Search Results

You are looking at 1 - 10 of 17 items for

  • Author or Editor: Per Enblad x
Clear All Modify Search
Restricted access

Fartein Velle, Anders Lewén, Timothy Howells, Per Enblad and Pelle Nilsson

OBJECTIVE

Refractory intracranial pressure (ICP) hypertension following traumatic brain injury (TBI) is a severe condition that requires potentially harmful treatment strategies such as barbiturate coma. However, the use of barbiturates may be restricted due to concerns about inducing multiorgan system complications related to the therapy. The purpose of this study was to evaluate the outcome and occurrence of treatment-related complications to barbiturate coma treatment in children with refractory intracranial hypertension (RICH) due to TBI in a modern multimodality neurointensive care unit (NICU).

METHODS

The authors conducted a retrospective cohort study of 21 children ≤ 16 years old who were treated in their NICU between 2005 and 2015 with barbiturate coma for RICH following TBI. Demographic and clinical data were acquired from patient records and physiological data from digital monitoring system files.

RESULTS

The median age of these 21 children was 14 years (range 2–16 years) and at admission the median Glasgow Coma Scale score was 7 (range 4–8). Barbiturate coma treatment was added due to RICH at a median of 46 hours from trauma and had a median duration of 107 hours. The onset of barbiturate coma resulted in lower ICP values, lower pulse amplitudes on the ICP curve, and decreased amount of A-waves. No major disturbances in blood gases, liver and kidney function, or secondary insults were observed during this period. Outcome 1 year later revealed a median Glasgow Outcome Scale score of 5 (good recovery), however on the King’s Outcome Scale for Childhood Head Injury, the median was 4a (moderate disability).

CONCLUSIONS

The results of this study indicate that barbiturate coma, when used in a modern NICU, is an effective means of lowering ICP without causing concomitant severe side effects in children with RICH and was compatible with good long-term outcome.

Restricted access

Kai Arnell, Per Enblad, Tomas Wester and Jan Sjölin

Object

There are no randomized studies comparing the efficacy of different antibiotic regimens for the treatment of cerebrospinal fluid (CSF) shunt infections, and in the studies that have been reported, efficacy data are limited. The aim of this study was therefore to report the authors' experience using a specific protocol for the management of shunt infections in children. Standard treatment included a two-stage procedure involving externalization of the ventricular catheter in combination with intraventricular and systemic administration of antibiotic medication followed by shunt replacement. Intraventricular treatment consisted of daily instillations of vancomycin or gentamicin with trough concentrations held at high levels of 7 to 17 mg/L for both antibiotic agents.

Methods

During a 13-year study period, the authors treated 34 consecutive intraventricular shunt infections in 30 children. Infections with coagulase-negative staphylococci predominated, and Gram-negative bacterial infection occurred in five children. Ten of the children were initially treated with intravenous antibiotic therapy for at least 3 days, but this treatment did not sterilize the CSF. After externalization of the ventricular catheter, high-dose intraventricular treatment was given for a median of 8 days (range 3–17 days) before shunt replacement.

Results

The CSF was found to be sterile (cultures were negative for bacteria) in one of three, seven of eight, 20 of 20, and six of six cases after 1, 2, 3, and more than 3 days' treatment, respectively. In no case was any subsequent culture positive after a negative result had been obtained. Clinical symptoms resolved in parallel with the sterilization of the CSF. There were no relapses or deaths during the 6-month follow-up period, and there have been none as of April 2007.

Conclusions

Despite the ventricular catheter being left in place and the short duration of therapy, the treatment regimen described by the authors resulted in quick sterilization of the CSF, a low relapse rate, and survival of all patients in this series.

Restricted access

Lennart Persson, Johann Valtysson, Per Enblad, Per-Erik Wärme, Kristina Cesarini, Anders Lewén and Lars Hillered

