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  • 1.
    Abu Hamdeh, Sami
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Marklund, Niklas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lannsjö, Marianne
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Rehabilitation Medicine. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Centre for Research and Development, Gävleborg.
    Howells, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Raininko, Raili
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Wikström, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Extended anatomical grading in diffuse axonal injury using MRI: Hemorrhagic lesions in the substantia nigra and mesencephalic tegmentum indicate poor long-term outcome2017In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 5, no 34, p. 341-352Article in journal (Refereed)
    Abstract [en]

    Clinical outcome after traumatic diffuse axonal injury (DAI) is difficult to predict. In this study, three magnetic resonance imaging (MRI) sequences were used to quantify the anatomical distribution of lesions, to grade DAI according to the Adams grading system, and to evaluate the value of lesion localization in combination with clinical prognostic factors to improve outcome prediction. Thirty patients (mean 31.2 years ±14.3 standard deviation) with severe DAI (Glasgow Motor Score [GMS] <6) examined with MRI within 1 week post-injury were included. Diffusion-weighted (DW), T2*-weighted gradient echo and susceptibility-weighted (SWI) sequences were used. Extended Glasgow outcome score was assessed after 6 months. Number of DW lesions in the thalamus, basal ganglia, and internal capsule and number of SWI lesions in the mesencephalon correlated significantly with outcome in univariate analysis. Age, GMS at admission, GMS at discharge, and low proportion of good monitoring time with cerebral perfusion pressure <60 mm Hg correlated significantly with outcome in univariate analysis. Multivariate analysis revealed an independent relation with poor outcome for age (p = 0.005) and lesions in the mesencephalic region corresponding to substantia nigra and tegmentum on SWI (p  = 0.008). We conclude that higher age and lesions in substantia nigra and mesencephalic tegmentum indicate poor long-term outcome in DAI. We propose an extended MRI classification system based on four stages (stage I—hemispheric lesions, stage II—corpus callosum lesions, stage III—brainstem lesions, and stage IV—substantia nigra or mesencephalic tegmentum lesions); all are subdivided by age (≥/<30 years).

  • 2.
    Abu Hamdeh, Sami
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Marklund, Niklas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Howells, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Raininko, Raili
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Wikström, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Intracranial pressure elevations in diffuse axonal injury: association with nonhemorrhagic MR lesions in central mesencephalic structures2019In: Journal of Neurosurgery, ISSN 0022-3085, E-ISSN 1933-0693, Vol. 131, no 2, p. 604-611Article in journal (Refereed)
    Abstract [en]

    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.

  • 3.
    Abu Hamdeh, Sami
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Marklund, Niklas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Raininko, Raili
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Wikström, Johan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Intracranial pressure elevations in diffuse axonal injury are associated with non-hemorrhagic MR lesions in central mesencephalic structuresIn: Article in journal (Other academic)
    Abstract [en]

    Objective: Increased intracranial pressure (ICP) in severe traumatic brain injury (TBI) patients 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 DAI patients.

    Methods: Fifty-two severe TBI patients (median 24, range 9-61 years), with ICP-monitoring and DAI on MRI, using T2*-weighted gradient echo, susceptibility-weighted and diffusion-weighted (DW) sequences, were enrolled. Proportion of good monitoring time (GMT) with ICP>20 mmHg during the first 120 hours post-injury was calculated and associations with clinical and MRI-related factors were evaluated using linear regression. 

    Results: All patients had episodes of ICP>20 mmHg. The mean proportion of GMT with ICP>20 mmHg was 5% and 27% of the patients (14/52) had more than 5% of GMT with ICP>20 mmHg. Glasgow Coma Scale motor score at admission (P=0.04) and lesions on DW images in the substantia nigra and mesencephalic tegmentum (SN-T, P=0.001) were associated with the proportion of GMT with ICP>20 mmHg. In multivariate linear regression, lesions on DW images in SN-T (8% of GMT with ICP>20 mmHg, 95% CI 3–13%, P=0.004) and young age (-0.2% of GMT with ICP>20 mmHg, 95% CI -0.07–-0.3%, P=0.0008) were associated with increased ICP.   

    Conclusions: Increased ICP occurs in ~1/3 of severe TBI patients with DAI. Age and lesions on DW images in the central mesencephalon (SN-T) associate with elevated ICP. These findings suggest that MR lesion localization may aid prediction of increased ICP in DAI patients.

