INTERPRETIVE ALGORITHMS FOR THE SYMPTOM-LIMITED EXERCISE TEST - ASSESSING DYSPNEA IN PERSIAN-GULF-WAR VETERANS

Interpretation of symptom-limited exercise testing requires analysis o f a large body of simultaneously recorded cardiopulmonary data. Karlma n Wasserman has recommended an algorithmic approach to interpretation (WA) that leads to a dichotomous choice between pulmonary and cardiova scular impairment. An alternative algorithm published by William Esche nbacher (EA) provides for concurrent assessment of cardiovascular and pulmonary exercise impairment. We analyzed a group of 29 individuals r eferred to the Pulmonary Physiology Laboratory at the Washington Veter ans Affairs Medical Center for evaluation of dyspnea following service in the Persian Gulf War to assess the concordance of the two algorith ms in determining the cause of dyspnea and exercise impairment in thes e individuals. They each performed a progressive, ramped, symptom-limi ted exercise test on a bike for a minimum of 6 min. Exercise measureme nts were analyzed by both interpretive algorithms. Concordance was fou nd in 28% of tests. The greatest discordance occurred in identifying p ulmonary limitation. Eleven had pulmonary limitation by EA; of these, WA found 1 to have pulmonary limitation, 5 to be normal, 4 indetermina te, and 1 musculoskeletal limitation. Of the 11 with pulmonary limitat ion by EA, but not by WA, 5 had abnormal resting pulmonary function me asurements. Analysis of the differences between these two interpretive approaches is given. The EA algorithm may be more sensitive for detec ting exercise impairment of pulmonary origin, but its specificity rema ins to be determined.