Hyperbaric oxygen in traumatic brain injury

Hyperbaric oxygen therapy for the treatment of hypoxic/ischemic injury upon perinatal asphyxia-are we there yet?

Birth asphyxia and its main sequel, hypoxic-ischemic encephalopathy, are one of the leading causes of children's deaths worldwide and can potentially worsen the quality of life in subsequent years. Despite extensive research efforts, efficient therapy against the consequences of hypoxia-ischemia occurring in the perinatal period of life is still lacking. The use of hyperbaric oxygen, improving such vital consequences of birth asphyxia as lowered partial oxygen pressure in tissue, apoptosis of neuronal cells, and impaired angiogenesis, is a promising approach. This review focused on the selected aspects of mainly experimental hyperbaric oxygen therapy. The therapeutic window for the treatment of perinatal asphyxia is very narrow, but administering hyperbaric oxygen within those days improves outcomes. Several miRNAs (e.g., mir-107) mediate the therapeutic effect of hyperbaric oxygen by modulating the Wnt pathway, inhibiting apoptosis, increasing angiogenesis, or inducing neural stem cells. Combining hyperbaric oxygen therapy with drugs, such as memantine or ephedrine, produced promising results. A separate aspect is the use of preconditioning with hyperbaric oxygen. Overall, preliminary clinical trials with hyperbaric oxygen therapy used in perinatal asphyxia give auspicious results.

Clinical analysis of hyperbaric oxygen combined with subdural drilling and drainage in the management of subdural effusion type IV with intracranial infection in infant patients

Background

To explore the therapeutic effect of hyperbaric oxygen combined with subdural drilling and drainage (SDD) on subdural effusion type IV with intracranial infection in infant patients.

Methods

This retrospective controlled study included 328 infant patients with subdural effusion type 4 with intracranial infection between January 2005 and January 2023. 178 patients were treated by hyperbaric oxygen combined with SDD (group A). 142 cases were treated with SDD (group B). 97 infants were only received hyperbaric oxygen (group C). Clinical outcomes, the control time of intracranial infection, complications, and the degree of brain re-expansion after 6 months of treatment were compared among the three groups. According to the comprehensive evaluation of treatment effectiveness and imaging results, it is divided into four levels: cured, significantly effective, improved, and ineffective.

Results

No patient died during follow-up. The three groups were similar regarding age, sex, the general information, and clinical symptoms (p > 0.05). All intracranial infections in the children were effectively controlled. There was no difference in infection control time between group A and group B, and there was no statistical significance. However, the control time of intracranial infection between the two groups was different from that of group C, which was statistically significant. Compared with group B and group C, the degree of brain re-expansion in group A has obvious advantages and significant differences. The effective rates of the three groups were 83.7%, 58.5%, and 56.7%, respectively. There were 28 cases of subcutaneous hydrops in group A and 22 cases of subcutaneous hydrops in group B after operation, and no other serious complications.

Conclusion

The SDD is safe and effective for infant patients with intracranial infections through fluid replacement and intrathecal antibacterial. Hyperbaric oxygen is effective as an adjuvant therapy to promote brain re-expansion.

The use of hyperbaric oxygen for veterans with PTSD: basic physiology and current available clinical data

Post-traumatic stress disorder (PTSD) affects up to 30% of veterans returning from the combat zone. Unfortunately, a substantial proportion of them do not remit with the current available treatments and thus continue to experience long-term social, behavioral, and occupational dysfunction. Accumulating data implies that the long-standing unremitting symptoms are related to changes in brain activity and structure, mainly disruption in the frontolimbic circuit. Hence, repair of brain structure and restoration of function could be a potential aim of effective treatment. Hyperbaric oxygen therapy (HBOT) has been effective in treating disruptions of brain structure and functions such as stroke, traumatic brain injury, and fibromyalgia even years after the acute insult. These favorable HBOT brain effects may be related to recent protocols that emphasize frequent fluctuations in oxygen concentrations, which in turn contribute to gene expression alterations and metabolic changes that induce neuronal stem cell proliferation, mitochondrial multiplication, angiogenesis, and regulation of the inflammatory cascade. Recently, clinical findings have also demonstrated the beneficial effect of HBOT on veterans with treatment-resistant PTSD. Moderation of intrusive symptoms, avoidance, mood and cognitive symptoms, and hyperarousal were correlated with improved brain function and with diffusion tensor imaging-defined structural changes. This article reviews the current data on the regenerative biological effects of HBOT, and the ongoing research of its use for veterans with PTSD.

HBOT has a better cognitive outcome than NBH for patients with mild traumatic brain injury: A randomized controlled clinical trial

BACKGROUND

Normobaric hyperoxia (NBH) and hyperbaric oxygen therapy (HBOT) are effective treatment plan for traumatic brain injury (TBI). The aim of this study was to compare cognitive outcome after mild TBI between NBH and HBOT so as to provide a more suitable treatment strategy for patients with mild TBI.

METHODS

A prospective research was conducted between October 2017 and March 2023, enrolling patients with mild TBI (Glasgow coma scale score: 13-15 points) within 24 hours of injury in Cangzhou Central Hospital. Patients were randomized into 3 groups: group control (C), group NBH and group HBOT. The patients in HBOT group received hyperbaric oxygen therapy in high pressure oxygen chamber and patients in NBH group received hyperbaric oxygen therapy. at 0 minute before NBH or HBOT (T1), 0 minute after NBH or HBOT (T2) and 30 days after NBH or HBOT (T3), level of S100β, NSE, GFAP, HIF-1α, and MDA were determined by ELISA. At the same time, the detection was performed for MoCA and MMSE scores, along with rSO2.

RESULTS

The results showed both NBH and HBOT could improve the score of MoCA and MMSE, as well as the decrease the level of S100β, NSE, GFAP, HIF-1α, MDA, and rSO2 compared with group C. Furthermore, the patients in group HBOT have higher score of MoCA and MMSE and lower level of S100β, NSE, GFAP, HIF-1α, MDA, and rSO2.

CONCLUSION

Both NBH and HBOT can effectively improve cognitive outcome for patients with mild TBI by improving cerebral hypoxia and alleviating brain injury, while HBOT exert better effect than NBH.

Oxidative stress and mitochondrial dysfunction following traumatic brain injury: From mechanistic view to targeted therapeutic opportunities

Traumatic brain injury (TBI) is one of the most prevalent causes of permanent physical and cognitive disabilities. TBI pathology results from primary insults and a multi-mechanistic biochemical process, termed as secondary brain injury. Currently, there are no pharmacological agents for definitive treatment of patients with TBI. This article is presented with the purpose of reviewing molecular mechanisms of TBI pathology, as well as potential strategies and agents against pathological pathways. In this review article, materials were obtained by searching PubMed, Scopus, Elsevier, Web of Science, and Google Scholar. This search was considered without time limitation. Evidence indicates that oxidative stress and mitochondrial dysfunction are two key mediators of the secondary injury cascade in TBI pathology. TBI-induced oxidative damage results in the structural and functional impairments of cellular and subcellular components, such as mitochondria. Impairments of mitochondrial electron transfer chain and mitochondrial membrane potential result in a vicious cycle of free radical formation and cell apoptosis. The results of some preclinical and clinical studies, evaluating mitochondria-targeted therapies, such as mitochondria-targeted antioxidants and compounds with pleiotropic effects after TBI, are promising. As a proposed strategy in recent years, mitochondria-targeted multipotential therapy is a new hope, waiting to be confirmed. Moreover, based on the available findings, biologics, such as stem cell-based therapy and transplantation of mitochondria are novel potential strategies for the treatment of TBI; however, more studies are needed to clearly confirm the safety and efficacy of these strategies.