✓ The authors have developed a method for routine monitoring of disturbances in brain energy metabolism and extracellular levels of excitatory amino acids using intracerebral microdialysis in 10 patients with subarachnoid hemorrhage. Microdialysis was conducted for periods ranging from 6 to 11 days after ictus. Altogether, 16,054 chemical analyses from 1647 dialysate samples were performed. Concentrations of the energy-related substances lactate, pyruvate, glucose, and hypoxanthine were measured, and the lactate/pyruvate ratio was calculated. The excitatory amino acids glutamate and aspartate were measured. The microdialysis data were matched with computerized tomography findings, clinical course, and outcome. The results support the concepts that microdialysis is a promising tool for chemical monitoring of the human brain and that extracellular fluid levels of lactate, lactate/pyruvate ratio, glucose, hypoxanthine, and glutamate are useful markers of disturbances in brain energy metabolism in neurointensive care patients. These results have generated a working hypothesis that the pattern of these extracellular markers may help differentiate between various causes of energy perturbations, such as hypoxia and different degrees of ischemia. The correlation between the dialysate levels of excitatory amino acids and outcome supports the concept of glutamate receptor overactivation in acute human brain injury.

Full access

Sami Abu Hamdeh, Niklas Marklund, Anders Lewén, Tim Howells, Raili Raininko, Johan Wikström and Per Enblad

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.

Restricted access

Peter Frykholm, Lars Hillered, Bengt Långström, Lennart Persson, Johann Valtysson and Per Enblad

Object. Changes in lactate and glucose levels in the brain may be used to monitor a dynamic ischemic process. The authors related extracellular concentrations of glucose and lactate to regional cerebral blood flow (rCBF) and cerebral metabolic rate of oxygen (CMRO2) in a model of ischemia.

Methods. Transient (2 hours) middle cerebral artery occlusion (MCAO) was performed in eight macaque monkeys. Extracellular measurements of glucose and lactate levels using microdialysis (two probes in each brain) and sequential positron emission tomography measurements were performed during MCAO and reperfusion. Glucose and lactate levels were related to rCBF and CMRO2 as well as the pathophysiological categories of severe ischemia and penumbra.

In probe regions characterized by severe ischemia, there were significant changes in glucose and lactate levels and the lactate/glucose ratio. In probe regions distinguished by penumbra, only lactate levels increased significantly and, in general, the changes were smaller and transient. This difference between severe ischemic and penumbral regions was significant for all microdialysis parameters.

There was a significant correlation between glucose, and CBF and CMRO2. Lactate concentration was correlated with CMRO2.

Conclusions. Extracellular glucose levels might be limited by rCBF, whereas lactate levels were more related to CMRO2. Lactate concentration is a better marker of irreversible ischemia than glucose concentration, although near-zero levels of glucose during MCAO probably signals near-complete cessation of rCBF. In situations with elevated lactate levels, glucose may help to discriminate between partial and severe ischemia.

Restricted access

Henrik Engquist, Anders Lewén, Lars Hillered, Elisabeth Ronne-Engström, Pelle Nilsson, Per Enblad and Elham Rostami

OBJECTIVE

Despite the multifactorial pathogenesis of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH), augmentation of cerebral blood flow (CBF) is still considered essential in the clinical management of DCI. The aim of this prospective observational study was to investigate cerebral metabolic changes in relation to CBF during therapeutic hypervolemia, hemodilution, and hypertension (HHH) therapy in poor-grade SAH patients with DCI.

METHODS

CBF was assessed by bedside xenon-enhanced CT at days 0–3, 4–7, and 8–12, and the cerebral metabolic state by cerebral microdialysis (CMD), analyzing glucose, lactate, pyruvate, and glutamate hourly. At clinical suspicion of DCI, HHH therapy was instituted for 5 days. CBF measurements and CMD data at baseline and during HHH therapy were required for study inclusion. Non-DCI patients with measurements in corresponding time windows were included as a reference group.

RESULTS

In DCI patients receiving HHH therapy (n = 12), global cortical CBF increased from 30.4 ml/100 g/min (IQR 25.1–33.8 ml/100 g/min) to 38.4 ml/100 g/min (IQR 34.2–46.1 ml/100 g/min; p = 0.006). The energy metabolic CMD parameters stayed statistically unchanged with a lactate/pyruvate (L/P) ratio of 26.9 (IQR 22.9–48.5) at baseline and 31.6 (IQR 22.4–35.7) during HHH. Categorized by energy metabolic patterns during HHH, no patient had severe ischemia, 8 showed derangement corresponding to mitochondrial dysfunction, and 4 were normal. The reference group of non-DCI patients (n = 11) had higher CBF and lower L/P ratios at baseline with no change over time, and the metabolic pattern was normal in all these patients.

