Alternative Uses of Hyperbaric Oxygen Therapy in Military Medicine: Current Positions and Future Directions

Refractory Osteomyelitis in a Military Service Member Resolved With Adjunctive Hyperbaric Oxygen Therapy

Refractory osteomyelitis is typically defined as a chronic infection that persists or recurs despite definitive surgical management and antibiotic therapy. Cases often involve complex wounds or fractures and can be challenging to treat, resulting in multiple courses of broad-spectrum antibiotic therapy and numerous surgeries over periods of months to years. Adjuncts to improve resolution of these complicated infections are sorely needed. Here, we describe the case of a 47-year-old active duty military member who sustained an open right ankle fracture during a skydiving accident that was subsequently complicated by refractory osteomyelitis. The patient failed more than three courses of combined medical and surgical management over a 9-month period before undergoing adjunctive hyperbaric oxygen therapy (HBOT), ultimately resulting in resolution of the infection. Adjunctive HBOT for treatment of conditions such as refractory osteomyelitis may be an underutilized resource in part because of a general paucity of high-quality data in the literature supporting its use, as well as a relative lack of availability of this resource. Nonetheless, the overall accumulating body of evidence indicates that the use of adjunctive HBOT in select patients with refractory osteomyelitis is safe and effective and further research may be warranted given its relevance and potential impact to military populations.

Hyperbaric oxygen therapy as a neuromodulatory technique: a review of the recent evidence

Hyperbaric oxygen therapy (HBOT) has recently emerged as a promising neuromodulatory modality for treating several neurological and psychological disorders. Various studies indicate that HBOT can promote brain recovery and neuroplasticity through the modulation of key cellular and molecular mechanisms. HBOT affects multiple primary pathways and cellular functions including mitochondrial biogenesis and function (increased Bcl-2, reduced Bax, and enhanced ATP production), neurogenesis (upregulation of Wnt-3 and VEGF/ERK signaling), synaptogenesis (elevated GAP43 and synaptophysin expression), and anti-inflammatory responses (reduced TNF-α and IL-6). These mechanisms contribute to significant clinical benefits, such as enhanced cognitive function, improved recovery from traumatic brain injury and post-concussion syndrome, and symptom reduction in conditions like post-traumatic stress disorder and fibromyalgia. By influencing these molecular targets, HBOT offers a novel approach to neuromodulation that warrants further exploration. This review discusses the representative mechanisms of action of HBOT and highlights its therapeutic neuromodulatory effects and potential clinical applications across various neurological and psychiatric conditions.

mTBI Biological Biomarkers as Predictors of Postconcussion Syndrome-Review

Postconcussion syndrome (PCS) is one of the leading complications that may appear in patients after mild head trauma. Every day, thousands of people, regardless of age, gender, and race, are diagnosed in emergency departments due to head injuries. Traumatic Brain Injury (TBI) is a significant public health problem, impacting an estimated 1.5 million people in the United States and up to 69 million people worldwide each year, with 80% of these cases being mild. An analysis of the available research and a systematic review were conducted to search for a solution to predicting the occurrence of postconcussion syndrome. Particular biomarkers that can be examined upon admission to the emergency department after head injury were found as possible predictive factors of PCS development. Setting one unequivocal definition of PCS is still a challenge that causes inconsistent results. Neuron Specific Enolase (NSE), Glial Fibrillary Acidic Protein (GFAP), Ubiquitin C-terminal Hydrolase-L1 (UCH-L1), Serum Protein 100 B (s100B), and tau protein are found to be the best predictors of PCS development. The presence of all mentioned biomarkers is confirmed in severe TBI. All mentioned biomarkers are used as predictors of PCS. A combined examination of NSE, GFAP, UCH-1, S100B, and tau protein should be performed to detect mTBI and predict the development of PCS.

Oxidative Stress Response Kinetics after 60 Minutes at Different (1.4 ATA and 2.5 ATA) Hyperbaric Hyperoxia Exposures

