OBJECTIVE: Hyperbaric oxygen therapy (HBOT) has been reported to improve neurological function in the chronic phase of stroke in a single trial having significant limitations, including a lack of a sham control.
METHODS: We conducted a single-center, parallel-group, randomized trial to determine the effectiveness of HBOT compared with a sham control in adults who were 6 to 36 months post-ischemic stroke. The treatment group received 40 sessions of HBOT at the Vancouver General Hospital Hyperbaric Unit. The control group received 40 sessions of sham treatment designed to replicate an HBOT experience. Due to recruitment challenges and timeline/feasibility tracking by the research team, the control arm was altered after 20 months to a waitlist in the hope of increasing participation. In the second phase, participants were randomized to receive HBOT immediately or following an eight-week observation period. The primary outcome was the post-treatment Stroke Impact Scale-16 (SIS-16). Secondary outcomes included the National Institute of Health Stroke Scale, Berg Balance Test, Digit Symbol Substitution Test, 5-Metre Walk Test, 6-Minute Walk Test, Grip Strength, Montreal Cognitive Assessment, Box/Block Test, and Center for Epidemiological Studies - Depression and Short Form-36. Based on detecting a clinically important between-group difference of 10 on the SIS-16 score, our target sample size was 68 participants per arm.  Results: From January 5, 2016 to October 9, 2018, 34 participants were enrolled in the trial, 27 during the first phase and seven in the second phase. The study was stopped after 36 months, and prior to meeting the sample size target, due to low recruitment. At the end of treatment, the difference in the SIS-16 between groups was 5.5 (95% CI: 1.3 to 9.7, p = 0.01) in favor of the sham group.
CONCLUSIONS: Our results exclude a clinically important benefit of HBOT on the primary outcome of the SIS-16. These findings do not support the use of HBOT in chronic stroke survivors.

A 78-year-old man with dementia experienced waxing and waning of symptoms with changes in altitude as he traveled from his home in the Rocky Mountains to lower elevations and back. To replicate the improvement in his symptoms with travel to lower elevations (higher pressure), the patient was treated with a near-identical repressurization in a hyperbaric chamber using compressed air. With four 1-h treatments at 1.3 Atmospheres Absolute (ATA) and concurrent administration of low-dose oral glutathione amino acid precursors, he recovered speech and showed improvement in activities of daily living. Regional broadcast media had documented his novel recovery. Nosocomial COVID-19 and withdrawal of hyperbaric air therapy led to patient demise 7 months after initiation of treatment. It is theorized that hyperbaric air therapy stimulated mitochondrial biochemical and physical changes, which led to clinical improvement.

UNASSIGNED: Inhalation of high concentrations of carbon dioxide (CO₂) at atmospheric pressure can be toxic with dose-dependent effects on the cardiorespiratory system or the central nervous system. Exposure to both hyperbaric and hypobaric environments can result in decompression sickness (DCS). The effects of CO₂ on DCS are not well documented with conflicting results. The objective was to review the literature to clarify the effects of CO₂ inhalation on DCS in the context of hypobaric or hyperbaric exposure.
UNASSIGNED: The systematic review included experimental animal and human studies in hyper- and hypobaric conditions evaluating the effects of CO₂ on bubble formation, denitrogenation or the occurrence of DCS. The search was based on MEDLINE and PubMed articles with no language or date restrictions and also included articles from the underwater and aviation medicine literature.
UNASSIGNED: Out of 43 articles, only 11 articles were retained and classified according to the criteria of hypo- or hyperbaric exposure, taking into account the duration of CO₂ inhalation in relation to exposure and distinguishing experimental work from studies conducted in humans.
UNASSIGNED: Before or during a stay in hypobaric conditions, exposure to high concentrations of CO₂ favors bubble formation and the occurrence of DCS. In hyperbaric conditions, high CO₂ concentrations increase the occurrence of DCS when exposure occurs during the bottom phase at maximum pressure, whereas beneficial effects are observed when exposure occurs during decompression. These opposite effects depending on the timing of exposure could be related to 1) the physical properties of CO₂, a highly diffusible gas that can influence bubble formation, 2) vasomotor effects (vasodilation), and 3) anti-inflammatory effects (kinase-nuclear factor and heme oxygenase-1 pathways). The use of O₂-CO₂ breathing mixtures on the surface after diving may be an avenue worth exploring to prevent DCS.

