scholarly journals Physiologic Characteristics of Hyperosmolar Therapy After Pediatric Traumatic Brain Injury

2021 ◽  
Vol 12 ◽  
Author(s):  
Jeffrey Wellard ◽  
Michael Kuwabara ◽  
P. David Adelson ◽  
Brian Appavu
Keyword(s):  
Heart Rate ◽  
Injury Severity ◽  
Cohort Analysis ◽  
Pulse Amplitude ◽  
Reactivity Index ◽  
Hyperosmolar Therapy ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Improved Outcomes ◽  
Pre Treatment

All work was performed at the Barrow Neurological Institute at Phoenix Children's Hospital.Objective: Investigate injury severity, neuroimaging, physiology, and outcomes with bolus hyperosmolar therapy (HT) of 3% hypertonic saline or mannitol.Methods: Retrospective cohort analysis was performed. Physiologic variables included intracranial pressure (ICP), arterial blood pressure (ABP), and heart rate (HR). Volume-pressure compensation (PVC) indices included ICP pulse amplitude (AMP) and correlation of AMP and ICP (RAP). Cerebrovascular pressure reactivity (CVPR) indices included pressure reactivity index (PRx), pulse amplitude index (PAx), wavelet PRx (wPRx), and correlation of AMP and cerebral perfusion pressure (RAC). Heart rate variability (HRV) indices included heart rate standard deviation (HRsd), heart rate root mean square of successive differences (HRrmssd) and low-high frequency ratio (LHF). Outcome was assessed using Glasgow Outcomes Scale Extended Pediatrics, 12-months post-injury. Generalized estimating equations was applied to investigate associations of physiologic changes and pre-treatment indices with HT efficacy. Repeated measures analysis of variance was applied to investigate changes after HT without intracranial hypertension (ICH). Wilcoxon rank-sum was applied to investigate HT responsiveness with age, injury severity, neuroimaging, and outcomes.Results: Thirty children received bolus HT. ICH reduction after HT was associated with reduced ICP (p = 0.0064), ABP (p = 0.0126), PRx (p = 0.0063), increased HRsd (p = 0.0408), and decreased pretreatment RAC (p = 0.0115) and wPRx (p = 0.0072). HT-responsive patients were older and had improved outcomes (p = 0.0394). HT without ICH was associated with increased ICP (P < 0.0001) and ABP (P < 0.0001), increases in all HRV indices and decreases in all PVC indices.Conclusion: After pediatric TBI, efficacious HT is associated with decreased ICP and ABP, pre-treatment indices suggesting efficient CVPR, and potentially improved outcomes.

scholarly journals Validation of non-invasive cerebrovascular pressure reactivity and pulse amplitude reactivity indices in traumatic brain injury

2019 ◽  
Vol 162 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Leanne A. Calviello ◽  
András Czigler ◽  
Frederick A. Zeiler ◽  
Peter Smielewski ◽  
Marek Czosnyka
Keyword(s):  
Correlation Coefficient ◽  
Pulse Amplitude ◽  
Slow Waves ◽  
Reactivity Index ◽  
Non Invasive ◽  
Reactivity Indices ◽  
Full Waveform ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Predictive Strength

