| 1. |
- Abu Hamdeh, Sami, et al.
(author)
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Intracranial pressure elevations in diffuse axonal injury : association with nonhemorrhagic MR lesions in central mesencephalic structures
- 2019
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 131:2, s. 604-611
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Journal article (peer-reviewed)abstract
- Objective: Increased intracranial pressure (ICP) in patients with severe traumatic brain injury (TBI) with diffuse axonal injury (DAI) is not well defined. This study investigated the occurrence of increased ICP and whether clinical factors and lesion localization on MRI were associated with increased ICP in patients with DAI.Methods: Fifty-two patients with severe TBI (median age 24 years, range 9–61 years), who had undergone ICP monitoring and had DAI on MRI, as determined using T2*-weighted gradient echo, susceptibility-weighted imaging, and diffusion-weighted imaging (DWI) sequences, were enrolled. The proportion of good monitoring time (GMT) with ICP > 20 mm Hg during the first 120 hours postinjury was calculated and associations with clinical and MRI-related factors were evaluated using linear regression.Results: All patients had episodes of ICP > 20 mm Hg. The mean proportion of GMT with ICP > 20 mm Hg was 5%, and 27% of the patients (14/52) spent more than 5% of GMT with ICP > 20 mm Hg. The Glasgow Coma Scale motor score at admission (p = 0.04) and lesions on DWI sequences in the substantia nigra and mesencephalic tegmentum (SN-T, p = 0.001) were associated with the proportion of GMT with ICP > 20 mm Hg. In multivariable linear regression, lesions on DWI sequences in SN-T (8% of GMT with ICP > 20 mm Hg, 95% CI 3%–13%, p = 0.004) and young age (−0.2% of GMT with ICP > 20 mm Hg, 95% CI −0.07% to −0.3%, p = 0.002) were associated with increased ICP.Conclusions: Increased ICP occurs in approximately one-third of patients with severe TBI who have DAI. Age and lesions on DWI sequences in the central mesencephalon (i.e., SN-T) are associated with elevated ICP. These findings suggest that MR lesion localization may aid prediction of increased ICP in patients with DAI.Abbreviations: ADC = apparent diffusion coefficient; CPP = cerebral perfusion pressure; DAI = diffuse axonal injury; DWI = diffusion-weighted imaging; EVD = external ventricular drain; GCS = Glasgow Coma Scale; GMT = good monitoring time; GOSE = Glasgow Outcome Scale–Extended; ICC = intraclass correlation coefficient; ICP = intracranial pressure; MAP = mean arterial blood pressure; NICU = neurointensive care unit; SN-T = substantia nigra and mesencephalic tegmentum; SWI = susceptibility-weighted imaging; TBI = traumatic brain injury; T2*GRE = T2*-weighted gradient echo.
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| 2. |
- Borota, Ljubisa, et al.
(author)
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Dual lumen balloon catheter - An effective substitute for two single lumen catheters in treatment of vascular targets with challenging anatomy
- 2018
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In: Journal of clinical neuroscience. - : Elsevier BV. - 0967-5868 .- 1532-2653. ; 51, s. 91-99
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Journal article (peer-reviewed)abstract
- The aim of this study was to describe our experience in the treatment of various pathological conditions of the cranial and spinal blood vessels and hypervascularized lesions using dual lumen balloon catheters. Twenty-five patients were treated with endovascular techniques: two with vasospasm of cerebral blood vessels caused by subarachnoid hemorrhage, one with a hypervascularized metastasis in the vertebral body, two with spinal dural fistula, four with cerebral dural fistula, three with cerebral arteriovenous malformations, and 13 with aneurysms. The dual lumen balloon catheters were used for remodeling of the coil mesh, injection of various liquid embolic agents, particles and nimodipine, for the prevention of reflux and deployment of coils and stents. The diameter of catheterized blood vessels varied from 0.7 mm to 4 mm. Two complications occurred: perforation of an aneurysm in one case and gluing of the tip of balloon catheter by embolic material in another case. All other interventions were uneventful, and therapeutic goals were achieved in all cases except in the case with gluing of the tip of balloon catheter. The balloons effectively prevented reflux regardless of the type of the embolic material and diameter of blood vessel. The results of our study show that dual lumen balloon catheters allow complex interventions in the narrow cerebral and spinal blood vessels where the safe use of two single lumen catheters is either limited or impossible.