  • 4.
    Donald, Rob
    et al.
    Stats Res Ltd, Dingwall, Scotland.
    Howells, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Piper, Ian
    Queen Elizabeth Univ Hosp, Inst Neurol Sci, Clin Phys, Glasgow, Lanark, Scotland.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Nilsson, Pelle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Chambers, I.
    James Cook Univ Hosp, Dept Med Phys, Middlesbrough, Cleveland, England.
    Gregson, B.
    Newcastle Univ, Neurosurg Trials Grp, Newcastle Upon Tyne, Tyne & Wear, England.
    Citerio, G.
    Hosp San Gerardo, Neurorianimaz, Monza, Italy.
    Kiening, K.
    Ruprecht Karls Univ Hosp, Dept Neurosurg, Heidelberg, Germany.
    Neumann, J.
    Ruprecht Karls Univ Hosp, Dept Neurosurg, Heidelberg, Germany.
    Ragauskas, A.
    Kaunas Univ Technol, Kaunas, Lithuania.
    Sahuquillo, J.
    Vall dHebron Univ Hosp, Dept Neurosurg, Barcelona, Spain.
    Sinnott, R.
    Univ Melbourne, Dept Informat Syst, Parkville, Vic, Australia.
    Stell, A.
    Univ Glasgow, Dept Clin Phys, Glasgow, Lanark, Scotland.
    Forewarning of hypotensive events using a Bayesian artificial neural network in neurocritical care2019In: Journal of clinical monitoring and computing, ISSN 1387-1307, E-ISSN 1573-2614, Vol. 33, no 1, p. 39-51Article in journal (Refereed)
    Abstract [en]

    Traumatically brain injured (TBI) patients are at risk from secondary insults. Arterial hypotension, critically low blood pressure, is one of the most dangerous secondary insults and is related to poor outcome in patients. The overall aim of this study was to get proof of the concept that advanced statistical techniques (machine learning) are methods that are able to provide early warning of impending hypotensive events before they occur during neuro-critical care. A Bayesian artificial neural network (BANN) model predicting episodes of hypotension was developed using data from 104 patients selected from the BrainIT multi-center database. Arterial hypotension events were recorded and defined using the Edinburgh University Secondary Insult Grades (EUSIG) physiological adverse event scoring system. The BANN was trained on a random selection of 50% of the available patients (n = 52) and validated on the remaining cohort. A multi-center prospective pilot study (Phase 1, n = 30) was then conducted with the system running live in the clinical environment, followed by a second validation pilot study (Phase 2, n = 49). From these prospectively collected data, a final evaluation study was done on 69 of these patients with 10 patients excluded from the Phase 2 study because of insufficient or invalid data. Each data collection phase was a prospective non-interventional observational study conducted in a live clinical setting to test the data collection systems and the model performance. No prediction information was available to the clinical teams during a patient's stay in the ICU. The final cohort (n = 69), using a decision threshold of 0.4, and including false positive checks, gave a sensitivity of 39.3% (95% CI 32.9-46.1) and a specificity of 91.5% (95% CI 89.0-93.7). Using a decision threshold of 0.3, and false positive correction, gave a sensitivity of 46.6% (95% CI 40.1-53.2) and specificity of 85.6% (95% CI 82.3-88.8). With a decision threshold of 0.3, > 15min warning of patient instability can be achieved. We have shown, using advanced machine learning techniques running in a live neuro-critical care environment, that it would be possible to give neurointensive teams early warning of potential hypotensive events before they emerge, allowing closer monitoring and earlier clinical assessment in an attempt to prevent the onset of hypotension. The multi-centre clinical infrastructure developed to support the clinical studies provides a solid base for further collaborative research on data quality, false positive correction and the display of early warning data in a clinical setting.

  • 5.
    Howells, Tim
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Johnson, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    McKelvey, Tomas
    Chalmers, Dept Signals & Syst, Gothenburg, Sweden..
    Ronne-Engström, Elisabeth
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    The effects of ventricular drainage on the intracranial pressure signal and the pressure reactivity index2017In: Journal of clinical monitoring and computing, ISSN 1387-1307, E-ISSN 1573-2614, Vol. 31, no 2, p. 469-478Article in journal (Refereed)
    Abstract [en]