Pulmonary injury as a predictor of cerebral hypoxia in traumatic brain injury: from physiology to physiopathology

Traumatic brain injury is caused by mechanical forces impacting the skull and its internal structures and constitutes one of the main causes of morbidity and mortality in the world. Clinically, severe traumatic brain injury is associated with the development of acute lung injury and so far, few studies have evaluated the cellular, molecular and immunological mechanisms involved in this pathophysiological process. Knowing and investigating these mechanisms allows us to correlate pulmonary injury as a predictor of cerebral hypoxia in traumatic brain injury and to use this finding in decision making during clinical practice. This review aims to provide evidence on the importance of the pathophysiology of traumatic brain injury-acute lung injury, and thus confirm its role as a predictor of cerebral hypoxia, helping to establish an appropriate therapeutic strategy to improve functional outcomes and reduce mortality.

Molecular and Therapeutic Aspects of Hyperbaric Oxygen Therapy in Neurological Conditions

In hyperbaric oxygen therapy (HBOT), the subject is placed in a chamber containing 100% oxygen gas at a pressure of more than one atmosphere absolute. This treatment is used to hasten tissue recovery and improve its physiological aspects, by providing an increased supply of oxygen to the damaged tissue. In this review, we discuss the consequences of hypoxia, as well as the molecular and physiological processes that occur in subjects exposed to HBOT. We discuss the efficacy of HBOT in treating neurological conditions and neurodevelopmental disorders in both humans and animal models. We summarize by discussing the challenges in this field, and explore future directions that will allow the scientific community to better understand the molecular aspects and applications of HBOT for a wide variety of neurological conditions.

Chemogenomics Systems Pharmacology Mapping of Potential Drug Targets for Treatment of Traumatic Brain Injury

Traumatic brain injury (TBI) is associated with high mortality and morbidity. Though the death rate of initial trauma has dramatically decreased, no drug has been developed to effectively limit the progression of the secondary injury caused by TBI. TBI appears to be a predisposing risk factor for Alzheimer's disease (AD), whereas the molecular mechanisms remain unknown. In this study, we have conducted a research investigation of computational chemogenomics systems pharmacology (CSP) to identify potential drug targets for TBI treatment. TBI-induced transcriptional profiles were compared with those induced by genetic or chemical perturbations, including drugs in clinical trials for TBI treatment. The protein-protein interaction network of these predicted targets were then generated for further analyses. Some protein targets when perturbed, exhibit inverse transcriptional profiles in comparison with the profiles induced by TBI, and they were recognized as potential therapeutic targets for TBI. Drugs acting on these targets are predicted to have the potential for TBI treatment if they can reverse the TBI-induced transcriptional profiles that lead to secondary injury. In particular, our results indicated that TRPV4, NEUROD1, and HPRT1 were among the top therapeutic target candidates for TBI, which are congruent with literature reports. Our analyses also suggested the strong associations between TBI and AD, as perturbations on AD-related genes, such as APOE, APP, PSEN1, and MAPT, can induce similar gene expression patterns as those of TBI. To the best of our knowledge, this is the first CSP-based gene expression profile analyses for predicting TBI-related drug targets, and the findings could be used to guide the design of new drugs targeting the secondary injury caused by TBI.

Gastrodin pretreatment alleviates rat brain injury caused by cerebral ischemic-reperfusion

Brain damage, including blood-brain barrier (BBB) dysfunction, neurological behavior deficit, cerebral infarction and inflammation, is commonly caused by ischemic-reperfusion (I/R) injury. Prevention of the above biological process defects is considered beneficial for patient recovery after I/R injury. This study was aimed to assess the neuroprotective effect of Gastrodin (GAS), an herbal agent, in experimentally induced cerebral ischemia. Sprague-Dawley adult rats were randomly divided into six groups: Sham-operated control group (Sham), middle cerebral artery occlusion (MCAO) group, GAS (50, 100, and 200 mg/kg) pretreatment + MCAO groups (GAS) and Nimodipine (NIM) + MCAO, namely, the NIM group. Additionally, an OGD/R model using BV-2 microglia was established in vitro to simulate I/R injury. We showed here that the neurological scores of rats in the GAS groups were significantly improved compared with the MCAO group. Moreover, the area of cerebral infarction in the GAS pretreatment groups and the NIM group was significantly reduced. Furthermore, Evans blue leakage volume was significantly reduced with GAS pretreatment notably at dose 100 mg/kg. Expression of matrix metalloproteinase 2 (MMP2) and MMP9 in GAS groups was markedly decreased when compared with MCAO group. In BV-2 microglia exposed to OGD/R given GAS pretreatment, MMP2 and MMP9 positive cells were reduced in numbers. The present results have shown that GAS pretreatment significantly compensated for neurological behavior defects in rats with I/R-induced injury, reduced brain infarction size, reversed BBB impairment, and attenuated inflammation. It is suggested that pretreatment with GAS before surgery is beneficial during recovery from I/R injury.

Hyperbaric Oxygen Protects Against Cerebral Damage in Permanent Middle Cerebral Artery Occlusion Rats and Inhibits Autophagy Activity

BACKGROUND

To investigate the effects of hyperbaric oxygen (HBO) on brain damage and autophagy levels in a rat model of middle cerebral artery occlusion.

METHODS

Neurologic injury and infarcted areas were evaluated according to the modified neurological severity score and 2,3,5-triphenyltetrazolium chloride staining. Western blots were used to determine beclin1, caspase-3 and fodrin1 protein expression. Beclin1 protein expression (an autophagy marker), positive terminal dUTP nick-end labeling (TUNEL) staining (an apoptosis marker) and positive propidium iodide (PI) staining (a necrosis marker) were detected by immunofluorescence.

RESULTS

Our results indicated that HBO could decrease the infarct volume and speed up the recovery of the neurological deficit scores in ischemic rats. Beclin1 was down-regulated after HBO treatment. HBO treatment inhibited fodrin1 protein expression and decreased the number of PI-positive cells. HBO also down-regulated caspase-3 and decreased the number of TUNEL-positive cells.

CONCLUSION

Cerebral ischemia caused early neuronal death due to necrosis, followed by delayed neuronal death due to apoptosis. Consequently, autophagy might be involved in all processes of ischemia. HBO could protect the brain against ischemic injury, and the possible mechanisms might be correlated with decreased autophagy activity and decreased apoptosis and necrosis levels.

Hyperbaric oxygen therapy attenuates neuronal apoptosis induced by traumatic brain injury via Akt/GSK3β/β-catenin pathway

BACKGROUND

Given that the therapeutic effect of hyperbaric oxygen (HBO) therapy on traumatic brain injury (TBI) has been debated for a long time, it is necessary to clarify the mechanism underlying the effect of HBO on acute TBI.

