Misdiagnosis of Pneumonia in Patients Needing Mechanical Respiration

During a prospective study of tracheostomy and mechanical ventilation, it was found that the primary physicians made a clinical diagnosis of pneumonia in 60 of 111 patients. The primary indications for assisted ventilation included multiple trauma and ventilatory failure after major operations. Only 18 patients had supportive evidence for a diagnosis of pneumonia. Evaluation of the pulmonary processes indicated a diagnosis of atelectasis or postthoracotomy changes in 20 patients while pneumonia could not be differentiated from atelectasis in eight. Atypical pulmonary edema was misinterpreted as pneumonia in five patients and two had uremic infiltrates. The diagnosis was based on fever and positive tracheal cultures in seven patients without physical or roentgenographic findings.

Previous emphasis on infection in respirator patients, coupled with misinterpretation of tracheal cultures and x-ray films of the chest made with a standard portable unit may result in overdiagnosis of pneumonia.