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Although survival rates for acute respiratory distress syndrome have increased, there is only limited information regarding the quality of life and the relationship between quality of life and pulmonary function after survival. We prospectively measured pulmonary function, emotional function, and health-related quality of life in a cohort of acute respiratory distress syndrome survivors recruited from patients who were enrolled in a randomized clinical trial of high versus low tidal volume mechanical ventilation at 1 year after their recovery. No significant differences were found between the patients treated with high and low tidal volumes on any pulmonary function measure. Approximately 80% of the patients in both groups demonstrated reduced diffusing capacity; 20% had airflow obstruction, and 20% had chest restriction. Scores on measures of depression and anxiety were within the normal ranges, suggesting that they did not have significant affective symptoms. However, both groups reported decreased health-related quality of life in physical functioning, physical ability to maintain their roles (role-physical), bodily pain, general health, and vitality (energy) on the Medical Outcome Study Short Form Health Survey with similar physical limitations reported on the Sickness Impact Profile questionnaire. The pulmonary function abnormalities correlated with decreased health-related quality of life for domains reflecting physical function. Acute respiratory distress syndrome survivors treated with high and low tidal volumes have abnormal pulmonary function that was related to decreased health-related quality of life 1 year after hospital discharge. [ABSTRACT FROM AUTHOR]

Acute respiratory distress syndrome (ARDS) has a high mortality and is associated with significant morbidity. Prior outcome studies have focused predominant on short-term outcomes (6-12 months). We assessed longitudinal neurocognitive, emotional, and quality of life in ARDS survivors at hospital discharge, and 1 and 2 years after hospital discharge using neuropsychologic tests and emotional and quality-of-life questionnaires. Neurocognitive sequelae occurred in 73% (54 of 74) of ARDS survivors at hospital discharge, 46% (30 of 66) at 1 year, and 47% (29 of 62) at 2 years. ARDS survivors report moderate to severe depression (16% and 23%) and anxiety (24% and 23%) at 1 and 2 years, respectively. The ARDS survivors had decreased quality of life, with the physical domains improving at 1 year, with no additional change at 2 years. Role emotional, pain, and general health did not change from hospital discharge to 2 years. Mental health improved during the first year and declined at 2 years. ARDS results in significant neurocognitive and emotional morbidity and decreased quality of life that persists at least 2 years after hospital discharge. ARDS can cause significant long-term, brain-related morbidity manifest by neurocognitive impairments and decreased quality of life. [ABSTRACT FROM AUTHOR]

Primary objective: To assess cognitive sequelae, depression and anxiety following carbon monoxide (CO) poisoning. Research design: Prospective cohort study. Methods and procedures: This study prospectively followed 256 patients, 55 with less severe and 201 with more severe CO-poisoning. The prevalence of cognitive sequelae, depression and anxiety at 6 weeks, 6 months and 12 months was compared in patients with less severe and more severe CO-poisoning. Main outcomes and results: Of the less severe CO-poisoned patients, 39% had cognitive sequelae, 21% depression and 30% anxiety at 6 weeks. Of the more severe CO-poisoned patients, 35% had cognitive sequelae, 16% depression and 11% anxiety at 6 weeks. There was no difference in the prevalence of cognitive sequelae at any time. The prevalence of depression was higher in patients with less compared with more severe CO-poisoning at 6 months (p = 0.04), but not 6 weeks or 12 months. The prevalence of anxiety was higher in patients with less compared to more severe CO-poisoning at 6 weeks (p = 0.008), but not 6 or 12 months. Anxiety decreased over time in the less severe group (p < 0.01). Conclusion: CO-related cognitive sequelae, depression and anxiety are common and may be independent of poisoning severity. [ABSTRACT FROM AUTHOR]