    In subarachnoid hemorrhage (SAH) patients intracranial pressure (ICP) is usually monitored via an extraventricular drain (EVD), which can produce false readings when the drain is open. It is established that both the ICP cardiac pulse frequency and long term trends over several hours are often seriously corrupted. The aim of this study was to establish whether or not the intermediate frequency bands [respiratory, Mayer wave and very low frequency (VLF)] were also corrupted. The VLF range is of special interest because it is important in cerebral autoregulation studies. Using a pattern recognition algorithm we retrospectively identified 718 cases of EVD opening in 80 SAH patients. An analysis of differences between closed and open-drain periods showed that ICP amplitude decreased significantly in all of the three lower frequency bands when the EVD was open. A similar analysis of systemic arterial pressure signal revealed similar changes in the same frequency bands that were positively correlated with the ICP changes. Therefore we concluded that the changes in the ICP signal represented real, physiological changes and not artifact. Pressure reactivity index (PRx) values were also computed during closed and open-drain periods. We found a small but statistically significant decrease during open-drain periods. Based on analysis of the change in the PRx distribution during open drainage we concluded that this decrease also represented physiological changes rather than artifact. In summary the ICP respiratory, Mayer wave, and VLF frequency bands are not corrupted when the EVD is open, and it safe to use these for autoregulation studies.

  • 6.
    Mazzeo, Anna Teresa
    et al.
    Univ Turin, Dept Surg Sci, Anesthesia & Intens Care Unit, Turin, Italy..
    Filippini, Claudia
    Univ Turin, Dept Surg Sci, Turin, Italy..
    Rosato, Rosalba
    Univ Turin, Dept Psychol, Turin, Italy..
    Fanelli, Vito
    Univ Turin, Dept Surg Sci, Anesthesia & Intens Care Unit, Turin, Italy..
    Assenzio, Barbara
    Univ Turin, Dept Surg Sci, Anesthesia & Intens Care Unit, Turin, Italy..
    Piper, Ian
    So Gen Hosp, Dept Clin Phys, Glasgow, Lanark, Scotland..
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Mastromauro, Ilaria
    Univ Turin, Dept Surg Sci, Anesthesia & Intens Care Unit, Turin, Italy..
    Berardino, Maurizio
    AOU Citta Salute & Sci Torino, Presidio CTO, Anesthesia & Intens Care Unit, Turin, Italy..
    Ducati, Alessandro
    Univ Turin, Dept Neurosci, Neurosurg Unit, Turin, Italy..
    Mascia, Luciana
    Univ Roma La Sapienza, Dipartimento Sci & Biotecnol Med Chirurg, Rome, Italy..
    Multivariate projection method to investigate inflammation associated with secondary insults and outcome after human traumatic brain injury: a pilot study2016In: Journal of Neuroinflammation, ISSN 1742-2094, E-ISSN 1742-2094, Vol. 13, article id 157Article in journal (Refereed)
    Abstract [en]

    Background: Neuroinflammation has been proposed as a possible mechanism of brain damage after traumatic brain injury (TBI), but no consensus has been reached on the most relevant molecules. Furthermore, secondary insults occurring after TBI contribute to worsen neurological outcome in addition to the primary injury. We hypothesized that after TBI, a specific pattern of cytokines is related to secondary insults and outcome. Methods: A prospective observational clinical study was performed. Secondary insults by computerized multimodality monitoring system and systemic value of different cytokines were collected and analysed in the first week after intensive care unit admission. Neurological outcome was assessed at 6 months (GOSe). Multivariate projection technique was applied to analyse major sources of variation and collinearity within the cytokines dataset without a priori selecting potential relevant molecules. Results: Twenty-nine severe traumatic brain injury patients undergoing intracranial pressure monitoring were studied. In this pilot study, we demonstrated that after TBI, patients who suffered of prolonged and severe secondary brain damage are characterised by a specific pattern of cytokines. Patients evolving to brain death exhibited higher levels of inflammatory mediators compared to both patients with favorable and unfavorable neurological outcome at 6 months. Raised ICP and low cerebral perfusion pressure occurred in 21 % of good monitoring time. Furthermore, the principal components selected by multivariate projection technique were powerful predictors of neurological outcome. Conclusions: The multivariate projection method represents a valuable methodology to study neuroinflammation pattern occurring after secondary brain damage in severe TBI patients, overcoming multiple putative interactions between mediators and avoiding any subjective selection of relevant molecules.

