Argon gas poisoning leading to persistent memory impairment: A 2-year case report.

RATIONALE: Argon gas poisoning is an often overlooked yet critical public health concern with the potential for severe and persistent neurological consequences. Current treatment protocols primarily focus on acute-phase management, but a comprehensive understanding of the long-term neurological effects remains incomplete. PATIENT CONCERNS: A 22-year-old male worker was found unconscious in the furnace room of an argon production facility. After regaining consciousness, he presented with symptoms of dizziness, headache, fatigue, and irritability. Neurological examination revealed impairments in both recent and remote memory, notably pronounced short-term memory deficits and reduced arithmetic skills. DIAGNOSIS: Argon gas poisoning, hypoxic encephalopathy, and mild hepatic and renal dysfunction. INTERVENTIONS: Upon admission, symptomatic supportive measures included oxygen therapy via nasal cannula (3 L/min), daily hyperbaric oxygen therapy (1.5 ATA, 60 minutes), oral neurotrophic methylcobalamin (0.5 mg, 3 times daily), and intravenous vitamin C infusion (2 g daily) to scavenge oxygen free radicals. OUTCOME: A 2-year telephone follow-up indicated persistent short-term memory impairment, particularly with memorizing numbers. In a memory test, he achieved a digit span forward of 5 but a digit span backward of 2, indicating impairment. Despite these challenges, his daily life and work performance remained largely unaffected. LESSON: This case offers valuable insights into the biological mechanisms underlying prolonged neurological sequelae following asphyxiating gas exposure, specifically the persistent impairment of hippocampal function.

Novel perfluorocarbon-based oxygenation therapy alleviates Post-SAH hypoxic brain injury by inhibiting HIF-1α.

In comparison to other stroke types, subarachnoid hemorrhage (SAH) is characterized by an early age of onset and often results in poor prognosis. The inadequate blood flow at the site of the lesion leads to localized oxygen deprivation, increased level of hypoxia-inducible factor-1α (HIF-1α), and triggers inflammatory responses and oxidative stress, ultimately causing hypoxic brain damage. Despite the potential benefits of oxygen (O2) administration, there is currently a lack of efficient focal site O2 delivery following SAH. Conventional clinical O2 supply methods, such as transnasal oxygenation and hyperbaric oxygen therapy, do not show the ideal therapeutic effect in severe SAH patients. The perfluorocarbon oxygen carrier (PFOC) demonstrates efficacy in transporting O2 and responding to elevated levels of CO2 at the lesion site. Through cellular experiments, we determined that PFOC oxygenation serves as an effective therapeutic approach in inhibiting hypoxia. Furthermore, our animal experiments showed that PFOC oxygenation outperforms O2 breathing, leading to microglia phenotypic switching and the suppression of inflammatory response via the inhibition of HIF-1α. Therefore, as a new type of O2 therapy after SAH, PFOC oxygenation can effectively reduce hypoxic brain injury and improve neurological function.

Hyperbaric oxygen treatment in delayed post-hypoxic encephalopathy following inhalation of liquefied petroleum gas: a case report.

Delayed post-hypoxic encephalopathy can occur after an episode of anoxia or hypoxia. Symptoms include apathy, confusion, and neurological deficits. We describe a 47-year-old male patient who inhaled gas from a kitchen stove liquid petroleum gas cylinder. He was diagnosed with hypoxic ischaemic encephalopathy 12 hours after his emergency department admission. He received six sessions of hyperbaric oxygen treatment (HBOT) and was discharged in a healthy state after six days. Fifteen days later, he experienced weakness, loss of appetite, forgetfulness, depression, balance problems, and inability to perform self-care. One week later, he developed urinary and fecal incontinence and was diagnosed with post-hypoxic encephalopathy. After 45 days from the onset of symptoms, he was referred to the Underwater and Hyperbaric Medicine Department for HBOT. The patient exhibited poor self-care and slow speech rate, as well as ataxic gait and dysdiadochokinesia. Hyperbaric oxygen was administered for twenty-four sessions, which significantly improved the patient's neurological status with only hypoesthesia in the left hand remaining at the end of treatment. Hyperbaric oxygen has been reported as successful in treating some cases of delayed neurological sequelae following CO intoxication. It is possible that HBO therapy may also be effective in delayed post-hypoxic encephalopathy from other causes. This may be achieved through mechanisms such as transfer of functional mitochondria to the injury site, remyelination of damaged neurons, angiogenesis and neurogenesis, production of anti-inflammatory cytokines, and balancing of inflammatory and anti-inflammatory cytokines.