Rationale: Carbon monoxide poisoning is common and causes cognitive sequelae. Hyperbaric oxygen (HBO(2)) reduces cognitive sequelae incidence, but which patients may benefit from HBO(2) is unclear. Objectives: Risk factor determination for 6-wk cognitive sequelae from CO poisoning and risk modification with HBO(2). Methods: Patients were from a randomized controlled trial, enrolling acutely CO-poisoned patients more than 15 years of age. Patients eligible but not enrolled in the randomized trial, and not receiving HBO(2), were followed during the study interval. In patients not receiving HBO(2), we performed univariate analyses including risk factors identified by randomized trial subgroup analyses. A multivariable analysis was performed using univariate results with and without HBO(2). Measurements and Main Results: In 163 patients not receiving HBO(2), 68 (42%) manifested sequelae. Risk factors for sequelae from subgroup analyses were loss of consciousness, age of 36 years or more, and carboxyhemoglobin levels greater than or equal to 25%. By univariate analyses, risks for sequelae were age of 36 years or more (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.3-4.9; P = 0.005), and exposure intervals greater than or equal to 24 hours (OR, 2.4; 95% CI, 1.2-4.8; P = 0.019). Including 75 patients receiving HBO(2), cognitive sequelae was reduced in patients age of 36 years or more (OR, 0.3; 95% CI, 0.2-0.6; P < 0.001). Exposure intervals greater than or equal to 24 hours are an independent risk factor for sequelae (OR, 2.0; 95% CI, 1.0-3.8; P = 0.046). Conclusions: HBO(2) oxygen is indicated for patients with acute CO poisoning who are 36 years or older or have exposure intervals greater than or equal to 24 hours. In addition, subgroup analyses support that patients with loss of consciousness or higher carboxyhemoglobin levels warrant HBO(2). [ABSTRACT FROM AUTHOR]

In this double-blind randomized trial, adults with persistent symptoms following non-stroke brain injury received 40 hyperbaric oxygen (HBO 2 ) sessions or 40 sham sessions over 12 weeks. Three months later, all were offered 40 unblinded HBO 2 sessions. Participants completed the Neurobehavioral Symptom Inventory (NSI) at baseline, 13 weeks (after 40 chamber sessions), 6 months, 9 months (after the second chamber series), and 12 months, with prime outcome at 13 weeks, and additional questionnaires, neuropsychological tests, and functional measures. We enrolled 49 participants and analyzed 47 due to drop-out/exclusion (26 males, 40 with traumatic brain injury). Baseline NSI was 35.9 ± 15.8 in the HBO 2 group (n = 26) and 30.7 ± 16.9 in the sham group (n = 21) (p = 0.28). Mean 13-week change scores were 10.6 ± 10.6 (HBO 2 group) and 3.6 ± 5.9 (sham group) (mean difference 7.0, 95% CI 1.7-12.3, p = 0.01). The HBO 2 group improved on measures of olfaction, anxiety, sleep difficulties, and vestibular complaints. Both groups reported improvements in depression, headaches, PTSD symptoms, physical quality of life, and degree to which difficulties interfere with daily life. With an additional 40 HBO 2 sessions, the original HBO 2 group reported additional improvements on NSI at 12 months. Only 15 original sham participants completed the second chamber series, limiting conclusions from that data., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Purpose: Our purpose was to determine changes in patient-reported hematuria and urinary symptoms after hyperbaric oxygen (HBO 2 ) treatment for radiation cystitis (RC)., Materials and Methods: We analyzed prospectively collected data from the Multicenter Registry for Hyperbaric Oxygen Therapy Consortium accumulated within a week of beginning and ending HBO 2 . Measures included the modified Radiation Therapy Oncology Group (RTOG) Hematuria Scale, Urinary Distress Inventory Short Form, and EuroQol Five Dimension Five Level instrument. RTOG hematuria and Urinary Distress Inventory Short Form scores were compared using the sign test. Logistic regression was used to evaluate characteristics associated with hematuria improvement., Results: A total of 470 registry patients had RC. The median age, number of HBO 2 sessions, and years after radiation were 73 (IQR 12) years, 39 (IQR 10) sessions, and 5 (IQR 8) years, respectively. Eighty-four percent of patients (393/470) had prostate cancer‒related radiation. EuroQol Five Dimension Five Level scores improved from 0.83 (IQR 0.14) to 0.85 (IQR 0.22; P < .001. Three hundred seventy patients had complete RTOG hematuria scores that improved from 2 (IQR 2) to 0 (IQR 2; P < .001. Two hundred forty-six patients had complete Urinary Distress Inventory Short Form ratings that decreased from 33.3 (IQR 44) to 22.2 (IQR 33; P < .001). Regression analysis of those with visible hematuria before HBO 2 showed lower improvement odds associated with higher HBO 2 hematuria scores (odds ratio [OR] 0.44, 95% CI 0.26-0.73; P < .01), a smoking history (OR 0.44, 95% CI 0.21-0.92; P = .03), or a nonprostate cancer history (OR 0.32, 95% CI 0.10-0.99; P = .05)., Conclusions: HBO 2 for RC improved reported hematuria, urinary function, and quality of life. Higher baseline hematuria scores, smoking, and nonprostate cancer history were associated with lower odds of hematuria improvement.

