False statement about type I respiratory failure is:

Answer is D (Normal A-a gradient) Type I Respiratory failure is characterized by an increase in alveolar aerial 02 gradient. Respiratory failure is defined as a disorder wherein, lung function is inadequate to meet the metabolic demands of the individual and is unable to maintain normal aerial gas levels in the blood. It is of two types: Type I Respiratory failure Type II Respiratory failure Represents failure of oxygenation and is characterized by a low Pa02 with normal or low PaCO2. Represents a defect in ventilation (hypoventilation) and is characterized by decreased PaO, with increase PaCO2. Pa02 : Low (< 60 mm Hg) Pa02 : Decreased (< 60 mm Hg) PaCO2 : Normal or low 49 mm Hg) PaCO2 : Increased (> 49 mm Hg) PA-a0' : Increased PA-a02 : Normal Causes : Causes : This type is caused by conditions which affect oxygenation, like: Parenchymal diseases (V-Q mismatch) Diseases of vasculature/shunts Examples: - Pneumonia Q - ARDS Q - Emphysema Q - Right to left shunts Q This type is caused by conditions causing hypoventilation as in: Obstructive lung disease: COPD, F. body Decreased central respiratory drive e.g. CNS disorders like : Brain injury, Meningitis Weakness of respiratory muscle e.g. - Peripheral N.S. disorders like: M. gravis. - Interstitial lung disease. Q - MS disorders like polymyositis. - Rib cage disorders : Kyphoscoliosis