Meaning of Intracranial Pressure-to-Blood Pressure Fisher-Transformed Pearson Correlation–Derived Optimal Cerebral Perfusion Pressure: Testing Empiric Utility in a Mechanistic Model

Akhondi-Asl, Alireza; Vonberg, Frederick W.; Au, Cheuk Chung; Tasker, Robert C.

doi:10.1097/ccm.0000000000003434

Cited by 7 publications

(6 citation statements)

References 31 publications

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“…Akhondi-Asl et al stated that the PRx could only be evaluated when there are slow, but sufficient changes in ICP and ABP waves. This shows the sensitivity of the PRx calculation to slow wave changes, and only slight PRx variance can be seen with small slow wave changes [21]. In other words, if there are higher or lower wave changes in ABP(t) and ICP(t), the diagnostic PRx value would be different.…”

Section: Discussionmentioning

confidence: 95%

“…Moreover, a recent study by Akhondi-Asl et al [21] found that PRx can only be evaluated when there are slow, but sufficient changes in ABP(t) and ICP(t) waves. The results revealed the sensitivity of the PRx calculation towards small slow wave changes in ABP(t) and ICP(t), and only slight PRx variance was observed [21], which indicated that if ABP(t) and ICP(t) waves changed with a filtering approach, the diagnostic value of the PRx may change.…”

Section: Introductionmentioning

confidence: 99%

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Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient’s Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring

Bajpai¹,

Preikšaitis²,

Vosylius³

et al. 2020

Medicina

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Background and Objectives: The aim of this study was to explore the association between the cerebral autoregulation (CA) index, the pressure reactivity index (PRx), the patient’s clinical outcome, and the quality of arterial blood pressure (ABP(t)) and intracranial blood pressure (ICP(t)) signals by comparing two filtering methods to derive the PRx. Materials and Methods: Data from 60 traumatic brain injury (TBI) patients were collected. Moving averaging and FIR (Finite Impulse Response) filtering were performed on the ABP(t) and ICP(t) signals, and the PRx was estimated from both filtered datasets. Sensitivity, specificity, and receiver-operating characteristic (ROC) curves with the area under the curves (AUCs) were determined using patient outcomes as a reference. The outcome chosen for comparison among the two filtering methods were mortality and survival. Results: The FIR filtering approach, compared with clinical outcome, had a sensitivity of 70%, a specificity of 81%, and a level of significance p = 0.001 with an area under the curve (AUC) of 0.78. The moving average filtering method compared with the clinical outcome had a sensitivity of 58%, a specificity of 72%, and a level of significance p = 0.054, with an area under the curve (AUC) of 0.66. Conclusions: The FIR (optimal) filtering approach was found to be more sensitive for discriminating between two clinical outcomes, namely intact (survival) and impaired (death) cerebral autoregulation for TBI treatment decision making.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient’s Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring

Bajpai¹,

Preikšaitis²,

Vosylius³

et al. 2020

Medicina

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“…However, hypocapnia does not directly reduce ICP by reducing blood vessel volume but indirectly reduces blood vessel volume by decreasing CBF. 9 …”

Section: Arbon D Ioxide In S mentioning

confidence: 99%

The role of carbon dioxide in acute brain injury

Deng

et al. 2020

Med Gas Res

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Carbon dioxide is a common gas in the air which has been widely used in medical treatment. A carbon dioxide molecule consists of two oxygen atoms and one carbon atom through a covalent bond. In the body, carbon dioxide reacts with water to produce carbonic acid. In healthy people, carbon dioxide is maintained within a narrow range (35–45 mmHg) by physiological mechanisms. The role of hypocapnia (partial pressure of carbon dioxide < 35 mmHg) and hypercapnia (partial pressure of carbon dioxide > 45 mmHg) in the nervous system is intricate. Past researches mainly focus on the effect of hypocapnia to nerve protection. Nevertheless, Hypercapnia seems to play an important role in neuroprotection. The mechanisms of hypocapnia and hypercapnia in the nervous system deserve our attention. The purpose of this review is to summarize the effect of hypocapnia and hypercapnia in stroke and traumatic brain injury.