UNASSIGNED: Bupivacaine hydrochloride is widely used as the primary drug for spinal anesthesia.
UNASSIGNED: This research aimed to evaluate the intrathecal administration of both isobaric and hyperbaric bupivacaine (HB) in lower abdominal surgery.
UNASSIGNED: A randomized, controlled, double-blind trial was conducted on 50 patients classified as American Society of Anesthesiologists (ASA) class I to II, scheduled for lower abdominal surgery under spinal anesthesia. The patients were allocated randomly into two groups of similar size. Group A (control group) received 20 mg HB 0.5% intrathecally. Group B (case group) received 10 mg HB 0.5% and 10 mg isobaric bupivacaine (IB) 0.5%.
UNASSIGNED: There was a significant decline in heart rate and mean arterial pressure in Group A compared to Group B (P < 0.05). Group A had a significantly greater sensory level at 10 and 20 minutes than Group B (P = 0.008 and 0.006, respectively). Group A had an earlier duration in reaching Bromage 3 and the first need for analgesia, compared to group B (P = 0.001 and 0.003, respectively).
UNASSIGNED: In lower abdominal surgery, the intrathecal administration of HB with IB increased hemodynamic stability and duration of both sensory and motor blockade but with slower recovery from anesthesia compared to HB alone.

UNASSIGNED: SCUBA diving exposes participants to a unique hyperbaric environment, but few studies have examined the effects of such an environment on intraocular pressure (IOP) and glaucoma. This systematic review aims to consolidate recent literature findings regarding the impact of increased atmospheric pressure on IOP and glaucoma.
UNASSIGNED: Three online databases were searched to identify publications encompassing the subjects of diving or increased atmospheric pressure in conjunction with IOP or glaucoma. Three reviewers independently screened the publications and identified eligible articles. Relevant data was extracted from each article. The heterogeneity of the data precluded the conduct of a meta-analysis.
UNASSIGNED: Nine studies met the inclusion criteria. Six experimental studies employed hyperbaric chambers to measure IOP under simulated diving conditions. Among these, IOP exhibited a reduction with increased atmospheric pressures in four studies, while the findings of two studies were inconclusive. One study measured IOP pre- and post-dive and another measured IOP with and without a diving mask. Post-dive, a decrease in IOP was observed, and a statistically significant reduction was noted when subjects wore a diving mask. A retrospective study examining the incidence of acute angle closure glaucoma attack found no association with weather or atmospheric pressure.
UNASSIGNED: The majority of studies found IOP to decrease with increased atmospheric pressure and after diving. The mechanisms underlying this reduction remain incompletely understood, with potential contributors including changes in ocular blood flow, sympathetic responses, and increased oxygenation. Hyperbaric chambers may have potential in future glaucoma treatments, but more studies are required to draw reliable conclusions regarding the safety of diving for glaucoma patients.

Extracorporeal gas exchange therapies evolved considerably within the first three-four decades of their appearance, and have since reached a mature stage, where minor alterations and discrete fine-tuning might offer some incremental improvement. A different approach is introduced here, making use of modern, purely diffusive membrane materials, and taking advantage of the elevated concentration gradient ensuing from gas pressure buildup in the gas chamber of the oxygenator. An assortment of silicone membrane gas exchangers were tested in vitro as per a modified protocol in pursuance of assessing their gas exchange efficiency under both regular and high-pressure aeration conditions. The findings point to a stark performance gain when pressurization of the gas compartment is involved; a 40% rise above atmospheric pressure elevates oxygen transfer rate (OTR) by nearly 30%. Carbon dioxide transfer rate (CTR) does not benefit as much from this principle, yet it retains a competitive edge when higher gas flow/blood flow ratios are employed. Moreover, implementation of purely diffusive membranes warrants a bubble-free circulation. Further optimization of the introduced method ought to pave the way for in vivo animal trials, which in turn may potentially unveil new realms of gas exchange performance for therapies associated with extracorporeal circulation.