Abstract Background Two transcranial Doppler (TCD) estimators of cerebral arterial blood volume (CaBV) coexist: continuous outflow of arterial blood outside the cranium through a low-pulsatile venous system (continuous flow forward, CFF) and pulsatile outflow through regulating arterioles (pulsatile flow forward, PFF). We calculated non-invasive equivalents of the pressure reactivity index (PRx) and the pulse amplitude index PAx with slow waves of mean CaBV and its pulse amplitude. Methods About 273 individual TBI patients were retrospectively reviewed. PRx is the correlation coefficient between 30 samples of 10-second averages of ICP and mean ABP. PAx is the correlation coefficient between 30 samples of 10-second averages of the amplitude of ICP (AMP, derived from Fourier analysis of the raw full waveform ICP tracing) and mean ABP. nPRx is calculated with CaBV instead of ICP and nPAx with the pulse amplitude of CaBV instead of AMP (calculated using both the CFF and PFF models). All reactivity indices were additionally compared with Glasgow Outcome Score (GOS) to verify potential outcome-predictive strength. Results When correlated, slow waves of ICP demonstrated good coherence between slow waves in CaBV (>0.75); slow waves of AMP showed good coherence with slow waves of the pulse amplitude of CaBV (>0.67) in both the CFF and PFF models. nPRx was moderately correlated with PRx (R = 0.42 for CFF and R = 0.38 for PFF; p < 0.0001). nPAx correlated with PAx with slightly better strength (R = 0.56 for CFF and R = 0.41 for PFF; p < 0.0001). nPAx_CFF showed the strongest association with outcomes. Conclusions Non-invasive estimators (nPRx and nPAx) are associated with their invasive counterparts and can provide meaningful associations with outcome after TBI. The CFF model is slightly superior to the PFF model.

scholarly journals Epidural Oscillating Cardiac-Gated Intracranial Implant Modulates Cerebral Blood Flow

Neurosurgery ◽  
2020 ◽  
Author(s):  
Mark G Luciano ◽  
Stephen M Dombrowski ◽  
Serge El-Khoury ◽  
Jun Yang ◽  
Suraj Thyagaraj ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Balloon Catheter ◽  
Pulse Amplitude ◽  
Mean Values ◽  
Arterial Blood ◽  
Amplitude Increase ◽  
And Inversion ◽  
Change In Mean

Abstract Background We have previously reported a method and device capable of manipulating ICP pulsatility while minimally effecting mean ICP. Objective To test the hypothesis that different modulations of the intracranial pressure (ICP) pulse waveform will have a differential effect on cerebral blood flow (CBF). Methods Using an epidural balloon catheter attached to a cardiac-gated oscillating pump, 13 canine subjects underwent ICP waveform manipulation comparing different sequences of oscillation in successive animals. The epidural balloon was implanted unilaterally superior to the Sylvian sulcus. Subjects underwent ICP pulse augmentation, reduction and inversion protocols, directly comparing time segments of system activation and deactivation. ICP and CBF were measured bilaterally along with systemic pressure and heart rate. CBF was measured using both thermal diffusion, and laser doppler probes. Results The activation of the cardiac-gate balloon implant resulted in an ipsilateral/contralateral ICP pulse amplitude increase with augmentation (217%/202% respectively, P &lt; .0005) and inversion (139%/120%, P &lt; .0005). The observed changes associated with the ICP mean values were smaller, increasing with augmentation (23%/31%, P &lt; .0001) while decreasing with inversion (7%/11%, P = .006/.0003) and reduction (4%/5%, P &lt; .0005). CBF increase was observed for both inversion and reduction protocols (28%/7.4%, P &lt; .0001/P = .006 and 2.4%/1.3%, P &lt; .0001/P = .003), but not the augmentation protocol. The change in CBF was correlated with ICP pulse amplitude and systolic peak changes and not with change in mean ICP or systemic variables (heart rate, arterial blood pressure). Conclusion Cardiac-gated manipulation of ICP pulsatility allows the study of intracranial pulsatile dynamics and provides a potential means of altering CBF.

scholarly journals Short pressure reactivity index versus long pressure reactivity index in the management of traumatic brain injury

2015 ◽  
Vol 122 (3) ◽  
pp. 588-594 ◽  
Author(s):  
Erhard W. Lang ◽  
Magdalena Kasprowicz ◽  
Peter Smielewski ◽  
Edgar Santos ◽  
John Pickard ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Outcome Prediction ◽  
Fatal Outcome ◽  
Reactivity Index ◽  
Pressure Reactivity Index ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Significant Difference ◽  
Spearman Test

