In-vivovalidation of a new non-invasive continuous ventricular stroke volume monitoring system in an animal model

Abstract

IntroductionRecently, a non-invasive, continuous ventricular stroke volume monitoring system using skin electrodes has been developed. In contrast to impedance-based methods, the new technique (ventricular field recognition) enables measurement of changes in ventricular volume. A prototype using this new method was built (the hemologic cardiac profiler, HCP) and validated against a reference method in a pig model during variations in cardiac output.MethodsIn six Dalland pigs, cardiac output was simultaneously measured with the HCP (CO-HCP), and an invasive ultrasonic flow-probe around the ascending aorta (CO-FP). Variations in CO were achieved by change in ventricular loading conditions, cardiac pacing, and dobutamine administration. Data were analysed according to Bland-Altman analysis and Pearson's correlation.ResultsPearson's correlation between the CO-HCP and the CO-FP was r = 0.978. Bland-Altman analysis showed a bias of - 0.114 L/minute, and a variability of the bias (2 standard deviations, 2SD) of 0.55 L/minute.ConclusionsThe results of the present study demonstrate that CO-HCP is comparable to CO-FP in an animal model of cardiac output measurements during a wide variation of CO. Therefore, the HCP has the potential to become a clinical applicable cardiac output monitor.

Evolution of Critical Care Cardiology: Transformation of the Cardiovascular Intensive Care Unit and the Emerging Need for New Medical Staffing and Training Models

“…55,56 Noninvasive methods for hemodynamic assessment continue to be refined. 57,58 Lastly, the role of intelligent information systems in the ICU has grown, providing new opportunities for decision support, safety flags, and tools for improved communication and quality improvement.…”

A new electric method for non-invasive continuous monitoring of stroke volume and ventricular volume-time curves

“…(2)) and $\left({\Phi }_{\left(n\right)}^{\left(k\right)}\right({\tau }_{\mathrm{ES}})-{\Phi }_{\left(n\right)}^{\left(k\right)}(0\left)\right)\ll {\Phi }_{\left(n\right)}^{\left(k\right)}\left(0\right)$(empirical fact, see e.g. [15] and [23]), and ${\Phi }_{\left(n\right)}^{\left(k\right)}\left(0\right)\propto E_0$, the three proportionalities indicated under the braces in eq. (32), i.e.…”

“…In a previous paper [15], we presented an animal study, in which the cardiac output readings using the new VFR method were compared to the cardiac output readings from a flow probe around the aorta, resulting in a bias of - 0.114 L/minute and a variability of the bias (2 standard deviations, 2SD) of 0.55 L/minute in a Bland-Altman analysis; without however providing any mathematical details about the principle of operation of the new method. In the present paper, the physics and mathematics of the principle of operation of the VFR method is presented, and some basic assumptions underlying the VFR method are analysed and investigated.…”

Year in review 2011: Critical Care - cardiology

“…There is a continuous search to develop new devices that non-invasively measure CO. An innovative technique based on measurement of spatial patterns of voltage changes distributed over the thoracic skin has been presented [23]. When applying a weak electric current over the thorax, emptying and filling of the ventricles during the cardiac cycle induce cyclic voltage changes on the thoracic skin, generating specific two-dimensional spatial patterns.…”