Emerging indications for hyperbaric oxygen

Hyperbaric oxygen attenuates chronic postsurgical pain by regulating the CD73/adenosine/A1R axis of the spinal cord in rats

Chronic postsurgical pain (CPSP) affects postoperative rehabilitation and quality of life in patients, but its mechanisms are still poorly understood. Hyperbaric oxygen (HBO) attenuates neuropathic pain in animal and human studies, but its efficacy for CPSP treatment and its underlying mechanism have not been elucidated. This study aimed to investigate the analgesic effect of HBO in a CPSP rat model and the role of spinal cord adenosine circulation in HBO-induced analgesia. A skin/muscle incision and retraction (SMIR) rat model was used to mimic CPSP, and HBO treatment (2.5 ATA, 60 min) was administered once daily for five consecutive days beginning three days after surgery. The role of spinal cord adenosine circulation in HBO-induced analgesia was investigated using APCP (a CD73 inhibitor), DPCPX (an A1R antagonist) or an intrathecal injection of adenosine. The mechanical paw withdrawal threshold (PWT) was determined at different time points before and after surgery. The spinal cord adenosine and ATP contents were analyzed using high-performance liquid chromatography (HPLC), and the spinal cord expression of A1R, CD73, and ADK was examined by Western blotting and immunofluorescence staining. The results showed that the mechanical PWT of the ipsilateral hind paw and the adenosine content decreased, and the spinal cord expression of A1R, CD73, and ADK and ATP content increased within 14 days after surgery. HBO treatment alleviated mechanical allodynia, reduced ATP content, and increased adenosine content by activating CD73 but downregulated the spinal cord expression of A1R, CD73, and ADK. Intrathecal adenosine alleviated mechanical allodynia after SMIR and downregulated the spinal cord expression of A1R and CD73, and intrathecal APCP or DPCPX attenuated the analgesic effect of HBO treatment on SMIR-induced CPSP. PERSPECTIVE: Spinal cord adenosine is involved in the occurrence and development of CPSP, and HBO treatment alleviates CPSP by regulating adenosine production/metabolism in the spinal cord. Thus, HBO may be employed for the treatment of CPSP with favorable efficacy.

Safety and performance of intravenous pumps and syringe drivers in hyperbaric environments

INTRODUCTION

Critically ill patients require continuation of their care when receiving hyperbaric oxygen treatment. This care may be facilitated via portable electrically powered devices such as intravenous (IV) infusion pumps and syringe drivers, which may create risks in the absence of a comprehensive safety evaluation. We reviewed published safety data for IV infusion pumps and powered syringe drivers in hyperbaric environments and compared the evaluation processes to key requirements documented in safety standards and guidelines.

METHODS

A systematic literature review was undertaken to identify English language papers published in the last 15 years, describing the safety evaluations of IV pumps and/or syringe drivers for use in hyperbaric environments. Papers were critically assessed in relation to the requirements of international standards and safety recommendations.

RESULTS

Eight studies of IV infusion devices were identified. There were deficiencies in the published safety evaluations of IV pumps for hyperbaric use. Despite a simple, published process for evaluating new devices, and available guidelines for fire safety, only two devices had comprehensive safety assessments. Most studies focused only on whether the device functioned normally under pressure and did not consider implosion/explosion risk, fire safety, toxicity, oxygen compatibility or risk of pressure damage.

CONCLUSIONS

Intravenous infusion (and other electrically powered) devices require comprehensive assessment before use under hyperbaric conditions. This would be enhanced by a publicly accessible database hosting the risk assessments. Facilities should conduct their own assessments specific to their environment and practices.

Hyperbaric Oxygen Therapy and Tissue Regeneration: A Literature Survey

By addressing the mechanisms involved in transcription, signaling, stress reaction, apoptosis and cell-death, cellular structure and cell-to-cell contacts, adhesion, migration as well as inflammation; HBO upregulates processes involved in repair while mechanisms perpetuating tissue damage are downregulated. Many experimental and clinical studies, respectively, cover wound healing, regeneration of neural tissue, of bone and cartilage, muscle, and cardiac tissue as well as intestinal barrier function. Following acute injury or in chronic healing problems HBO modulates proteins or molecules involved in inflammation, apoptosis, cell growth, neuro- and angiogenesis, scaffolding, perfusion, vascularization, and stem-cell mobilization, initiating repair by a variety of mechanisms, some of them based on the modulation of micro-RNAs. HBO affects the oxidative stress response via nuclear factor erythroid 2-related factor 2 (Nrf2) or c-Jun N-terminal peptide and downregulates inflammation by the modulation of high-mobility group protein B1 (HMGB-1), toll-like receptor 4 and 2 (TLR-4, TLR-2), nuclear factor kappa-B (NFκB), hypoxia-inducible factor (HIF-1α) and nitric oxide (NO•). HBO enhances stem-cell homeostasis via Wnt glycoproteins and mammalian target of rapamycin (mTOR) and improves cell repair, growth, and differentiation via the two latter but also by modulation of extracellular-signal regulated kinases (ERK) and the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathway. The HBO-induced downregulation of matrix metalloproteinases-2 and 9 (MMP-2/-9), rho-associated protein kinase (ROCK) and integrins improve healing by tissue remodeling. Interestingly, the action of HBO on single effector proteins or molecules may involve both up- or downregulation, respectively, depending on their initial level. This probably mirrors a generally stabilizing potential of HBO that tends to restore the physiological balance rather than enhancing or counteracting single mechanisms.

