Effects of temperature changes on cerebral biochemistry in spontaneous intracerebral hematoma

Optimizing the Time Window of Minimally Invasive Stereotactic Surgery for Intracerebral Hemorrhage Evacuation Combined with Rosiglitazone Infusion Therapy in Rabbits

OBJECTIVE

This study aimed to explore the effects of minimally invasive surgery (MIS) in combination with rosiglitazone (RSG) on intracerebral hemorrhage (ICH) and determine the optimal time window.

METHODS

An ICH rabbit model was constructed using the injection of autologous arterial blood and then treated with RSG, MIS, and MIS combined with RSG at 6, 12, 18, and 24 hours. Thereafter, rabbits that underwent different treatments were used to measure the neurological deficit score, brain water content, and glutamate content. Expression of peroxisome proliferator-activated receptor γ (PPARγ) and CD36 in the different groups was detected using real-time quantitative polymerase chain reaction and Western blotting. In addition, oxidative stress-related and inflammation-related genes were examined.

RESULTS

Brain computed tomography indicated that an ICH rabbit model was successfully established. Compared to those in the control rabbits, the neurological deficit scores, brain water content, and glutamate content in the ICH rabbits were significantly increased at each time window (P < 0.05), while they were decreased at each time window after MIS combined with RSG treatment and declined to the lowest at 6 hours. Additionally, ICH significantly upregulated PPARγ and CD36 expression (P < 0.05). Moreover, superoxide dismutase content decreased after ICH, and nitric oxide synthase 2, tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta mRNA expression was upregulated, whereas MIS combined with RSG treatment reversed the levels caused by ICH.

CONCLUSIONS

Evacuation of MIS hematoma combined with RSG infusion at an early stage (6 hours) may attenuate secondary brain damage caused by ICH by regulating the PPARγ/CD36 pathway.

The effect of the volemic and cardiac status on brain oxygenation in patients with subarachnoid hemorrhage: a bi-center cohort study

Background

Fluid management in patients after subarachnoid hemorrhage (SAH) aims at the optimization of cerebral blood flow and brain oxygenation. In this study, we investigated the effects of hemodynamic management on brain oxygenation by integrating advanced hemodynamic and invasive neuromonitoring.

Methods

This observational cohort bi-center study included data of consecutive poor-grade SAH patients who underwent pulse contour cardiac output (PiCCO) monitoring and invasive neuromonitoring. Fluid management was guided by the transpulmonary thermodilution system and aimed at euvolemia (cardiac index, CI ≥ 3.0 L/min/m²; global end-diastolic index, GEDI 680–800 mL/m²; stroke volume variation, SVV < 10%). Patients were managed using a brain tissue oxygenation (P_btO₂) targeted protocol to prevent brain tissue hypoxia (BTH, P_btO₂ < 20 mmHg). To assess the association between CI and P_btO₂ and the effect of fluid challenges on CI and P_btO₂, we used generalized estimating equations to account for repeated measurements.

Results

Among a total of 60 included patients (median age 56 [IQRs 47–65] years), BTH occurred in 23% of  the monitoring time during the first 10 days since admission. Overall, mean CI was within normal ranges (ranging from 3.1 ± 1.3 on day 0 to 4.1 ± 1.1 L/min/m² on day 4). Higher CI levels were associated with higher P_btO₂ levels (Wald = 14.2; p < 0.001). Neither daily fluid input nor fluid balance was associated with absolute P_btO₂ levels (p = 0.94 and p = 0.85, respectively) or the occurrence of BTH (p = 0.68 and p = 0.71, respectively). P_btO₂ levels were not significantly different in preload dependent patients compared to episodes of euvolemia. P_btO₂ increased as a response to fluid boluses only if BTH was present at baseline (from 13 ± 6 to 16 ± 11 mmHg, OR = 13.3 [95% CI 2.6–67.4], p = 0.002), but not when all boluses were considered (p = 0.154).

Conclusions

In this study a moderate association between increased cardiac output and brain oxygenation was observed. Fluid challenges may improve P_btO₂ only in the presence of baseline BTH. Individualized hemodynamic management requires advanced cardiac and brain monitoring in critically ill SAH patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00960-z.

Individualized blood pressure targets in the postoperative care of patients with intracerebral hemorrhage

OBJECTIVE

Recent guidelines recommend targeting a systolic blood pressure (SBP) < 140 mm Hg in the early management of patients with spontaneous intracerebral hemorrhage (ICH). The optimal SBP targets for ICH patients after hematoma evacuation (HE) remain unclear. Here, the authors aimed to define the optimal SBP range based on multimodal neuromonitoring data.

