Objectives: To examine cerebral autoregulation in children with complex mild traumatic brain injury. Design: Prospective observational convenience sample. Setting: PICU at a level I trauma center. Patients: Children with complex mild traumatic brain injury (trauma, admission Glasgow Coma Scale score 13–15 with either abnormal head CT, or history of loss of consciousness). Interventions: Cerebral autoregulation was tested using transcranial Doppler ultrasound between admission day 1 and 8. Measurements and Main Results: The primary outcome was prevalence of impaired cerebral autoregulation (autoregulation index < 0.4),determined using transcranial Doppler ultrasonography and tilt testing. Secondary outcomes examined factors associated with and evolution and extent of impairment. Cerebral autoregulation testing occurred in 31 children 10 years (sd, 5.2 yr), mostly male (59%) with isolated traumatic brain injury (91%), median admission Glasgow Coma Scale 15, Injury Severity Scores 14.2 (sd, 7.7), traumatic brain injury due to fall (50%), preadmission loss of consciousness (48%), and abnormal head CT scan (97%). Thirty-one children underwent 56 autoregulation tests. Impaired cerebral autoregulation occurred in 15 children (48.4%) who underwent 19 tests; 68% and 32% of tests demonstrated unilateral and bilateral impairment, respectively. Compared with children on median day 6 of admission after traumatic brain injury, impaired autoregulation was most common in the first 5 days after traumatic brain injury (day 1: relative risk, 3.7; 95% CI, 1.9–7.3 vs day 2: relative risk, 2.7; 95% CI, 1.1–6.5 vs day 5: relative risk, 1.33; 95% CI, 0.7–2.3). Children with impaired autoregulation were older (12.3 yr [sd, 1.3 yr] vs 8.7 yr [sd, 1.1 yr]; p = 0.04) and tended to have subdural hematoma (64% vs 44%), epidural hematoma (29% vs 17%), and subarachnoid hemorrhage (36% vs 28%). Eight children (53%) were discharged home with ongoing impaired cerebral autoregulation. Conclusions: Impaired cerebral autoregulation is common in children with complex mild traumatic brain injury, despite reassuring admission Glasgow Coma Scale 13–15. Children with complex mild traumatic brain injury have abnormal cerebrovascular hemodynamics, mostly during the first 5 days. Impairment commonly extends to the contralateral hemisphere and discharge of children with ongoing impaired cerebral autoregulation is common.
Various cardiovascular abnormalities are common after spontaneous ICH. The workup of patients with spontaneous ICH should involve 12-lead ECG, cardiac troponin-I, as well as BNP, and echocardiogram to evaluate for heart failure. Blood pressure control with preservation of cerebral perfusion pressure is a cornerstone of hemodynamic management after ICH. The perioperative implications of hemodynamic perturbations after ICH warrant urgent further examination.
Four editions of the Brain Trauma Foundation's (BTF) evidence-based guidelines have been published to guide clinical management after severe traumatic brain injury (TBI) and increase TBI research. We reviewed the association between published clinical severe TBI research and BTF guideline year of publication and guideline chapter topics. Using PubMed, we searched for peerreviewed articles on severe TBI research published between 1975 and 2019. The frequency and study design of publications on chapter topics included in all 4 BTF guideline editions was collected and the relationship with published TBI research examined using linear regression and the coefficient of determination (r 2 ). A total of 845 relevant articles were identified, with an average of 19 articles published per year. There was an increase in the overall number of publications (r 2 = 0.72), with the largest increase occurring between the third and the fourth guideline editions (r 2 = 0.70, 31 articles/y). Across all 4 guideline editions, 54% (n = 460) of publications were retrospective studies, 27.2% (n = 230) prospective studies, 12% (n = 101) randomized controlled trials, and 7.6% (n = 64) meta-analyses/systematic reviews. Publication of retrospective study numbers increased the most (r 2 = 0.61), followed by prospective observational studies and meta-analyses/systematic reviews (r 2 = 0.47 each), and randomized controlled trials (r 2 = 0.39). The 3 most highly published guideline chapter topic areas were ventilator-associated pneumonia (r 2 = 0.70), hyperosmolar therapy (r 2 = 0.47), and decompressive craniectomy (r 2 = 0.41). In summary, the TBI research output increased over time and was associated with BTF guideline release. However, the increase in published TBI research was not consistent between serial editions of the BTF guidelines, and many studies did not incorporate high-quality prospective research designs.
We read with interest the letter to the editor by Tremlett and Kanthimanthanithan (1) in response to our previously published article (2). The authors raise an important question regarding the utility of screening and continuous estimation of cerebral autoregulation in routine neurocritical care after traumatic brain injury (TBI). As there are no comparative trials of methods that assess cerebral autoregulation, we cannot comment on the utility of techniques that continuously examine cerebral autoregulation versus those that document impairment once a day. Few modalities assess the ability of the cerebral vasculature to adapt to changes in blood pressure and regardless of technique, cerebral autoregulation has been shown to be impaired after TBI by all methods (3-5). Moreover, there may be no need for continuous measurement if a daily signal is sufficient, especially since real time measurements do not result in real time treatments using methods such as PRx, which largely remains a research tool. What is one important distinguishing feature of provocative tests of cerebral autoregulation compared to the PRx method is that the latter passively estimates changes in CBF, whereas tilt tests, (6) pharmacological tests ( 7) and the transient hyperemic response ratio method (8) directly examine changes in CBF measures in response to changes in pressure and flow stimuli when cerebral metabolic rates and hematocrit remain stable.While routine assessment for cerebral autoregulation status after pediatric TBI is aspirational and desired based on studies that document poor outcomes (3, 4) with impairment early after TBI, published guidelines for pediatric TBI care (9) do not address this topic. Also, it is unclear what proportion of institutions have the ability to provide testing for cerebral autoregulation status, leading to relatively infrequent use of both transcranial Doppler ultrasound and PRx based approaches. Yet, we agree that gathering cerebral autoregulation data that would allow us to understand the prevalence, and magnitude of impaired cerebral
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