  • 7.
    Nyholm, Lena
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Predictive Factors That May Contribute to Secondary Insults With Nursing Interventions in Adults With Traumatic Brain Injury2017In: Journal of Neuroscience Nursing, ISSN 0888-0395, E-ISSN 1945-2810, Vol. 49, no 1, p. 49-55Article in journal (Refereed)
    Abstract [en]

    Background: Nursing interventions pose risks and benefits to patients with traumatic brain injury at a neurointensive care unit. Objectives: The aim of this study was to investigate the risk of inducing high intracranial pressure (ICP) related to interventions and whether intracranial compliance, baseline ICP, or autoregulation could be used as predictors. Methods: The study had a quantitative, prospective, observational design. Twenty-eight patients with TBI were included, and 67 interventions were observed. The definition of a secondary ICP insult was ICP of 20 mm Hg or greater for 5 minutes or more within a continuous 10-minute period. Results: Secondary ICP insults related to nursing interventions occurred in 6 patients (21%) and 8 occasions (12%). Patients with baseline ICP of 15 mm Hg or greater had 4.7 times higher risk of developing an insult. The predictor with the best combination of sensitivity and specificity was baseline ICP. Conclusions: Baseline ICP of 15 mm Hg or greater was the most important factor to determine the risk of secondary ICP insult related to nursing intervention.

  • 8.
    Nyholm, Lena
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    The influence of hyperthermia on intracranial pressure, cerebral oximetry and cerebral metabolism in traumatic brain injury2017In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 122, no 3, p. 177-184Article in journal (Refereed)
    Abstract [en]

    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.

  • 9.
    Purins, Karlis
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Brain tissue oxygenation and cerebral metabolic patterns in focal and diffuse traumatic brain injury2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, article id 64Article in journal (Refereed)
    Abstract [en]

    Introduction: Neurointensive care of traumatic brain injury (TBI) patients is currently based on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) targeted protocols. There are reasons to believe that knowledge of brain tissue oxygenation (BtipO2) would add information with the potential of improving patient outcome. The aim of this study was to examine BtipO2 and cerebral metabolism using the Neurovent-PTO probe and cerebral microdialysis (MD) in TBI patients.

    Methods: Twenty-three severe TBI patients with monitoring of physiological parameters, ICP, CPP, BtipO2, and MD for biomarkers of energy metabolism (glucose, lactate, and pyruvate) and cellular distress (glutamate, glycerol) were included. Patients were grouped according to injury type (focal/diffuse) and placement of the Neurovent-PTO probe and MD catheter (injured/non-injured hemisphere).

    Results: We observed different patterns in BtipO2 and MD biomarkers in diffuse and focal injury where placement of the probe also influenced the results (ipsilateral/contralateral). In all groups, despite fairly normal levels of ICP and CPP, increased MD levels of glutamate, glycerol, or the L/P ratio were observed at BtipO2 <5 mmHg, indicating increased vulnerability of the brain at this level.

    Conclusion: Monitoring of BtipO2 adds important information in addition to traditional ICP and CPP surveillance. Because of the different metabolic responses to very low BtipO2 in the individual patient groups we submit that brain tissue oximetry is a complementary tool rather than an alternative to MD monitoring.

  • 10.
    Rostami, Elham
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Engquist, Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Johnson, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Radiology.
    Ronne-Engström, Elisabeth
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Nilsson, Pelle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Early low cerebral blood flow and high cerebral lactate: prediction of delayed cerebral ischemia in subarachnoid hemorrhage2018In: Journal of Neurosurgery, ISSN 0022-3085, E-ISSN 1933-0693, Vol. 128, no 6, p. 1762-1770Article in journal (Refereed)
    Abstract [en]

    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.

  • 11.
    Rostami, Elham
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Engquist, Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Ronne-Engström, Elisabeth
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Nilsson, Pelle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars Tomas
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    The Correlation between Cerebral Blood Flow Measured by Bedside Xenon-CT and Brain Chemistry Monitored by Microdialysis in the Acute Phase following Subarachnoid Hemorrhage2017In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 8, article id 369Article in journal (Refereed)
    Abstract [en]

    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.