Hyperbaric oxygen therapy (HBOT) is a therapeutical approach based on exposure to pure oxygen in an augmented atmospheric pressure. Although it has been used for years, the exact kinetics of the reactive oxygen species (ROS) between different pressures of hyperbaric oxygen exposure are still not clearly evidenced. In this study, the metabolic responses of hyperbaric hyperoxia exposures for 1 h at 1.4 and 2.5 ATA were investigated. Fourteen healthy non-smoking subjects (2 females and 12 males, age: 37.3 ± 12.7 years old (mean ± SD), height: 176.3 ± 9.9 cm, and weight: 75.8 ± 17.7 kg) volunteered for this study. Blood samples were taken before and at 30 min, 2 h, 24 h, and 48 h after a 1 h hyperbaric hyperoxic exposure. The level of oxidation was evaluated by the rate of ROS production, nitric oxide metabolites (NOx), and the levels of isoprostane. Antioxidant reactions were assessed through measuring superoxide dismutase (SOD), catalase (CAT), cysteinylglycine, and glutathione (GSH). The inflammatory response was measured using interleukine-6, neopterin, and creatinine. A short (60 min) period of mild (1.4 ATA) and high (2.5 ATA) hyperbaric hyperoxia leads to a similar significant increase in the production of ROS and antioxidant reactions. Immunomodulation and inflammatory responses, on the contrary, respond proportionally to the hyperbaric oxygen dose. Further research is warranted on the dose and the inter-dose recovery time to optimize the potential therapeutic benefits of this promising intervention.

Hyperbaric Oxygen Therapy for Veterans With Treatment-resistant PTSD: A Longitudinal Follow-up Study

INTRODUCTION

PTSD is common among veteran combatants. PTSD is characterized by brain changes, for which available treatments have shown limited effect. In a short-term study, we showed that hyperbaric oxygen therapy (HBOT) induced neuroplasticity and improved clinical symptoms of veterans with treatment-resistant PTSD. Here, we evaluated the long-term clinical symptoms of the participants of that study.

MATERIALS AND METHODS

Veterans from our short-term study were recruited 1 or more years after completing HBOT. The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) and self-reported questionnaires were administered at a single site visit. Changes in clinical scores between long-term, short-term, and pretreatment evaluations were analyzed.

RESULTS

Of the 28 participants who received HBOT during or following the short-term study, 22 agreed to participate in the current study. At a mean of 704 ± 230 days after completing the HBOT course, the mean CAPS-5 score (26.6 ± 14.4) was significantly better (lower) than at the pre-HBOT evaluation (47.5 ± 13.1, P < .001) and not statistically different from the short-term evaluation (28.6 ± 16.7, P = .745). However, for the CAPS-5 subcategory D (cognition and mood symptoms), the mean score was significantly better (lower) at long-term than at short-term evaluation (7.6 ± 5.1 vs. 10.0 ± 6.0, P < .001). At the long-term compared to the pretreatment evaluation, higher proportions of the participants were living with life partners (10 (46%) vs. 17 (77%), P = .011) and were working (9 (41%) vs. 16 (73%), P = .033). Decreases were observed between pretreatment and the long-term follow-up, in the number of benzodiazepine users (from 10 (46%) to 4 (18%), P = .07) and in the median (range) cannabis daily dose (from 40.0 g (0-50) to 22.5 g (0-30), P = .046).

CONCLUSIONS

The beneficial clinical effects of HBOT are persistent and were not attenuated at long-term follow-up of about 2 years after completion of HBOT. Additional long-term effects of the treatment were observed in social function and in decreased medication use.

Effect sizes for symptomatic and cognitive improvements in traumatic brain injury following hyperbaric oxygen therapy

Hyperbaric oxygen therapy has been proposed as a method to treat traumatic brain injuries. The combination of pressure and increased oxygen concentration produces a higher content of dissolved oxygen in the bloodstream, which could generate a therapeutic benefit for brain injuries. This dissolved oxygen penetrates deeper into damaged brain tissue than otherwise possible and promotes healing. The result includes improved cognitive functioning and an alleviation of symptoms. However, randomized controlled trials have failed to produce consistent conclusions across multiple studies. There are numerous explanations that might account for the mixed evidence, although one possibility is that prior evidence focuses primarily on statistical significance. The current analyses explored existing evidence by calculating an effect size from each active treatment group and each control group among previous studies. An effect size measure offers several advantages when comparing across studies, as it can be used to directly contrast evidence from different scales, and it provides a proximal measure of clinical significance. When exploring the therapeutic benefit through effect sizes, there was a robust and consistent benefit to individuals who underwent hyperbaric oxygen therapy. Placebo effects from the control condition could account for approximately one-third of the observed benefits, but there appeared to be a clinically significant benefit to using hyperbaric oxygen therapy as a treatment intervention for traumatic brain injuries. This evidence highlights the need for design improvements when exploring interventions for traumatic brain injury and the importance of focusing on clinical significance in addition to statistical significance.