METHODS

Forty poor-grade ICH patients who had undergone HE and then monitoring of intracerebral pressure, brain tissue oxygen tension (PbtO2), and cerebral metabolism (via cerebral microdialysis [CMD]) were prospectively included. Episodes of brain tissue hypoxia (BTH) (1-hour averaged PbtO2 < 20 mm Hg) and metabolic distress (CMD-lactate/pyruvate ratio [LPR] ≥ 40) were identified and linked to corresponding parameters of hemodynamic monitoring (SBP and cerebral perfusion pressure [CPP]). Multivariable regression analysis was performed using generalized estimating equations to identify associations between SBP levels, PbtO2, and brain metabolism.

RESULTS

The mean patient age was 60 (range 51-66) years and the median [IQR] initial ICH volume was 47 [29-60] ml. In multivariable models adjusted for Glasgow Coma Scale score, probe location, ICH volume, and age, lower SBP was independently associated with a higher risk of BTH (≤ 120 mm Hg: adjusted OR 2.9, p = 0.007; 120-130 mm Hg: adj OR 2.4, p = 0.002; 130-140 mm Hg: adj OR 1.6, p = 0.017) compared to a reference range of 140-150 mm Hg at the level of the foramen interventriculare Monroi, which corresponded to a CPP of 70-80 mm Hg and SBP levels between 150 and 160 mm Hg at the heart level. After exclusion of episodes with mitochondrial dysfunction, SBP targets < 140 mm Hg were associated with higher odds of cerebral metabolic distress (≤ 130 mm Hg: OR 2.5, p = 0.041; 130-140 mm Hg: OR 2.3, p = 0.033). Patients with a modified Rankin Scale score ≥ 5 at neurological ICU discharge more often exhibited BTH than patients with better outcomes (51% vs 10%, p = 0.003).

CONCLUSIONS

These data suggest that lower SPB and CPP levels are associated with a higher risk for BTH. Further studies are needed to evaluate whether a higher SPB target may prevent BTH and improve outcomes.

How to diagnose delayed cerebral ischaemia and symptomatic vasospasm and prevent cerebral infarction in patients with subarachnoid haemorrhage

PURPOSE OF REVIEW

Delayed cerebral ischaemia (DCI) complicates the clinical course of patients with subarachnoid haemorrhage (SAH) in 20--30% and substantially worsens outcome. In this review, we describe a multimodal diagnostic approach based on underlying mechanisms of DCI and provide treatment options with a special focus on the most recently published literature.

RECENT FINDINGS

Symptomatic vasospasm refers to clinical deterioration in the presence of vasospasm whereas DCI constitutes multiple causes. Pathophysiologic mechanisms underlying DCI range beyond large vessel vasospasm from neuroinflammation, to microthromboembolism, impaired cerebral autoregulation, cortical spreading depolarizations and many others. The current definition of DCI can be challenged by these mechanisms. We propose a pragmatic approach using a combination of clinical examination, cerebral ultrasonography, neuroimaging modalities and multimodal neuromonitoring to trigger therapeutic interventions in the presence of DCI. In addition to prophylactic nimodipine and management principles to improve oxygen delivery and decrease the brain metabolic demand, other specific interventions include permissive hypertension, intra-arterial application of calcium channel blockers and in selected patients angioplasty.

SUMMARY

The complex pathophysiology underlying DCI urges for a multimodal diagnostic approach triggering targeted interventions. Novel treatment concepts still have to be proven in large trials.

The Importance of PbtO2 Probe Location for Data Interpretation in Patients with Intracerebral Hemorrhage

Background/objective

Monitoring of brain tissue oxygen tension (P_btO₂) provides insight into brain pathophysiology after intracerebral hemorrhage (ICH). Integration of probe location is recommended to optimize data interpretation. So far, little is known about the importance of P_btO₂ catheter location in ICH patients.

Methods

We prospectively included 40 ICH patients after hematoma evacuation (HE) who required P_btO₂-monitoring. P_btO₂-probe location was evaluated in all head computed tomography (CT) scans within the first 6 days after HE and defined as location in the healthy brain tissue or perilesional when the catheter tip was located within 1 cm of a focal lesion (hypodense or hyperdense). Generalized estimating equations were used to investigate levels of P_btO₂ in relation to different probe locations.