OBJECT The pressure reactivity index (PRx) correlates with outcome after traumatic brain injury (TBI) and is used to calculate optimal cerebral perfusion pressure (CPPopt). The PRx is a correlation coefficient between slow, spontaneous changes (0.003–0.05 Hz) in intracranial pressure (ICP) and arterial blood pressure (ABP). A novel index—the so-called long PRx (L-PRx)—that considers ABP and ICP changes (0.0008–0.008 Hz) was proposed. METHODS The authors compared PRx and L-PRx for 6-month outcome prediction and CPPopt calculation in 307 patients with TBI. The PRx- and L-PRx–based CPPopt were determined and the predictive power and discriminant abilities were compared. RESULTS The PRx and L-PRx correlation was good (R = 0.7, p < 0.00001; Spearman test). The PRx, age, CPP, and Glasgow Coma Scale score but not L-PRx were significant fatal outcome predictors (death and persistent vegetative state). There was a significant difference between the areas under the receiver operating characteristic curves calculated for PRx and L-PRx (0.61 ± 0.04 vs 0.51 ± 0.04; z-statistic = −3.26, p = 0.011), which indicates a better ability by PRx than L-PRx to predict fatal outcome. The CPPopt was higher for L-PRx than for PRx, without a statistical difference (median CPPopt for L-PRx: 76.9 mm Hg, interquartile range [IQR] ± 10.1 mm Hg; median CPPopt for PRx: 74.7 mm Hg, IQR ± 8.2 mm Hg). Death was associated with CPP below CPPopt for PRx (χ2 = 30.6, p < 0.00001), and severe disability was associated with CPP above CPPopt for PRx (χ2 = 7.8, p = 0.005). These relationships were not statistically significant for CPPopt for L-PRx. CONCLUSIONS The PRx is superior to the L-PRx for TBI outcome prediction. Individual CPPopt for L-PRx and PRx are not statistically different. Deviations between CPP and CPPopt for PRx are relevant for outcome prediction; those between CPP and CPPopt for L-PRx are not. The PRx uses the entire B-wave spectrum for index calculation, whereas the L-PRX covers only one-third of it. This may explain the performance discrepancy.

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

Medicina ◽  
2020 ◽  
Vol 56 (3) ◽  
pp. 143
Author(s):  
Basant K. Bajpai ◽  
Aidanas Preiksaitis ◽  
Saulius Vosylius ◽  
Saulius Rocka
Keyword(s):  
Blood Pressure ◽  
Clinical Outcome ◽  
Cerebral Autoregulation ◽  
Area Under The Curve ◽  
Reactivity Index ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Level Of Significance ◽  
Filtering Approach

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.

scholarly journals Relationship Between Measures of Cerebrovascular Reactivity and Intracranial Lesion Progression in Acute TBI Patients: an Exploratory Analysis

2019 ◽  
Vol 32 (2) ◽  
pp. 373-382 ◽  
Author(s):  
François Mathieu ◽  
Frederick A. Zeiler ◽  
Daniel P. Whitehouse ◽  
Tilak Das ◽  
Ari Ercole ◽  
...  
Keyword(s):  
Cerebral Perfusion Pressure ◽  
Cerebral Perfusion ◽  
Perfusion Pressure ◽  
Cohort Analysis ◽  
Pulse Amplitude ◽  
Cerebrovascular Reactivity ◽  
Reactivity Index ◽  
Lesion Volume ◽  
Intracranial Lesion ◽  
Univariate Analyses