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| 3. |
- Dyhrfort, Philip, et al.
(author)
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Monitoring of Protein Biomarkers of Inflammation in Human Traumatic Brain Injury Using Microdialysis and Proximity Extension Assay Technology in Neurointensive Care
- 2019
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In: Journal of Neurotrauma. - : MARY ANN LIEBERT, INC. - 0897-7151 .- 1557-9042. ; 36:20, s. 2872-2885
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Journal article (peer-reviewed)abstract
- Traumatic brain injury (TBI) is followed by secondary injury mechanisms strongly involving neuroinflammation. To monitor the complex inflammatory cascade in human TBI, we used cerebral microdialysis (MD) and multiplex proximity extension assay (PEA) technology and simultaneously measured levels of 92 protein biomarkers of inflammation in MD samples every three hours for five days in 10 patients with severe TBI under neurointensive care. One mu L MD samples were incubated with paired oligonucleotide-conjugated antibodies binding to each protein, allowing quantification by real-time quantitative polymerase chain reaction. Sixty-nine proteins were suitable for statistical analysis. We found five different patterns with either early (<48 h; e.g., CCL20, IL6, LIF, CCL3), mid (48-96 h; e.g., CCL19, CXCL5, CXCL10, MMP1), late (>96 h; e.g., CD40, MCP2, MCP3), biphasic peaks (e.g., CXCL1, CXCL5, IL8) or stable (e.g., CCL4, DNER, VEGFA)/low trends. High protein levels were observed for e.g., CXCL1, CXCL10, MCP1, MCP2, IL8, while e.g., CCL28 and MCP4 were detected at low levels. Several proteins (CCL8, -19, -20, -23, CXCL1, -5, -6, -9, -11, CST5, DNER, Flt3L, and SIRT2) have not been studied previously in human TBI. Cross-correlation analysis revealed that LIF and CXCL5 may play a central role in the inflammatory cascade. This study provides a unique data set with individual temporal trends for potential inflammatory biomarkers in patients with TBI. We conclude that the combination of MD and PEA is a powerful tool to map the complex inflammatory cascade in the injured human brain. The technique offers new possibilities of protein profiling of complex secondary injury pathways.
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| 4. |
- Engquist, Henrik, et al.
(author)
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Effect of HHH-Therapy on Regional CBF after Severe Subarachnoid Hemorrhage Studied by Bedside Xenon-Enhanced CT
- 2018
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In: Neurocritical Care. - : Springer Science and Business Media LLC. - 1541-6933 .- 1556-0961. ; 28:2, s. 143-151
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Journal article (peer-reviewed)abstract
- BACKGROUND:Management of delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is difficult and still carries controversies. In this study, the effect of therapeutic hypervolemia, hemodilution, and hypertension (HHH-therapy) on cerebral blood flow (CBF) was assessed by xenon-enhanced computerized tomography (XeCT) hypothesizing an increase in CBF in poorly perfused regions.METHODS:Bedside XeCT measurements of regional CBF in mechanically ventilated SAH patients were routinely scheduled for day 0-3, 4-7, and 8-12. At clinical suspicion of DCI, patients received 5-day HHH-therapy. For inclusion, XeCT was required at 0-48 h before start of HHH (baseline) and during therapy. Data from corresponding time-windows were also collected for non-DCI patients.RESULTS:Twenty patients who later developed DCI were included, and twenty-eight patients without DCI were identified for comparison. During HHH, there was a slight nonsignificant increase in systolic blood pressure (SBP) and a significant reduction in hematocrit. Median global cortical CBF for the DCI group increased from 29.5 (IQR 24.6-33.9) to 38.4 (IQR 27.0-41.2) ml/100 g/min (P = 0.001). There was a concomitant increase in regional CBF of the worst vascular territories, and the proportion of area with blood flow below 20 ml/100 g/min was significantly reduced. Non-DCI patients showed higher CBF at baseline, and no significant change over time.CONCLUSIONS:HHH-therapy appeared to increase global and regional CBF in DCI patients. The increase in SBP was small, while the decrease in hematocrit was more pronounced, which may suggest that intravascular volume status and rheological effects are of importance. XeCT may be potentially helpful in managing poor-grade SAH patients.