METHODS

This study investigated the effect of HBO therapy on neuronal apoptosis induced by acute TBI using the mouse model of TBI. The number of apoptotic cells and expression of apoptosis-associated factors (including caspase 3, pAkt/Akt, pGSK3β/GSK3β, and β-catenin) in pericontusional cortices of mice exposed to sham, TBI, and TBI + HBO treatment were measured and analyzed using TUNEL assay, quantitative reverse-transcription PCR, and Western blot.

RESULTS

Results showed that acute TBI increased the number of apoptotic neurons and mRNA expression and activated caspase 3 protein. With regard to proteins, acute TBI also resulted in decreased levels of pAkt/Akt, pGSK3β/GSK3β, and β-catenin, which facilitates neuronal apoptosis. This study shows that HBO therapy reversed these changes of pAkt/Akt, pGSK3β/ GSK3β, and β-catenin induced by acute TBI and attenuated the apoptotic process in the pericontusional cortex.

CONCLUSION

This study demonstrates the beneficial effect of HBO therapy on neuronal apoptosis caused by acute TBI. Furthermore, the mechanism underlying the therapeutic effect of HBO on acute TBI partly involves the Akt/GSK3β/β-catenin pathway.

Neurotrauma: The Crosstalk between Neurotrophins and Inflammation in the Acutely Injured Brain

Traumatic brain injury (TBI) is a major cause of morbidity and mortality among young individuals worldwide. Understanding the pathophysiology of neurotrauma is crucial for the development of more effective therapeutic strategies. After the trauma occurs, immediate neurologic damage is produced by the traumatic forces; this primary injury triggers a secondary wave of biochemical cascades together with metabolic and cellular changes, called secondary neural injury. In the scenario of the acutely injured brain, the ongoing secondary injury results in ischemia and edema culminating in an uncontrollable increase in intracranial pressure. These areas of secondary injury progression, or areas of “traumatic penumbra”, represent crucial targets for therapeutic interventions. Neurotrophins are a class of signaling molecules that promote survival and/or maintenance of neurons. They also stimulate axonal growth, synaptic plasticity, and neurotransmitter synthesis and release. Therefore, this review focuses on the role of neurotrophins in the acute post-injury response. Here, we discuss possible endogenous neuroprotective mechanisms of neurotrophins in the prevailing environment surrounding the injured areas, and highlight the crosstalk between neurotrophins and inflammation with focus on neurovascular unit cells, particularly pericytes. The perspective is that neurotrophins may represent promising targets for research on neuroprotective and neurorestorative processes in the short-term following TBI.

Treatment of persistent post-concussion syndrome due to mild traumatic brain injury: current status and future directions

Persistent post-concussion syndrome caused by mild traumatic brain injury has become a major cause of morbidity and poor quality of life. Unlike the acute care of concussion, there is no consensus for treatment of chronic symptoms. Moreover, most of the pharmacologic and non-pharmacologic treatments have failed to demonstrate significant efficacy on both the clinical symptoms as well as the pathophysiologic cascade responsible for the permanent brain injury. This article reviews the pathophysiology of PCS, the diagnostic tools and criteria, the current available treatments including pharmacotherapy and different cognitive rehabilitation programs, and promising new treatment directions. A most promising new direction is the use of hyperbaric oxygen therapy, which targets the basic pathological processes responsible for post-concussion symptoms; it is discussed here in depth.

A Narrative Review of Pharmacologic and Non-pharmacologic Interventions for Disorders of Consciousness Following Brain Injury in the Pediatric Population

Traumatic brain injury (TBI) is the most common cause of long-term disability in the United States. A significant proportion of children who experience a TBI will have moderate or severe injuries, which includes a period of decreased responsiveness. Both pharmacological and non-pharmacological modalities are used for treating disorders of consciousness after TBI in children. However, the evidence supporting the use of potential therapies is relatively scant, even in adults, and overall, there is a paucity of study in pediatrics. The goal of this review is to describe the state of the science for use of pharmacologic and non-pharmacologic interventions for disorders of consciousness in the pediatric population.

Effects of Normobaric Hyperoxia in Traumatic Brain Injury: A Randomized Controlled Clinical Trial

Background

Traumatic brain injury (TBI) is one of the important causes of morbidity and mortality throughout the world, especially in young people. In recent years normobaric hyperoxia has become an important and useful step for recovery and improvement of outcome in TBI.

Objectives

The purpose of this study was to evaluate the effects of normobaric hyperoxia on clinical neurological outcomes of patients with severe traumatic brain injuries. We used the Glasgow outcome scale (GOS), barthel index, and modified rankin scale (mRS) to measure the outcomes of patients with TBI.

Patients and Methods

Sixty-eight consecutive patients with severe TBI (mean Glasgow coma scale [GCS] score: 7.4) who met the inclusion criteria were entered in this randomized controlled clinical trial. The patients were randomized into two groups, as follows: 1) experimental: received 80% oxygen via mechanical ventilator in the first 6 hours of admission, 2) control: received 50% oxygen by mechanical ventilator in the first 6 hours of admission and then standard medical care. We measured the GOS, Barthel Index, and mRS at the time of discharge from hospital and reassessed these measurements at the 6-month follow-up after injury.

Results

According to our study, there were no significant sex or age differences between the two groups (P = 0.595 and 0.074). The number of days in the intensive care unit (ICU) in the control group and experimental group were 11.4 and 9.4 days, respectively (P = 0.28), while the numbers of days of general ward admission were 13.9 and 11.4 days (P = 0.137) respectively. The status of GOS at time of discharge were severe = 13 and 10, moderate = 16 and 19, and low = 5 and 5 in the control and experimental groups, respectively (P = 0.723); 6 months after injury, the scores were as follows: moderate = 16 and 9, low = 15 and 25, and severe = 3 and 0 (P = 0.024). The Barthel index scores in the control and experimental groups were 59.7 and 63.9 at time of discharge (P = 0.369) and 82.7 and 91.3 at 6 months after injury (P = 0.018), respectively. The mRS results were 2.6 and 2.3 at time of discharge (P = 0.320) and 1.6 and 0.7 at 6 months after injury (P = 0.006) for the control and experimental groups, respectively.

Conclusions

According to the results of this study, oxygen therapy by mechanical ventilator in the first 6 hours after injury in patients with severe TBI can improve the final GOS, Barthel index, and mRS scores. It could also improve long-term outcomes and enhance rehabilitation and the quality of life.

Current Neurogenic and Neuroprotective Strategies to Prevent and Treat Neurodegenerative and Neuropsychiatric Disorders

The adult central nervous system is commonly known to have a very limited regenerative capacity. The presence of functional stem cells in the brain can therefore be seen as a paradox, since in other organs these are known to counterbalance cell loss derived from pathological conditions. This fact has therefore raised the possibility to stimulate neural stem cell differentiation and proliferation or survival by either stem cell replacement therapy or direct administration of neurotrophic factors or other proneurogenic molecules, which in turn has also originated regenerative medicine for the treatment of otherwise incurable neurodegenerative and neuropsychiatric disorders that take a huge toll on society. This may be facilitated by the fact that many of these disorders converge on similar pathophysiological pathways: excitotoxicity, oxidative stress, neuroinflammation, mitochondrial failure, excessive intracellular calcium and apoptosis. This review will therefore focus on the most promising achievements in promoting neuroprotection and neuroregeneration reported to date.