UNASSIGNED: The World Health Organization defines long COVID as \"the continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation.\" Estimations of approximately 50 million individuals suffer from long COVID, reporting low health-related quality of life. Patients develop ongoing persistent symptoms that continue for more than 12 weeks that are not explained by another alternative diagnosis. To date, no current therapeutics are effective in treating the underlying pathophysiology of long COVID.
UNASSIGNED: A comprehensive literature search using PubMed and Google Scholar was conducted and all available articles from November 2021 to January 2024 containing keywords long covid and hyperbaric oxygen were reviewed. These published studies, including case series and randomized trials, demonstrate that utilizing Hyperbaric Oxygen Therapy (HBO) provided significant improvement in patients with long COVID.
UNASSIGNED: A large cohort of patients suffer from long COVID or post-COVID-19 syndrome after recovery from their acute infection with no effective treatment options. HBO is a safe treatment and may provide benefit for this population and should continue to be researched for adjunctive treatment of long COVID.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) involves patients breathing 100% oxygen in a pressurized chamber, above 1 atmosphere. Many centers are now promoting the use of HBOT for skin rejuvenation. However, the current indications for HBOT do not encompass aesthetic applications.
OBJECTIVE: The aim of this evidence-based review was to assess the existing literature regarding the utilization of HBOT in medical aesthetics and rejuvenation, evaluate its effectiveness and safety, and conduct a cost analysis.
METHODS: PubMed Interface, Cochrane Library, Google Scholar, and Embase searches were carried out. The Best Bets methodology was used, and the risk of bias was appraised using the Quality Assessment Tool for Quantitative Studies.
UNASSIGNED: This review included a total of 17 human studies with a total of 766 participants. Three studies were classified as level II evidence, three studies were of level III evidence, and 11 were of level IV evidence. All the included studies were judged at high risk of bias. The most relevant findings supported by level II evidence were that HBOT decreased the shedding rate post-FUE hair transplant (27.6 ± 2.6% vs. 69.1 ± 2.4%) but this did not affect the final outcome between HBOT (96.9 ± 0.5%) and the control (93.8 ± 0.6%). Moreover, level III evidence demonstrated that following HBOT, there was a significant increase in elastic fiber length (p ≤ 0.0001, effect size = 2.71) and a significant decrease in fiber fragmentation (p = 0.012). There was also a significant increase in collagen fiber density following HBOT (p = 0.0001, effect size = 1.10). However, there was no significant effect of antioxidant vitamins A, C, and E with HBOT. The inflammatory response significantly decreased after 7 days of HBOT with a decreased expression of IL-12p40, MIP-1β, and PDGF-BB and a higher expression of IL-1Ra. Moreover, HBOT was used prophylactically prior to abdominoplasty to decrease the risk of complications. In this study, complications were decreased from 32.6% (89 patients) to 8.4% (7 patients) with a p < 0.001, and in a multivariate analysis, preoperative HBOT was an independent protective factor against postoperative complications (p < 0.001).
CONCLUSIONS: There is conflicting evidence on how the method of action of HBOT can have a beneficiary effect in aesthetic and whether the treatment is justifiable. To our knowledge, this is the first comprehensive review discussing the available evidence regarding the use of HBOT in many aesthetic clinical scenarios, including preventive, medical, and surgical settings. However, randomized clinical trials with longer follow-up and better patient selection are needed to be able to generate a reliable conclusion.

UNASSIGNED: Improving oxygen delivery to challenging wound types has been shown to optimize and accelerate several key contributors to healing. This study aims to compare selective skin substitutes and primary dressings and evaluate their ability to transfer oxygen to the wound.
UNASSIGNED: Visual and quantitative methods were employed to measure gas and fluid movement across several skin substitutes, including a bilayer nylon and silicone dressing coated with porcine gelatin and aloe vera (CNS), a porous bovine collagen-glycosaminoglycan (GAG) matrix dressing coated with silicone (UBC), and a urethane biodegradable temporizing matrix (PFD).
UNASSIGNED: Fluids did not move across solid silicone membranes or urethane foam while oxygen movement across solid silicone membranes was inversely proportional to the thickness of the membrane. Oxygen moved across the coated nylon and silicone dressing 5.63 times faster than across the bovine-GAG scaffold and 2.0 times faster than the biodegradable temporizing matrix of polyurethane.
UNASSIGNED: The coated nylon and silicone matrix functioned like a membrane oxygenator, potentially augmenting atmospheric oxygen delivery to healing wounds.

Individual susceptibility to pulmonary oxygen toxicity (PO2tox) is highly variable and currently lacks a reliable biomarker for predicting pulmonary hyperoxic stress. As nitric oxide (NO) is involved in many respiratory system processes and functions, we aimed to determine if expired nitric oxide (FENO) levels can provide an indication of PO2tox susceptibility in humans. Eight U.S. Navy-trained divers volunteered as subjects. The hyperoxic exposures consisted of six- and eight-hour hyperbaric chamber dives conducted on consecutive days in which subjects breathed 100% oxygen at 202.65 kPa. Subjects\' individual variability in pulmonary function and FENO was measured twice daily over five days and compared with their post-dive values to assess susceptibility to PO2tox. Only subjects who showed no decrements in pulmonary function following the six-hour exposure conducted the eight-hour dive. FENO decreased by 55% immediately following the six-hour oxygen exposure (n = 8, p < 0.0001) and by 63% following the eight-hour exposure (n = 4, p < 0.0001). Four subjects showed significant decreases in pulmonary function immediately following the six-hour exposure. These subjects had the lowest baseline FENO, had the lowest post-dive FENO, and had clinical symptoms of PO2tox. Individuals with low FENO were the first to develop PO2tox symptoms and deficits in pulmonary function from the hyperoxic exposures. These data suggest that endogenous levels of NO in the lungs may protect against the development of PO2tox.