accuracy of impulse oscillometry in airway dysfunction

background: the purpose of this study was to calculate and compare the specificity and sensitivity of impulse oscillometry (ios) as a new technique in the detection of airways dysfunction by means of a simple pulmonary function test in chemical warfare injured cases suffering from respiratory diseases.   methods: the study was performed prospectively in 100 patients, who complained of dyspnea as a result of sulfur mustard gas exposure in the iran-iraq war, between 1981 and 1988. following a physical examination, ios and spirometery were performed for all the patients. then, the specificity and sensitivity of ios parameters were calculated and compared with those of spirometery.   results : with a routine cut-off point, r at 5hz and r at 20hz have a sensitivity and specificity of 48.9%, 70.4% and 40.0% and 85.2%, respectively. with a normal cut-off point of r at5hz=<240 or r at20hz=<180 or x at5hz=>-0.20 kpal/l/s, there is a 100% specificity (ppv=100%).   conclusion : while ios is a new, cooperation independent technique and specific in the detection of airways dysfunction, it is less sensitive than spirometery in spotting small airways obstructions. ios is a good diagnostic method in the detection of pulmonary involvements in uncooperative patients.