Preoperative Assessment of Optic Nerve Sheath Diameter and Gastric Residual Volume in Adult Traumatic Brain Injury Patients Undergoing Decompressive Craniectomy: A Prospective Case Series

Abstract

Traumatic brain injury (TBI) is frequently associated with delayed gastric emptying due to autonomic dysfunction, impaired consciousness, and raised intracranial pressure (ICP), increasing the risk of pulmonary aspiration. Gastric point-of-care ultrasound (POCUS) enables bedside assessment of gastric contents, while optic nerve sheath diameter (ONSD) is a noninvasive surrogate marker of elevated ICP. We explored whether increased ONSD was associated with greater residual gastric contents in TBI patients. This prospective case series included 15 adult patients with TBI undergoing decompressive craniectomy. Preinduction gastric POCUS was used to evaluate gastric contents using the Perlas grading system, while ONSD was measured bilaterally using a high-frequency linear probe, with values >5.5 mm considered suggestive of raised ICP. Correlation between ONSD and Perlas grade was analyzed using Spearman's rank correlation. All patients had a documented fasting duration exceeding 8 hours. Perlas Grades 0, 1, and 2 stomachs were observed in 40, 33.3, and 26.7% of patients, respectively. ONSD values ranged from 4.8 to 7.2 mm. A moderate positive correlation was observed between ONSD and Perlas grade (Spearman's ρ = 0.46); however, the association did not reach statistical significance (p = 0.10). Patients with higher ONSD values generally demonstrated higher gastric content grades. In adult TBI patients undergoing decompressive craniectomy, ONSD showed a moderate positive association with gastric residual contents despite prolonged fasting. Combined ONSD and gastric POCUS assessment is feasible and may aid perioperative aspiration risk stratification. Larger prospective studies are needed to confirm the relationship between intracranial hypertension and delayed gastric emptying.