Mannitol and HS cause an increase in cerebrospinal fluid osmolality, and are associated with similar brain relaxation scores and arteriovenous oxygen and lactate difference during craniotomy.

There is little information on gender differences in cerebral autoregulation. The purpose of this study was to compare autoregulation of the anterior and posterior circulations using the tilt test method in healthy boys and girls who were 10 -16 y of age. Transcranial Doppler was used to measure middle cerebral artery and basilar artery flow velocities (Vmca and Vbas). Cerebral autoregulation (ARI) of the middle cerebral (ARImca) and basilar arteries (ARIbas) was examined using the tilt test method. An ARI Ͻ0.4 indicates impaired autoregulation. Among the 13 boys and 13 girls, Vmca and Vbas were higher in girls. All children demonstrated intact autoregulation, but boys had higher ARImca than girls, whereas girls had higher ARIbas than boys. Girls demonstrated greater autoregulation in the basilar artery, whereas boys demonstrated greater autoregulation in the middle cerebral artery. Girls had higher flow velocities in both vessels. This study provides normative data on cerebral autoregulation of the poste- Autoregulation of cerebral blood flow (CBF) is a physiologic and homeostatic process that maintains nearly constant CBF over a range of mean arterial pressures (MAPs). Disease states, including traumatic brain injury, can impair cerebral autoregulation, rendering the brain susceptible to inadequate (cerebral ischemia) or excessive (cerebral hyperemia) CBF (1). Despite its critical role in maintaining CBF, there is limited information on cerebral autoregulation in healthy children.Little has been published on pediatric cerebral autoregulation in children outside the clinical arena of neurogenic syncope (2-4). In one study that examined dynamic cerebral autoregulation in awake adolescent study participants, the time to return of middle cerebral artery flow velocity (Vmca) to normal after a transient hypotensive stimulus was reported to be more in healthy adolescents compared with their healthy adult counterparts (5). However, in a subsequent evaluation of cerebral autoregulation in children versus adults during general anesthesia using static autoregulation testing, the investigators reported no age-related differences in autoregulatory capacity and no difference in cerebral autoregulation compared with adults (6). Because both of these studies examined cerebral autoregulation of the anterior circulation only, differences in cerebral autoregulation between the anterior and posterior circulation in children could not be evaluated. In addition, to our knowledge, there is no information regarding cerebral autoregulation of the posterior circulation in children, no information on gender differences in cerebral autoregulation in children, and finally no normative data on cerebral autoregulation using the tilt test method. Therefore, the purpose of this study was to 1) provide normative data on cerebral autoregulation using the tilt test method, 2) describe cerebral autoregulation of the posterior cerebral circulation, and 3) examine gender-related differences in autoregulatory capacity in healthy, awake boys and girl...

Repeat head computed tomography imaging is frequently used. About 30% of repeated computed tomographies showed new or worsening brain injury. However, worsening brain injury on repeat computed tomography rarely resulted in neurosurgical intervention. Patients with moderate or severe head injury and intraparenchymal injuries were more likely to show worsening brain injury and undergo neurosurgical intervention.

The pharmacologic profile of the alpha-2 agonist dexmedetomidine (Dex) suggests that it may be an ideal sedative drug for deep brain stimulator (DBS) implantation. We performed a retrospective chart review of anesthesia records of patients who underwent DBS implantation from 2001 to 2004. In 2003, a clinical protocol with Dex sedation for DBS implantation was initiated. Demographic data, use of antihypertensive medication, and duration of mapping were compared between patients who received Dex (11 patients/13 procedures) and patients who did not receive any sedation (controls: 8 patients/9 procedures). There were no differences in severity of illness between the two groups. Dex provided patient comfort and surgical satisfaction with mapping in all cases, and significantly reduced the use of antihypertensive medication (54% in the Dex group, versus 100% in controls, P = 0.048). In DBS implantation, sedation with Dex did not interfere with electrophysiologic mapping, and provided hemodynamic stability and patient comfort. Routine use of Dex in these procedures may be indicated.

Similar to older children and adults, girls between 4 and 8 years of age had higher middle cerebral and basilar artery flow velocity than age-matched boys. This difference may reflect inherent differences in cerebral metabolic rate and/or estimated cerebrovascular resistance between the genders.