Diagnostic accuracy of peak nasal inspiratory flow and rhinomanometry in functional rhinosurgery.

OBJECTIVES: Sensitivity and specificity of active anterior rhinomanometry (RMM) and peak nasal inspiratory flow (PNIF) in the diagnosis of functionally relevant structural nasal deformities should be assessed. The reference standard was clinical judgment based on all clinical data available. STUDY DESIGN: Prospective study of diagnostic accuracy at a tertiary rhinologic referral center. METHODS: RMM and PNIF were performed on 53 patients with symptomatic nasal stenosis and 40 healthy volunteers. Cut-offs for RMM and PNIF were defined by receiver operating characteristic analysis. RESULTS: A cut-off between normal and pathological of 700 mL/second for RMM at a transnasal pressure difference of 150 Pa, and of 2,000 mL/second (120 l per minute) for PNIF was calculated. No significant differences in terms of sensitivity of RMM and PNIF (0.77 vs. 0.66), specificity (0.8 vs. 0.8) and diagnostic accuracy (0,79 vs. 0.72) were found. CONCLUSION: RMM and PNIF provide valuable information to support clinical decision making. However, with both methods, approximately 25% of symptomatic patients with functionally relevant nasal structural deformity were not detected. A negative test outcome of RMM or PNIF does not exclude a functionally relevant nasal stenosis.