Dynamic optic nerve sheath diameter changes upon moderate hyperventilation in patients with traumatic brain injury

Background: Sonographic assessment of optical nerve sheath diameter (ONSD) has the potential for non-invasive monitoring of intracranial pressure (ICP). Hyperventilation (HV) -induced hypocapnia is used in the management of patients with traumatic brain injury (TBI) to reduce ICP. This study investigates, whether sonography is a reliable tool to detect dynamic changes in ONSD. Methods: This prospective single center trial included patients with TBI and neuromonitoring within 36 h after injury. Data collection and ONSD measurements were performed at baseline and during moderate HV for 50 min. Patients not suffering from TBI were recruited as control group. Results: Ten patients with TBI (70% males, mean age 35 ± 14 years) with a median of first GCS of 5.9 and ten control patients (40% males, mean age 45 ± 16 years) without presumed intracranial hypertension were included. During HV, ICP decreased significantly (p < .0001) in the TBI group. An ONSD response was found for HV (p = .05). Conclusion: We observed a dynamic decrease of ONSD during moderate HV. This suggests a potential use of serial ONSD measurements when applying HV in cases of suspected intracranial hypertension.