Subcutaneous Bioimpedance Recording: Assessment of a Method for Hemodynamic Monitoring by Implanted Devices

Autor:	Keith G. Lurie, Scott McKNITE, Deviprasad Venugopal, Rajat Jhanjee, Andres Belalcazar, Robert P Patterson, David G. Benditt
Rok vydání:	2009
Předmět:	Mean arterial pressure medicine.medical_specialty Swine Pectoral muscle Monitoring Ambulatory Hemodynamics Blood volume Diagnostic evaluation Sensitivity and Specificity Physiology (medical) Internal medicine Electric Impedance medicine Animals Diagnosis Computer-Assisted Plethysmography Impedance Muscle Skeletal skin and connective tissue diseases Pulse (signal processing) business.industry Reproducibility of Results Equipment Design Prostheses and Implants Pulse pressure Equipment Failure Analysis Anesthesia Cardiology Arterial blood Female sense organs Rheology Cardiology and Cardiovascular Medicine business Algorithms Blood Flow Velocity
Zdroj:	Journal of Cardiovascular Electrophysiology. 20:76-81
ISSN:	1540-8167 1045-3873
Popis:	Background: Diagnostic evaluation of patients with suspected symptomatic arrhythmias is limited by inability to assess the hemodynamic impact of a detected rhythm. Objective: To address this limitation, we utilized closely spaced subcutaneous electrodes, small enough to incorporate within an implantable monitor, to detect blood flow-induced pectoral muscle bioimpedance (Z) changes in a swine model of hemorrhage-induced hypotension. Methods: In seven anesthetized and ventilated adult pigs, small ring electrodes (current electrodes 5 cm apart; voltage electrodes 3.5 cm apart) were positioned on the left pectoral muscle. Z signals (Biopac® system) and invasive arterial blood pressures were recorded. Hypotension was induced by hemorrhage (50% blood volume reduction). Mean arterial pressure (MAP) and pulse pressure (PP) with corresponding pulse Z (ΔZ) and base Z (Zo) were measured. A longitudinal mixed model with a first-order autoregressive error structure was used to test for associations (change in ΔZ vs change in MAP and change in ΔZ vs change in PP) taking into account within pig correlation. Results: During bleeding-induced hypotension, Zo increased. Changes of ΔZ correlated with both a change in MAP (coefficient = 1.17, P < 0.0001) and change in PP (coefficient = 0.98, P < 0.0001). A change in ΔZ of 1–2 orders of magnitude corresponded to an approximate 40–70% drop in MAP and PP in a porcine model in which the baseline MAP was 69–70 mmHg. Conclusion: Our findings suggest that closely spaced subcutaneous electrodes identify changes in local tissue/vascular bioimpedance that correlate well with direct invasive measures of induced hypotension in a porcine model.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::614a4ef619347f49cc6aecd534e64bf4 https://doi.org/10.1111/j.1540-8167.2008.01271.x Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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