Upper airway patency is presumed to be maintained by neuromuscular mechanisms. In conditions such as obstructive sleep apnea and during diaphragm pacing, airway occlusion appears to occur in the region of the oropharynx but is associated with ineffective muscle activation at all levels of the upper airway. Basic information is lacking on the mechanical properties of upper airway structures in order to understand where the upper airway is vulnerable to collapse and how muscles might act to modulate resistance. The proposed studies to be performed in anesthetized dogs, are designed to evaluate these issues. Pressure-flow relationships in the nasal, oropharyngeal, and laryngeal regions will be evaluated under conditions of bias flow through a tracheal cannula. Regional geometry and compliance will be determined from measurements of cross-sectional area using biplane cine-radiography and area-distance estimations using sound wave reflection techniques. Measurements of regional resistance and compliance will be performed before and after respiratory stimulation with pharmacologic agents, electrical stimulation of various upper airway muscles, and physical manipulation of upper airway structures. These techniques also will be used to evaluate the site and mechanism of obstruction during diaphragm pacing in animals spontaneously breathing through the upper airway. To alleviate obstruction, we will stimulate electrically upper airway muscles. We will directly alter the timing and amplitude of upper airway and diaphragm stimulation to determine how changes in the relative activation of upper airway and chest wall muscles affect flow resistance, lung volume, and ventilation. We have proposed a model of control of respiration based on our observed patterns of activation of the genioglossal muscle and diaphragm. Results from these studies will be used to expand this model to account for the mechanical effects of upper airway muscle activation. This theory may give insight into mechanisms responsible for periodic breathing and sleep apnea. Such information may be helpful in developing a more rational approach to the diagnosis and treatment of obstructive and central apneas in humans.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL029726-05
Application #
3340810
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1983-01-01
Project End
1989-12-31
Budget Start
1987-01-01
Budget End
1987-12-31
Support Year
5
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Case Western Reserve University
Department
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
Haxhiu, M A; van Lunteren, E; Cherniack, N S (1991) Central effects of tachykinin peptide on tracheal secretion. Respir Physiol 86:405-14
Haxhiu, M A; Cherniack, N S; Strohl, K P (1991) Reflex responses of laryngeal and pharyngeal submucosal glands in dogs. J Appl Physiol 71:1669-73
Fouke, J M; Sugg, S; Wolin, A D (1990) A model of muscular control of upper airway geometry. J Biomech 23:639-46
Wolin, A D; Strohl, K P; Acree, B N et al. (1990) Responses to negative pressure surrounding the neck in anesthetized animals. J Appl Physiol 68:154-60
Fouke, J M; Wolin, A D (1989) Instrumentation for estimating pulmonary function in patients on positive end-expiratory pressure. Crit Care Med 17:265-8
Fouke, J M; Wolin, A D; Strohl, K P et al. (1989) Elastic characteristics of the airway wall. J Appl Physiol 66:962-7
Decker, M J; Conrad, K P; Strohl, K P (1989) Noninvasive oximetry in the rat. Biomed Instrum Technol 23:222-8
Strohl, K P; Decker, M J; Olson, L G et al. (1988) The nasal response to exercise and exercise induced bronchoconstriction in normal and asthmatic subjects. Thorax 43:890-5
Fouke, J M; Wolin, A D; Saunders, K G et al. (1988) Sensor for measuring surface fluid conductivity in vivo. IEEE Trans Biomed Eng 35:877-81
Fouke, J M; Delemos, R A; McFadden Jr, E R (1988) Airway response to ultra short-term exposure to ozone. Am Rev Respir Dis 137:326-30

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