Objective: To prospectively evaluate 1) use of endotracheal tube (ETT) surface electrodes for recurrent laryngeal nerve (RLN) monitoring in thyroid surgery in children, and 2) effects of thyroid surgery on the RLN in children.Methods: Patients <18 years old undergoing thyroidectomy were included. Vocal cord mobility was assessed pre-and postoperatively. RLNs were monitored using adhesive or integrated electrodes. Recordings were made before and after dissection, and area under the curve and latency were compared using mixed models.Results: Twenty-five children (44 nerves at risk), mean (standard deviation) age 13.1 (3.4) years (range 4.5-17.4 years), underwent thyroidectomy. Twelve (46%) monitors were adhesive. One nerve had unobtainable responses. Nerveäna Power Index (NPI) (Neurovision Medical Products, Ventura, CA) decreased, and latency increased pre-versus postdissection at all amplitudes (P < 0.0001), with change in slope of NPI affected by tumor size (P < 0.05). Postdissection, the NPI was lower, and the latency was longer when stimulating low in the neck versus near the cricothyroid joint at all stimulating amplitudes (P < 0.0001), with change in NPI related to tumor size (P < 0.0001). Changes were not associated with decreased vocal cord mobility, aspiration, or voice change. One patient had a temporary unilateral paresis that resolved by 7 weeks, and another had normal movement 3 weeks postoperatively and developed a paresis 2 months postoperatively.Conclusion: ETT surface electrodes are reliable for RLN monitoring in thyroid surgery in children. Thyroid surgery is associated with a decrease in RLN stimulability that is related to tumor size. The site of RLN stimulation matters when evaluating the nerve.

Objective Define the length of the subglottis and trachea in children to predict a safe intubation depth. Methods Patients <18 years undergoing rigid bronchoscopy from 2013 to 2020 were included. The carina and inferior borders of the cricoid and true vocal folds were marked on a bronchoscope and distances were measured. Patient age, weight, height, and chest height were recorded. Four styles of cuffed pediatric endotracheal tubes (ETT) were measured and potential positions of each cuff and tip were calculated within each trachea using five depth of intubation scenarios. Multivariate linear regression was performed to identify predictors of subglottic and tracheal length. Results Measurements were obtained from 210 children (141 male, 69 female), mean (SD) age 3.21 (3.66) years. Patient height was the best predictor of subglottic length (R2: 0.418): Lengthsg (mm) = 0.058 * height (cm) + 2.8, and tracheal length (R2: 0.733): Lengtht (mm) = 0.485 * height (cm) + 21.3. None of the depth of intubation scenarios maintained a cuff‐free subglottis for all ETT styles investigated. A formula for depth of intubation: Lengthdi (mm) = 0.06 * height (cm) + 8.8 found that no ETT cuffs would be in the subglottis and all tips would be above the carina. Conclusion Current strategies for determining appropriate depth of intubation pose a high risk of subglottic ETT cuff placement. Placing the inferior border of the vocal cords 0.06 * height (cm) + 8.8 from the superior border of the inflated ETT cuff may prevent subglottic cuff placement and endobronchial intubation. Level of Evidence 4 Laryngoscope, 132:S1–S10, 2022