Experience with clinical cerebral autoregulation testing in children hospitalized with traumatic brain injury: Translating research to bedside

Abstract

ObjectiveTo report our institutional experience with implementing a clinical cerebral autoregulation testing order set with protocol in children hospitalized with traumatic brain injury (TBI).MethodsAfter IRB approval, we examined clinical use, patient characteristics, feasibility, and safety of cerebral autoregulation testing in children aged <18 years between 2014 and 2021. A clinical order set with a protocol for cerebral autoregulation testing was introduced in 2018.Results25 (24 severe TBI and 1 mild TBI) children, median age 13 years [IQR 4.5; 15] and median admission GCS 3[IQR 3; 3.5]) underwent 61 cerebral autoregulation tests during the first 16 days after admission [IQR1.5; 7; range 0–16]. Testing was more common after implementation of the order set (n = 16, 64% after the order set vs. n = 9, 36% before the order set) and initiated during the first 2 days. During testing, patients were mechanically ventilated (n = 60, 98.4%), had invasive arterial blood pressure monitoring (n = 60, 98.4%), had intracranial pressure monitoring (n = 56, 90.3%), brain-tissue oxygenation monitoring (n = 56, 90.3%), and external ventricular drain (n = 13, 25.5%). Most patients received sedation and analgesia for intracranial pressure control (n = 52; 83.8%) and vasoactive support (n = 55, 90.2%) during testing. Cerebral autoregulation testing was completed in 82% (n = 50 tests); 11 tests were not completed [high intracranial pressure (n = 5), high blood pressure (n = 2), bradycardia (n = 2), low cerebral perfusion pressure (n = 1), or intolerance to blood pressure cuff inflation (n = 1)]. Impaired cerebral autoregulation on first assessment resulted in repeat testing (80% impaired vs. 23% intact, RR 2.93, 95% CI 1.06:8.08, p = 0.03). Seven out of 50 tests (14%) resulted in a change in cerebral hemodynamic targets.ConclusionFindings from this series of children with TBI indicate that: (1) Availability of clinical order set with protocol facilitated clinical cerebral autoregulation testing, (2) Clinicians ordered cerebral autoregulation tests in children with severe TBI receiving high therapeutic intensity and repeatedly with impaired status on the first test, (3) Clinical cerebral autoregulation testing is feasible and safe, and (4) Testing results led to change in hemodynamic targets in some patients.

Effect of Increasing Blood Pressure on Brain Tissue Oxygenation in Adults After Severe Traumatic Brain Injury*

“…Our study shows that some patients may benefit from MAP augmentation but the observed heterogeneity in PbtO 2 patterns with MAP augmentation suggests that other factors that affect PbtO 2 must be considered, to identify which patients with severe TBI will be PbtO 2 responders to MAP augmentation (15). For example, cerebral autoregulation is often impaired in patients with severe TBI and can result in cerebral hypoperfusion, cerebral hypoxia, and cerebral ischemia and while we did not detect a relationship between impaired cerebral autoregulation status and PbtO 2 pattern, cerebrovascular pressure reactivity methods are reported to correlate CPP changes with changes in PbtO 2 (16)(17)(18)(19). An observational study of 38 patients with severe TBI showed that PbtO 2 was pressure-dependent when cerebral autoregulation was impaired and stable if cerebral autoregulation was intact (20) and data from another observational study of 77 patients found a shorter plateau in a triphasic response between PbtO 2 and CPP, with cerebrovascular pressure reactivity impaired compared to when it was intact (11).…”

Critical Care Experience With Clinical Cerebral Autoregulation Testing in Adults With Traumatic Brain Injury

“…Patient factors, such as systemic hypertension, bradycardia, and high ICP, were transient and required no medical intervention. However, we think that testing environments should include plans for treating sustained or severe hypertension, high ICP, and bradycardia and that rates of adverse events are consistent with our prior experience [ 12 ]. Static cerebral autoregulation testing is a provocative challenge test that appears to add additional value to multimodal neuromonitoring, and this deserves further study.…”

“…Cerebral autoregulation studies are performed by one certified cerebrovascular laboratory technologist. An electronic order set [ 12 ] details the desired type of cerebral autoregulation testing (static or dynamic), as well as baseline and testing boundaries and conditions. Given the large number of patients with TBI who have polytrauma, static cerebral autoregulation testing is preferred to thigh cuff methods [ 13 ].…”

“…between January 1, 2014, and December 31, 2021, with moderate (admission Glasgow coma scale (GCS) score of[9][10][11][12] or severe (admission GCS 3-8) TBI, with or without polytrauma. Exclusion criteria were stroke patients and brain aneurysms.…”

Cerebral Autoregulation-guided Management of Adult and Pediatric Traumatic Brain Injury

“…7 Since TCDbased techniques rely on provocative testing during which MAP is augmented, some patients may experience excessive systemic hypertension, bradycardia, or intracranial hypertension during testing. 8 Hence, careful patient selection, including the consideration of baseline intracranial pressure (ICP), vasopressor requirement and PaCO 2 levels during the pre-testing review, is essential to avoid incomplete testing due to patients' exposure to undesirable cerebrovascular targets. In contrast, continuous dynamic CA testing relies on the presence of an ICP monitoring device and thus restricts its use to patients with this monitoring in place.…”