Effects of hyperbaric oxygen on eye tracking abnormalities in males after mild traumatic brain injury

The effects of hyperbaric oxygen (HBO2) on eye movement abnormalities in 60 military servicemembers with at least one mild traumatic brain injury (TBI) from combat were examined in a single-center, randomized, double-blind, sham-controlled, prospective study at the Naval Medicine Operational Training Center. During the 10 wk of the study, each subject was delivered a series of 40, once a day, hyperbaric chamber compressions at a pressure of 2.0 atmospheres absolute (ATA). At each session, subjects breathed one of three preassigned oxygen fractions (10.5%, 75%, or 100%) for 1 h, resulting in an oxygen exposure equivalent to breathing either surface air, 100% oxygen at 1.5 ATA, or 100% oxygen at 2.0 ATA, respectively. Using a standardized, validated, computerized eye tracking protocol, fixation, saccades, and smooth pursuit eye movements were measured just prior to intervention and immediately postintervention. Between and within groups testing of pre- and postintervention means revealed no significant differences on eye movement abnormalities and no significant main effect for HBO2 at either 1.5 ATA or 2.0 ATA equivalent compared with the sham-control. This study demonstrated that neither 1.5 nor 2.0 ATA equivalent HBO2 had an effect on postconcussive eye movement abnormalities after mild TBI when compared with a sham-control.

The effect of hyperbaric oxygen on persistent postconcussion symptoms

BACKGROUND

The high incidence of persistent postconcussion symptoms in service members with combat-related mild traumatic brain injury has prompted research in the use of hyperbaric oxygen (HBO2) for management.

OBJECTIVE

The effects of HBO2 on persistent postconcussion symptoms in 60 military service members with at least 1 combat-related mild traumatic brain injury were examined in a single-center, double-blind, randomized, sham-controlled, prospective trial at the Naval Medicine Operational Training Center at Naval Air Station Pensacola.

METHODS

Over a 10-week period, subjects received a series of 40, once-daily, hyperbaric chamber compressions at 2.0 atmospheres absolute (ATA). During each session, subjects breathed 1 of 3 preassigned oxygen fractions (10.5%, 75%, or 100%) for 60 minutes, resulting in an oxygen exposure equivalent to breathing surface air, 100% oxygen at 1.5 ATA, or 100% oxygen at 2.0 ATA, respectively. Individual, subscale and total item responses on the Rivermead Postconcussion Symptom Questionnaire and individual and total Posttraumatic Disorder Checklist-Military Version were measured just prior to intervention and immediately postintervention.

RESULTS

Between-group testing of pre- and postintervention means revealed no significant differences on individual or total scores on the Posttraumatic Disorder Checklist-Military Version or Rivermead Postconcussion Symptom Questionnaire, demonstrating a successful randomization and no significant main effect for HBO2 at 1.5 or 2.0 ATA equivalent compared with the sham compression. Within-group testing of pre- and postintervention means revealed significant differences on several individual items for each group and difference in the Posttraumatic Disorder Checklist-Military Version total score for the 2.0 ATA HBO2 group.

DISCUSSION

The primary analyses of between group differences found no evidence of efficacy for HBO2. The scattered within group differences are threatened by Type 2 errors and could be explained by nonspecific effects.

CONCLUSION

This study demonstrated that HBO2 at either 1.5 or 2.0 ATA equivalent had no effect on postconcussion symptoms after mild traumatic brain injury when compared with sham compression.

Repetitive long-term hyperbaric oxygen treatment (HBOT) administered after experimental traumatic brain injury in rats induces significant remyelination and a recovery of sensorimotor function

Cells in the central nervous system rely almost exclusively on aerobic metabolism. Oxygen deprivation, such as injury-associated ischemia, results in detrimental apoptotic and necrotic cell loss. There is evidence that repetitive hyperbaric oxygen therapy (HBOT) improves outcomes in traumatic brain-injured patients. However, there are no experimental studies investigating the mechanism of repetitive long-term HBOT treatment-associated protective effects. We have therefore analysed the effect of long-term repetitive HBOT treatment on brain trauma-associated cerebral modulations using the lateral fluid percussion model for rats. Trauma-associated neurological impairment regressed significantly in the group of HBO-treated animals within three weeks post trauma. Evaluation of somatosensory-evoked potentials indicated a possible remyelination of neurons in the injured hemisphere following HBOT. This presumption was confirmed by a pronounced increase in myelin basic protein isoforms, PLP expression as well as an increase in myelin following three weeks of repetitive HBO treatment. Our results indicate that protective long-term HBOT effects following brain injury is mediated by a pronounced remyelination in the ipsilateral injured cortex as substantiated by the associated recovery of sensorimotor function.

Use of hyperbaric oxygenation in neonatal patients: a pilot study of 8 patients

This article presents a pilot study to determine the value of hyperbaric oxygenation (HBO₂) in the acute management of neonatal hypoxia (hypoxic ischemic encephalopathy) and necrotizing enterocolitis. Neonates with hypoxic-ischemic encephalopathy and NE were treated in a Sechrist monoplace chamber. Electroencephalogram, evoked potential, ophthalmic evaluation, ultrasonograph, laboratory exams, and radiographs were obtained before and after HBO₂. Treatment protocol was 2.0 atm abs/45 minutes. Preventive myringotomies were conducted in all patients. A follow-up was done at 3 and 6 months. All patients (n = 8) were ventilator-dependent and required bag-valve-mask ventilation by a neonatologist during the treatment. All showed a resolution after HBO₂. There was also a dramatic improvement (P < .05) in hemoglobin, hematocrit, total proteins, serum sodium, triglycerides, and pH. There were favorable changes in all other studies although they did not meet statistical significance. There was a marked reduction of the morbidity and mortality. There were no adverse effects on the ophthalmologic or Central Nervous System. When used promptly, HBO₂ can modify the local and systemic inflammatory response caused by intestinal inflammation or cerebral or systemic hypoxia. It helps to preserve the marginal tissue and recover the ischemic and metabolic penumbra. This pilot study suggests that HBO₂ could be a safe and effective treatment in the acute management of neonatal necrotizing enterocolitis or hypoxic ischemic encephalopathy. There is a need for a prospective, randomized, controlled, and double-blinded study to determine the real use of HBO₂ in these cases.

Hyperbaric oxygen therapy can improve post concussion syndrome years after mild traumatic brain injury - randomized prospective trial

Background

Traumatic brain injury (TBI) is the leading cause of death and disability in the US. Approximately 70-90% of the TBI cases are classified as mild, and up to 25% of them will not recover and suffer chronic neurocognitive impairments. The main pathology in these cases involves diffuse brain injuries, which are hard to detect by anatomical imaging yet noticeable in metabolic imaging. The current study tested the effectiveness of Hyperbaric Oxygen Therapy (HBOT) in improving brain function and quality of life in mTBI patients suffering chronic neurocognitive impairments.

Methods and Findings

The trial population included 56 mTBI patients 1–5 years after injury with prolonged post-concussion syndrome (PCS). The HBOT effect was evaluated by means of prospective, randomized, crossover controlled trial: the patients were randomly assigned to treated or crossover groups. Patients in the treated group were evaluated at baseline and following 40 HBOT sessions; patients in the crossover group were evaluated three times: at baseline, following a 2-month control period of no treatment, and following subsequent 2-months of 40 HBOT sessions. The HBOT protocol included 40 treatment sessions (5 days/week), 60 minutes each, with 100% oxygen at 1.5 ATA. “Mindstreams” was used for cognitive evaluations, quality of life (QOL) was evaluated by the EQ-5D, and changes in brain activity were assessed by SPECT imaging. Significant improvements were demonstrated in cognitive function and QOL in both groups following HBOT but no significant improvement was observed following the control period. SPECT imaging revealed elevated brain activity in good agreement with the cognitive improvements.