Despite established exposure limits and safety standards, and the availability of carbon monoxide (CO) alarms, each year an estimated 50,000 people in the United States visit emergency departments for CO poisoning. Carbon monoxide poisoning can occur from brief exposures to high levels of CO or from longer exposures to lower levels. If the CO exposure is sufficiently high, unconsciousness and death occur quickly, and without symptoms. With non-lethal exposures to CO, common symptoms include headaches, nausea and vomiting, dizziness, general malaise, and altered mental status. Some patients may have chest pain, shortness of breath, and myocardial ischemia, and may require mechanical ventilation and treatment of shock. Individuals poisoned by CO often develop brain injury. As with brain injury from non- CO causes such as traumatic brain injury, the clinical expression of brain injury caused by CO poisoning includes the domains of cognition, affect, neurological, and somatic. Common problems are neurological: imbalance, motor weakness, neuropathies, hearing loss, tinnitus, Parkinson's-like syndrome, vestibular, gaze, auditory processing, cognitive, anxiety and depression, posttraumatic stress, personality change, persistent headaches, dizziness, sleep problems, and others. In addition, some will have cardiac or other problems. While breathing oxygen hastens the removal of carboxyhemoglobin (COHb), hyperbaric oxygen (HBO 2 ) hastens COHb elimination and favorably modulates inflammatory processes instigated by CO poisoning, an effect not observed with breathing normobaric oxygen. Hyperbaric oxygen improves mitochondrial function, inhibits lipid peroxidation transiently, impairs leukocyte adhesion to injured microvasculature, and reduces brain inflammation caused by CO-induced adduct formation of myelin basic protein. Based upon supportive randomized clinical trials in humans and considerable evidence from animal studies, HBO 2 should be considered for all cases of acute symptomatic CO poisoning. Hyperbaric oxygen is indicated for CO poisoning complicated by cyanide poisoning, often concomitantly with smoke inhalation., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Objective: The present study was undertaken to evaluate high-quality care delivery in the context of provider goal-setting activities and a multidisciplinary care model using an electronic health record (EHR)-enabled pediatric lupus registry. We then determined associations between care quality and prednisone use among youth with systemic lupus erythematosus (SLE)., Methods: We implemented standardized EHR documentation tools to autopopulate a SLE registry. We compared pediatric Lupus Care Index (pLCI) performance (range 0.0-1.0; 1.0 representing perfect metric adherence) and timely follow-up 1) before versus during provider goal-setting activities and population management, and 2) in a multidisciplinary lupus nephritis versus rheumatology clinic. We estimated associations between pLCI and subsequent prednisone use adjusted for time, current medication, disease activity, clinical features, and social determinants of health., Results: We analyzed 830 visits by 110 patients (median 7 visits per patient [interquartile range 4-10]) over 3.5 years. The provider-directed activity was associated with improved pLCI performance (adjusted β 0.05 [95% confidence interval (95% CI) 0.01, 0.09]; mean 0.74 versus 0.69). Patients with nephritis in multidisciplinary clinic had higher pLCI scores (adjusted β 0.06 [95% CI 0.02, 0.10]) and likelihood of timely follow-up than those in rheumatology (adjusted relative risk [RR] 1.27 [95% CI 1.02, 1.57]). A pLCI score of ≥0.50 was associated with 0.72-fold lower adjusted risk of subsequent prednisone use (95% CI 0.53, 0.93). Minoritized race, public insurance, and living in areas with greater social vulnerability were not associated with reduced care quality or follow-up, but public insurance was associated with higher risk of prednisone use., Conclusion: Greater attention to quality metrics is associated with better outcomes in childhood SLE. Multidisciplinary care models with population management may additionally facilitate equitable care delivery., (© 2023 American College of Rheumatology.)

