Evaluation of the effect of mouth gag placement on ultrasonographic optic nerve sheath diameter in pediatric patients who will have tonsillectomy and adenotonsillectomy surgery

Adenotonsillectomy, in which the palatine and adenoid tonsils surrounding the throat are excised, is one of the most frequently performed surgical operations in the pediatric patient group. Endotracheal intubation and placement of Boyle-Davis mouth gag applied to perform the operation is known to have an effect to increase the intracranial pressure. Increased intracranial pressure is associated with perioperative mortality and morbidity. Ultrasonographic measurement of optic nerve sheath diameter (ONSD) and optic nerve sheath diameter/ eyeball transverse diameter (ONSD/ ETD) appears to be a safe and noninvasive indicator of increased intracranial pressure. In this study, our aim was to evaluate the effect of surgery on the ratio of ONSD and ONSD/ ETD at different predetermined time intervals in patients who underwent adenotonsillectomy. After the approval of the ethics committee, 120 patients with ASA scores of 1 and 2, aged between 1 and 16 years, who underwent adenotonsillectomy between 15.05.2019 and 21.10.2021 were included in the study. ONSD/ETD measurements and simultaneous vital parameters of the patients were recorded on ultrasonographic images. Measurement times were determined as T0: post-induction, T1: 10 minutes after intubation, T2: 10 minutes after mouth gag insertion, T3: 10 minutes after mouth gag removal. There is a statistically significant change in the left-sided ONSD, ETD, and ONSD/ETD levels over time (p=0.012, p=0.003 and p=0.007, respectively). Higher ONSD levels in T2 compared to T0 (p=0.026), higher ETD levels in T4 compared to T0 (p<0.001) and lower ONSD/ETD levels in T4 compared to T2 was (p=0.007). According to the baseline, with the percentage change in the levels of ONSD, ETD, and ONSD/ETD at the other follow-up times, respectively; There was no statistically significant correlation between the patients' age, fluid amount, body weight percentile, height percentile, total time the mouth opener was left, and the time between intubation and mouth opener (p>0.0041, p>0.0041). In conclusion, we believe that the sonographic measurement of the ONSD and ONSD/ETD ratios in pediatric patients is a reproducible and noninvasive indicator of increased intracranial pressure that can be safely used in children with a clinical suspicion in increased intracranial pressure or in cases where there is a risk of increased intracranial pressure and monitoring of intracranial pressure is indicated.