Aspiration pneumonia. Results of treatment by positive-pressure ventilation in dogs

Unilateral right-sided pneumonia was produced in dogs by instilling hydrochloric acid into the right main stem bronchus. Untreated animals survived an average of 4 days following aspiration before dying of respiratory failure. Animals treated with immediate positive-pressure ventilation all survived. If treatment with a respirator was delayed for twenty-four hours after aspiration, survival was identical to that of the untreated controls. Pulmonary scans revealed that irreversible changes had probably taken place in the pulmonary circulation of those untreated animals that did not survive, despite occasional clearing of pneumonia radiographically.