  • 12.
    Rostami, Elham
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Engquist, Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Johnson, Ulf
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Ronne-Engström, Elisabeth
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Nilsson, Pelle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Monitoring of Cerebral Blood Flow and Metabolism Bedside in Patients with Subarachnoid Hemorrhage - A Xenon-CT and Microdialysis Study2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, article id 89Article in journal (Refereed)
    Abstract [en]

    Cerebral ischemia is the leading cause of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). Although 70% of the patients show angiographic vasospasm only 30% develop symptomatic vasospasm defined as delayed cerebral ischemia (DCI). Early detection and management of reversible ischemia is of critical importance in patients with SAH. Using a bedside Xenon enhanced computerized tomography (Xenon-CT) scanner makes it possible to measure quantitative regional Cerebral blood flow (CBF) bedside in the neurointensive care setting and intracerebral microdialysis (MD) is a method that offers the possibility to monitor the metabolic state of the brain continuously. Here, we present results from nine SAH patients with both MD monitoring and bedside Xenon-CT measurements. CBF measurements were performed within the first 72 h following bleeding. Six out of nine patients developed DCI at a later stage. Five out of six patients who developed DCI had initial global CBF below 26 ml/100 g/min whereas one had 53 ml/100 g/min. The three patients who did not develop clinical vasospasm all had initial global CBF above 27 ml/100 g/min. High lactate/pyruvate (L/P) ratio was associated with lower CBF values in the area surrounding the catheter. Five out of nine patients had L/P ratio ≥25 and four of these patients had CBF ≤ 22 ml/100 g/min. These preliminary results suggest that patients with initially low global CBF on Xenon-CT may be more likely to develop DCI. Initially low global CBF was accompanied with metabolic disturbances determined by the MD. Most importantly, pathological findings on the Xenon-CT and MD could be observed before any clinical signs of DCI. Combining bedside Xenon-CT and MD was found to be useful and feasible. Further studies are needed to evaluate if DCI can be detected before any other signs of DCI to prevent progress to infarction.

  • 13.
    Svedung Wettervik, Teodor
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lenell, Samuel
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Nyholm, Lena
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Howells, Tim
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurosurgery.
    Decompressive craniectomy in traumatic brain injury: usage and clinical outcome in a single centre2018In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940, Vol. 160, no 2, p. 229-237Article in journal (Refereed)
    Abstract [en]

    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.

  • 14.
    Svedung-Wettervik, Teodor
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Temporal Neurophysiological Dynamics in Traumatic Brain Injury: Role of Pressure Reactivity and Optimal Cerebral Perfusion Pressure for Predicting Outcome2019In: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 36, no 11, p. 1818-1827Article in journal (Refereed)
    Abstract [en]

    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.

  • 15.
    Svedung-Wettervik, Teodor
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Howells, Timothy
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Hillered, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Nilsson, Pelle
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Engquist, Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care.
    Lewén, Anders
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Enblad, Per
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Rostami, Elham
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Enblad: Neurosurgery.
    Mild hyperventilation in traumatic brain injury - relation to cerebral energy metabolism, pressure autoregulation and clinical outcome2019In: World Neurosurgery, ISSN 1878-8750, E-ISSN 1878-8769, Vol. 133, p. e567-e575Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Hyperventilation is a controversial treatment in traumatic brain injury (TBI). Prophylactic severe hyperventilation below 3.3 kPa/25 mm Hg) is generally avoided, due to the risk of cerebral ischemia. Mild hyperventilation (arterial pCO2 within 4.0-4.5 kPa/30-34 mm Hg) in cases of intracranial hypertension is commonly used, but its safety and benefits are not fully elucidated. The aim of this study was to evaluate the use of mild hyperventilation and its relation to, cerebral energy metabolism, pressure autoregulation and clinical outcome in TBI.

    METHOD: This retrospective study was based on 120 patients with severe TBI treated at the neurointensive care unit, Uppsala university hospital, Sweden, 2008-2018. Data from cerebral microdialysis (glucose, pyruvate and lactate), arterial pCO2 and pressure reactivity index (PRx55-15) were analyzed for the first three days post-injury.

    RESULTS: Mild hyperventilation 4.0-4.5 kPa (30-34 mm Hg) was more frequently used early and the patients were gradually normoventilated. Low pCO2 was associated with slightly higher intracranial pressure and slightly lower cerebral perfusion pressure (p-value < 0.01). There was no univariate correlation between low pCO2 and worse cerebral energy metabolism. Multiple linear regression analysis showed that mild hyperventilation was associated with lower PRx55-15 day 2 (p-value = 0.03), suggesting better pressure autoregulation. Younger age and lower ICP were also associated with lower PRx55-15.

    CONCLUSIONS: These findings support the notion that mild hyperventilation is safe and may improve cerebrovascular reactivity.

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