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| 5. |
- Engquist, Henrik, et al.
(author)
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Hemodynamic Disturbances in the Early Phase After Subarachnoid Hemorrhage : Regional Cerebral Blood Flow Studied by Bedside Xenon-enhanced CT.
- 2018
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In: Journal of Neurosurgical Anesthesiology. - 0898-4921 .- 1537-1921. ; 30:1, s. 49-58
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Journal article (peer-reviewed)abstract
- BACKGROUND: The mechanisms leading to neurological deterioration and the devastating course of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) are still not well understood. Bedside xenon-enhanced computerized tomography (XeCT) enables measurements of regional cerebral blood flow (rCBF) during neurosurgical intensive care. In the present study, CBF characteristics in the early phase after severe SAH were explored and related to clinical characteristics and early clinical course outcome.MATERIALS AND METHODS: Patients diagnosed with SAH and requiring mechanical ventilation were prospectively enrolled in the study. Bedside XeCT was performed within day 0 to 3.RESULTS: Data from 64 patients were obtained. Median global CBF was 34.9 mL/100 g/min (interquartile range [IQR], 26.7 to 41.6). There was a difference in CBF related to age with higher global CBF in the younger patients (30 to 49 y). CBF was also related to the severity of SAH with lower CBF in Fisher grade 4 compared with grade 3. rCBF disturbances and hypoperfusion were common; in 43 of the 64 patients rCBF<20 mL/100 g/min was detected in more than 10% of the region-of-interest (ROI) area and in 17 patients such low-flow area exceeded 30%. rCBF was not related to the localization of the aneurysm; there was no difference in rCBF of ipsilateral compared with contralateral vascular territories. In patients who initially were in Hunt & Hess grade I to III, median global CBF day 0 to 3 was significantly lower for patients who were in poor neurological state at discharge compared with patients in good neurological state, 25.5 mL/100 g/min (IQR, 21.3 to 28.3) versus 37.8 mL/100 g/min (IQR, 30.5 to 47.6).CONCLUSIONS: CBF disturbances are common in the early phase after SAH. In many patients, CBF was heterogenic and substantial areas with low rCBF were detected. Age and CT Fisher grade were factors influencing global cortical CBF. Bedside XeCT may be a tool to identify patients at risk of deteriorating so they can receive intensified management, but this needs further exploration.
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| 6. |
- Johnson, Ulf, et al.
(author)
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Increased risk of critical CBF levels in SAH patients with actual CPP below calculated optimal CPP
- 2017
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In: Acta Neurochirurgica. - : Springer Science and Business Media LLC. - 0001-6268 .- 0942-0940. ; 159:6, s. 1065-1071
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Journal article (peer-reviewed)abstract
- Background Cerebral pressure autoregulation can be quantified with the pressure reactivity index (PRx), based on the correlation between blood pressure and intracranial pressure. Using PRx optimal cerebral perfusion pressure (CPPopt) can be calculated, i.e., the level of CPP where autoregulation functions best. The relation between cerebral blood flow (CBF) and CPPopt has not been examined. The objective was to assess to which extent CPPopt can be calculated in SAH patients and to investigate CPPopt in relation to CBF.Methods Retrospective study of prospectively collected data. CBF was measured bedside with Xenon-enhanced CT (Xe-CT). The difference between actual CPP and CPPopt was calculated (CPPa dagger). Correlations between CPPa dagger and CBF parameters were calculated with Spearman's rank order correlation coefficient (rho). Separate calculations were done using all patients (day 0-14 after onset) as well as in two subgroups (day 0-3 and day 4-14).Results Eighty-two patients with 145 Xe-CT scans were studied. Automated calculation of CPPopt was possible in adjunct to 60% of the Xe-CT scans. Actual CPP < CPPopt was associated with higher numbers of low-flow regions (CBF < 10 ml/100 g/min) in both the early phase (day 0-3, n = 39, Spearman's rho = -0.38, p = 0.02) and late acute phase of the disease (day 4-14, n = 35, Spearman's rho = -0.39, p = 0.02). CPP level per se was not associated with CBF.Conclusions Calculation of CPPopt is possible in a majority of patients with severe SAH. Actual CPP below CPPopt is associated with low CBF.
