1. Atelectasis

2. Definition
Definition ; atelectasis refers to the closure or collapse of alveoli . Atelectasis may be acute or chronic . The acute atelectasis which occurs frequently in the postoperative setting or in people who are immobilized and have shallow , monotonous breathing pattern

3. . Excess secretion or mucus plungs may also cause obstruction of airflow and result in atelectasis .
Atelectasis also is observed in patients with a chronic airway obstruction that imparids or blocks airflow to an area of lung . This type pf atelectasis is more insidious and slower in onset .

4. Pathophysiology
Atelectasis may occur in adults of reduced alveolar ventilation or any type of blockage . the trapped alveolar air becomes absorbed into the blood stream and no additional air can enter into the alveoli because of the blockage . As a result , the affected portion of the lung becomes airless and the alveoli collapse.

5. Patients are at high risk for atelectasis
Poatoperatively because of the numerous respiratory changes that may occur
a monotonous , low tidal breathing pattern may cause small airway closure and alveolar collapse . this can result from the effects of anesthesia or analgestic agents , supine positioning splinting of the chest wall because of the pain or abdominal distention .

6. excessive pressure on the lung tissue which restricts normal lung expansion on inspiration . Such pressure may be produced by fluid accumulating within the pleural space . Pressure may be produced by a pericardium distended with fluid , tumor growth within the thorax.

7. Clinical manifestations.
General Signs and symptoms include:
cough,
sputum production
low- grade fever .

8. In acute atelectasis:
involving a large amount of lung tissue (labor atelectasis ) marked respiratory distress may be observed . In addition to the previously mentioned signs and symnptoms ,dyspnea, tachycardia , tachypnea, pleural pain and central cyanosis ( late sign of hypoxemia ) may be anticipated .

9. In chronic atelectasis
sings and symptoms are similar to those of acute atelectasis . the chronic nature of the alveolar collapse predisposes patients to infection distal to the obstruction . Therefore the signs and symptoms of pulmonary infection also may be present .

10. Assessment and diagnostic findings
Increased respiratory rate and appear to labor with breathing . Decreased breath sounds and crackles are heard over the affected area .In addition , chest x ray findings may reveal patchy . Pulse oximetry (spo2) may demonstrate a low saturation of hemoglobin.

11. Prevention Frequent training early mobilization
voluntary deep- breathing maneuvers
directed cough suctioning , aerosol nebulizer
chest physical therapy (postural drainge and chest percussion ) and bronchoscopy .

12. Management
The goal of treatment is to improve ventilation and to remove secretions:
frequent turning
early ambulation ,
lung volume expansion maneuvers and coughing and serve as the first –line measures to minimize or treat atelectasis

13. . In patients who do not respond to first-line measures or who can't perform deep breathing exercises , other treatment such as positive end expiratory pressure PEEPor continuous or intermittent positive pressure – breathing (IPPB) or bronchscopy may be used .

14. Nebullizer treatments with a bronchodilator or sodium bicarbonate may be used to assist patients in the expectoration of secretions . If respiratory care measures fail to improve the obstruction a bronchoscopy is performed

15. Severe or massive atelectasis may lead to acute respiratory failure especially in patients with underlying lung disease endotracheal intubations and mechanical ventilation may be necessary . Treatment may include thoracentes or insertion of a chest tube .