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Background: The Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II randomized controlled trial used a tier-based management protocol based on brain tissue oxygen (PbtO 2 ) and intracranial pressure (ICP) monitoring to reduce brain tissue hypoxia after severe traumatic brain injury. We performed a secondary analysis to explore the relationship between brain tissue hypoxia, blood pressure (BP), and interventions to improve cerebral perfusion pressure (CPP). We hypothesized that BP management below the lower limit of autoregulation would lead to cerebral hypoperfusion and brain tissue hypoxia that could be improved with hemodynamic augmentation., Methods: Of the 119 patients enrolled in the Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase II trial, 55 patients had simultaneous recordings of arterial BP, ICP, and PbtO 2 . Autoregulatory function was measured by interrogating changes in ICP and PbtO 2 in response to fluctuations in CPP using time-correlation analysis. The resulting autoregulatory indices (pressure reactivity index and oxygen reactivity index) were used to identify the "optimal" CPP and limits of autoregulation for each patient. Autoregulatory function and percent time with CPP outside personalized limits of autoregulation were calculated before, during, and after all interventions directed to optimize CPP., Results: Individualized limits of autoregulation were computed in 55 patients (mean age 38 years, mean monitoring time 92 h). We identified 35 episodes of brain tissue hypoxia (PbtO 2  < 20 mm Hg) treated with CPP augmentation. Following each intervention, mean CPP increased from 73 ± 14 mm Hg to 79 ± 17 mm Hg (p = 0.15), and mean PbtO 2 improved from 18.4 ± 5.6 mm Hg to 21.9 ± 5.6 mm Hg (p = 0.01), whereas autoregulatory function trended toward improvement (oxygen reactivity index 0.42 vs. 0.37, p = 0.14; pressure reactivity index 0.25 vs. 0.21, p = 0.2). Although optimal CPP and limits remained relatively unchanged, there was a significant decrease in the percent time with CPP below the lower limit of autoregulation in the 60 min after compared with before an intervention (11% vs. 23%, p = 0.05)., Conclusions: Our analysis suggests that brain tissue hypoxia is associated with cerebral hypoperfusion characterized by increased time with CPP below the lower limit of autoregulation. Interventions to increase CPP appear to improve autoregulation. Further studies are needed to validate the importance of autoregulation as a modifiable variable with the potential to improve outcomes., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society.)

Background and Purpose: As survival rates have increased for intracerebral hemorrhage (ICH) patients, there is limited information regarding recovery beyond 3-6 months. This study was conducted to examine recovery curves using the modified Rankin Scale (mRS) and Barthel Index (BI) up to 12 months post-injury., Methods: We prospectively enrolled 173 patients admitted with ICH who were subsequently evaluated using the mRS and BI at discharge as well as 3, 6, and 12 months. Repeated measures nonparametric testing was conducted to assess functional trajectories across time., Results: The mRS scores showed significant improvement between discharge (median 4) and 3 (median 4), 6 (median 4), and 12 months (median 3) (p values <0.001). However, the mRS scores did not differ between follow-up time-points (i.e., 3-6, 6-12 months). There was significant improvement in scores using the BI (p values <0.001), showing improvement between discharge (mean 43.0) and 3 (mean 73.0), 6 (mean 78.2), and 12 months (mean 83.4). Additionally, there were differences in the BI between 3 and 12 months (p = 0.013), as well as between 6 and 12 months (p = 0.025)., Conclusions: The BI may be a more sensitive measure of long-term recovery post-injury than the mRS, which shows minimal improvement for some survivors after 3 months. BI scores indicate survivors continually improve till 12 months post-injury. These results may have implications for the prognostication of ICH and design of clinical trial outcome measures.

