Physiological Fluctuations in Nasal Resistance May Interfere with Nasal Monitoring in the Nasal Provocation Test

Abstract

The physiological fluctuations in nasal flow and resistance in allergic subjects were studied by monitoring 12 subjects with perennial occupational allergic rhinitis with active anterior rhinomanometry (AAR) for 3h at ISmin intervals. The subjects were then challenged bilaterally with the diluent solution for allergen extracts and the effect was monitored with AAR. In AAR, cellular rubber nose adapters were used. Many physiological fluctuations in nasal patency were observed. Reference intervals were calculated for the changes in flow and resistance at the gradient pressure of 150 pa. For example, a 100% increase in unilateral resistance was found to be significant at the risk level of 5-10% for the observation time of 30-60 min. The corresponding increase for bilateral resistance was close to 70%. Challenge with diluent solution had a negliglible effect on the resistance fluctuation, the reference intervals being close to those for baseline monitoring. In conclusion, rapid changes in nasal flow and resistance in allergic subjects were common, and caution is necessary when interpreting these changes as a positive nasal reaction in the nasal provocation test. In addition, the use of other objective parameters, such as the amount of nasal secretion is recommended.