Exhaled Nitric Oxide Measurement before Pediatric Adenotonsillectomy: A Feasibility Study.

BACKGROUND Exhaled nitric oxide (eNO) is a known biomarker for the diagnosis and monitoring of bronchial hyperreactivityin adults and children. AIMS To investigatethe potential role of eNOmeasurement for predicting perioperative respiratory adverse events in children, we sought to determine its feasibility and acceptability before adenotonsillectomy. METHODS We attempted eNO testing in children, 4 to 12 years of age, immediately prior to admission for outpatient adenotonsillectomy. We used correlations between eNO levels and postoperative adverse respiratory events to make sample size predictions for future studies that address the predictability of the device. RESULTS One hundred three (53%) of 192 children were able to provide an eNO sample. The success rate increased with age from 23% [9%-38%] at age 4 to over 85% [54% - 98%] after age 9.Using the eNO normal value (< 20 ppb) as a cutoff, an expected sample size to detect a significant difference between children with and without adverse events is 868, assuming that respiratory adverse events occur in 29% of children. CONCLUSIONS eNO testing on the day of surgery has limited feasibility in children younger than 7 years of age. The most common reason for failure was inadequate physical performance while interacting with the testing device. The role of this respiratory biomarker in the context of perioperative outcomes for pediatric adenotonsillectomy remains unknown and should be further studied with improved technologies.