Conclusions

HBOT can induce neuroplasticity leading to repair of chronically impaired brain functions and improved quality of life in mTBI patients with prolonged PCS at late chronic stage.

Trial Registration

ClinicalTrials.gov

NCT00715052

Combined administration of hyperbaric oxygen and hydroxocobalamin improves cerebral metabolism after acute cyanide poisoning in rats

Hyperbaric oxygen therapy (HBOT) or intravenous hydroxocobalamin (OHCob) both abolish cyanide (CN)-induced surges in interstitial brain lactate and glucose concentrations. HBOT has been shown to induce a delayed increase in whole blood CN concentrations, whereas OHCob may act as an intravascular CN scavenger. Additionally, HBOT may prevent respiratory distress and restore blood pressure during CN intoxication, an effect not seen with OHCob administration. In this report, we evaluated the combined effects of HBOT and OHCob on interstitial lactate, glucose, and glycerol concentrations as well as lactate-to-pyruvate ratio in rat brain by means of microdialysis during acute CN poisoning. Anesthetized rats were allocated to three groups: 1) vehicle (1.2 ml isotonic NaCl intra-arterially); 2) potassium CN (5.4 mg/kg intra-arterially); 3) potassium CN, OHCob (100 mg/kg intra-arterially) and subsequent HBOT (284 kPa in 90 min). OHCob and HBOT significantly attenuated the acute surges in interstitial cerebral lactate, glucose, and glycerol concentrations compared with the intoxicated rats given no treatment. Furthermore, the combined treatment resulted in consistent low lactate, glucose, and glycerol concentrations, as well as in low lactate-to-pyruvate ratios compared with CN intoxicated controls. In rats receiving OHCob and HBOT, respiration improved and cyanosis disappeared, with subsequent stabilization of mean arterial blood pressure. The present findings indicate that a combined administration of OHCob and HBOT has a beneficial and persistent effect on the cerebral metabolism during CN intoxication.

Quantitative evaluation of hyperbaric oxygen efficacy in experimental traumatic brain injury: an MRI study

To use DCE-magnetic resonance imaging (MRI) and diffusion-weighted imaging to evaluate the hyperbaric oxygen efficacy (HBO) in experimental traumatic brain injury (TBI). Forty-two rabbits were randomly divided into four groups: TBI, TBI + HBO, sham group, sham + HBO. The TBI + HBO and sham + HBO received a total of 10 HBO treatments within 7 days following TBI, and MRI was performed within a month after TBI. Functional assessments were performed pre-TBI, and at 1 and 30 days. In focal lesion area, K(trans) in TBI + HBO group was lower than TBI group at both acute and subacute phase (p < 0.05). ADC was higher in TBI + HBO group than TBI group at acute phase (p < 0.01), but lower at subacute phase (p < 0.05). In perifocal area, K(trans) were lower in TBI + HBO group than TBI group at acute phase (p < 0.01) after TBI. ADC was lower in the TBI + HBO group than in the TBI group at both acute and subacute phase (p < 0.01).The VCS was higher in TBI + HBO group than TBI group at 30 days (p < 0.05). HBO could improve the impaired BBB and cytotoxic edema after TBI and promote the recovery of neurofunction.

Hyperbaric oxygenation alters temporal expression pattern of superoxide dismutase 2 after cortical stab injury in rats

Aim

To evaluate the effect of hyperbaric oxygen therapy (HBOT) on superoxide dismutase 2 (SOD2) expression pattern after the cortical stab injury (CSI).

Methods

CSI was performed on 88 male Wistar rats, divided into control, sham, lesioned, and HBO groups. HBOT protocol was the following: pressure applied was 2.5 absolute atmospheres, for 60 minutes, once a day for consecutive 3 or 10 days.‎ The pattern of SOD2 expression and cellular localization was analyzed using real-time polymerase chain reaction, Western blot, and double-label fluorescence immunohistochemistry. Neurons undergoing degeneration were visualized with Fluoro-Jade^®B.

Results

CSI induced significant transient increase in SOD2 protein levels at day 3 post injury, which was followed by a reduction toward control levels at post-injury day 10. At the same time points, mRNA levels for SOD2 in the injured cortex were down-regulated. Exposure to HBO for 3 days considerably down-regulated SOD2 protein levels in the injured cortex, while after 10 days of HBOT an up-regulation of SOD2 was observed. HBOT significantly increased mRNA levels for SOD2 at both time points compared to the corresponding L group, but they were still lower than in controls. Double immunofluorescence staining revealed that 3 days after CSI, up-regulation of SOD2 was mostly due to an increased expression in reactive astrocytes surrounding the lesion site. HBOT attenuated SOD2 expression both in neuronal and astroglial cells. Fluoro-Jade^®B labeling showed that HBOT significantly decreased the number of degenerating neurons in the injured cortex.

Conclusion

HBOT alters SOD2 protein and mRNA levels after brain injury in a time-dependent manner.

Mitochondria in traumatic brain injury and mitochondrial-targeted multipotential therapeutic strategies

Traumatic brain injury (TBI) is a major health and socioeconomic problem throughout the world. It is a complicated pathological process that consists of primary insults and a secondary insult characterized by a set of biochemical cascades. The imbalance between a higher energy demand for repair of cell damage and decreased energy production led by mitochondrial dysfunction aggravates cell damage. At the cellular level, the main cause of the secondary deleterious cascades is cell damage that is centred in the mitochondria. Excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), Bcl-2 family, caspases and apoptosis inducing factor (AIF) are the main participants in mitochondria-centred cell damage following TBI. Some preclinical and clinical results of mitochondria-targeted therapy show promise. Mitochondria- targeted multipotential therapeutic strategies offer new hope for the successful treatment of TBI and other acute brain injuries.

Hyperbaric oxygen therapy for the adjunctive treatment of traumatic brain injury

BACKGROUND

Traumatic brain injury is a common health problem with significant effect on quality of life. Each year in the USA approximately 0.56% of the population suffer a head injury, with a case fatality rate of about 40% for severe injuries. These account for a high proportion of deaths in young adults. In the USA, 2% of the population live with long-term disabilities following head injuries. The major causes are motor vehicle crashes, falls, and violence (including attempted suicide). Hyperbaric oxygen therapy (HBOT) is the therapeutic administration of 100% oxygen at environmental pressures greater than 1 atmosphere absolute (ATA). This involves placing the patient in an airtight vessel, increasing the pressure within that vessel, and administering 100% oxygen for respiration. In this way, it is possible to deliver a greatly increased partial pressure of oxygen to the tissues. HBOT can improve oxygen supply to the injured brain, reduce the swelling associated with low oxygen levels and reduce the volume of brain that will ultimately perish. It is, therefore, possible that adding HBOT to the standard intensive care regimen may reduce patient death and disability. However, a concern for patients and families is that using HBOT may result in preventing a patient from dying only to leave them in a vegetative state, entirely dependent on medical care. There are also some potential adverse effects of the therapy, including damage to the ears, sinuses and lungs from the effects of the pressure and oxygen poisoning, so the benefits and risks of the therapy need to be carefully evaluated.