[Emergency Resuscitation Techniques:Airway, Breathing, and Circulation].

Cardiac arrest causes cerebral anoxia, resulting in loss of consciousness within seconds and irreversible brain damage within 3-5 min. Emergency resuscitation is generally performed on patients in cardiopulmonary or near-cardiopulmonary arrest, i.e., life-threatening conditions, and requires rapid stabilization of the airway, breathing, and circulation(or "ABC")to maintain cerebral perfusion. Generally, the ABC approach represents the order of medical treatment for critically ill patients. It provides supportive care(resuscitation)after ensuring the flow of oxygen supply necessary to sustain life. The most important goal in emergency resuscitation is to ensure a secure airway, without which, resuscitation is hopeless. Clinicians should be prepared daily to avoid missing any opportunity to ensure a secure airway. Even in cardiac arrest, high-quality cardiopulmonary resuscitation is necessary to reduce the duration of cerebral anoxia. An algorithm for this high-quality cardiopulmonary resuscitation is described in this article.

Therapeutic hypothermia in neonatal hypoxic encephalopathy: A systematic review and meta-analysis.

Background: Therapeutic hypothermia (TH) is regarded as the most efficacious therapy for neonatal hypoxic encephalopathy. However, limitations in previous systematic reviews and the publication of new data necessitate updating the evidence. We conducted this up-to-date systematic review to evaluate the effects of TH in neonatal encephalopathy on clinical outcomes. Methods: In this systematic review and meta-analysis, we searched Medline, Cochrane Library, Embase, LIVIVO, Web of Science, Scopus, CINAHL, major trial registries, and grey literature (from inception to October 31, 2021), for randomized controlled trials (RCT) comparing TH vs normothermia in neonatal encephalopathy. We included RCTs enrolling neonates (gestation ≥35 weeks) with perinatal asphyxia and encephalopathy, who received either TH (temperature ≤34°C) initiated within 6 hours of birth for ≥48 hours, vs no cooling. We excluded non-RCTs, those with delayed cooling, or cooling to >34°C. Two authors independently appraised risk-of-bias and extracted data on mortality and neurologic disability at four time points: neonatal (from randomization to discharge/death), infancy (18-24 months), childhood (5-10 years), and long-term (>10 years). Other outcomes included seizures, EEG abnormalities, and MRI findings. Summary data from published RCTs were pooled through fixed-effect meta-analysis. Results: We identified 36 863 citations and included 39 publications representing 29 RCTs with 2926 participants. Thirteen studies each had low, moderate, and high risk-of-bias. The pooled risk ratios (95% confidence interval, CI) were as follows: neonatal mortality: 0.87 (95% CI = 0.75, 1.00), n = 2434, I2 = 38%; mortality at 18-24 months: 0.88 (95% CI = 0.78, 1.01), n = 2042, I2 = 51%; mortality at 5-10 years: 0.81 (95% CI = 0.62, 1.04), n = 515, I2 = 59%; disability at 18-24 months: 0.62 (95% CI = 0.52, 0.75), n = 1440, I2 = 26%; disability at 5-10 years: 0.68 (95% CI = 0.52, 0.90), n = 442, I2 = 3%; mortality or disability at 18-24 months: 0.78 (95% CI = 0.72, 0.86), n = 1914, I2 = 54%; cerebral palsy at 18-24 months: 0.63 (95% CI = 0.50, 0.78), n = 1136, I2 = 39%; and childhood cerebral palsy: 0.63 (95% CI = 0.46, 0.85), n = 449, I2 = 0%. Some outcomes showed significant differences by study-setting; the risk ratio (95% CI) for mortality at 18-24 months was 0.79 (95% CI = 0.66,0.93), n = 1212, I2 = 7% in high-income countries, 0.67 (95% CI = 0.41, 1.09), n = 276, I2 = 0% in upper-middle-income countries, and 1.18 (95% CI = 0.94, 1.47), n = 554, I2 = 75% in lower-middle-income countries. The corresponding pooled risk ratios for 'mortality or disability at 18-24 months' were 0.77 (95% CI = 0.69, 0.86), n = 1089, I2 = 0%; 0.56 (95% CI = 0.41, 0.78), n = 276, I2 = 30%; and 0.92 (95% CI = 0.77, 1.09), n = 549, I2 = 86% respectively. Trials with low risk of bias showed risk ratio of 0.97 (95% CI = 0.80, 1.16, n = 1475, I2 = 62%) for neonatal mortality, whereas trials with higher risk of bias showed 0.71 (95% CI = 0.55, 0.91), n = 959, I2 = 0%. Likewise, risk ratio for mortality at 18-24 months was 0.96 (95% CI = 0.83, 1.13), n = 1336, I2 = 58% among low risk-of-bias trials, but 0.72 (95% CI = 0.56, 0.92), n = 706, I2 = 0%, among higher risk of bias trials. Conclusions: Therapeutic hypothermia for neonatal encephalopathy reduces neurologic disability and cerebral palsy, but its effect on neonatal, infantile and childhood mortality is uncertain. The setting where it is implemented affects the outcomes. Low(er) quality trials overestimated the potential benefit of TH.

