[Acoustic rhinometry in the evaluation of intranasal aspirin challenge]

Nasal lysine aspirin (Lys-ASA) challenge is an alternative to oral and bronchial challenges in the diagnosis of aspirin (ASA) hypersensitivity. The aim of the study was to evaluate the acoustic rhinometry as an objective method of assessment of Lys-ASA nasal challenge.

Twenty patients with aspirin induced asthma (ASA-S) and 10 controls (ASA-NS group: 5 patients with allergic rhinitis and 5 healthy subjects) were included. Nasal challenge was performed with placebo (saline) and 14.4 mg of Lys-ASA introduced as aerosol to both nostrils (total dose: 16 mg of acetylsalicylic acid). Measurements of nasal volume bilaterally were performed with the use of acoustic rhinometer before and 1, 2, 4 and 24 hours after the challenge. For further analysis the sum of both nasal cavities volume at the level of 2 to 5 cm from nostrils was used.

Mean total bilateral volume in ASA-S group after placebo was: 7.74, 6.21, 7.11, 7.12, 7.24 cm(3) and 7.24, 5.77, 6.31, 6.27, 6.98 cm(3) after Lys-ASA (before and after 1, 2, 4 and 24 hours, respectively; p = 0,048 and p = 0,02, in 2nd and 4th hour, Lys-ASA v. placebo, Wilcoxon's test). With cut off point of nasal volume decrease by 10% in the 1st hour the sensitivity of the test was 70%, specificity 60%, positive predictive value 77.78% and negative predictive value 50%.

In conclusion, acoustic rhinometry with measurement of nasal cavities volume changes at 2 to 5 cm from nostrils does not appear to be sufficiently sensitive and specific as a single method for evaluation of studied challenge method.