Respiratory acidosis is the result of too much carbon dioxide in the body. For several reasons, the lungs are unable to release the rising systemic carbon dioxide. When this happens, the body's acid-base balance becomes unstable, causing body fluids, particularly blood, to become too acidic. Acute respiratory acidosis is the rapid buildup of carbon dioxide before the kidneys can compensate. Chronic respiratory acidosis occurs over a longer period, allowing the kidneys to compensate by increasing the body's level of bicarbonate. Acid-base balance is dependent upon the ratio between acid or carbon dioxide, and base or bicarbonate in the body. When one is out of balance, the other will try to compensate.
Asthma and Chronic Obstructive Pulmonary Disease
Airway diseases such as asthma, emphysema and chronic bronchitis cause the airway and alveoli, or air sacs, in the lungs to become less compliant by allowing the air in, but making it difficult to breathe the air out. This leads to carbon dioxide retention. In an acute situation such as an asthma attack, when the body is reacting to an allergen, this carbon dioxide retention happens quickly, causing respiratory acidosis.
Chest Deformity
Chest deformities from paralysis, cerebral palsy, spina bifida, chronic lung disease, trauma and other conditions physically limit the lungs' ability to exchange oxygen and carbon dioxide. In an acute situation, such as sudden illness, ventilatory or respiratory failure can occur as a result of uncompensated respiratory acidosis.
Drugs
Narcotics can suppress the respiratory drive, allowing the buildup of carbon dioxide. As soon as the carbon dioxide level begins to rise, the kidneys try to compensate by releasing bicarbonate. However, kidney response has a much slower onset than the respiratory response. Certain drugs can also prevent the kidneys from compensating. Full compensation or returning the body to an acid-base balance can sometimes take days.
Obesity
Obesity can limit chest excursion, or the lungs' ability to expand and contract, causing the carbon dioxide levels to rise. Obese individuals are often told to sleep in a reclining position in order to allow the lungs to expand more easily.
Symptoms and Diagnosis
Symptoms of respiratory acidosis may include drowsiness, shortness of breath, lethargy, a sudden or gradual onset of fatigue and confusion. As the carbon dioxide level increases, the oxygen level decreases, depriving the brain, heart and organs of the oxygen needed to sustain life.
An arterial blood gas measures the amount of oxygen, carbon dioxide and the pH level in the body.