Early cerebral hypoxia in extremely preterm infants and neurodevelopmental impairment at 2 year of age: A post hoc analysis of the SafeBoosC II trial.

BACKGROUND: The SafeBoosC II, randomised clinical trial, showed that the burden of cerebral hypoxia was reduced with the combination of near infrared spectroscopy and a treatment guideline in extremely preterm infants during the first 72 hours after birth. We have previously reported that a high burden of cerebral hypoxia was associated with cerebral haemorrhage and EEG suppression towards the end of the 72-hour intervention period, regardless of allocation. In this study we describe the associations between the burden of cerebral hypoxia and the 2-year outcome. METHODS: Cerebral oxygenation was continuously monitored from 3 to 72 hours after birth in 166 extremely preterm infants. At 2 years of age 114 of 133 surviving children participated in the follow-up program: medical examination, Bayley II or III test and the parental Ages and Stages Questionnaire. The infants were classified according to the burden of hypoxia: within the first three quartiles (n = 86, low burden) or within in the 4th quartile (n = 28, high burden). All analyses were conducted post hoc. RESULTS: There were no statistically significant differences between the quantitative assessments of neurodevelopment in the groups of infants with the low burden of cerebral hypoxia versus the group of infants with the high burden of cerebral hypoxia. The infants in the high hypoxia burden group had a higher-though again not statistically significant-rate of cerebral palsy (OR 2.14 (0.33-13.78)) and severe developmental impairment (OR 4.74 (0.74-30.49). CONCLUSIONS: The burden of cerebral hypoxia was not significantly associated with impaired 2-year neurodevelopmental outcome in this post-hoc analysis of a feasibility trial.

Brain tissue oxygenation guided therapy and outcome in non-traumatic subarachnoid hemorrhage.