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| 7. |
- Lenell, Samuel, et al.
(author)
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Clinical outcome and prognostic factors in elderly traumatic brain injury patients receiving neurointensive care
- 2019
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In: Acta Neurochirurgica. - : SPRINGER WIEN. - 0001-6268 .- 0942-0940. ; 161:6, s. 1243-1254
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Journal article (peer-reviewed)abstract
- Background: The probability of favorable outcome after traumatic brain injury (TBI) decreases with age. Elderly,≥60 years, are an increasing part of our population. Recent studies have shown an increase of favorable outcome in elderly over time. However,the optimal patient selection and neurointensive care (NIC) treatments may differ in the elderly and the young. The aims of this study were to examine outcome in a larger group of elderly TBI patients receiving NIC and to identify demographic and treatmentrelated prognostic factors.Methods: Patients with TBI≥60 years receiving NIC at our department between 2008 and 2014 were included. Demographics, co-morbidity, admission characteristics, and type of treatments were collected. Clinical outcome at around 6 months was assessed. Potential prognostic factors were included in univariate and multivariate regression analysis with favorable outcomeas dependent variable.Results: Two hundred twenty patients with mean age 70 years (median 69; range 60–87) were studied. Overall, favorable outcome was 46% (Extended Glasgow Outcome Scale (GOSE) 5–8), unfavorable outcome 27% (GOSE 2–4), and mortality 27% (GOSE 1). Significant independent negative prognostic variables were high age (p< 0.05), multiple injuries (p<0.05),GCSM≤3 on admission (p< 0.05), and mechanical ventilation (p<0.001).Conclusions: Overall, the elderly TBI patients> 60 years receiving modern NIC in this study had a fair chance of favorable outcome without large risks for severe deficits and vegetative state, also in patients over 75 years of age. High age, multiple injuries, GCS M≤3 on admission, and mechanical ventilation proved to be independent negative prognostic factors. The results underline that a selected group of elderly with TBI should have access to NIC
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| 8. |
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| 9. |
- Nyholm, Lena, 1973-, et al.
(author)
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The influence of hyperthermia on intracranial pressure, cerebral oximetry and cerebral metabolism in traumatic brain injury
- 2017
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In: Upsala Journal of Medical Sciences. - : Uppsala Medical Society. - 0300-9734 .- 2000-1967. ; 122:3, s. 177-184
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Journal article (peer-reviewed)abstract
- Background: Hyperthermia is a common secondary insult in traumatic brain injury (TBI). The aim was to evaluate the relationship between hyperthermia and intracranial pressure (ICP), and if intracranial compliance and cerebral blood flow (CBF) pressure autoregulation affected that relationship. The relationships between hyperthermia and cerebral oximetry (B(ti)pO(2)) and cerebral metabolism were also studied. Methods: A computerized multimodality monitoring system was used for data collection at the neurointensive care unit. Demographic and monitoring data (temperature, ICP, blood pressure, microdialysis, B(ti)pO(2)) were analyzed from 87 consecutive TBI patients. ICP amplitude was used as measure of compliance, and CBF pressure autoregulation status was calculated using collected blood pressure and ICP values. Mixed models and comparison between groups were used. Results: The influence of hyperthermia on intracranial dynamics (ICP, brain energy metabolism, and B(ti)pO(2)) was small, but individual differences were seen. Linear mixed models showed that hyperthermia raises ICP slightly more when temperature increases in the groups with low compliance and impaired CBF pressure autoregulation. There was also a tendency (not statistically significant) for increased B(ti)pO(2), and for increased pyruvate and lactate, with higher temperature, while the lactate/pyruvate ratio and glucose were stable. Conclusions: The major finding was that the effects of hyperthermia on intracranial dynamics (ICP, brain energy metabolism, and B(ti)pO(2)) were not extensive in general, but there were exceptional cases. Hyperthermia treatment has many side effects, so it is desirable to identify cases in which hyperthermia is dangerous. Information from multimodality monitoring may be used to guide treatment in individual patients.