Background: Single-breath diffusing capacity for carbon monoxide (D LCO ) quantifies gas transfer in the lungs. D LCO measurement is affected by barometric pressure (Pb) and alveolar partial pressure of oxygen (PAO 2 ). The current equations for adjusting D LCO for Pb and PAO 2 may not be accurate given advances in test performance and technology. We quantify changes in D LCO with alterations in Pb in normal and COPD subjects, determine the accuracy of the current Pb and PAO 2 adjustment equations and develop updated adjustment equations., Methods: We measured D LCO in 13 normal and 10 COPD subjects at 1330 m altitude and in a hypobaric/hyperbaric chamber at altitudes of sea-level and 2500 m; six normal subjects were tested at 3600 m. We determined if there were significant differences in D LCO between altitudes. We developed an equation for adjusting D LCO for changes in Pb from sea-level. We compared this equation with the existing Pb adjustment equation in normal and COPD subjects. We determined the accuracy of the current PAO 2 adjustment equation and developed a new PAO 2 adjustment equation., Results: D LCO significantly increased with decreasing Pb. We developed a Pb adjustment equation that adjusts D LCO measured at altitudes between 1330 m and 3600 m to sea-level values. This Pb adjustment equation yields D LCO results that are not significantly different than the currently recommended equation. We developed a more accurate PAO 2 adjustment equation., Conclusion: D LCO measurement is significantly affected by altitude. We developed equations that accurately adjust D LCO for changes in Pb and PAO 2 in normal and COPD subjects., Competing Interests: Declarations of interest None., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Introduction: Hyperbaric oxygen (HBO₂) improves outcome in patients with acute carbon monoxide (CO) poisoning, but optimal dose/timing are unknown. In this double-blind, sham-controlled randomized trial, we compared neuropsychological sequelae at six weeks and six months in patients receiving three HBO₂ sessions or one HBO₂ session and two sham chamber sessions after acute CO poisoning., Methods: After completing one HBO₂ session (3.0 ATA, 60 minutes, 2.0 ATA, 65 minutes), CO-poisoned patients were randomized (1:1): two sham chamber sessions (1 ATA air, 120 minutes) or two additional HBO₂sessions (2.0 ATA, 90 minutes at pressure, 120 minutes in chamber) completed within 24 hours. Eligible patients were >24 hours from accidental poisoning, English-speaking, and not intubated. We planned 150 participants., Results: The study was stopped early for enrollment futility. From 2006 to 2016, we screened 395 patients: 136 were deemed eligible to participate, and 75 signed informed consent. Two were later withdrawn for past brain injury/PTSD (one sham, one HBO₂), and one for performance validity (sham). Of the 72 analyzed, mean age was 42 ± 15 years, 40 (56%) were male, 20 (28%) had loss of consciousness, and mean initial carboxyhemoglobin was 22 ± 9%. The rate of six-week neuropsychological sequelae was 50% in the one-HBO₂ session group and 55% in the three-HBO₂ sessions group (p = 0.80), and at six months was 42% versus 46%, respectively (p = 0.76)., Conclusions: There was no difference in the rate of neuropsychological sequelae in those who received three HBO₂ sessions and those who received one HBO₂ sessions and two sham sessions. The higher rate of neuropsychological sequelae compared to an earlier study may be due to neuropsychological test-retest effects or previously identified risk factors for cognitive sequelae (age, duration of poisoning, cerebellar dysfunction). This study's rates of cognitive difficulties, affective complaints, and other symptoms suggest brain injury after CO poisoning is common., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