Results

Patients were 60 [51–66] years old and had a median ICH-volume of 47 [29–60] mL. Neuromonitoring probes remained for a median of 6 [2–11] days. P_btO₂-probes were located in healthy brain tissue in 18/40 (45%) patients and in perilesional brain tissue in 22/40 (55%) patients. In the acute phase after HE (0–72 h), P_btO₂ levels were significantly lower (21 ± 12 mmHg vs. 29 ± 10 mmHg, p = 0.010) and brain tissue hypoxia (BTH) was more common in the perilesional area as compared to healthy brain tissue (46% vs. 19%, adjOR 4.0, 95% CI 1.54–10.58, p = 0.005). Episodes of BTH significantly decreased over time in patients with probes in perilesional location (p = 0.001) but remained stable in normal appearing area (p = 0.485). A significant association between BTH and poor functional outcome was only found when probes were located in the perilesional brain tissue (adjOR 6.6, 95% CI 1.3–33.8, p = 0.023).

Conclusions

In the acute phase, BTH was more common in the perilesional area compared to healthy brain tissue. The improvement of BTH in the perilesional area over time may be the result of targeted treatment interventions and tissue regeneration. Due to the localized measurement of invasive neuromonitoring devices, integration of probe location in the clinical management of ICH patients and in research protocols seems mandatory.

Perihematomal glutamate level is associated with the blood-brain barrier disruption in a rabbit model of intracerebral hemorrhage

Objective

To observe the relationship between the perihematomal glutamate levels and the blood–brain barrier (BBB) permeability in a rabbit model of intracerebral hemorrhage (ICH).

Methods

Seventy-two rabbits were randomly divided into an intracerebral hemorrhage (ICH) model group and a normal control (NC) group, and each group of 36 rabbits was subsequently divided into 6, 12, 18, 24, 48 and 72 h groups (n = 6 each). An ICH model was induced by stereotactic injection of autologous, arterial, non-anticoagulated blood into rabbit basal ganglia. The same procedures were performed in the NC group, but blood was not injected. The rabbits were sacrificed at specific time points after the experiment began depending on their group. Perihematomal brain tissues were collected to determine glutamate levels, BBB permeability and brain water content (BWC).

Results

All of the assessed parameters were increased 6 hour after blood infusion and continued to gradually increase, peaking at 48 hours. Differences were observed when ICH values were compared with those of the NC group (p < 0.05).

Conclusions

Perihematomal glutamate increased significantly after ICH. High levels of glutamate are closely associated with BBB disruption and the brain edema. Therefore, glutamate may play an important role in the pathogenesis of secondary brain injury after (ICH).

Minimally invasive procedures for intracerebral hematoma evacuation in early stages decrease perihematomal glutamate level and improve neurological function in a rabbit model of ICH

INTRODUCTION

To observe the effects of performing a minimally invasive procedure at different stages after intracerebral hemorrhage (ICH) on perihematomal glutamate level and neurological function.

METHODS

Forty-eight rabbits were randomly placed into a model control group (MC group, 24 rabbits) or a minimally invasive group (MI group, 24 rabbits). An ICH model was established in all of the animals. In the MI group, the ICH was evacuated by minimally invasive procedures in 6h (6 rabbits), 12h (6 rabbits), 18h (6 rabbits) and 24h (6 rabbits) after the ICH model was successfully induced. All of the animals were sacrificed within 48h after the hematoma was evacuated by surgery. A neurological deficit score was determined, and the perihematomal glutamate level and the BBB permeability were measured.

RESULTS

The neurological deficit score, perihematomal glutamate level and BBB permeability of the MI group were decreased significantly compared with the MC group. Performing the minimally invasive procedures in 6-12 h after ICH showed the most significant decreases of the glutamate level, BBB permeability and neurological deficit score.

CONCLUSIONS

The optimal time window of performing the minimally invasive procedures for the intracerebral hematoma evacuation might be within 6-12 h after hemorrhage.

The pathophysiological time window study of performing minimally invasive procedures for the intracerebral hematoma evacuation in rabbit