Abstract Background Failure of cerebral autoregulation and progression of intracranial lesion have both been shown to contribute to poor outcome in patients with acute traumatic brain injury (TBI), but the interplay between the two phenomena has not been investigated. Preliminary evidence leads us to hypothesize that brain tissue adjacent to primary injury foci may be more vulnerable to large fluctuations in blood flow in the absence of intact autoregulatory mechanisms. The goal of this study was therefore to assess the influence of cerebrovascular reactivity measures on radiological lesion expansion in a cohort of patients with acute TBI. Methods We conducted a retrospective cohort analysis on 50 TBI patients who had undergone high-frequency multimodal intracranial monitoring and for which at least two brain computed tomography (CT) scans had been performed in the acute phase of injury. We first performed univariate analyses on the full cohort to identify non-neurophysiological factors (i.e., initial lesion volume, timing of scan, coagulopathy) associated with traumatic lesion growth in this population. In a subset analysis of 23 patients who had intracranial recording data covering the period between the initial and repeat CT scan, we then correlated changes in serial volumetric lesion measurements with cerebrovascular reactivity metrics derived from the pressure reactivity index (PRx), pulse amplitude index (PAx), and RAC (correlation coefficient between the pulse amplitude of intracranial pressure and cerebral perfusion pressure). Using multivariate methods, these results were subsequently adjusted for the non-neurophysiological confounders identified in the univariate analyses. Results We observed significant positive linear associations between the degree of cerebrovascular reactivity impairment and progression of pericontusional edema. The strongest correlations were observed between edema progression and the following indices of cerebrovascular reactivity between sequential scans: % time PRx > 0.25 (r = 0.69, p = 0.002) and % time PAx > 0.25 (r = 0.64, p = 0.006). These associations remained significant after adjusting for initial lesion volume and mean cerebral perfusion pressure. In contrast, progression of the hemorrhagic core and extra-axial hemorrhage volume did not appear to be strongly influenced by autoregulatory status. Conclusions Our preliminary findings suggest a possible link between autoregulatory failure and traumatic edema progression, which warrants re-evaluation in larger-scale prospective studies.

Age, intracranial pressure, autoregulation, and outcome after brain trauma

2005 ◽  
Vol 102 (3) ◽  
pp. 450-454 ◽  
Author(s):  
Marek Czosnyka ◽  
Marcella Balestreri ◽  
Luzius Steiner ◽  
Piotr Smielewski ◽  
Peter J. Hutchinson ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Older Patients ◽  
Brain Trauma ◽  
Reactivity Index ◽  
Content Type ◽  
Cerebrovascular Autoregulation ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Age Related ◽  
Fine Print

Object. The object of this study was to investigate whether a failure of cerebrovascular autoregulation contributes to the relationship between age and outcome in patients following head injury. Methods. Data obtained from continuous bedside monitoring of intracranial pressure (ICP), arterial blood pressure (ABP), and cerebral perfusion pressure (CPP = ABP — ICP) in 358 patients with head injuries and intermittent monitoring of transcranial Doppler blood flow velocity (FV) in the middle cerebral artery in 237 patients were analyzed retrospectively. Indices used to describe cerebral autoregulation and pressure reactivity were calculated as correlation coefficients between slow waves of systolic FV and CPP (autoregulation index [ARI]) and between ABP and ICP (pressure reactivity index [PRI]). Older patients had worse outcomes after brain trauma than younger patients (p = 0.00001), despite the fact that the older patients had higher initial Glasgow Coma Scale scores (p = 0.006). When age was considered as an independent variable, it appeared that ICP decreased with age (p = 0.005), resulting in an increasing mean CPP (p = 0.0005). Blood FV was not dependent on age (p = 0.58). Indices of autoregulation and pressure reactivity demonstrated a deterioration in cerebrovascular control with advancing age (PRI: p = 0.003; ARI: p = 0.007). Conclusions. An age-related decline in cerebrovascular autoregulation was associated with a relative deterioration in outcome in elderly patients following head trauma.

scholarly journals Continuous monitoring of cerebrovascular pressure reactivity in patients with head injury

2008 ◽  
Vol 25 (4) ◽  
pp. E2 ◽  
Author(s):  
Christian Zweifel ◽  
Andrea Lavinio ◽  
Luzius A. Steiner ◽  
Danila Radolovich ◽  
Peter Smielewski ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Continuous Monitoring ◽  
Surrogate Marker ◽  
Interquartile Range ◽  
Reactivity Index ◽  
Temperature Threshold ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Cerebrovascular Pressure Reactivity

