DYSPNEA IN THE ADVANCED CANCER-PATIENT

Optimal management of dyspnea in terminal cancer patients requires an understanding of the responsible pathophysiological mechanisms. This p rospective study assessed visual analogue scales (VAS) of shortness of breath (SOB) and anxiety, bedside spirometry, maximum inspiratory pre ssure (MIP), chest radiography, arterial blood gases, hemoglobin, and electrocardiogram, if indicated, in 100 terminally ill cancer patients . Forty-nine percent of the patients had lung cancer. The median VAS s cores for SOB and anxiety were 53 mm and 29 mm, respectively. Spiromet ry was abnormal in 93% of patients, with 5% having obstructive, 41% re strictive, and 47% mixed patterns. The median MIP was -16 cm H2O. Sixt y-five percent of the patients had parenchymal or pleural involvement on chest radiograph. Twenty-nine percent had evidence of cardiac ische mia, recent or current myocardial infarction or atrial fibrillation. P atients had a median of five different abnormalities that could have c ontributed to their shortness of breath. Only anxiety (p = 0.001), a h istory smoking (p = 0.02), and pCO(2) levels were statistically signif icantly correlated with SOB VAS scores. The potentially correctable ca uses of dyspnea included hypoxia (40%), anemia (20%), and bronchospasm (52%). The finding of very low MIPs suggests severe respiratory muscl e weakness may contribute significantly to dyspnea in this patient pop ulation. Further studies are needed to confirm this finding and charac terize the underlying pathophysiology. (C) U.S. Cancer Pain Relief Com mittee, 1998.