Brain hypoxia can occur after non-traumatic subarachnoid hemorrhage (SAH), even when levels of intracranial pressure (ICP) remain normal. Brain tissue oxygenation (PbtO2) can be measured as a part of a neurological multimodal neuromonitoring. Low PbtO2 has been associated with poor neurologic recovery. There is scarce data on the impact of PbtO2 guided-therapy on patients' outcome. This single-center cohort study (June 2014-March 2020) included all patients admitted to the ICU after SAH who required multimodal monitoring. Patients with imminent brain death were excluded. Our primary goal was to assess the impact of PbtO2-guided therapy on neurological outcome. Secondary outcome included the association of brain hypoxia with outcome. Of the 163 patients that underwent ICP monitoring, 62 were monitored with PbtO2 and 54 (87%) had at least one episode of brain hypoxia. In patients that required treatment based on neuromonitoring strategies, PbtO2-guided therapy (OR 0.33 [CI 95% 0.12-0.89]) compared to ICP-guided therapy had a protective effect on neurological outcome at 6 months. In this cohort of SAH patients, PbtO2-guided therapy might be associated with improved long-term neurological outcome, only when compared to ICP-guided therapy.

Microalgae-based photosynthetic strategy for oxygenating avascularised mouse brain tissue - An in vitro proof of concept study.

Hypoxic brain injury is a leading cause of loss of quality of life globally for which there are currently no effective treatments. There has been increasing interest in incorporating photosynthesising agents into hypoxic tissue as a mechanism for in situ oxygen delivery, independent of vascular perfusion. To date this has not been tested in the brain. The oxygen production capacity of Chlamydomonas reinhardtii microalgal cultures was measured in artificial cerebrospinal fluid (aCSF) in benchtop assays and in cortical slices in situ. Cortical slice function was quantified by measuring the length, frequency and amplitude of seizure-like event (SLE) activity - in conventionally oxygenated aCSF, C. reinhardtii cultures, unoxygenated and deoxygenated aCSF. The possibility of direct toxic algal effects was investigated by exposing slices to cultures for 5 h. An oxygen level of 25 mg.L-1 was achieved with C. reinhardtii in no-Mg aCSF. Slice SLE function was preserved in C. reinhardtii, without the need for supplemental oxygen. In contrast, functional parameters deteriorated in unoxygenated and deoxygenated aCSF. In the former, there was a 66% reduction in SLE frequency and a 37% reduction in event amplitude. In the latter, SLE activity ceased completely. No toxic algae effects were seen in slices exposed to cultures for 5 h. These results confirm that C. reinhardtii oxygenation of aCSF can sustain cortical network activity - without tissue toxicity for the normal lifespan of an acute cortical slice. This study shows promise for the concept of photosynthesis as a mechanism for providing oxygen to rescue ischaemic avascularised brain tissue.

Impact of neonatal anoxia and hypothermic treatment on development and memory of rats.

Therapeutic hypothermia (TH) is well established as a standard treatment for term and near-term infants. However, therapeutic effects of hypothermia following neonatal anoxia in very premature babies remains inconclusive. The present rodent model of preterm neonatal anoxia has been shown to alter developmental milestones and hippocampal neurogenesis, and to disrupt spatial learning and memory in adulthood. These effects seem to be reduced by post-insult hypothermia. Epigenetic-related mechanisms have been postulated as valuable tools for developing new therapies. Dentate gyrus neurogenesis is regulated by epigenetic factors. This study evaluated whether TH effects in a rodent model of preterm oxygen deprivation are based on epigenetic alterations. The effects of TH on both developmental features (somatic growth, maturation of physical characteristics and early neurological reflexes) and performance of behavioral tasks at adulthood (spatial reference and working memory, and fear conditioning) were investigated in association with the possible involvement of the epigenetic operator Enhancer of zeste homolog 2 (Ezh2), possibly related to long-lasting effects on hippocampal neurogenesis. Results showed that TH reduced both anoxia-induced hippocampal neurodegeneration and anoxia-induced impairments on risk assessment behavior, acquisition of spatial memory, and extinction of auditory and contextual fear conditioning. In contrast, TH did not prevent developmental alterations caused by neonatal anoxia and did not restore hippocampal neurogenesis or cause changes in EZH2 levels. In conclusion, despite the beneficial effects of TH in hippocampal neurodegeneration and in reversing disruption of performance of behavioral tasks following oxygen deprivation in prematurity, these effects seem not related to developmental alterations and hippocampal neurogenesis and, apparently, is not caused by Ezh2-mediated epigenetic alteration.

