Pulse oximetry and P. carinii pneumonia - Pneumocystis carinii - Tips from Other Journals

Date: Oct, 1993

Pneumocystis carinii pneumonia is commonly diagnosed by examination of induced sputum or performing bronchoalveolar lavage. However, induced sputum tests have a diagnostic yield of 55 to 92 percent, making bronchoalveolar lavage necessary for diagnosis in patients with false-negative or true-negative test results. Bronchoalveolar lavage is a reliable diagnostic tool, but it is invasive and expensive. Chouaid and colleagues evaluated the effectiveness of exercise oximetry testing in screening for P. carinii pneumonia.

Eighty-five patients infected with the human immunodeificiency virus (HIV) were prospectively studied. Suspicion of P. carinii was based on clinical findings, abnormal chest radiographs or hypoxemia. In all of the patients, finger pulse oximetry was performed before, during and after exercise on a treadmill. A test was considered abnormal if oxygen saturation dropped below 85 percent, if the heart rate rose above 180 beats per minute, or if the patient was unable to complete the test because of exhaustion.

The sensitivity of exercise oximetry testing was 100 percent; all patients with P. carinii had an abnormal test result. The specificity was only 77 percent; 15 patients (23 percent) without P. carinii pneumonia had a false-positive result. Neither the stage of HIV disease nor the prophylactic use of aerosolized pentamidine affected the results of exercise oximetry testing.

Analysis revealed that exercise oximetry testing was cost-effective, especially in populations with a low prevalence of P. carinii pneumonia. In areas where P. carinii is more prevalent, exercise oximetry testing would be less useful.

The authors conclude that exercise oximetry testing is a sensitive, noninvasive and rapid method of ruling out P. carinii pneumonia. Because many pulmonary infections have similar presentations, oximetry can be useful in determining the necessity of more invasive or more time-consuming tests for P. carinii pneumonia.

COPYRIGHT 1993 American Academy of Family PhysiciansCOPYRIGHT 2004 Gale Group

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