We appreciate the comments about our study.1 Our goal was to determine whether transcranial Doppler (TCD) measurements on arrival could detect secondary neurological deterioration in patients with mild to moderate traumatic brain injury (TBI). The point was not to repeat TCD measurements before making any medical decision, as seen in the management of patients with severe TBI in the intensive care unit, but to identify early TCD abnormalities possibly associated with signs of secondary neurological deterioration to improve the initial disposition of high-risk and low-risk patients. Because of the bulk of patients with mild to moderate TBI admitted to the emergency department, such triage needs easy-to-use and informative procedures that might be achieved with 1 TCD examination. Given this context, we paid attention to rule out confounding factors such as anemia, arterial hypotension, and arrhythmia. TCD imaging was performed only in patients in stable condition after cerebral computed tomography scan with no evidence of moderate or severe brain lesions. The 2 sides of the brain were explored in all patients to detect asymmetry in the systolic blood flow velocity suggesting traumatic arterial dissection.2 Therefore, patients with diffuse intracranial disease, stroke, or severe cardiopathy were unlikely to be included in this cohort. Patients with severe anxiety and possible hyperventilation were not studied as well because of their lack of cooperation. The time elapsed between trauma and TCD examination was also considered in the view of temporal changes in cerebral blood flow, as shown after severe TBI.3 In our study, TCD imaging was performed at a median of 227 minutes (range, 42-700 minutes) after injury. No correlation was found between this delay and the diastolic blood flow velocity (r2 = 0.008) or pulsatility index (r2 = 0.003). Overall, it should be emphasized that TCD measurements should require stable conditions, especially after moderate TBI. Providing these methodological cautions and external validation in a larger cohort study, the combination of computed tomography scanning and TCD measurements could therefore help to screen mild to moderate TBI patients and improve their initial management. Pierre Bouzat Jean-François Payen Grenoble, France