Acoustic rhinometry, rhinomanometry and the amount of nasal secretion in the clinical monitoring of the nasal provocation test.

BACKGROUND: The reliable interpretation of the nasal provocation test in allergy diagnosis requires objective and measurable monitoring parameters for clinical practice. The clinical usefulness of the nasal provocation test has been limited by scanty knowledge of the specificity and sensitivity of the test and a lack of reference values.

OBJECTIVE: To test and compare three objective monitoring parameters of a nasal provocation test in occupational allergic rhinitis. To evaluate the magnitude of the nasonasal effects in a unilateral allergen challenge.

METHODS: The monitoring parameters of the nasal reaction were derived from the minimum cross-sectional area on acoustic rhinometry, the nasal resistance on active anterior rhinomanometry and the amount of nasal secretion measured at 15 min intervals for 60 min. Twenty-three bovine-allergic dairy and beef cattle farmers and 19 exposed, non-allergic control subjects were challenged first with a control solution and then with the cow allergen.

RESULTS: All the three monitoring parameters showed high specificity and sensitivity in finding allergic and non-allergic subjects. The secretion parameter was found to be slightly superior to the acoustic rhinometry and rhinomanometry parameters. The side difference in the nasal response between the allergen-challenged and the contralateral diluent-challenged cavity was significant for all the parameters among the allergic subjects. The contralateral secretion amount was 1/3 of the ipsilateral secretion, indicating the magnitude of the contralateral nasonasal reflex. A nasonasal reflex was also noted in the nasal patency monitoring. The coefficient of variation was significantly lower for the acoustic rhinometry than for the rhinomanometry (P=0.0001). The optimal threshold values for a positive test were a secretion amount of 100 mg, a 15% decrease in the minimum cross-sectional area and a 50% increase in the resistance for the observation period of 30 min and correspondingly 210 mg, 30% and 100% for 60 min.

CONCLUSION: The low-pressure aspiration of the nasal secretion from the anterior part of the nasal cavity was found to be a reliable and practical monitoring parameter to be used together with acoustic rhinometry or rhinomanometry in the nasal provocation test for clinical purposes. Although significant nasonasal effects took place in the unilateral allergen challenge, the response was more prominent in the allergen-challenged than in the contralateral diluent-challenged nasal cavity in most allergic subjects.