Assessing Middle Cerebral Artery Blood Flow Velocities and Outcomes in Pediatric Severe Traumatic Brain Injury using Transcranial Doppler Ultrasound

Abstract

Objective: To assess the impact cerebrovascular flow velocities of pediatric traumatic brain injury (TBI) patients using transcranial doppler (TCD) and to assess for acute and long-term clinical correlations. Methods: This is a retrospective study of pediatric patients who suffered a severe TBI defined as Glasgow Coma Scale < 8. A total of 47 patients were treated between January 2014 and August 2018 and all patients received TCD assessments for cerebral blood flow velocity for a total of 210 measurements. The primary outcome measure was the correlation between middle cerebral artery (MCA) mean flow velocities (MFVs) and clinical characteristics. MCA velocities were identified as high flow or low flow states using age-adjusted standardized velocities. Persistent low flow states were defined as >50% of TCD recordings per patient displaying the specified flow state without resolution to a flow state within 2 standard deviations of age-sex defined normal. Secondary outcomes included mortality and the global function using Pediatric Glasgow Outcome Scale-Extended (GOS-E Peds) at 3, 6 and 12 month and the association of the TCD findings to other physiologic variables at the time of scanning. Results: Of the 47 patients, the mean age was 8.24 years (+ 5.82) and there were 33 (70%) males and 24 (51%) Hispanic. At least 1 low flow velocity (>2 SDs below agenormalized mean) was identified in 20 (43%) patients and at least one high flow (>2 SDs above age-normalized mean) in 10 (21%) patients. There were no associations between demographics and single episodes of low or high flow velocity, however, patients aged >5 and <10 and non-Hispanic patients were more likely to have persistent low flow states. Persistent low flow states were significantly associated with mortality (p=0.014). Conclusions: TCD can be used to assess cerebrovascular function following pediatric TBI and may be used to for earlier identification of abnormal flow velocities.