Online Issues

Journal Vol 50 (3)

Breathing and Sleep: Measurement Methods, Genetic Influences, and Developmental Impacts

David M. Baekey, Pingfu Feng, Michael J. Decker, and Kingman P. Strohl

David M. Baekey, PhD, is an instructor and Pingfu Feng, MD, PhD, an assistant professor of medicine in the Pulmonary and Critical Care Division, both in the Department of Medicine at Case Western Reserve University in Cleveland, Ohio. Michael J. Decker, PhD, RN, RRT, DABSM, is Senior Scientist in the Chronic Viral Diseases Branch in the National Center for Zoonotic, Vector-borne Enteric Diseases at the Centers for Disease Control and Prevention in Atlanta, Georgia. Kingman P. Strohl, MD, is Director of the Center for Sleep Disorders Research at the Louis Stokes Cleveland DVA Medical Center, and a professor in the Division of Pulmonary, Critical Care, and Sleep Medicine at Case Western Reserve University.

Address correspondence and reprint requests to Dr. David M. Baekey, Department of Medicine, Case Western Reserve University, Room 622 Mailstop 5067, 11100 Euclid Avenue, Cleveland, OH 44106-5067 or email david.baekey@case.edu.

Abstract

Sleep-disordered breathing comprises alterations in respiratory rate, rhythm, and depth that present during sleep and may or may not be recognizable in breathing during wakefulness. Primary disorders include repetitive apneas, near apneas (hypopneas), or reductions in overall ventilation during sleep (hypoventilation), all of which lead to reductions in pulmonary gas exchange resulting in arousals, arrhythmia, hypercapnia, acidosis, and/or hypoxic stress responses such as pulmonary hypertension or polycythemia. Because the underlying mechanisms resulting in sleep-disordered breathing and its resulting comorbidities remain unclear, researchers use a variety of animal models to better understand the disorder. These models allow for conditioning paradigms, more detailed measurements of respiratory control, and the use of fewer preparations to provide a detailed picture of the individual components that contribute to breathing patterns. Both noninvasive and reduced methods are applicable with conditioned, inbred, and/or genetically manipulated animals to determine effect size and imply mechanisms. Research in animals has established preclinical models showing that intermediate traits of breathing pattern (e.g., responses to hypoxia, hypercapnia, and reoxygenation) vary according to genetic background and conditioning. Such findings permit new ideas about pathogenesis and prevention and form the rationale for observational and interventional studies in the human population. In this article we focus on methods of investigating respiratory control and applicable rodent models.

Key Words: hypoxia; neonate; periodic breathing; respiratory measurement; rodent model; sleep apnea; ventilatory control