Table of Contents
ISRN Pulmonology
Volume 2012, Article ID 926345, 5 pages
http://dx.doi.org/10.5402/2012/926345
Research Article

A Model Simulation for Decreased Left Ventricular Stroke Volume in Obstructive Sleep-Disordered Breathing

Department of Anesthesiology, Wexner Medical Center at The Ohio State University, 410 W. 10th Avenue, Columbus, OH 43210, USA

Received 18 August 2012; Accepted 27 September 2012

Academic Editors: P. Von Wichert and C. C. Witt

Copyright © 2012 Ernesto Goldman. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Increased negative intrathoracic pressures are recognized to exacerbate left ventricular dysfunction in obstructive sleep-disordered breathing. Reportedly left ventricular stroke volume (LVSV) decline appeared greater than predicted by the obstruction alone. Objectives. Whether this effect is more dependent on biventricular elasticity and fluid shifts than on breathing-related transmural pressures could be inferred from a mathematical model simulation. Design. A previously validated cardiopulmonary model in healthy subjects during inspiratory loading was modified by parameter adjustments to fit its ventricular volumes output to published clinical data of decreased LVSV in obstructed breathing. Results. Reduced left ventricular end-diastolic compliance and increased central blood volume from baseline each simulated a 20% drop in LVSV whereas twice as much change was the result of increasing a mere 400 mL to the unstressed volume of systemic veins. An intermediate value was obtained by decreasing right ventricular end-diastolic compliance and higher systemic venous compliance. Conclusions. Simulations encompassing a wide range of decreased stroke volume at comparable intrathoracic pressures suggested a prominent role of decreased myocardial distensibility (possibly coupled to fluid migration) in the stroke volume fall.