OBJECTIVES

To assess the effects of adjunctive HBOT for traumatic brain injury.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL and DORCTHIM electronic databases. We also searched the reference lists of eligible articles, handsearched relevant journals and contacted researchers. All searches were updated to March 2012.

SELECTION CRITERIA

Randomised studies comparing the effect of therapeutic regimens which included HBOT with those that did not, for people with traumatic brain injury.

DATA COLLECTION AND ANALYSIS

Three authors independently evaluated trial quality and extracted data.

MAIN RESULTS

Seven studies are included in this review, involving 571 people (285 receiving HBOT and 286 in the control group). The results of two studies indicate use of HBOT results in a statistically significant decrease in the proportion of people with an unfavourable outcome one month after treatment using the Glasgow Outcome Scale (GOS) (relative risk (RR) for unfavourable outcome with HBOT 0.74, 95% CI 0.61 to 0.88, P = 0.001). This five-point scale rates the outcome from one (dead) to five (good recovery); an 'unfavourable' outcome was considered as a score of one, two or three. Pooled data from final follow-up showed a significant reduction in the risk of dying when HBOT was used (RR 0.69, 95% CI 0.54 to 0.88, P = 0.003) and suggests we would have to treat seven patients to avoid one extra death (number needed to treat (NNT) 7, 95% CI 4 to 22). Two trials suggested favourably lower intracranial pressure in people receiving HBOT and in whom myringotomies had been performed. The results from one study suggested a mean difference (MD) with myringotomy of -8.2 mmHg (95% CI -14.7 to -1.7 mmHg, P = 0.01). The Glasgow Coma Scale (GCS) has a total of 15 points, and two small trials reported a significant improvement in GCS for patients treated with HBOT (MD 2.68 points, 95%CI 1.84 to 3.52, P < 0.0001), although these two trials showed considerable heterogeneity (I(2) = 83%). Two studies reported an incidence of 13% for significant pulmonary impairment in the HBOT group versus 0% in the non-HBOT group (P = 0.007).In general, the studies were small and carried a significant risk of bias. None described adequate randomisation procedures or allocation concealment, and none of the patients or treating staff were blinded to treatment.

AUTHORS' CONCLUSIONS

In people with traumatic brain injury, while the addition of HBOT may reduce the risk of death and improve the final GCS, there is little evidence that the survivors have a good outcome. The improvement of 2.68 points in GCS is difficult to interpret. This scale runs from three (deeply comatose and unresponsive) to 15 (fully conscious), and the clinical importance of an improvement of approximately three points will vary dramatically with the starting value (for example an improvement from 12 to 15 would represent an important clinical benefit, but an improvement from three to six would leave the patient with severe and highly dependent impairment). The routine application of HBOT to these patients cannot be justified from this review. Given the modest number of patients, methodological shortcomings of included trials and poor reporting, the results should be interpreted cautiously. An appropriately powered trial of high methodological rigour is required to define which patients, if any, can be expected to benefit most from HBOT.

The effect of hyperbaric oxygen on symptoms after mild traumatic brain injury

In this single-center, double-blind, randomized, sham-controlled, prospective trial at the U.S. Air Force School of Aerospace Medicine, the effects of 2.4 atmospheres absolute (ATA) hyperbaric oxygen (HBO₂) on post-concussion symptoms in 50 military service members with at least one combat-related, mild traumatic brain injury were examined. Each subject received 30 sessions of either a sham compression (room air at 1.3 ATA) or HBO₂ treatments at 2.4 ATA over an 8-week period. Individual and total symptoms scores on Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®) and composite scores on Post-traumatic Disorder Check List-Military Version (PCL-M) were measured just prior to intervention and 6 weeks after completion of intervention. Difference testing of post-intervention means between the sham-control and HBO₂ group revealed no significant differences on the PCL-M composite score (t=-0.205, p=0.84) or on the ImPACT total score (t=-0.943, p=0.35), demonstrating no significant effect for HBO₂ at 2.4 ATA. PCL-M composite scores and ImPACT total scores for sham-control and HBO(2) groups revealed significant improvement over the course of the study for both the sham-control group (t=3.76, p=0.001) and the HBO₂ group (t=3.90, p=0.001), demonstrating no significant HBO₂ effect. Paired t-test results revealed 10 ImPACT scale scores in the sham-control group improved from pre- to post-testing, whereas two scale scores significantly improved in the HBO₂ group. One PCL-M measure improved from pre- to post-testing in both groups. This study showed that HBO₂ at 2.4 ATA pressure had no effect on post-concussive symptoms after mild TBI.

Early management of severe traumatic brain injury

Severe traumatic brain injury remains a major health-care problem worldwide. Although major progress has been made in understanding of the pathophysiology of this injury, this has not yet led to substantial improvements in outcome. In this report, we address present knowledge and its limitations, research innovations, and clinical implications. Improved outcomes for patients with severe traumatic brain injury could result from progress in pharmacological and other treatments, neural repair and regeneration, optimisation of surgical indications and techniques, and combination and individually targeted treatments. Expanded classification of traumatic brain injury and innovations in research design will underpin these advances. We are optimistic that further gains in outcome for patients with severe traumatic brain injury will be achieved in the next decade.

Tension pneumocephalus as a complication of hyperbaric oxygen therapy in a patient with chronic traumatic brain injury

Although hyperbaric oxygen therapy has not been accepted as a standard therapy for traumatic brain injuries, it has been used, along with rehabilitative exercises, for traumatic brain injuries, and the standard protocol has a low risk of complications. We report a case of chronic traumatic brain injury that progressed to tension pneumocephalus after hyperbaric oxygen therapy. The patient was a 25-yr-old man who presented with left occipital bone fracture and subarachnoid and subdural hemorrhage after being hit by a car. He underwent craniectomy to remove the hematoma and cerebrospinal fluid diversion with a ventriculoperitoneal shunt for the treatment of hydrocephalus. Fifteen months after the trauma, the patient received hyperbaric oxygen therapy to promote functional recovery. Tension pneumocephalus developed after the first session of hyperbaric oxygen therapy, and immediate burr hole drainage followed by ligation of the ventriculoperitoneal shunt was performed. The patient's consciousness recovered gradually, and he was discharged home. We suggest that patients with unrepaired skull base fracture and cerebrospinal fluid diversion should be carefully evaluated before receiving hyperbaric oxygen therapy.

Evaluation of the effects of hyperbaric oxygen therapy for spinal cord lesion in correlation with the moment of intervention

STUDY DESIGN

Experimental, controlled, animal study.

OBJECTIVES

To evaluate the functional effect of hyperbaric oxygen therapy administered shortly, one day after, and no intervention (control) in standardized experimental spinal cord lesions in Wistar rats.

SETTING

São Paulo, Brazil.

METHODS

In all, 30 Wistar rats with spinal cord lesions were divided into three groups: one group was submitted to hyperbaric oxygen therapy beginning half an hour after the lesion and with a total of 10 one-hour sessions, one session per day, at 2 atm; the second received the same treatment, but beginning on the day after the lesion; and the third received no treatment (control). The Basso, Beattie and Bresnahan scales were used for functional evaluation on the second day after the lesion and then weekly, until being killed 1 month later.

