Hypoventilation Syndromes

Hypoventilation means that effective alveolar ventilation is insufficient to clear the carbon dioxide produced by the body. The respiratory rate may appear normal when each breath is too shallow or ineffective, so assessment must include depth, effort, chest movement, mental status, and gas exchange rather than rate alone. Hypercapnia may develop from impaired respiratory drive, respiratory-muscle weakness, restricted chest-wall movement, airway or lung disease, or respiratory-depressant substances. Obesity hypoventilation syndrome (OHS) is an important adult pattern. It combines obesity, sleep-disordered breathing, and raised awake carbon dioxide after other causes of hypoventilation have been excluded. Obstructive sleep apnea (OSA) commonly coexists, but OSA alone does not establish OHS because the defining ventilatory abnormality is present while the person is awake. Nursing priorities are to recognize deterioration, support prescribed oxygenation and ventilation, identify likely contributors, and, for emergency red flags, activate the local emergency team and notify the physician or nurse practitioner immediately without independently diagnosing the cause or changing prescribed device settings.