The objective of this study was to observe the pathophysiological time window of performing minimally invasive procedures for the intracerebral hematoma evacuation. Thirty-six rabbits were randomly placed in either a normal control group (NC group, 6 rabbits), a model control group (MC group, 6 rabbits) or a minimally invasive group (MI group, 24 rabbits). A model of intracerebral hemorrhage (ICH) was established in the MC and MI groups. In the MI group, the intracerebral hematoma was evacuated by stereotactic minimally invasive procedures over 6h (6 rabbits), 12h (6 rabbits), 18 h (6 rabbits) and 24h (6 rabbits), following successful induction of ICH. All of the animals in each group were sacrificed 48 h after the successful induction of ICH. Perihematomal brain tissues were removed to determine the glutamate level, BBB permeability and brain water content (BWC). The perihematomal glutamate level, BBB permeability and the BWC in the MI group were significantly decreased compared with those of the MC group. Performing minimally invasive procedures for evacuation of ICH in 6h showed the most remarkable decrease of the glutamate level, BBB permeability and BWC, followed by a significant difference observed at 12h within the MI subgroups. Performing minimally invasive procedures in early stages after ICH for the hematoma evacuation could decrease the perihematomal glutamate level, BBB permeability and BWC significantly. The pathophysiological time window of minimally invasive procedures for hematoma evacuation might be 6-12h after hemorrhage.

A critical appraisal of experimental intracerebral hemorrhage research

The likelihood of translating therapeutic interventions for stroke rests on the quality of preclinical science. Given the limited success of putative treatments for ischemic stroke and the reasons put forth to explain it, we sought to determine whether such problems hamper progress for intracerebral hemorrhage (ICH). Approximately 10% to 20% of strokes result from an ICH, which results in considerable disability and high mortality. Several animal models reproduce ICH and its underlying pathophysiology, and these models have been widely used to evaluate treatments. As yet, however, none has successfully translated. In this review, we focus on rodent models of ICH, highlighting differences among them (e.g., pathophysiology), issues with experimental design and analysis, and choice of end points. A Pub Med search for experimental ICH (years: 2007 to 31 July 2011) found 121 papers. Of these, 84% tested neuroprotectants, 11% tested stem cell therapies, and 5% tested rehabilitation therapies. We reviewed these to examine study quality (e.g., use of blinding procedures) and choice of end points (e.g., behavioral testing). Not surprisingly, the problems that have plagued the ischemia field are also prevalent in ICH literature. Based on these data, several recommendations are put forth to facilitate progress in identifying effective treatments for ICH.

Minimally invasive procedures for evacuation of intracerebral hemorrhage reduces perihematomal glutamate content, blood-brain barrier permeability and brain edema in rabbits

BACKGROUND

To observe the effects of the minimally invasive removal of an intracerebral hematoma on the glutamate concentration, blood-brain barrier (BBB) permeability and brain water content in the brain tissue surrounding the hematoma and to provide a theoretical basis for minimally invasive removal of intracerebral hematomas.

METHODS

Thirty rabbits (2.8-3.4 kg body weight) were selected to establish a model of intracerebral hemorrhage, and they were randomly divided into a model control group and a minimally invasive group after the model was prepared successfully. The intracerebral hematoma was evacuated by stereotactic procedures in minimally invasive group 6 h after the model was established. The glutamate content, the permeability of the BBB and the brain water content in perihematomal brain tissues were determined and compared between the two groups.

RESULTS

The glutamate content, the permeability of the BBB and the brain water content in the perihematomal brain tissues were significantly decreased compared to the model control group 1, 3, and 7 days after the minimally invasive removal of the intracerebral hematoma.

CONCLUSIONS

Minimally invasive surgery for removal of an intracerebral hematoma could significantly reduce the glutamate content, BBB permeability and the brain water content in perihematomal brain tissues.

Interstitium: the next diagnostic and therapeutic platform in critical illness

BACKGROUND

For decades we have been testing blood either ex vivo or else placing monitors directly in the bloodstream to "see" what might be going on in tissues. In the last 20 yrs, conceptual and practical advances in interstitial monitoring have begun to challenge traditional approaches. In this review we explore how interstitial monitoring might be used as a platform for future diagnostics and therapy in critical illness.

RESULTS

From a diagnostic perspective, interstitial analysis has been instructive about the pathophysiology of critical illness. Valuable insights have been gained into the pathophysiology of critical illness. To this end, examples from the areas of interstitial oxygenation and acid base, endocrine pathophysiology, and head injury monitoring have been used. From a therapeutic perspective, the main focus has been on antibiotic therapy and an improved understanding of pharmacokinetics and pharmacodynamics in critical illness.

CONCLUSIONS

Monitoring of the interstitium is feasible and can be achieved through minimally invasive techniques. It has improved the understanding of the pathophysiology of critical illness, holds potential in the diagnosis and management of sepsis, may allow early prediction of organ deterioration, and finally offers the possibility of reduction of blood testing and minimizing blood loss. While all of these hold promise, randomized trials will need to be conducted based on interstitial end points rather than plasma end points. This will pave the way for a more rational approach to the therapy of critically ill patients.