RESULTS

There were no significant differences between the groups in the functional analysis on the second day after the lesion. There was no functional difference comparing Groups 1 and 2 (treated shortly after or one day after) in any evaluation moment. On the 7th day, as well as on the 21st and 28th postoperative days, the evaluation showed that groups 1 and 2 performed significantly better than the control group (receiving no therapy).

CONCLUSION

Hyperbaric chamber therapy is beneficial in the functional recovery of spinal cord lesions in rats, if it is first administered just after spinal cord injury or within 24 h.

Hyperbaric oxygen therapy for traumatic brain injury

Traumatic brain injury (TBI) is a major public health issue. The complexity of TBI has precluded the use of effective therapies. Hyperbaric oxygen therapy (HBOT) has been shown to be neuroprotective in multiple neurological disorders, but its efficacy in the management of TBI remains controversial. This review focuses on HBOT applications within the context of experimental and clinical TBI. We also discuss its potential neuroprotective mechanisms. Early or delayed multiple sessions of low atmospheric pressure HBOT can reduce intracranial pressure, improve mortality, as well as promote neurobehavioral recovery. The complimentary, synergistic actions of HBOT include improved tissue oxygenation and cellular metabolism, anti-apoptotic, and anti-inflammatory mechanisms. Thus HBOT may serve as a promising neuroprotective strategy that when combined with other therapeutic targets for TBI patients which could improve long-term outcomes.

Controlled evaluation of the effects of hyperbaric oxygen therapy on the behavior of 16 children with autism spectrum disorders

Hyperbaric oxygen therapy (HBOT) has been used to treat individuals with autism. However, few studies of its effectiveness have been completed. The current study examined the effects of 40 HBOT sessions at 24% oxygen at 1.3 ATA on 11 topographies of directly observed behavior. Five replications of multiple baselines were completed across a total of 16 participants with autism spectrum disorders. No consistent effects were observed across any group or within any individual participant, demonstrating that HBOT was not an effective treatment for the participants in this study. This study represents the first relatively large-scale controlled study evaluating the effects of HBOT at the level of the individual participant, on a wide array of behaviors.

Neuroprotective effects of hyperbaric oxygen treatment on traumatic brain injury in the rat

This study was designed to evaluate the potential benefits of hyperbaric oxygen (HBO) in the treatment of traumatic brain injury (TBI). The right cerebral cortex of rats was injured by the impact of a 20-g object dropped from a predetermined height. The rats received HBO treatment at 3 ATA for 60 min after TBI. Neurological behavior score, brain water content, neuronal loss in the hippocampus, and cell apoptosis in brain tissue surrounding the primary injury site were examined to determine brain damage severity. Three and six hours after TBI, HBO-treated rats displayed a significant reduction in brain damage. However, by 12 h after TBI, the efficacy of HBO treatment was considerably attenuated. Furthermore, at 24, 48, and 72 h after TBI, the HBO treatment did not show any notable effects. In contrast, multiple HBO treatments (three or five times in all), even when started 48 h after TBI, remarkably reduced neurology deficit scores and the loss of neuronal numbers in the hippocampus. Although multiple treatments started at 48 h significantly improved neurological behaviors and reduced brain injury, the overall beneficial effects were substantially weaker than those seen after a single treatment at 6 h. These results suggest that: (1) HBO treatment could alleviate brain damage after TBI; (2) a single treatment with HBO has a time limitation of 12 h post-TBI; and (3) multiple HBO treatments have the possibility to extend the post-TBI delivery time window. Therefore, our results clearly suggest the validity of HBO therapy for the treatment of TBI.

Hyperbaric oxygen therapy (1.5 ATA) in treating sports related TBI/CTE: two case reports

Despite adequate evidence, including randomized controlled trials; hyperbaric oxygen is not yet recognized as efficacious for treating various forms of brain injury, specifically traumatic brain injury. Political-economic issues have kept this benign therapy from being widely adopted despite the lack of viable alternatives. Two football players with TBI/CTE are herewith shown to benefit from being treated with hyperbaric oxygen as documented by neurocognitive examinations and functional brain imaging, in one case treatment commenced decades after the brain injury. Perhaps the interest in HBOT by those participating in high-risk sports will help expand this orphan therapy into mainstream medicine.

Normobaric hyperoxia in traumatic brain injury: does brain metabolic state influence the response to hyperoxic challenge?

This study sought to investigate whether normobaric hyperoxia (NH) improves brain oxygenation and brain metabolism in the early phase of severe and moderate traumatic brain injury (TBI) and whether this effect occurs uniformly in all TBI patients. Thirty patients (9 women and 21 men) with a median initial Glasgow Coma Score (GCS) of 6 (range, 3-12) were monitored using a brain microdialysis (MD) catheter with a brain tissue oxygen sensor (PtiO(2)) placed in the least-injured hemisphere. The inspired oxygen fraction was increased to 100% for 2 h. Patients were divided into two groups: Group 1: patients with baseline brain lactate ≤3 mmol/L and Group 2: patients with baseline brain lactate >3 mmol/L, and therefore increased anaerobic metabolism in the brain. In Group 1, no significant changes in brain metabolic parameters were found after hyperoxic challenge, whereas a significant increase in glucose and a decrease in the lactate-pyruvate ratio (LPR) were found in Group 2. In this latter group of patients, brain glucose increased on average by 17.9% (95% CI, +9.2% to +26.6%, p<0.001) and LPR decreased by 11.6% (95% CI, -16.2% to -6.9%, p<0.001). The results of our study show that moderate and severe TBI may induce metabolic alterations in the brain, even in macroscopically normal brain tissue. We observed that NH increased PaO(2) and PtiO(2) and significantly decreased LPR in patients in whom baseline brain lactate levels were increased, suggesting that NH improved the brain redox state. In patients with normal baseline brain lactate levels, we did not find any significant changes in the metabolic variables after NH. This suggests that the baseline metabolic state should be taken into account when applying NH to patients with TBI. This maneuver may only be effective in a specific group of patients.

Hyperbaric oxygen therapy promotes neurogenesis: where do we stand?

Neurogenesis in adults, initiated by injury to the central nervous system (CNS) presents an autologous repair mechanism. It has been suggested that hyperbaric oxygen therapy (HBOT) enhances neurogenesis which accordingly may improve functional outcome after CNS injury. In this present article we aim to review experimental as well as clinical studies on the subject of HBOT and neurogenesis. We demonstrate hypothetical mechanism of HBOT on cellular transcription factors including hypoxia-inducible factors (HIFs) and cAMP response element binding (CREB). We furthermore reveal the discrepancy between experimental findings and clinical trials in regards of HBOT. Further translational preclinical studies followed by improved clinical trials are needed to elucidate potential benefits of HBOT.

Combined hyperbaric oxygen and hypothermia treatment on oxidative stress parameters after spinal cord injury: an experimental study

BACKGROUND AND AIMS

We undertook this study to investigate the possible beneficial effects of combined hypothermia and hyperbaric oxygen (HBO) treatment in comparison with methylprednisolone in experimental spinal cord injury (SCI).