How to deliver best care in various clinical settings remains a vexing problem. All pertinent healthcare-related questions have not, cannot, and will not be addressable with costly time- and resource-consuming controlled clinical trials. At present, evidence-based guidelines can address only a small fraction of the types of care that clinicians deliver. Furthermore, underserved areas rarely can access state-of-the-art evidence-based guidelines in real-time, and often lack the wherewithal to implement advanced guidelines. Care providers in such settings frequently do not have sufficient training to undertake advanced guideline implementation. Nevertheless, in advanced modern healthcare delivery environments, use of eActions (validated clinical decision support systems) could help overcome the cognitive limitations of overburdened clinicians. Widespread use of eActions will require surmounting current healthcare technical and cultural barriers and installing clinical evidence/data curation systems. The authors expect that increased numbers of evidence-based guidelines will result from future comparative effectiveness clinical research carried out during routine healthcare delivery within learning healthcare systems., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Clinicians often rely on measurement of carboxyhemoglobin (COHb) to confirm or rule out a diagnosis of carbon monoxide (CO) poisoning., Methods: We report two cases of false negative COHb in patients with CO poisoning and one case of false positive COHb in a patient without CO poisoning., Results: In the first case, a 20-year-old male developed headache, confusion, and near-syncope while operating a gasoline-powered pressure washer in an enclosed space. In the emergency department (ED), his COHb was 1.8%, but this level was disregarded, and he was referred for hyperbaric oxygen. His COHb just before hyperbaric oxygen was 4.1%, and later analysis of his blood collected at ED arrival revealed a COHb of 20.1%. The referral ED blood gas machine calibration and controls were within specification. In the second case, a 45-year-old male presented with several others to the ED with symptoms of CO poisoning after exposure at a conference. All others had elevated COHb levels, but his COHb was 2%. He was discharged but returned shortly with continued symptoms and requested his COHb be repeated. The repeat COHb was 17% (84 minutes after the first). After three hours of oxygen, his COHb was 7%. In the final case, an 83-year-old non-smoking male presented to an ED with breathlessness and tachypnea and was diagnosed with COVID-19 pneumonia. His COHb was 7.1%, but he reported living in an all-electric home. Another adult who lived with him and rode with him to the ED was asymptomatic and had a COHb of 3%. Later, COHb of 1.9% was measured from blood collected at ED arrival, and gas chromatography/mass spectrometry confirmed this result (2%)., Conclusions: COHb levels are not always accurate. Clinicians should use clinical judgment to manage their patients, including rejecting laboratory values that do not fit the clinical situation., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Decompression sickness (DCS) is a known complication of scuba diving. DCS occurs when bubbles are formed as pressure is reduced during and after ascent from a dive, following inert gas uptake during the dive. The bubbles cause inflammation and hypoxia. The definitive treatment for decompression sickness is hyperbaric oxygen therapy. We present a case of a healthy 16-year-old male who presented with decompression sickness and an incidental pulmonary cyst discovered by chest CT, likely congenital. The patient was successfully treated with U.S. Navy Treatment Table 6 (TT6) for his decompression sickness, but he continued to have chest pain, requiring hospitalization and consultation with pediatric pulmonology and cardiothoracic surgery from the cyst. Three years later he complained of chest pain with changes in altitude. Chest CT showed persistence of this cyst, and additional cysts. Case conference with pulmonologists and chest radiologist could not offer a definite etiology without lung biopsy, felt to not be indicated. We believe that the changes in pressure/volumes during the dives and TT6 exacerbated his pulmonary cyst., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Efficacious treatments against Acanthamoeba Keratitis (AK) is challenging, often ineffective and linked to the intragenotype variation in the drug efficacy. Increased oxygen can facilitate host response and can inhibit some organisms. Herein, we report the effect of increased oxygen concentrations on Acanthamoeba spp. growth and its effect on ROS (reactive oxygen species) production. The exposition to pure oxygen could reduce cell growth by at least 60% for Acanthamoeba castellanii Neff, Acanthamoeba polyphaga, and Acanthamoeba griffini. The increase in ROS production confirming that oxygen cell's growth inhibition was due to oxidative