Differentiation of pulmonary embolism from high altitude pulmonary edema

ABSTRACT

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. Design: A prospective study. Place and Duration of Study The study was carried out at CMH, Skardu, from October 2001 to December 2002. Subjects and 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]. 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 > 500ng/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. 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