To the Editor: Autonomic dysfunction secondary to traumatic brain injury (TBI) is underreported in the literature and the data provided by Svedung Wettervik et al1 is remarkable for addressing the goals in the management of TBI. Svedung Wettervik et al1 reported 362 patients with TBI undergoing monitoring for arterial blood pressure and intracranial pressure (ICP). In this study, variables “advanced age,” “increase in mean arterial blood pressure (MAP),” “sympathetic stimulation,” “decreased ICP,” and “arterial compliance” were proved to be associated with a decrease in the cerebral perfusion pressure (CPP) below 60 mmHg, which was considered as an outcome variable of “poor clinical outcome.”1 The mechanism by which the blood pressure variability (BPV) influences the traumatized brain in the old patients is not clearly displayed. The authors1 attempted to explain this relationship through the high incidence of diabetes and cardiovascular diseases in this age group. According to them, the response to the catecholamine release originated by the tissue injury is different from that of young adults, who are, indeed, the predominant age group suffering TBI. Nevertheless, in the older age group, the resultant neurological insult was not associated with BPV rather than the normal physiological processes which were not well described.1 Although the sympathetic stimulation in response to a decreased level of consciousness is not well explained in this study, there is no sympathetic predominance in some poly-traumatized patients. Circulatory shock (neurogenic or hypovolemic) is usually associated with serious brain or spinal cord injury which should be omitted from this study and the reader should be aware of this disorder.2,3 The occurrence of autonomic dysreflexia, also known as paroxysmal sympathetic hyperactivity, is an impairment of cerebrovascular autoregulation due to increment of sympathetic tone in response to TBI. That, in real, affects the blood pressure and the optimum CPP. A more stable blood pressure could be achieved in targeted therapy protocols. Actually, further studies are still in need to document the relation between the BPV and optimum CPP related insults and outcomes.4 In the literature, the motor score component of the Glasgow Coma Scale (GCS) has been shown to be associated with overall outcome in TBI. Still, a total of GCS components is largely followed to decide the management protocols.5 It will be interesting to understand the role of GCS score and its components (total vs individual components) to decide the management protocols. Additionally, though BPV is a major risk factor, other variables may affect the outcome of TBI and their roles (particularly age6,7 and injury patterns on imaging7) need to be further explored. For example, induced hypothermia has a well-documented role in the management of intracranial hypertension in head-injured patients. Also, the endogenous release of some substances other than catecholamine and deficiency of others may affect the outcome.8,9 Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.