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| 10. |
- Redzwan, Syaiful, et al.
(author)
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Initial in-vitro trial for intra-cranial pressure monitoring using subdermal proximity-coupled split-ring resonator
- 2018
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In: IMBioc 2018 - 2018 IEEE/MTT-S International Microwave Biomedical Conference. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538659182 ; , s. 73-75
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Conference paper (peer-reviewed)abstract
- Intra cranial pressure (ICP) monitoring is used in treating severe traumatic brain injury (TBI) patients. All current clinical available measurement methods are invasive presenting considerable social costs. This paper presents a preliminary investigation of the feasibility of ICP monitoring using an innovative microwave-based non-invasive approach. A phantom mimicking the dielectric characteristics of human tissues of the upper part of the head at low microwave frequencies is employed together to a proof-of-concept prototype based on the proposed approach consisting in a readout system and a sub-dermally implanted passive device, both based in split ring resonator techniques. This study shows the potential of our approach to detect two opposite pressure variation stages inside the skull. The employed phantom model needs to be improved to support finer variations in the pressure and better phantom parts, principally for the skull mimic and the loss tangent of all mimics.
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| 11. |
- Rostami, Elham, 1979-, et al.
(author)
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Early low cerebral blood flow and high cerebral lactate : prediction of delayed cerebral ischemia in subarachnoid hemorrhage
- 2018
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In: Journal of Neurosurgery. - 0022-3085 .- 1933-0693. ; 128:6, s. 1762-1770
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Journal article (peer-reviewed)abstract
- OBJECTIVE Delayed cerebral ischemia (DCI) following subarachnoid hemorrhage (SAH) is one of the major contributors to poor outcome. It is crucial to be able to detect early signs of DCI to prevent its occurrence. The objective of this study was to determine if low cerebral blood flow (CBF) measurements and pathological microdialysis parameters measured at the bedside can be observed early in patients with SAH who later developed DCI. METHODS The authors included 30 patients with severe SAH. The CBF measurements were performed at Day 0-3 after disease onset, using bedside xenon-CT. Interstitial glucose, lactate, pyruvate, glycerol, and glutamate were measured using microdialysis. RESULTS Nine of 30 patients developed DCI. Patients with DCI showed significantly lower global and regional CBF, and lactate was significantly increased in these patients. A high lactate/pyruvate ratio was also detected in patients with DCI. CONCLUSIONS Early low CBF measurements and a high lactate and lactate/pyruvate ratio may be early warning signs of the risk of developing DCI. The clinical value of these findings needs to be confirmed in larger studies.
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| 12. |
- Rostami, Elham, 1979-, et al.
(author)
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The Correlation between Cerebral Blood Flow Measured by Bedside Xenon-CT and Brain Chemistry Monitored by Microdialysis in the Acute Phase following Subarachnoid Hemorrhage
- 2017
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In: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 8
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Journal article (peer-reviewed)abstract
- Cerebral microdialysis (MD) may be used in patients suffering from subarachnoid hemorrhage (SAH) to detect focal cerebral ischemia. The cerebral MD catheter is usually placed in the right frontal lobe and monitors the area surrounding the catheter. This generates the concern that a fall in cerebral blood flow (CBF) and ischemic events distant to the catheter may not be detected. We aimed to investigate if there is a difference in the association between the MD parameters and CBF measured around the MD catheter compared to global cortical CBF and to CBF in the vascular territories following SAH in the early acute phase. MD catheter was placed in the right frontal lobe of 30 SAH patients, and interstitial glucose, lactate, pyruvate, glycerol, and lactate/pyruvate ratio were measured hourly. CBF measurements were performed during day 0-3 after SAH. Global cortical CBF correlated strongly with CBF around the microdialysis catheter (CBF-MD) (r = 0.911, p ≤ 0.001). This was also the case for the anterior, middle, and posterior vascular territories in the right hemisphere. A significant negative correlation was seen between lactate and CBF-MD (r = -0.468, p = 0.009). The same relationship was observed between lactate and CBF in anterior vascular territory but not in the middle and posterior vascular territories. In conclusion, global CBF 0-3 days after severe SAH correlated strongly with CBF-MD. High lactate level was associated with low global CBF and low regional CBF in the right anterior vascular territory, when the MD catheter was placed in the right frontal lobe.
