Accuracy of Impulse Oscillometry in Airway Dysfunction

Background: the purpose of this study was to calculate andcompare the specificity and sens itivity of impulse oscillometry(los) as a new technique in the detection of airways dysfunctionby means of a simple pulmonary function test in chemicalwarfare injured cases sufferin g from respiratory dise ases .methods: the study was performed prospectively in 100 patients,who complained of dyspnea as a result of sulfur mustardgas exposure in the iran-iraq war , between 1981 and1988 . following a physical examination, los and spirometerywer e performed for all the patients. then, the specificity andsens itivity of los parameters were calculated and comparedwith those of spirometery.results: with a routine cut- off point, r at 5hz and r at 20hzhave a sensitivity and specificity of 48 .9%, 70.4% and 40.0%and 85.2%, respe ctively. with a normal cut-off point of rat5hz=<240 or r at20hz=<180 or x at5hz=>-0. 20 kpal//s ,there is a 100% specificity (ppv= 100%).conclusion : while los is a new , cooperation independenttechnique and specific in the detection of airways dysfunction,it is less sensitive than spirometery in spotting small airwaysobstructions. los is a good diagnostic method in the detectionof pulmonary involvements in uncooperative patients.