![]() Inclusions were prospectively recorded in an electronic data capture form. An abnormal TCD pattern was one in which FVd less than or equal to 25 cm/s or PI greater than or equal to 1.25. According to our previous study, 10 normal TCD pattern was defined as the combination of FVd greater than 25 cm/s and PI less than 1.25. The higher PI and the lower flow velocity between the right and left MCAs were considered for statistical analysis. Time-averaged mean blood flow velocity (FVm), systolic blood flow velocity (FVs), and FVd (in centimeter per second) and the PI were then calculated. Tracings had to be stable over a 30-s recording period. The M1 segment of the middle cerebral artery (MCA) was identified and manual angle correction then applied to measure blood flow velocity in each MCA (in centimeter per second) by the inbuilt software. Color-coded sonography enabled identification of the circle of Willis. For echo-Doppler measurements, the clinoid process of the sphenoid bone and the brain stem were initially identified. In all patients, both middle cerebral arteries were insonated through the transtemporal window at a depth of 50 to 60 mm, and tracings were recorded for at least 10 cardiac cycles in patients showing stable conditions, i.e., no agitation or pain, no cardiorespiratory distress. TCD measurements were performed in the ED within the first 8 h post-TBI using a Doppler instrument operating at 2 MHz or an echo-Doppler device with a 1- to 5-MHz transducer. Physicians with an adequate background in transcranial ultrasonography were allowed to include patients in each center. The reliability of TCD recordings was checked. Transcranial DopplerĬenters were visited by P.B. An injury severity score (ISS) was also measured upon admission. Biologic data consisted of serum sodium concentration, serum glucose concentration, hemoglobin concentration, platelet count, coagulation parameters, and arterial blood gases if available. Data collected on admission were age, mechanism of injury, time from trauma to initial CT scan, time from trauma to TCD, heart rate, arterial blood pressure, respiratory rate, and score for the visual analog pain scale. Patients were excluded if they met one of the following criteria: previous treatment with anticoagulant or antiplatelet drugs except aspirin, mechanical ventilation with sedation on admission, systolic arterial blood pressure less than 90 mmHg, arterial pulse oximetry less than 92%, no CT scan on admission, evidence of moderate or severe brain lesions on initial CT scan ( i.e., TCDB classification III-VI), any craniotemporal lesion impeding satisfactory TCD examination, more than 8-h delay between initial injury and TCD measurements, or a history of intracranial procedures. Due to a lower rate of recruitment, we extended the inclusion criterion to 15-yr-old patients because their TCD velocities were not different from those of adult patients. Initially, patients more than 18 yr were planned to be included. CT scans were all classified by a senior radiologist from each center. Patients aged more than 15 yr admitted to the ED after mild to moderate TBI (GCS, 9 to 15) were included in the study if they underwent TCD within 8 h post injury and their initial CT scan satisfied the Traumatic Coma Data Bank (TCDB) II classification: diffuse injury with cisterns present, a midline shift between 0 and 5 mm, and/or no high- or mixed-density lesions of at least 25 ml. ![]() The aim of the current study was to validate these TCD thresholds for outcome prediction in a large multicenter cohort study population after mild to moderate TBI and minor lesions on initial CT scan. ![]() However, these cut-offs were proposed from one single-center study and an external validation of TCD from multiple sites is required to promote the use of TCD in the ED. 10 The thresholds of 1.25 and 25 cm/s for PI and FVd accurately predicted neurologic worsening with 90% sensitivity and 91% specificity. 8, 9 In a previous study including patients with normal or mild brain lesions on initial CT scan, we found a correlation between TCD measurements on admission and early neurologic status. TCD has been used on admission to improve cerebral hemodynamics in patients with severe TBI. 7 In patients with TBI, this technique can reveal low diastolic blood flow velocity (FVd) and high pulsatility index (PI) values induced by high vascular bed resistance. Transcranial Doppler (TCD) is a technique that explores cerebral blood flow velocities. ![]()
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