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| 13. |
- Svedung Wettervik, Teodor, et al.
(author)
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Decompressive craniectomy in traumatic brain injury : usage and clinical outcome in a single centre
- 2018
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In: Acta Neurochirurgica. - : SPRINGER WIEN. - 0001-6268 .- 0942-0940. ; 160:2, s. 229-237
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Journal article (peer-reviewed)abstract
- Background: Two randomised controlled trials (RCTs) of decompressive craniectomy (DC) in traumatic brain injury (TBI) have shown poor outcome, but there are considerations of how these protocols relate to real practice. The aims of this study were to evaluate usage and outcome of DC and thiopental in a single centre.Method: The study included all TBI patients treated at the neurointensive care unit, Akademiska sjukhuset, Uppsala, Sweden, between 2008 and 2014. Of 609 patients aged 16 years or older, 35 treated with DC and 23 treated with thiopental only were studied in particular. Background variables, intracranial pressure (ICP) measures and global outcome were analysed.Results: Of 35 DC patients, 9 were treated stepwise with thiopental before DC, 9 were treated stepwise with no thiopental before DC and 17 were treated primarily with DC. Six patients received thiopental after DC. For 23 patients, no DC was needed after thiopental. Eighty-eight percent of our DC patients would have qualified for the DECRA study and 38% for the Rescue-ICP trial. Favourable outcome was 44% in patients treated with thiopental before DC, 56% in patients treated with DC without prior thiopental, 29% in patients treated primarily with DC and 52% in patients treated with thiopental with no DC.Conclusions: The place for DC in TBI management must be evaluated better, and we believe it is important that future RCTs should have clearer and less permissive ICP criteria regarding when thiopental should be followed by DC and DC followed by thiopental.
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| 14. |
- Svedung-Wettervik, Teodor, et al.
(author)
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High Arterial Glucose is Associated with Poor Pressure Autoregulation, High Cerebral Lactate/Pyruvate Ratio and Poor Outcome Following Traumatic Brain Injury
- 2019
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In: Neurocritical Care. - : HUMANA PRESS INC. - 1541-6933 .- 1556-0961. ; 31:3, s. 526-533
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Journal article (peer-reviewed)abstract
- Background Arterial hyperglycemia is associated with poor outcome in traumatic brain injury (TBI), but the pathophysiology is not completely understood. Previous preclinical and clinical studies have indicated that arterial glucose worsens pressure autoregulation. The aim of this study was to evaluate the relationship of arterial glucose to both pressure reactivity and cerebral energy metabolism. Method This retrospective study was based on 120 patients with severe TBI treated at the Uppsala University hospital, Sweden, 2008-2018. Data from cerebral microdialysis (glucose, pyruvate, and lactate), arterial glucose, and pressure reactivity index (PRx55-15) were analyzed the first 3 days post-injury. Results High arterial glucose was associated with poor outcome/Glasgow Outcome Scale-Extended at 6-month follow-up (r = - 0.201, p value = 0.004) and showed a positive correlation with both PRx55-15 (r = 0.308, p = 0.001) and cerebral lactate/pyruvate ratio (LPR) days 1-3 (r = 0. 244, p = 0.014). Cerebral lactate-to-pyruvate ratio and PRx55-15 had a positive association day 2 (r = 0.219, p = 0.048). Multivariate linear regression analysis showed that high arterial glucose predicted poor pressure autoregulation on days 1 and 2. Conclusions High arterial glucose was associated with poor outcome, poor pressure autoregulation, and cerebral energy metabolic disturbances. The latter two suggest a pathophysiological mechanism for the negative effect of arterial hyperglycemia, although further studies are needed to elucidate if the correlations are causal or confounded by other factors.
