Pulmonary embolism in soldiers serving at high altitude

To determine the frequency of different risk factors for pulmonary embolism with particular reference to high altitude as one of the factors.

Cross sectional, analytical study.

Department of Pulmonology, Military Hospital Rawalpindi, from December 2006 to December 2007.

A total of 50 serving soldiers suspected of pulmonary embolism were enrolled. A detailed history and physical examination was carried out to ascertain the risk factors of the disease. Screening profile was performed for connective tissue and infectious diseases, thrombophilic disorders and plasma homocystein levels. If soldiers were evacuated from high altitude, their approximate height from sea level was noted. Pulmonary embolism was confirmed on spiral CT scan of chest and/or ventilation-perfusion lung scan. Results were analyzed by SPSS version 11.

About 86% of patients were between 20-40 years of age. Dyspnea was the commonest symptom (40%) while tachypnea was the commonest clinical finding in these soldiers. D-dimer value was < 250 in only 10% of patients. Pleural effusion was the commonest radiological abnormality(40%) while non-specific T-wave inversions were noted as the most frequent ECG change(44%). Ventilation-perfusion (V/Q) scan was confirmatory in 80% of patients and spiral CT chest in 56%. When the frequency of risk factors of pulmonary embolism were analyzed, 50% of patients had high altitude as the only risk factor. Hereditary thrombophilic disorder was found in 14%, connective tissue disorder/infections in 20% and miscellaneous others in 16%.

Pulmonary embolism occurs at an increased frequency in soldiers working at high altitude, without any other co-existent risk factor.