stress. Further studies are needed to determine oxygen saturation level, time of oxygen exposition, and number of sessions needed to eliminate the parasite., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Clinical decision-making is based on knowledge, expertise, and authority, with clinicians approving almost every intervention-the starting point for delivery of "All the right care, but only the right care," an unachieved healthcare quality improvement goal. Unaided clinicians suffer from human cognitive limitations and biases when decisions are based only on their training, expertise, and experience. Electronic health records (EHRs) could improve healthcare with robust decision-support tools that reduce unwarranted variation of clinician decisions and actions. Current EHRs, focused on results review, documentation, and accounting, are awkward, time-consuming, and contribute to clinician stress and burnout. Decision-support tools could reduce clinician burden and enable replicable clinician decisions and actions that personalize patient care. Most current clinical decision-support tools or aids lack detail and neither reduce burden nor enable replicable actions. Clinicians must provide subjective interpretation and missing logic, thus introducing personal biases and mindless, unwarranted, variation from evidence-based practice. Replicability occurs when different clinicians, with the same patient information and context, come to the same decision and action. We propose a feasible subset of therapeutic decision-support tools based on credible clinical outcome evidence: computer protocols leading to replicable clinician actions (eActions). eActions enable different clinicians to make consistent decisions and actions when faced with the same patient input data. eActions embrace good everyday decision-making informed by evidence, experience, EHR data, and individual patient status. eActions can reduce unwarranted variation, increase quality of clinical care and research, reduce EHR noise, and could enable a learning healthcare system., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The SARS-Cov-2 (COVID-19) pandemic remains a major worldwide public health issue. Initially, improved supportive and anti-inflammatory intervention, often employing known drugs or technologies, provided measurable improvement in management. We have recently seen advances in specific therapeutic interventions and in vaccines. Nevertheless, it will be months before most of the world's population can be vaccinated to achieve herd immunity. In the interim, hyperbaric oxygen (HBO2) treatment offers several potentially beneficial therapeutic effects. Three small published series, one with a propensity-score-matched control group, have demonstrated safety and initial efficacy. Additional anecdotal reports are consistent with these publications. HBO2 delivers oxygen in extreme conditions of hypoxemia and tissue hypoxia, even in the presence of lung pathology. It provides anti-inflammatory and anti-proinflammatory effects likely to ameliorate the overexuberant immune response common to COVID-19. Unlike steroids, it exerts these effects without immune suppression. One study suggests HBO2 may reduce the hypercoagulability seen in COVID patients. Also, hyperbaric oxygen offers a likely successful intervention to address the oxygen debt expected to arise from a prolonged period of hypoxemia and tissue hypoxia. To date, 11 studies designed to investigate the impact of HBO2 on patients infected with SARS-Cov-2 have been posted on clinicaltrials.gov. This paper describes the promising physiologic and biochemical effects of hyperbaric oxygen in COVID-19 and potentially in other disorders with similar pathologic mechanisms., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Objective: To describe the structural sequelae of carbon monoxide (CO) poisoning on the heart assessed using stress cardiac MRI (CMR). CO poisoning is common. While acute cardiac injury is frequent among survivors, the mid- and long-term effects of CO on the myocardium are unclear., Methods: CMR studies performed between the years 2005 and 2014 for a primary diagnosis of CO poisoning at a tertiary care center were reviewed by an experienced cardiologist. Variables of interest were compared between patients with normal and abnormal studies to identify factors associated with cardiac dysfunction., Results: Eighty-eight