American journal of respiratory and critical care medicine
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Am. J. Respir. Crit. Care Med. · Jul 1994
Cardiovascular effects of periodic obstructive and central apneas in dogs.
Patients with sleep apnea may experience two types of apnea, central and obstructive. We compared cardiovascular effects of these two types of apnea matched for changes in arterial blood gas tensions and periodicity. In 12 anesthetized, closed chest dogs, obstructive apneas were induced by completely occluding the endotracheal tube at end-expiration for 1 min and allowing 1 min of spontaneous ventilation. ⋯ During obstructive apneas, right atrial pressure increased, as did right heart blood volume. During central apneas, both right atrial pressure and left atrial pressure increased, as did pulmonary blood volume. We conclude that: (1) HR decreases are more severe during central apnea, most likely due to lack of respiratory mechanoreceptor input; (2) CO decreases more with central compared with obstructive apnea due to the heart rate response; (3) HR-induced cardiac dysfunction with central apnea could lead to pulmonary vascular congestion.