<prompt> CO2 retention is seen in:Carbon monoxide poisoningRespiratory failureHigh altitudeAll  <response>: B i.e. Respiratory failure Type II respiratory failure, which occurs dt hypoventilation i.e. failure of ventilation is characterized by hypoxemia with hypercapnia CO2 retention but normal not increased alveolar-aerial oxygen gradient IP 1 Aa02, Hypercapnia hypercarbia or CO2 retention is defined as an elevation in aerial paial pressure of carbon dioxide Pco2. It characteristically occurs secondary to inadequate alveolar ventilation hypoventilation, in type II respiratory failure. - - Type II respiratory failure or alveolar hypoventilation alveolar ventilatory failure hypercapnia hypercarbia CO2 retention respiratory acidosis or normal PA-a02 is seen in reduced compliance of chest like kyphoscoliosisQ, reduced lung compliance like pulmonary alveolar edetnaQ, obstructive lung disease like COPDQ, weakness of respiratory muscle like bulbar poliomyelitisQ, bronchospasm and decreased central respiratory drive. Drowning may cause bronchospasm pulmonary edema so CO2 retention. - Type I respiratory failure results from failure in exchange diffusion of respiratory gases at the alveolar-capillary junction as a result of disease of lung parenchyma like pneumonia, or vasculature like right to left shunt, and ventilation-perfusion mismatchQ. It is characterized by increased alveolar-aerial oxygen gradient PA-ao2Q, hypoxemia and normal or low PaCO2. - At high altitudes alveolar CO2 decreases bo hyperventilation. 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 cas level in the blood. Type Characteristic Features Causes RF-I Represents failure of oxygenation, and is characterized by dysponea and secondary hyperventilation lt Results from failure in exchange of respiratory gases mainly 02at the alveolar capillary junction i.e. alveolar capillary block syndrome as a result of disease of lung parenchyma. There is thickening of alveolar or capillary wall resulting in ventilation -perfusion V-Q - Hypoxemia Pao2 - decreased; mismatch. Only 02 transfers is affected because CO2 is 20 times more diffusible. So causes 60 mm Hg are - Increased alveolar - aerial I. Parenchymal interstitial lung diseases Oxygen gradients PA-ao2 15 mm Hg - which thicken alveolar - capillary membrane eg. asbestosis, sarcoidosis, pneumoconiosis, berylliosis, diffuse interstitial fibrosis, infiltrative lung disease like - Normal or decreased Paco2 40 malignancy granulomatosis. mmHg i.e. respiratory alkalosis - Which separate A-C membrane like pulmonary interstial edema in cardiac failure and exudates pneumonitis or pneumonia2 and resultant pulmonary fibrosis. II. Mixing of venous blood with aerial blood like right to left shuntQ. III. Ventilation - Perfusion mismatch Q: In emphysema surface area for diffusion decreases i.e. poorly ventilated alveoli increase. Mn: RAPE-VIP Right to left shunt, Alveolar pulmonary edema, parenchymal disease pneumonia, emphysema - ventilation perfusion mismatch. RF II Represents failure defect in I. Decreased central respiratory drive to breathe ventilation and is characterized by - Drug like morphine, sedative anesthetics overdose. hypoventilation lit - Brain stem injury, bulbar poliomyelitisQ, hypothyroidism, sleep disordered breathing. - Hypoxemia Pao2 decreased; 60 II. Respiratory muscle weakness mmHg - Normal alveolar-aerial oxygen - Neuromuscular disorders like myasthenia gravis, GB syndrome, bulbar poliomyelitis, ALS. gradient PA-ao2 15 mmHg - Myopathy, polymyositis, electrolyte derangement. - Hypercapnia Paco2 40 mm Hg III.Obstructive lung disease i.e. respiratory acidosis Q. - Acute obstruction like foreign body, laryngeal edema, bronchospasm, asthma - COPD esp during acute exacerbation like chronic bronchitis, emphysema, interstial lung disease. IV.Increased load on respiratory system dt - Resistive load eg bronchospasm - Reduced chest wall compliance eg. pleural effusion, pneumofibro - thorax, abdominal distension ascitis, rib cage disorder kyphoscoliosisQ, ankylosing spondylitis, flail chest. - Reduced lung compliance eg. atelectasis, lung resection, alveolar edema ARDSQ, PEEP positive end expiratory pressure. - Increased minute ventilation requirements eg pulmonary embolism with increased dead space, sepsis. RF III Also called peri-operative respiratory failure Occurs as a result of atelectasis and atelectasis is common in perioperative period RF IV Result of hypoperfusion of respiratory muscles Occurs in patient with shock 