Evaluation of the effect of Boyle-Davis mouth gag on intracranial pressure in patients undergoing adenotonsillectomy by using ultrasonographic optic nerve sheath diameter measurement

Evaluation of the effect of Boyle-Davis mouth gag on intracranial pressure in patients undergoing adenotonsillectomy by using ultrasonographic optic nerve sheath diameter measurement:



Publication date: Available online 31 December 2019

Source: International Journal of Pediatric Otorhinolaryngology

Author(s): Elif Karali, Abdullah Demirhan, Akif Günes, Ahmet Ural

ABSTRACT

Objective

We aimed to evaluate the effect of an increase in intracranial pressure (ICP) due to sympatho-adrenergic response caused by mouth gag and tongue depressor during adenotonsillectomy by measuring the optic nerve sheath diameter (ONSD) by ultrasonographic method.

Methods

Forty patients (age range 3 to 12 years) who underwent adenotonsillectomy were included in the study. All patients underwent surgery under general anesthesia with endotracheal intubation. Boyle-Davis mouth gag was used during the procedure. ONSD measurement was performed and a high-frequency linear probe. All ONSD measurements were performed by a single investigator experienced in the use of ultrasound. Ultrasonographically measured ONSD before induction was accepted as baseline (T0) value. Immediately after insertion of the mouth gag (T1), just before removal of the mouth gag (T2), and just before extubation (T3), ultrasonographic measurements of ONSD were recorded.

Results

When patients' baseline ONSD values were compared with the values obtained in T1, T2, T3, and a statistically significant increase was detected. The ONSD value measured before removing the mouth gag (T2) was significantly higher than the ONSD value measured immediately after the insertion of the mouth gag (T1). The ONSD value measured just before extubation (T3) and after removal of the mouth gag was significantly lower than the ONSD value (T2) measured just before removal of the mouth gag. When heart rate, mean arterial pressure (MAP), peripheral oxygen saturation (SpO₂) values of T0, T1, T2, T3 were compared, any statistically significant difference was not observed. When end-tidal carbon dioxide level (etCO₂) and peak inspiratory pressure (PIP) values of T1, T2, T3 were compared, any statistically significant difference was not observed.

Conclusion

This study showed that the Boyle-Davis mouth gag used during the adenotonsillectomy operation resulted in a significant increase in the diameter of the optic nerve sheath measured ultrasonographically and increased the ONSD even further during the time the mouth gag was remained in situ. In children with intracranial pathologies who will undergo adenotonsillectomy or those with increased ICP-related risk factors, the risks that may arise from the effect of the Boyle-Davis mouth gag on ICP should be considered.