Non-Invasive Triage for Intracranial Hypertension in Prehospital Care

Acute brain injuries, including hemorrhagic and ischemic stroke and traumatic brain injury, are leading causes of death and disability worldwide and in Brazil. A common and dangerous complication of these injuries is intracranial hypertension (elevated pressure inside the skull), which can cause irreversible brain damage if not identified and treated promptly. Currently, there is no reliable, non-invasive method to assess intracranial pressure in the prehospital setting, which can delay referral to hospitals with neurosurgical capability.

This study evaluates two non-invasive technologies for prehospital triage: the Brain4care (B4C) device, a wearable extensometer that detects micrometric skull deformations associated with intracranial pressure fluctuations, and ultrasound measurement of the optic nerve sheath diameter (ONSD), which correlates with intracranial pressure.

The study is conducted in two sequential phases by the Mobile Emergency Care Service (SAMU) in the metropolitan area of Salvador, Brazil.

Phase 1 is a prospective, blinded, observational proof-of-concept study in adult patients with suspected acute brain injury (stroke or moderate/severe traumatic brain injury). Both B4C and ONSD will be applied to all eligible patients, but results will not be used for clinical decision-making. Investigators interpreting reference-standard neuroimaging or invasive intracranial pressure monitoring will be blinded to the B4C and ONSD results. This phase will assess the diagnostic accuracy and operational feasibility of both methods in the prehospital environment.

Phase 2 is an open-label, randomized, controlled, parallel-group clinical trial. Eligible patients will be randomized to standard prehospital care (control group) or prehospital triage assisted by B4C and ONSD (intervention group). The primary outcome is the proportion of patients correctly referred to hospitals with neurosurgical capability. Secondary outcomes include time to neurosurgical intervention, 30-day mortality, 90-day functional outcome, length of hospital stay, adverse events, and cost-effectiveness.

This project was approved by the Research Ethics Committee of the Gonçalo Moniz Research Center - Fiocruz Bahia (CEP Opinion No. 8,050,683).

Inclusion criteria

• Age 18 years or older
• Attended by the Mobile Emergency Care Service (SAMU) in the metropolitan area of Salvador, Brazil
• Clinical presentation suggestive of acute stroke (sudden focal neurological deficit or sudden and severe headache) OR moderate/severe traumatic brain injury (Glasgow Coma Scale)

Exclusion criteria

• Individuals with brain injuries of other etiologies, such as prior traumatic brain injury (TBI) and/or stroke, neoplasms, infections, sepsis, arteriovenous malformation, intoxication, and illicit drug use;
• Individuals with scalp and/or skin lacerations that prevent positioning of the brain4care sensor;
• Individuals with craniectomy;
• Severe debilitating mental health disorders and/or severe debilitating neurological diseases;
• Agitated, aggressive, or uncooperative individuals whose condition prevents follow-up and outcome assessment;
• Pregnant women.