pulmonary disorders
Atelectasis
Introduction
Atelectasis is collapse of lung tissue with loss of volume. Patients may have dyspnea or respiratory failure if atelectasis is extensive. They may also develop pneumonia. Atelectasis is usually asymptomatic, but hypoxemia and pleuritic chest pain may be present in certain cases. Diagnosis is by chest x-ray. Treatment includes maintaining coughing and deep breathing and treating the cause. The natural tendency for open air spaces such as the alveoli to collapse is countered by the following: Surfactant (which maintains surface tension) Continuous breathing (which keeps the alveoli open) Intermittent deep breathing (which releases surfactant into the alveoli) Periodic coughing (which clears the airways of secretions) Major consequences of atelectasis include underventilation (with hypoxia and ventilation/perfusion [V/Q] mismatch) and pneumonia. 