based arterial vascular impedance and peripheral pressure-flow loops: a pilot study

Abstract

Objective: Arterial pressure-flow loops and vascular impedance provide additional data that could be used to assess the hemodynamic effects of therapeutic interventions in anesthetized patients. To evaluate the utility of such an approach, the authors sought to design a device that combines flow waveforms from an esophageal Doppler probe and pressure waveforms from a peripheral artery to produce real-time pressure-flow loops and estimates of arterial vascular impedance.

Design: Prospective, cohort study.

Setting: Single center, university-based teaching hospital.

Participants: Patients undergoing surgery in whom the attending anesthesiologist had opted to place an esophageal Doppler probe and a peripheral arterial catheter for hemodynamic monitoring.

Interventions: This was a non-interventional study designed to record pressure-flow loops and arterial vascular impedance intraoperatively using a novel, noninvasive device.

Measurements and main results: Pressure-flow loops and arterial vascular impedance were measured noninvasively using radial artery pressure and descending thoracic aorta flow waveforms in real time.

Conclusions: Real-time arterial vascular impedance and peripheral pressure-volume loops can be determined using available monitoring devices. Technical feasibility of this technology in patients is a crucial first step to permit meaningful evaluation of the clinical value of this approach for accurate determination of complex hemodynamic indices and, eventually, improvement of outcomes.

Keywords: arterial waveforms, monitoring; doppler; hemodynamics; impedance; pressure flow loops.