Curcumin protects against cognitive impairments in a rat model of chronic cerebral hypoperfusion combined with diabetes mellitus by suppressing neuroinflammation, apoptosis, and pyroptosis.

BACKGROUND: Chronic cerebral hypoperfusion (CCH) is regarded as a high-risk factor for cognitive decline in vascular dementia (VaD). We have previously shown that diabetes mellitus (DM) synergistically promotes CCH-induced cognitive dysfunction via exacerbating neuroinflammation. Furthermore, curcumin has been shown to exhibit anti-inflammatory and neuroprotective activities. However, the effects of curcumin on CCH-induced cognitive impairments in DM have remained unknown. METHODS: Rats were fed with a high-fat diet (HFD) and injected with low-dose streptozotocin (STZ), followed by bilateral common carotid artery occlusion (BCCAO), to model DM and CCH in vivo. After BCCAO, curcumin (50 mg/kg) was administered intraperitoneally every two days for eight weeks to evaluate its therapeutic effects. Additionally, mouse BV2 microglial cells were exposed to hypoxia and high glucose to model CCH and DM pathologies in vitro. RESULTS: Curcumin treatment significantly improved DM/CCH-induced cognitive deficits and attenuated neuronal cell death. Molecular analysis revealed that curcumin exerted protective effects via suppressing neuroinflammation induced by microglial activation, regulating the triggering receptor expressed on myeloid cells 2 (TREM2)/toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway, alleviating apoptosis, and reducing nod-like receptor protein 3 (NLRP3)-dependent pyroptosis. CONCLUSIONS: Taken together, our findings suggest that curcumin represents a promising therapy for DM/CCH-induced cognitive impairments.

Fetal Cerebral Oxygenation Is Impaired in Congenital Heart Disease and Shows Variable Response to Maternal Hyperoxia.

Background Impairments in fetal oxygen delivery have been implicated in brain dysmaturation seen in congenital heart disease (CHD), suggesting a role for in utero transplacental oxygen therapy. We applied a novel imaging tool to quantify fetal cerebral oxygenation by measuring T2* decay. We compared T2* in fetuses with CHD with controls with a focus on cardiovascular physiologies (transposition or left-sided obstruction) and described the effect of brief administration of maternal hyperoxia on T2* decay. Methods and Results This is a prospective study performed on pregnant mothers with a prenatal diagnosis of CHD compared with controls in the third trimester. Participants underwent a fetal brain magnetic resonance imaging scan including a T2* sequence before and after maternal hyperoxia. Comparisons were made between control and CHD fetuses including subgroup analyses by cardiac physiology. Forty-four mothers (CHD=24, control=20) participated. Fetuses with CHD had lower total brain volume (238.2 mm3, 95% CI, 224.6-251.9) compared with controls (262.4 mm3, 95% CI, 245.0-279.8, P=0.04). T2* decay time was faster in CHD compared with controls (beta=-14.4, 95% CI, -23.3 to -5.6, P=0.002). The magnitude of change in T2* with maternal hyperoxia was higher in fetuses with transposition compared with controls (increase of 8.4 ms, 95% CI, 0.5-14.3, P=0.01), though between-subject variability was noted. Conclusions Cerebral tissue oxygenation is lower in fetuses with complex CHD. There was variability in the response to maternal hyperoxia by CHD subgroup that can be tested in future larger studies. Cardiovascular physiology is critical when designing neuroprotective clinical trials in the fetus with CHD.

Window of opportunity for human amnion epithelial stem cells to attenuate astrogliosis after umbilical cord occlusion in preterm fetal sheep.

