Role of transcranial Doppler ultrasound as a predictor of outcome in severe traumatic brain injury and its correlation with full outline of unresponsiveness score

Abstract

Intro duction Traumatic brain injury (TBI) is a major public health problem. It is considered to be one of the leading causes of death and disability worldwide. After TBI, cerebral blood flow (CBF) becomes extremely low approaching ischemic thresholds. Concurrently, CBF velocities become strongly correlated to CBF itself post injury. Identification of such hemodynamic disturbances can be used to predict outcome in severe TBI when measured immediately postinjury using transcranial Doppler (TCD). TCD permits noninvasive assessment of different CBF velocities as well as pulsatility index (PI). Abnormal measurement of such indices is believed to correlate to poor outcome. Objective The aim of this work was to assess the predictive value of early TCD in patients with severe TBI and to correlate different TCD measurements with full outline of unresponsiveness (FOUR) score. Patients and methods In total, 74 patients with severe TBI, according to Glasgow Coma Scale (GCS), underwent TCD within 24 h posttrauma. Middle cerebral artery (MCA) velocities and pulsatility index (PI), as well as other clinical and neuroimaging data, were recorded and accordingly patients were divided into three groups: patients with normal TCD measurements, patients with hypoperfusion, and patients with vasospasm. Hypoperfusion was defined by meeting two out of three criteria: mean flow velocity of MCA less than 35 cm/s, end-diastolic velocity of MCA less than 20 cm/s, and PI more than 1.4. Vasospasm was defined as mean flow velocity more than 120 cm/s. Outcome was evaluated using the Glasgow Outcome Scale Extended at 3 months, as well as in-hospital mortality. TCD measurements were also correlated to GCS and FOUR score. Results There was a significant correlation between PI and Glasgow Outcome Scale Extended at 3 months. There was also significant correlation between PI and mortality. Strong negative correlation was recognized between PI and FOUR scores. Patients with hypoperfusion showed worst GCS and FOUR score and patients with vasospasm group showed worst Acute Physiology and Chronic Health Evaluation II score between all groups. Conclusion PI, when measured within the first 24 h posttrauma, is considered a good predictor of mortality as well as functional outcome at 3 months. PI values were associated with moderate negative correlation with the severity of injury FOUR score.