Adjunctive Hyperbaric Oxygen Therapy in Refractory Crohn's Disease: An Observational Study

Background and Aims

Patients may experience complications of Crohn's disease (CD) even when treated with optimal medical therapy strategies. Previous data have shown the efficacy of hyperbaric oxygen therapy (HBOT) in the management of complicated CD. However, there is no consensus regarding the optimal number of sessions or duration of treatment regimens. The aim of the present study was to investigate the efficacy of HBOT in CD patients who were refractory to conventional medical management.

Methods

This study included patients who underwent HBOT for the treatment of the following complications: perianal fistulizing Crohn's disease (pCD), enterocutaneous fistulas (ECF), or pyoderma gangrenosum (PG). Complete healing was defined as the closure of external orifice and the absence of active draining (in pCD), complete wound healing (in PG), and granulation or complete wound epithelialization with no enteric draining (in ECF). The persistence of draining and the absence of wound granulation were defined as incomplete healing.

Results

Forty patients were included. The mean CD duration was 10.6 ± 5.8 years. pCD comprised most of the included patients (25/62.5%), followed by ECF (n = 13/32.5%) and PG (n = 6/15%). In two patients (5%), a combination of ECF and PG was diagnosed, and in one patient (2.5%), all three complications were observed. A total of 32 patients (82.5%) had complete healing. Patients with PG had the highest healing rates (100%), followed by those with ECF (84.6%) and pCD (80%).

Conclusions

Adjunctive HBO was associated with significant healing rates for CD-associated complications such as pCD, ECF, and PG.

Bone marrow edema syndrome/transient osteoporosis of the hip joint and management with the utilization of hyperbaric oxygen therapy

Transient osteoporosis of hip (TOH) is a self-limited condition that affects young and middle aged women or men. The clinical manifestation is characterized by sudden or gradual onset of pain that is exacerbated on weight-bearing and at night. The treatment of TOH is either conservative or surgical. Conservative regimens include restriction of weight-bearing, pharmacological agents such as prostacyclin analogues (iloprost), non-steroid anti-inflammatory drugs (NSAIDs), extracorporeal shock wave and hyperbaric oxygen therapy (HBOT). Surgical intervention includes drilling or core decompression. The aim of this article is to review the clinical entity of TOH (clinical presentation, pathophysiology, diagnosis) and to further discuss the off-label utilization of HBOT as an alternative treatment regimen in patients suffering from TOH that fail to respond to other conservative methods.

Revisiting the expanded use of hyperbaric oxygen therapy for treatment of resistant migraines

There are currently 13 indications approved by the U.S. Food and Drug Administration for use of hyperbaric oxygen therapy. The European Consensus Conference on Hyperbaric Medicine has 28 indications approved for its use. However, neither includes the use of hyperbaric oxygen therapy for neurological conditions such as migraines with aura. Recent research has made the attempt to fully understand the use of hyperbaric therapy in treatment of neurological conditions, but results have so far been inconclusive. We report a 23-year-old female with an 11-year history of migraines with aura who has received inadequate pharmacological treatment for her migraines since she began having them. Migraines have led her to significant loss of function. The patient underwent treatment at 1.5 absolute atmospheres in a hyperbaric chamber Monday through Friday for 1 hour each day for a total of 40 sessions but reported missing a few sessions over the 8-week period. No more than 1 session during a given week was missed and the patient received no other treatments for her migraines throughout this time period. By her 24th treatment, the patient had only experienced a single migraine with aura but without debilitating pain. The patient stated she had never had a migraine with such little intensity prior to initiation of hyperbaric treatment and did not have to take any days off from work or school. Follow-up at the end of her 40-day treatment period revealed a highly-satisfied patient who had only experienced the single episode of a mild migraine during the entire course of treatment. Thus, we believe that further research needs to be done to realize the full potential of hyperbaric oxygen therapy in the treatment of neurological conditions as this case highlights the potential for using hyperbaric oxygen therapy as prophylaxis against attacks in patients with treatment resistant migraines with aura.