There is increasing evidence that administration of many types of stem cells, including human amnion epithelial cells (hAECs), can reduce hypoxic-ischemic injury, including in the perinatal brain. However, the therapeutic window for single dose treatment is not known. We compared the effects of early and delayed intracerebroventricular administration of hAECs in fetal sheep at 0.7 gestation on brain injury induced by 25 minutes of complete umbilical cord occlusion (UCO) or sham occlusion. Fetuses received either 1 × 106 hAECs or vehicle alone, as an infusion over 1 hour, either 2 or 24 hours after UCO. Fetuses were killed for brain histology at 7 days post-UCO. hAEC infusion at both 2 and 24 hours had dramatic anti-inflammatory and anti-gliotic effects, including significantly attenuating the increase in microglia after UCO in the white and gray matter and the number of astrocytes in the white matter. Both protocols partially improved myelination, but had no effect on total or immature/mature numbers of oligodendrocytes. Neuronal survival in the hippocampus was increased by hAEC infusion at either 2 or 24 hours, whereas only hAECs at 24 hours were associated with improved neuronal survival in the striatum and thalamus. Neither protocol improved recovery of electroencephalographic (EEG) power. These data suggest that a single infusion of hAECs is anti-inflammatory, anti-gliotic, and neuroprotective in preterm fetal sheep when given up to 24 hours after hypoxia-ischemia, but was associated with limited white matter protection after 7 days recovery and no improvement in the recovery of EEG power.

Superimposed Guillain-Barré Syndrome (GBS) in pediatric hypoxic brain injury.

BACKGROUND: Hypoxic brain injury results in severe disabilities that require extensive acute inpatient and outpatient rehabilitation to promote maximal functional and cognitive recovery. Brain hypoxemia can result from a multitude of causes, including but not limited to cardiac arrest, drug overdose, and/or shock. While recovery from a hypoxic brain injury alone can be challenging, dealing with concurrent debilitative diagnoses such as Guillain Barré Syndrome (GBS) further complicates the recovery and rehabilitation course. CASE REPORT: The current case study highlights the acute inpatient rehabilitation course of a 16 year old male who presented with cerebral hypoxia secondary to strangulation and subsequently developed GBS. Physical examination of the patient upon rehabilitation consult was inconsistent with a purely hypoxic brain injury, including the absence of rectal tone. This prompted further potential spinal cord injury evaluation and work up, with diagnostic testing confirmatory of GBS. RELEVANCE: This case is important as, to our knowledge from literature review, the first known documented instance of hypoxic brain injury complicated by GBS. Moreover, it highlights the importance of identifying all potential causes of functional disability, particularly when presented with physical exam findings inconsistent with chief diagnosis, in order to maximize functional recovery and rehabilitative gains during acute inpatient rehabilitation.

Hyperbaric oxygen therapy in acute stroke: is it time for Justitia to open her eyes?

Hypoxia is a critical component of neuronal death in patients with stroke. Therefore increasing oxygenation of brain tissue seems to be a logical therapy against cerebral ischemia. Oxygen therapy exists in two modalities: normobaric hyperoxia therapy and hyperbaric oxygen therapy (HBO). HBO is a therapeutic procedure in which pure (100%) oxygen is administered at greater than atmospheric pressure in HBO therapy chambers. In this review article, we aimed to summarize the current knowledge regarding the therapeutic use of HBO in acute stroke patients. Literature review and electronic search were performed using PubMed, Medscape, and UpToDate with the keywords stroke, acute stroke, hyperbaric oxygen therapy, and hyperoxia. According to the reviewed literature, the use of HBO as routine stroke therapy cannot be justified in acute stage of stroke. More randomized, controlled studies are needed regarding safety and especially effectives of HBO in stroke patients. Also, standardized definitionof HBO should be proposed and used in all future studies.

Enquiring beneath the surface: can a gene expression assay shed light into the heterogeneity among newborns with neonatal encephalopathy?