patients underwent stress CMR, age 34 years (range 11-70); 49% were male, 74 had acute poisoning and 14 had chronic poisoning (CO exposure for longer than 24 hours). Time from CO poisoning to imaging was 24 months (1 day-120 months). Patients were stratified into four categories, which included those with acute poisoning imaged: ≤12 months; 12-60 months; >60 months from the event; and those with chronic poisoning. Overall, 26 studies (30%) were abnormal. The most common findings were: left ventricular systolic dysfunction in 14 patients, right ventricular systolic dysfunction in nine, and LV dilatation in six. Abnormalities were mild in most cases and were equally prevalent in all four patient categories. Dyspnea at the time of follow-up was more frequent among those with abnormal studies., Conclusion: Mild alterations in ventricular structure and function are frequent in survivors of CO poisoning. Myocardial scarring is rare, suggesting that acute hypoxic injury may not fully explain these abnormalities., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Despite established exposure limits and safety standards as well as the availability of carbon monoxide (CO) alarms, each year 50,000 people in the United States visit emergency departments for CO poisoning. Carbon monoxide poisoning can occur from brief exposures to high levels of CO or from longer exposures to lower levels. Common symptoms can include headaches, nausea and vomiting, dizziness, general malaise, and altered mental status. Some patients may have chest pain, shortness of breath, and myocardial ischemia, and may require mechanical ventilation and treatment of shock. Individuals poisoned by CO often develop brain injury manifested by neurological problems, including cognitive sequelae, anxiety and depression, persistent headaches, dizziness, sleep problems, motor weakness, vestibular and balance problems, gaze abnormalities, peripheral neuropathies, hearing loss, tinnitus, Parkinsonian-like syndrome, and other problems. In addition, some will have cardiac issues or other ailments. While breathing oxygen hastens the removal of carboxyhemoglobin (COHb), hyperbaric oxygen (HBO2) hastens COHb elimination and favorably modulates inflammatory processes instigated by CO poisoning, an effect not observed with breathing normobaric oxygen. Hyperbaric oxygen improves mitochondrial function, inhibits lipid peroxidation transiently, impairs leukocyte adhesion to injured microvasculature, and reduces brain inflammation caused by the CO-induced adduct formation of myelin basic protein. Based upon three supportive randomized clinical trials in humans and considerable evidence from animal studies, HBO2 should be considered for all cases of acute symptomatic CO poisoning. Hyperbaric oxygen is indicated for CO poisoning complicated by cyanide poisoning, often concomitantly with smoke inhalation., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Introduction: Health care workers are vulnerable to workplace violence, including active shooter incidents. Little is known about how firearms could damage monoplace chamber acrylic and whether a breached pressurized chamber presents additional threat to the patient or bystanders., Methods: In a remote area where firearm discharge is permitted, we tested the durability of sections of monoplace hyperbaric chamber acrylic under various firearm discharges. Firearms were discharged at acrylic sections from a distance of 17 feet at 45 degrees and 10 degrees from perpendicular while wearing protective gear. Firearm calibers ranged from .22 caliber handgun to 5.56 mm AR-15 rifle. We also conducted similar testing on a monoplace hyperbaric chamber pressurized with >99% oxygen to a differential pressure of 14.7 psig (2.0 atmospheres absolute at sea level). Handguns were remotely fired at a distance of 12 feet from the chamber (30 degrees from perpendicular), while the rifles were fired at a distance of 60 feet from the chamber., Result: Higher-caliber handguns penetrated or fractured the acrylic sections only after multiple shots. The tested rifles caused full-thickness penetration and fracture with a single shot. However, the pressurized monoplace hyperbaric chamber required two shots from the AR-15 rifle, separated by approximately 60 mm, to penetrate the acrylic, resulting in rapid depressurization. The chamber otherwise remained intact, with no explosion or conflagration