METHODS

Forty eight male Wistar albino rats (200-250 g) were randomized into six groups; A (normothermic control group; only laminectomy), B (normothermic trauma group; laminectomy + spinal trauma), C (normothermic methylprednisolone group; laminectomy + spinal trauma + methylprednisolone treated), D (hypothermia group; laminectomy + spinal trauma + hypothermia treated); E (HBO group; laminectomy + spinal trauma + HBO therapy), F (hypothermia and HBO group; laminectomy + spinal trauma + hypothermia and HBO treated) each containing eight rats. Neurological assessments were performed 24 h after trauma and spinal cord tissue samples had been harvested for both biochemical and histopathological evaluation.

RESULTS

After SCI, tissue malondialdehyde (MDA) level of the control group was measured increased, and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzyme activities were measured decreased. In group F, it was also shown that MDA level elevation had been prevented, and group F has increased the antioxidant enzyme activities than the other experimental groups C, D, E (p <0.05).

CONCLUSIONS

We concluded that the use of combined hypothermia and HBO treatment might have potential benefits in spinal cord tissue on secondary damage.

Pretreatment with normobaric and hyperbaric oxygenation worsens cerebral edema and neurologic outcomes in a murine model of surgically induced brain injury

BACKGROUND

Hyperbaric oxygenation is a readily available treatment modality, and its ability to improve neurological outcomes in a variety of animal models has been demonstrated. This study was designed to investigate the use of a single pretreatment regimen of either hyperbaric oxygenation or normobaric oxygenation to determine its effects in a murine model of surgically induced brain injury (SBI).

MATERIALS AND METHODS

Hyperbaric oxygen (2.5ATM, 1 h), normobaric oxygen (100% FIO2, 1 h) or room air (21% FIO2, 1 h) was applied on CD-1 mice immediately, or at 1, 2 or 3 h followed by SBI or sham surgical operation. Neurological assessment of the animals was done by a blinded observer at 24 and 72 h using a 21-point modified Garcia scale, wire hanging test, and beam balance test. The brain edema was evaluated using brain water content at 24 and 72 h after SBI.

RESULTS

There was no statistically significant difference in the mortality rate after treatment compared with the SBI group. The brain water content after SBI was significantly increased in the right (ipsilateral) frontal lobe surrounding the site of surgical resection compared with the sham group. Both hyperbaric and normobaric oxygen treatment significantly increased the brain edema and worsened the neurological outcomes using a 21-point Garcia score compared with the SBI group. The brain edema at 24 h after injury was most pronounced in the group treated with normobaric oxygenation 2 h prior to surgery. These differences disappeared at 72 h after SBI.

CONCLUSION

Immediate pretreatment with either hyperbaric (2.5ATM, 1 h) or normobaric oxygen (100% FIO2, 1 h) increased brain edema and worsened neurological function at 24 h following SBI.

Neuromodulation on cervical spinal cord combined with hyperbaric oxygen in comatose patients--a preliminary report

BACKGROUND

Because both SCS and HBO therapy have shown some promise in treating patients with states of reduced consciousness, we evaluated the combination of therapies in a prospective trial in comatose patients.

METHODS

Twelve patients who had received median nerve stimulation for 3 months without improvement in consciousness received cSCS for 1 year combined with simultaneous HBO therapy for the first 3 months. Another group enrolled 12 patients who received median nerve stimulation only were served as control.

RESULTS

Six patients emerged from coma at 1 year (after conclusion of treatment). Glasgow Coma Scale score, SPECT imaging, and PVS scores (state and reaction subscores) of the 12 patients were all significantly increased at 1 year compared with enrollment (P < .05). Neither respirator nor tracheostomy was needed to assist respiration in any patient. Only 1 of 12 patients still needed nasogastric tube feeding at 1 year. By contrast, control patients (without cSCS and HBO therapy) showed no apparent improvement.

CONCLUSION

Increase of GCS score, cerebral blood perfusion, and PVS scores were observed in comatose patients treated with combined cSCS and HBO therapy.

[Paradoxal gazous embolism in hepatic trauma. Contribution of hyperbaric oxygenotherapy]

A young man was admitted for a polytraumatism associating head trauma and blunt abdominal trauma with hepatic injury. He was managed with a damage control surgery with a perihepatic packing. During the second look surgery, he developed a paradoxal gazous embolism by air aspiration in the sus-hepatic vein. This has never been described before in such traumatism. The patient presented a respiratory distress, a circulatory shock due to right infarction and an intracranial hypertension with bilateral mydriasis. He was immediately treated by hyperbaric oxygenotherapy. The evolution was good and he recovered without sequelae.

Hyperbaric oxygen in neurosurgery

BACKGROUND

The therapeutic use of pure oxygen, even under hyperbaric conditions, has been well established for about 50 years, whereas the discovery of oxygen occurred 250 years earlier. Many neurosurgical patients suffer from brain tissue damage, due to reduced blood flow, obstructive vessel disease, or as a result of traumatic brain injury.

METHODS AND RESULTS

The application of pure oxygen in these patients is the only method of increasing the O(2) concentration in tissue with impaired blood supply and can minimize secondary impairment of brain tissue.

DISCUSSION

In this brief historical overview we focus on the development and evidence of hyperbaric oxygenation in this specific field of insufficient oxygen supply to the central neural tissue.

CONCLUSION

With the use of modern biological methods and new study designs, HBO has a place in evidence-based treatment of patients with neural tissue damage.

Bench-to-bedside review: oxygen as a drug

Oxygen is one of the most commonly used therapeutic agents. Injudicious use of oxygen at high partial pressures (hyperoxia) for unproven indications, its known toxic potential, and the acknowledged roles of reactive oxygen species in tissue injury led to skepticism regarding its use. A large body of data indicates that hyperoxia exerts an extensive profile of physiologic and pharmacologic effects that improve tissue oxygenation, exert anti-inflammatory and antibacterial effects, and augment tissue repair mechanisms. These data set the rationale for the use of hyperoxia in a list of clinical conditions characterized by tissue hypoxia, infection, and consequential impaired tissue repair. Data on regional hemodynamic effects of hyperoxia and recent compelling evidence on its anti-inflammatory actions incited a surge of interest in the potential therapeutic effects of hyperoxia in myocardial revascularization and protection, in traumatic and nontraumatic ischemicanoxic brain insults, and in prevention of surgical site infections and in alleviation of septic and nonseptic local and systemic inflammatory responses. Although the margin of safety between effective and potentially toxic doses of oxygen is relatively narrow, the ability to carefully control its dose, meticulous adherence to currently accepted therapeutic protocols, and individually tailored treatment regimens make it a cost-effective safe drug.

Traumatic brain injury: future assessment tools and treatment prospects

Traumatic brain injury (TBI) is widespread and leads to death and disability in millions of individuals around the world each year. Overall incidence and prevalence of TBI are likely to increase in absolute terms in the future. Tackling the problem of treating TBI successfully will require improvements in the understanding of normal cerebral anatomy, physiology, and function throughout the lifespan, as well as the pathological and recuperative responses that result from trauma. New treatment approaches and combinations will need to be targeted to the heterogeneous needs of TBI populations. This article explores and evaluates the research evidence in areas that will likely lead to a reduction in TBI-related morbidity and improved outcomes. These include emerging assessment instruments and techniques in areas of structural/chemical and functional neuroimaging and neuropsychology, advances in the realms of cell-based therapies and genetics, promising cognitive rehabilitation techniques including cognitive remediation and the use of electronic technologies including assistive devices and virtual reality, and the emerging field of complementary and alternative medicine.