Object Cerebrovascular pressure reactivity is the ability of cerebral vessels to respond to changes in transmural pressure. A cerebrovascular pressure reactivity index (PRx) can be determined as the moving correlation coefficient between mean intracranial pressure (ICP) and mean arterial blood pressure. Methods The authors analyzed a database consisting of 398 patients with head injuries who underwent continuous monitoring of cerebrovascular pressure reactivity. In 298 patients, the PRx was compared with a transcranial Doppler ultrasonography assessment of cerebrovascular autoregulation (the mean index [Mx]), in 17 patients with the PET–assessed static rate of autoregulation, and in 22 patients with the cerebral metabolic rate for O2. Patient outcome was assessed 6 months after injury. Results There was a positive and significant association between the PRx and Mx (R2 = 0.36, p < 0.001) and with the static rate of autoregulation (R2 = 0.31, p = 0.02). A PRx > 0.35 was associated with a high mortality rate (> 50%). The PRx showed significant deterioration in refractory intracranial hypertension, was correlated with outcome, and was able to differentiate patients with good outcome, moderate disability, severe disability, and death. The graph of PRx compared with cerebral perfusion pressure (CPP) indicated a U–shaped curve, suggesting that too low and too high CPP was associated with a disturbance in pressure reactivity. Such an optimal CPP was confirmed in individual cases and a greater difference between current and optimal CPP was associated with worse outcome (for patients who, on average, were treated below optimal CPP [R2 = 0.53, p < 0.001] and for patients whose mean CPP was above optimal CPP [R2 = −0.40, p < 0.05]). Following decompressive craniectomy, pressure reactivity initially worsened (median −0.03 [interquartile range −0.13 to 0.06] to 0.14 [interquartile range 0.12–0.22]; p < 0.01) and improved in the later postoperative course. After therapeutic hypothermia, in 17 (70.8%) of 24 patients in whom rewarming exceeded the brain temperature threshold of 37°C, ICP remained stable, but the average PRx increased to 0.32 (p < 0.0001), indicating significant derangement in cerebrovascular reactivity. Conclusions The PRx is a secondary index derived from changes in ICP and arterial blood pressure and can be used as a surrogate marker of cerebrovascular impairment. In view of an autoregulation–guided CPP therapy, a continuous determination of a PRx is feasible, but its value has to be evaluated in a prospective controlled trial.

Acute Haemodynamic and Hormonal Effects of Captopril are Diminished by Indomethacin

1982 ◽  
Vol 62 (6) ◽  
pp. 611-615 ◽  
Author(s):  
H. Witzgall ◽  
F. Hirsch ◽  
B. Scherer ◽  
P. C. Weber
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Plasma Renin ◽  
Hormonal Effects ◽  
Arterial Blood ◽  
Before And After ◽  
Pre Treatment ◽  
Excretion Rates

1. The acute haemodynamic and hormonal effects of 100 mg of captopril (SQ 14.225) orally were tested in twelve healthy men in the sodium replete state before and after indomethacin pre-treatment. 2. Without indomethacin, mean arterial blood pressure was reduced at 30 and 60 min after captopril (P < 0.02). Heart rate did not change during the whole experiment. Although plasma renin activity (PRA) increased (P < 0.002), plasma and urinary aldosterone and plasma 18-hydroxycorticosterone (18-OH-B) decreased after captopril (P < 0.02). Prostaglandin (PG) E2, sodium and potassium excretion rates remained constant after captopril. 3. Under indomethacin pretreatment, the fall in mean arterial blood pressure was less than without indomethacin at 30 and 60 min after captopril (P < 0.05). Heart rate was constantly lower than without indomethacin during the whole experiment (P < 0.05). Indomethacin pretreatment decreased basal PGE2 excretion (P < 0.02) and baseline PRA as well as the increase in PRA after captopril (P < 0.05). Control mineralocorticoid levels were significantly lower than without indomethacin. In indomethacin-pretreated subjects, aldosterone did not further decrease after captopril, and 18-OH-B fell only slightly. 4. Without indomethacin pretreatment a significant, positive correlation was found between PRA values before captopril and the maximum decrease of mean arterial blood pressure after captopril. Under indomethacin pretreatment this correlation was no longer demonstrable. The results suggest that prostaglandins may contribute to the haemodynamic and hormonal actions of captopril.

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