CONCLUSIONS

Global and regional CBF improved and the cerebral energy metabolic CMD parameters stayed statistically unchanged during HHH therapy in DCI patients. None of the patients developed metabolic signs of severe ischemia, but a disturbed energy metabolic pattern was a common occurrence, possibly explained by mitochondrial dysfunction despite improved microcirculation.

Restricted access

Mendel Castle-Kirszbaum, Scott Ayton and Tony Goldschlager

Restricted access

Maria Zetterling, Lars Hillered, Per Enblad, Torbjörn Karlsson and Elisabeth Ronne-Engström

Object

The aim in the present investigation was to study the relation between brain interstitial and systemic blood glucose concentrations during the acute phase after subarachnoid hemorrhage (SAH). The authors also evaluated the effects of insulin administration on local brain energy metabolism.

Methods

Nineteen patients with spontaneous SAH were prospectively monitored with intracerebral microdialysis (MD). The relation between plasma glucose and MD-measured interstitial brain glucose concentrations as well as the temporal pattern of MD glucose, lactate, pyruvate, glutamate, and glycerol was studied for 7 days after SAH. Using a target plasma glucose concentration of 5–10 mmol/L, the effect of insulin injection was also evaluated.

Results

The mean (± SD) correlation coefficient between plasma glucose and MD glucose was 0.27 ± 0.27 (p = 0.0005), with a high degree of individual variation. Microdialysis glucose, the MD/plasma glucose ratio, and MD glutamate concentrations decreased in parallel with a gradual increase in MD pyruvate and MD lactate concentrations. There were no significant changes in the MD L/P ratio or MD glycerol levels. Insulin administration induced a decrease in MD glucose and MD pyruvate.

Conclusions

After SAH, there was a positive correlation between plasma and MD glucose concentrations with a high degree of individual variation. A gradual decline in MD glucose and the MD/plasma glucose ratio and an increase in MD pyruvate and MD lactate concentrations during the 1st week after SAH suggest a transition to a hyperglycolytic state with increased cerebral glucose consumption. The administration of insulin was related to a lowering of MD glucose and MD pyruvate, often to low levels even though plasma glucose values remained above 6 mmol/L. After SAH, the administration of insulin could impede the glucose supply of the brain.

Restricted access

Tim Howells, Kristin Elf, Patricia A. Jones, Elisabeth Ronne-Engström, Ian Piper, Pelle Nilsson, Peter Andrews and Per Enblad

Object. The aim of this study was to compare the effects of two different treatment protocols on physiological characteristics and outcome in patients with brain trauma. One protocol was primarily oriented toward reducing intracranial pressure (ICP), and the other primarily on maintaining cerebral perfusion pressure (CPP).

Methods. A series of 67 patients in Uppsala were treated according to a protocol aimed at keeping ICP less than 20 mm Hg and, as a secondary target, CPP at approximately 60 mm Hg. Another series of 64 patients in Edinburgh were treated according to a protocol aimed primarily at maintaining CPP greater than 70 mm Hg and, secondarily, ICP less than 25 mm Hg for the first 24 hours and 30 mm Hg subsequently.

The ICP and CPP insults were assessed as the percentage of monitoring time that ICP was greater than or equal to 20 mm Hg and CPP less than 60 mm Hg, respectively. Pressure reactivity in each patient was assessed based on the slope of the regression line relating mean arterial blood pressure (MABP) to ICP. Outcome was analyzed at 6 months according to the Glasgow Outcome Scale (GOS).

The prognostic value of secondary insults and pressure reactivity was determined using linear methods and a neural network. In patients treated according to the CPP-oriented protocol, even short durations of CPP insults were strong predictors of death. In patients treated according to the ICP-oriented protocol, even long durations of CPP insult—mostly in the range of 50 to 60 mm Hg—were significant predictors of favorable outcome (GOS Score 4 or 5). Among those who had undergone ICP-oriented treatment, pressure-passive patients (MABP/ICP slope ≥ 0.13) had a better outcome. Among those who had undergone CPP-oriented treatment, the more pressure-active (MABP/ICP slope < 0.13) patients had a better outcome.

Conclusions. Based on data from this study, the authors concluded that ICP-oriented therapy should be used in patients whose slope of the MABP/ICP regression line is at least 0.13, that is, in pressure-passive patients. If the slope is less than 0.13, then hypertensive CPP therapy is likely to produce a better outcome.