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“…Remarkably, the clinical utility of ICP monitoring for severe TBI in both children and adults is controversial [4,5]. Though attempts have been made to develop computational tools to enrich the utility of ICP monitoring data [6,7], there exists no widely accepted bedside tool to inform a proactive approach to management of severe TBI and treatment decisions remain largely reactive or empirical. Methodology that would guide individualized application of therapies to prevent ICP from exceeding threshold, optimize cerebral perfusion, prevent catastrophic herniation, and facilitate initiation, titration and weaning of therapies/ interventions would stand to significantly improve neurological outcomes.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Dynamic Intracranial Compliance in Children with Severe Traumatic Brain Injury: Proof-of-Concept

et al. 2020

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Background and Aims: Intracranial compliance refers to the relationship between a change in intracranial volume and the resultant change in intracranial pressure (ICP). Measurement of compliance is useful in managing cardiovascular and respiratory failure; however, there are no contemporary means to assess intracranial compliance. Knowledge of intracranial compliance could complement ICP and cerebral perfusion pressure (CPP) monitoring in patients with severe traumatic brain injury (TBI) and may enable a proactive approach to ICP management. In this proof-of-concept study, we aimed to capitalize on the physiologic principles of intracranial compliance and vascular reactivity to CO 2 , and standard-of-care neurocritical care monitoring, to develop a method to assess dynamic intracranial compliance. Methods: Continuous ICP and end-tidal CO 2 (ETCO 2) data from children with severe TBI were collected after obtaining informed consent in this Institutional Review Board-approved study. An intracranial pressure-PCO 2 Compliance Index (PCI) was derived by calculating the moment-to-moment correlation between change in ICP and change in ETCO 2. As such, "good" compliance may be reflected by a lack of correlation between time-synched changes in ICP in response to changes in ETCO 2 , and "poor" compliance may be reflected by a positive correlation between changes in ICP in response to changes in ETCO 2. Results: A total of 978 h of ICP and ETCO 2 data were collected and analyzed from eight patients with severe TBI. Demographic and clinical characteristics included patient age 7.1 ± 5.8 years (mean ± SD); 6/8 male; initial Glasgow Coma Scale score 3 [3-7] (median [IQR]); 6/8 had decompressive surgery; 7.1 ± 1.4 ICP monitor days; ICU length of stay (LOS) 16.1 ± 6.8 days; hospital LOS 25.9 ± 8.4 days; and survival 100%. The mean PCI for all patients throughout the monitoring period was 0.18 ± 0.04, where mean ICP was 13.7 ± 2.1 mmHg. In this cohort, PCI was observed to be consistently above 0.18 by 12 h after monitor placement. Percent time spent with PCI thresholds > 0.1, 0.2, and 0.3 were 62% [24], 38% [14], and 23% [15], respectively. The percentage of time spent with an ICP threshold > 20 mmHg was 5.1% [14.6]. Conclusions: Indirect assessment of dynamic intracranial compliance in TBI patients using standard-of-care monitoring appears feasible and suggests a prolonged period of derangement out to 5 days post-injury. Further study is ongoing to determine if the PCI-a new physiologic index, complements utility of ICP and/or CPP in guiding management of patients with severe TBI.

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Meaning of Intracranial Pressure-to-Blood Pressure Fisher-Transformed Pearson Correlation–Derived Optimal Cerebral Perfusion Pressure: Testing Empiric Utility in a Mechanistic Model

Abstract: Supplemental Digital Content is available in the text.

Cited by 7 publications

References 31 publications

Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient’s Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring

Association Between the Cerebral Autoregulation Index (Pressure Reactivity), Patient’s Clinical Outcome, and Quality of ABP(t) and ICP(t) Signals for CA Monitoring

The role of carbon dioxide in acute brain injury

Assessment of Dynamic Intracranial Compliance in Children with Severe Traumatic Brain Injury: Proof-of-Concept

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