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Measurement of diffusing capacity in pulmonary embolism.
H S Wimalaratna1, J Farrell, H Y Lee
1Orsett Hospital, Grays, Essex, U.K.
Respiratory Medicine
|November 1, 1989
Summary
Reduced lung diffusing capacity (TLCO) effectively screens for pulmonary embolism (PE). While lung scans normalize, persistently low TLCO indicates ongoing physiological defects despite treatment.
Area of Science:
- Pulmonary Medicine
- Diagnostic Imaging
- Respiratory Physiology
Background:
- Pulmonary embolism (PE) diagnosis relies on various tests.
- Standard pulmonary function tests (PFTs) show variable results in PE patients.
Purpose of the Study:
- To evaluate the diagnostic utility of TLCO in PE.
- To assess the long-term impact of PE on lung function.
Main Methods:
- Pulmonary function tests, including TLCO, FEV1, FVC, and arterial blood gases, were performed on 20 PE patients.
- Ventilation-perfusion lung scans were used for initial PE diagnosis.
- Patients were followed for up to 3 years with repeat assessments.
Main Results:
- TLCO was significantly reduced in all PE patients.
- FEV1, FVC, and blood gases showed high variability.
- Lung scans normalized within 3 months, but TLCO remained subnormal in most cases.
- A TLCO below 75% predicted normal was observed in all patients with abnormal lung scans.
Conclusions:
- Reduced TLCO is a sensitive indicator for PE, serving as a useful screening tool.
- A normal TLCO can effectively rule out PE.
- Persistent TLCO reduction suggests underlying physiological defects despite clinical and radiological improvement.