BACKGROUND: We aimed to assess whether a gene expression assay provided insights for understanding the heterogeneity among newborns affected by neonatal encephalopathy (NE). METHODS: Analysis by RT-qPCR of the mRNA expression of candidate genes in whole blood from controls (n = 34) and NE (n = 24) patients at <6, 12, 24, 48, 72 and 96 h of life, followed by determination of differences in gene expression between conditions and correlation with clinical variables. RESULTS: During the first 4 days of life, MMP9, PPARG, IL8, HSPA1A and TLR8 were more expressed and CCR5 less expressed in NE patients compared to controls. MMP9 and PPARG increased and CCR5 decreased in moderate/severe NE patients compared to mild. At 6-12 h of life, increased IL8 correlated with severe NE and death, decreased CCR5 correlated with chorioamnionitis and increased HSPA1A correlated with expanded multiorgan dysfunction, severe NE and female sex. CONCLUSIONS: MMP9, PPARG and CCR5 mRNA expression within first days of life correlates with the severity of NE. At 6-12 h, IL8 and HSPA1A are good reporters of clinical variables in NE patients. HSPA1A may have a role in the sexual dimorphism observed in NE. CCR5 is potentially involved in the link between severe NE and chorioamnionitis.

Effects of regional body temperature variation during asphyxial cardiac arrest on mortality and brain damage in a rat model.

To date, hypothermia has focused on improving rates of resuscitation to increase survival in patients sustaining cardiac arrest (CA). Towards this end, the role of body temperature in neuronal damage or death during CA needs to be determined. However, few studies have investigated the effect of regional temperature variation on survival rate and neurological outcomes. In this study, adult male rats (12 week-old) were used under the following four conditions: (i) whole-body normothermia (37 ± 0.5 °C) plus (+) no asphyxial CA, (ii) whole-body normothermia + CA, (iii) whole-body hypothermia (33 ± 0.5 °C)+CA, (iv) body hypothermia/brain normothermia + CA, and (v) brain hypothermia/body normothermia + CA. The survival rate after resuscitation was significantly elevated in groups exposed to whole-body hypothermia plus CA and body hypothermia/brain normothermia plus CA, but not in groups exposed to whole-body normothermia combined with CA and brain hypothermia/body normothermia plus CA. However, the group exposed to hypothermia/brain normothermia combined with CA exhibited higher neuroprotective effects against asphyxial CA injury, i.e. improved neurological deficit and neuronal death in the hippocampus compared with those involving whole-body normothermia combined with CA. In addition, neurological deficit and neuronal death in the group of rat exposed to brain hypothermia/body normothermia and CA were similar to those in the rats subjected to whole-body normothermia and CA. In brief, only brain hypothermia during CA was not associated with effective survival rate, neurological function or neuronal protection compared with those under body (but not brain) hypothermia during CA. Our present study suggests that regional temperature in patients during CA significantly affects the outcomes associated with survival rate and neurological recovery.

α7 Nicotinic Acetylcholine Receptor Mediates the Neuroprotection of Remote Ischemic Postconditioning in a Rat Model of Asphyxial Cardiac Arrest.

BACKGROUND: Remote ischemic postconditioning (RIPost) has been shown to reduce the ischemia-reperfusion injury of the heart and brain. However, the protection mechanisms have not yet been fully elucidated. We have observed that RIPost could alleviate the brain injury after cardiac arrest (CA). The aim of this study was to explore whether α7 nicotinic acetylcholine receptor (α7nAChR) mediates the neuroprotection of RIPost in a rat model of asphyxial CA. MATERIALS AND METHODS: Asphyxial CA model was induced by occlusion of the tracheal tube for 8 min and resuscitated later. RIPost produced by three cycles of 15-min occlusion and 15-min release of the right hind limb by a tourniquet was performed respectively at the moment and the third hour after restoration of spontaneous circulation. The α7nAChR agonist PHA-543613 and the antagonist methyllycaconitine (MLA) were used to investigate the role of α7nAChR in mediating neuroprotective effects. RESULTS: Results showed that α7nAChR was decreased in hippocampus and cortex after resuscitation, whereas RIPost could attenuate the reduction. The use of PHA-543613 provided neuroprotective effects against cerebral injury after CA. Furthermore, RIPost decreased the levels of neuron-specific enolase, inflammatory mediators, the number of apoptotic cells, and phosphorylation of nuclear factor-κB while increased the phosphorylation of signal transducer and activator of transcription-3. However, the above effects of RIPost were attenuated by α7nAChR antagonist methyllycaconitine. CONCLUSIONS: Neuroprotection of RIPost was related with the activation of α7nAChR, which could suppress nuclear factor-κB and activate signal transducer and activator of transcription-3 in a rat asphyxial CA model.

