Review Question - QID 100903

Untreated obstructive sleep apnea (OSA) is a known causative factor of pulmonary hypertension.

Nocturnal episodes of upper airway obstruction which are present in OSA reduce alveolar ventilation. The patient consequently suffers transient hypercarbia and hypoxemia, which causes pulmonary vasoconstriction and elevation in right heart pressures. Over a prolonged period, this may result in pulmonary hypertension and eventual right heart failure.

Victor explains the treatment of OSA in primary care. Physicians should suspect OSA in patients who are overweight, snore loudly, or have chronic daytime sleepiness. Diagnosis is confirmed with sleep studies. Treatment hinges on sufficient sleep, abstaining from depressants such as alcohol and sedatives, losing weight, avoiding the supine position during sleep, and using continuous positive airway pressure (CPAP) ventilation in more severe causes. It is important to ensure patient comfort in CPAP masks in order to achieve adequate compliance. Palatal surgery can decrease snoring but has not been shown to reduce incidence of OSA.

Kuniyoshi et al. describe the cardiovascular consequences of OSA. OSA is associated with hypertension, coronary artery disease, stroke, peripheral vascular disease, heart failure, and arrhythmias. Mechanisms that have been proposed to explain this include increased sympathetic drive, activation of metabolic and inflammatory markers, and impaired vascular function.

Incorrect answers:
Answers 2-5: OSA is not a risk factor for emphysema, idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, or pleural effusion.