The prognosis for patients who develop respiratory failure is poor, although those who require mechanical ventilation early are more likely to recover than those who develop late respiratory failure.26 In unventilated patients, pneumothorax results in prolonged hospitalization but does not increase mortality, whereas pneumothorax in ventilator-dependent patients almost always has a fatal outcome.27 Pneumothorax may be bilateral and recurrent, necessitating long-term chest tube placement or pleurodesis.
Determining whether a patient is responding to treatment may be difficult. It is important to remember that oxygenation typically reaches a nadir approximately 72 hours after therapy is begun.24 Because it generally takes several days for clinical improvement, therapy usually should not be changed for at least five to seven days. If a patient is not responding, a bronchoscopy should be performed to rule out the presence of another opportunistic process. P. carinii will still be present but, when no change or an increase in the organism count (if available) is found, the treatment may be failing and should be modified