The Management of Chronic Hypoventilation: Diagnostic Evaluation (1)
The hallmark of chronic hypoventilation is an arterial blood gas level showing compensated hypercarbia. Chronic hypoventilation is rarely missed in patients undergoing an evaluation for severe lung disease who usually have dyspnea and have blood gases tested as a routine part of their examination. However, patients with chronic hypoventilation due to neuromuscular diseases, central ventilatory defects, or mixed disturbances commonly have few or no respiratory complaints. Their earliest symptoms are related to the nocturnal exaggeration of C02 retention that disrupts normal sleep patterns and causes fretful sleeping, nightmares, enuresis, and morning headaches. buy asthma inhaler
During the day, fatigue, hypersomnolence, and mood disorders are common, often leading to the misdiagnosis of depression. The physician must be alert to the insidious manner in which chronic hypoventilation may present in these patients so that blood gases are obtained and the condition is not missed.