Differentiation of pulmonary embolism from high altitude pulmonary edema.

OBJECTIVE

To differentiate the high altitude pulmonary edema (HAPE) from pulmonary embolism (PE) by clinical probability model of PE, lactate dehydrogenase (LDH), aspartate transaminase (AST) and D-dimer assays at high altitude.

METHODS

A prospective study.

METHODS

The study was carried out at CMH, Skardu, from October 2001 to December 2002.

METHODS

Consecutive 40 patients evacuated from height > 3000 meters with symptoms of PE or HAPE were included. Clinical pretest probabilities scores of PE, Minutex D-dimer assay (Biopool international) and cardiac enzymes estimation by IFCC approved methods, were used for diagnosis. Mann-Whitney U test was applied by using SPSS and level of significance was taken at (p<0.05).

RESULTS

Out of 40 subjects, 31 HAPE and 9 patients of PE were initially diagnosed on the basis of clinical features, D-dimer assay and V-Q scanning. Out of 9 patients of PE; 3 had plasma D-dimer between 250-500 ng/ml and 6 > 500 ng/ml. Plasma D-dimer of 500 ng/ml was considered as cut-off value; 6 (66.7%) patients of PE could be diagnosed and 30 (96.7%) cases of HAPE excluded indicating very good negative predictive value. Serum LDH, AST and CK were raised above the reference ranges in 8 (89%), 7 (78 %) and 3 (33 %) patients of PE as compared to 11 (35%), 6 (19%) and 9 (29 %) of HAPE respectively.

CONCLUSIONS

Clinical assessment in combination with D-dimer assay, LDH and AST can be used for timely differentiation of PE from HAPE at high altitude where diagnostic imaging procedures are not available.