1. Acute Cardiopulmonary Failure From Sleep-Disordered Breathing
Gordon E. Carr, MD, Babak Mokhlesi, MD, FCCP, Brian K. Gehlbach, MD 
CHEST 
Volume 141, Issue 3, Pages (March 2012)
DOI: /chest
Copyright © 2012 The American College of Chest Physicians Terms and Conditions

2. Figure 1
Mechanisms of ventilatory failure. OHS=obesity hypoventilation syndrome. (Adapted with permission from Schmidt and Hall22)
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Copyright © 2012 The American College of Chest Physicians Terms and Conditions

3. Figure 2
Proposed “vicious cycle” of acute ventilatory failure in patients with obstructive sleep apnea (OSA). Diverse acute insults may occur (eg, pulmonary embolism, infection, or abdominal surgery). Because obese patients or patients with overlap syndrome have substantial chronic respiratory loads, they develop hypoventilation with a lower degree of acute insult. OSA compounds this hypoventilation because some patients with OSA have a blunted ventilatory response to hypercapnia. As respiratory failure progresses to somnolence and exhaustion, upper airway tone is compromised, further loading the respiratory system, and reinforcing the deleterious effects of the acute load. See Figure 1 legend for expansion of abbreviations.
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Copyright © 2012 The American College of Chest Physicians Terms and Conditions

4. Figure 3
Mechanisms of cardiac dysfunction in OSA. HR=heart rate; LV=left ventricle; SNA=sympathetic nervous system activity. See Figure 2 legend for expansion of other abbreviations.
(Reprinted with permission from the American Thoracic Society.50)
CHEST  , DOI: ( /chest )
Copyright © 2012 The American College of Chest Physicians Terms and Conditions