Impact of a Devastating Brain Injury Pathway on Outcomes, Resources, and Organ Donation: 3 Years' Experience in a Regional Neurosciences ICU.

OBJECTIVE: To assess the impact of introducing a devastating brain injury (DBI) pathway on patient outcome, intensive care unit (ICU) resources, and organ donation practice in the first 3 years of implementation in a regional neurosciences ICU in the South West of England. METHODS: Patients with DBI admitted to our ICU between 2015 and 2018 were identified from our ICU database and their outcomes compared to those of non-DBI patients. Data were also obtained from the national potential donor audit to compare organ donation metrics before and after the introduction of the DBI pathway. Organ donation metrics in DBI patients and non-DBI patients were compared once the pathway had been implemented. RESULTS: We admitted 85 DBI patients (1.3% of all admissions), with a significantly shorter median length of ICU stay than in non-DBI patients, 1.14 versus 2.93 days (p < 0.001). Decisions for withdraw life-sustaining treatments (WLST) were made significantly earlier in DBI patients, median 26.2 versus 84.8 h (p < 0.001). Over 8% of DBI patients survived, while 31% progressed to brain death compared to 7.1% in the general population (p < 0.001), and 25% become solid organ donors compared to 1.3% of the general population (p < 0.001). There was an increase in the proportion of donors after brain death (DBD) to donors after circulatory death (DCD) in the 3 years following the introduction of the DBI pathway (p = 0.024). There was also an increased proportion of DBD donors to DCD donors of 76% versus 24% in the DBI group compared to 62% versus 38% (p = 0,002) in the non-DBI population. Prognostic scoring systems do not provide accurate estimates of survival rate in this population. CONCLUSIONS: Admitting patients with perceived DBI to ICU and avoiding the early WLST allows identification of unexpected survivors and gives families more time in decision making at the end of life. The DBI pathway increases the potential for organ donation and increases the proportion of DBD donors. These benefits outweigh the small impact of a DBI pathway on ICU resources.

Detailed statistical analysis plan for the SafeBoosC III trial: a multinational randomised clinical trial assessing treatment guided by cerebral oxygenation monitoring versus treatment as usual in extremely preterm infants.

BACKGROUND: Infants born extremely preterm are at high risk of dying or suffering from severe brain injuries. Treatment guided by monitoring of cerebral oxygenation may reduce the risk of death and neurologic complications. The SafeBoosC III trial evaluates the effects of treatment guided by cerebral oxygenation monitoring versus treatment as usual. This article describes the detailed statistical analysis plan for the main publication, with the aim to prevent outcome reporting bias and data-driven analyses. METHODS/DESIGN: The SafeBoosC III trial is an investigator-initiated, randomised, multinational, pragmatic phase III trial with a parallel group structure, designed to investigate the benefits and harms of treatment based on cerebral near-infrared spectroscopy monitoring compared with treatment as usual. Randomisation will be 1:1 stratified for neonatal intensive care unit and gestational age (lower gestational age (< 26 weeks) compared to higher gestational age (≥ 26 weeks)). The primary outcome is a composite of death or severe brain injury at 36 weeks postmenstrual age. Primary analysis will be made on the intention-to-treat population for all outcomes, using mixed-model logistic regression adjusting for stratification variables. In the primary analysis, the twin intra-class correlation coefficient will not be considered. However, we will perform sensitivity analyses to address this. Our simulation study suggests that the inclusion of multiple births is unlikely to significantly affect our assessment of intervention effects, and therefore we have chosen the analysis where the twin intra-class correlation coefficient will not be considered as the primary analysis. DISCUSSION: In line with the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines, we have developed and published this statistical analysis plan for the SafeBoosC III trial, prior to any data analysis. TRIAL REGISTRATION: ClinicalTrials.org, NCT03770741. Registered on 10 December 2018.