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| 15. |
- Svedung-Wettervik, Teodor, et al.
(author)
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Temporal Neurophysiological Dynamics in Traumatic Brain Injury : Role of Pressure Reactivity and Optimal Cerebral Perfusion Pressure for Predicting Outcome
- 2019
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In: Journal of Neurotrauma. - : MARY ANN LIEBERT, INC. - 0897-7151 .- 1557-9042. ; 36:11, s. 1818-1827
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Journal article (peer-reviewed)abstract
- Intracranial pressure (ICP), cerebral perfusion pressure (CPP), and the pressure reactivity index (PRx) have been shown to correlate with outcome after traumatic brain injury (TBI), but their temporal evolution is less studied. Optimal CPP (CPPopt; i.e., the CPP with the lowest [optimal] PRx value) has been proposed as a dynamic, individualized CPP target. Our aim was to map the temporal course of these parameters and their relation to outcome, in particular the extent and impact of CPP insults based both on fixed CPP thresholds and on divergence from CPPopt. Data from 362 TBI patients with ICP-monitoring treated at the neurointensive care unit of Uppsala University Hospital, Uppsala, Sweden, between 2008-2016 were retrospectively analyzed for the temporal course of ICP, mean arterial blood pressure, CPP, PRx, PRx55-15 (a variant of PRx), and CPPopt the first 10 days post-injury. PRx and PRx55-15 showed significantly lower/better values for those with favorable outcome, most pronounced on Days 2 to 5. PRx55-15 gave better separation between the two groups. In the univariate analysis, CPP insults (both fixed and CPPopt-thresholds) were significantly correlated with outcome on these days. Multi-variate logistic regression showed that age, Glasgow Coma Score Motor, pupillary abnormality at admission, CPP > CPPopt, and PRx55-15 were significant independent outcome predictors. PRx was significant when PRx55-15 was excluded. High PRx55-15 and high grade of monitoring time with CPP > CPPopt, but not the traditional fixed CPP thresholds, were strong predictors for worse clinical outcome. The study supports the concept that CPPopt is an important parameter in TBI management.
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| 16. |
- Velander, Jacob, et al.
(author)
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A Four-Layer Phantom for Testing In-Vitro Microwave-Based Sensing Approach in Intra-Cranial Pressure Monitoring
- 2018
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In: Proceedings Of The 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBioC). - : IEEE. - 9781538659182 ; , s. 49-51
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Conference paper (peer-reviewed)abstract
- Multi-layer phantoms in proofs of concept, designs and validations of both microwave-based biomedical sensing and imaging system are becoming popular means to facilitate in-vitro experiments. In addition, they can contribute significantly to reduce animal use in scientific experimentation. In this paper, we design and fabricate a four-layer phantom composed of skin, skull, cerebrospinal fluid and brain mimic tissues to work between 2 and 3 GHz. In addition, the phantom incorporates a mechanism to produce pressure variation between the cerebrospinal fluid and the brain mimic tissues. This phantom is used in an in-vitro experiment to test and validate a new approach which could sense intra-cranial pressure variations through a microwave-based reflection method. The similarity of the phantom's tissues with human tissues from the viewpoint of the microwave response is analyzed in comparison with data from Italian Institute of Applied Physics in Florence. We found good agreement for the dielectric constant (Rel. Err. < 13 % for 68% of significance) in skin, cerebrospinal fluid and brain mimic tissues. For the skin, we got also good agreement for the loss tangent (Rel. Err. < 11 % for 68% of significance). The skull mimic phantom was stiff enough, but even presenting considerable errors, it was still good enough for the experiment. In addition, the capability of the phantom to operate at different pressures is discussed.
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