Reliability of the reflux finding score for infants in flexible versus rigid laryngoscopy.

Objectives: The Reflux Finding Score for Infants (RFS-I) was developed to assess signs of laryngopharyngeal reflux (LPR) in infants. With flexible laryngoscopy, moderate inter- and highly variable intraobserver reliability was found. We hypothesized that the use of rigid laryngoscopy would increase reliability and therefore evaluated the reliability of the RFS-I for flexible versus rigid laryngoscopy in infants.

Methods: We established a set of videos of consecutively performed flexible and rigid laryngoscopies in infants. The RFS-I was scored twice by 4 otorhinolaryngologists, 2 otorhinolaryngology fellows, and 2 inexperienced observers. Cohen's and Fleiss' kappas (k) were calculated for categorical data and the intraclass correlation coefficient (ICC) was calculated for ordinal data.

Results: The study set consisted of laryngoscopic videos of 30 infants (median age 7.5 (0-19.8) months). Overall interobserver reliability of the RFS-I was moderate for both flexible (ICC = 0.60, 95% CI 0.44-0.76) and rigid (ICC = 0.42, 95% CI 0.26-0.62) laryngoscopy. There were no significant differences in reliability of overall RFS-I scores and individual RFS-I items for flexible versus rigid laryngoscopy. Intraobserver reliability of the total RFS-I score ranged from fair to excellent for both flexible (ICC = 0.33-0.93) and rigid (ICC = 0.39-0.86) laryngoscopies. Comparing RFS-I results for flexible versus rigid laryngoscopy per observer, reliability ranged from no to substantial (k = -0.16-0.63, mean k = 0.22), with an observed agreement of 0.08-0.35.

Conclusion: Reliability of the RFS-I was moderate and did not differ between flexible and rigid laryngoscopies. The RFS-I is not suitable to detect signs or to guide treatment of LPR in infants, neither with flexible nor with rigid laryngoscopy.