Background and Purpose: Intracerebral hemorrhage (ICH) has the highest mortality rate among all strokes. While ICH location, lobar versus non-lobar, has been established as a predictor of mortality, less is known regarding the relationship between more specific ICH locations and functional outcome. This review summarizes current work studying how ICH location affects outcome, with an emphasis on how studies designate regions of interest., Methods: A systematic search of the OVID database for relevant studies was conducted during August 2015. Studies containing an analysis of functional outcome by ICH location or laterality were included. As permitted, the effect size of individual studies was standardized within a meta-analysis., Results: Thirty-seven studies met the inclusion criteria, the majority of which followed outcome at 3 months. Most studies found better outcomes on the Modified Rankin Scale (mRS) or Glasgow Outcome Score (GOS) with lobar compared to deep ICHs. While most aggregated deep structures for analysis, some studies found poorer outcomes for thalamic ICH in particular. Over half of the studies did not have specific methodological considerations for location designations, including blinding or validation., Conclusions: Multiple studies have examined motor-centric outcomes, with few studies examining quality of life (QoL) or cognition. Better functional outcomes have been suggested for lobar versus non-lobar ICH; few studies attempted finer topographic comparisons. This study highlights the need for improved reporting in ICH outcomes research, including a detailed description of hemorrhage location, reporting of the full range of functional outcome scales, and inclusion of cognitive and QoL outcomes.

Background: There is a growing interest in measuring cerebral autoregulation in patients with acute brain injury. Non-invasive finger photo-plethysmography (Finapres) is the method of choice to relate arterial blood pressure to changes in cerebral blood flow. Among acutely ill patients, however, peripheral vasoconstriction often limits the use of Finapres requiring direct intravascular blood pressure measurement. We evaluated how these two different forms of blood pressure monitoring affect the parameters of dynamic cerebral autoregulation (DCA)., Methods: We performed 37 simultaneous recordings of BP and cerebral blood flow velocity in 15 patients with acute brain injury. DCA was estimated in the frequency domain using transfer function analysis to calculate phase shift, gain, and coherence. In addition the mean velocity index (Mx) was calculated for assessment of DCA in the time domain., Results: The mean patient age was 58.1 ± 15.9 years, 80 % (n = 12) were women. We found good inter-method agreement between Finapres and direct intravascular measurement using Bland–Altman and correlation analyses. Finapres gives higher values for the efficiency of dynamic CA compared with values derived from radial artery catheter, as indicated by biases in the phase (26.3 ± 11.6° vs. 21.7 ± 10.5°, p = 0.001) and Mx (0.571 ± 0.137 vs. 0.649 ± 0.128, p < 0.001). Gain in the low frequency range did not significantly differ between the two arterial blood pressure methods. The average coherence between CBFV and ABP was higher when BP was measured with arterial catheter for frequencies above 0.05 Hz (0.8 vs. 0.73, p < 0.001)., Conclusion: Overall, both methods yield similar results and can be used for the assessment of DCA. However, there was a small but significant difference for both mean Mx and phase shift, which would need to be adjusted for during monitoring of patients when using both methods. When available, invasive arterial blood pressure monitoring may improve accuracy and thus should be the preferred method for DCA assessment in the ICU.

Background: There is a growing interest in measuring cerebral autoregulation in patients with acute brain injury. Non-invasive finger photo-plethysmography (Finapres) is the method of choice to relate arterial blood pressure to changes in cerebral blood flow. Among acutely ill patients, however, peripheral vasoconstriction often limits the use of Finapres requiring direct intravascular blood pressure measurement. We evaluated how these two different forms of blood pressure monitoring affect the parameters of dynamic cerebral autoregulation (DCA)., Methods: We performed 37 simultaneous recordings of BP and cerebral blood flow velocity in 15 patients with acute brain injury. DCA was estimated in the frequency domain using transfer function analysis to calculate phase shift, gain, and coherence. In addition the mean velocity index (Mx) was calculated for assessment of DCA in the time domain., Results: The mean patient age was 58.1 ± 15.9 years, 80 % (n = 12) were women. We found good inter-method agreement between Finapres and direct intravascular measurement using Bland-Altman and correlation analyses. Finapres gives higher values for the efficiency of dynamic CA compared with values derived from radial artery catheter, as indicated by biases in the phase (26.3 ± 11.6° vs. 21.7 ± 10.5°, p = 0.001) and Mx (0.571 ± 0.137 vs. 0.649 ± 0.128, p < 0.001). Gain in the low frequency range did not significantly differ between the two arterial blood pressure methods. The average coherence between CBFV and ABP was higher when BP was measured with arterial catheter for frequencies above 0.05 Hz (0.8 vs. 0.73, p < 0.001)., Conclusion: Overall, both methods yield similar results and can be used for the assessment of DCA. However, there was a small but significant difference for both mean Mx and phase shift, which would need to be adjusted for during monitoring of patients when using both methods. When available, invasive arterial blood pressure monitoring may improve accuracy and thus should be the preferred method for DCA assessment in the ICU.