observed., Conclusion: An intact or pressurized chamber performs differently than stand-alone acrylic sections under firearms testing. In a worst-case active shooter scenario, the pressurized monoplace chamber tested posed no additional threat to bystanders beyond the significant risk of ricochet., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Background and Purpose: Routine MR imaging findings are frequently normal following mild traumatic brain injury and have a limited role in diagnosis and management. Advanced MR imaging can assist in detecting pathology and prognostication but is not readily available outside research settings. However, 3D isotropic sequences with ∼1-mm 3 voxel size are available on community MR imaging scanners. Using such sequences, we compared radiologists' findings and quantified regional brain volumes between a mild traumatic brain injury cohort and non-brain-injured controls to describe structural imaging findings associated with mild traumatic brain injury., Materials and Methods: Seventy-one military personnel with persistent symptoms and 75 controls underwent 3T MR imaging. Three neuroradiologists interpreted the scans using common data elements. FreeSurfer was used to quantify regional gray and white matter volumes., Results: WM hyperintensities were seen in 81% of the brain-injured group versus 60% of healthy controls. The odds of ≥1 WM hyperintensity in the brain-injured group was about 3.5 times the odds for healthy controls (95% CI, 1.58-7.72; P  = .002) after adjustment for age. A frontal lobe-only distribution of WM hyperintensities was more commonly seen in the mild traumatic brain injury cohort. Furthermore, 7 gray matter, 1 white matter, and 2 subcortical gray matter regions demonstrated decreased volumes in the brain-injured group after multiple-comparison correction. The mild traumatic brain injury cohort showed regional parenchymal volume loss., Conclusions: White matter findings are nonspecific and therefore a clinical challenge. Our results suggest that prior trauma should be considered in the differential diagnosis of multifocal white matter abnormalities with a clinical history of mild traumatic brain injury, particularly when a frontal predilection is observed., (© 2020 by American Journal of Neuroradiology.)

Despite the prevalence of combat-related mild traumatic brain injury (mTBI) and relatively high incidence of concurrent post-traumatic stress disorder (PTSD), the joint effect of these conditions on the brain is not well understood. Further, few studies in the mTBI or PTSD populations focus on cortical surface area measures, despite known disruptions to cytoarchitecture of the cortex. This study examines the effects of comorbid mTBI and PTSD on age-related surface area changes across the cortex, as compared with a group with mTBI only. While a direct comparison of PTSD versus non-PTSD groups showed little difference on surface area measures, several regions showed a decline in surface area, with increasing age and a significant PTSD-by-age interaction effect, indicating an age-dependent decrease in surface area in those with both mTBI and PTSD. The findings suggest an apparent age-accelerated shrinking of the cortical surface area in some regions when mTBI and PTSD are present, a pattern that was not consistently found in those with mTBI only. Among the several cortical regions with significant age-by-group interactions were bilateral posterior cingulate cortex (left: p  = 0.03; right: p  = 0.02), isthmus of the cingulate (left: p  = 0.016; right: p  = 0.001), and lateral orbitofrontal cortex (left: p  = 0.038; right: p  = 0.02). It is possible that these findings are related to a larger pattern of premature neurodegeneration and age-acceleration noted in those with long-term PTSD.

Carbon monoxide poisoning remains common in the United States. One component of effective prevention involves identification of scenarios in which poisoning occurs to guide development of appropriate interventions. This study was conducted to determine the significance of the problem of carbon monoxide poisoning occurring in US hotels, motels and resorts. This is a population-based case series of guests staying at US hotels, motels, and resorts from 2005 to 2018. Details of incidents and individuals poisoned with carbon monoxide were collected from online searches and professional experience of the authors. Data extracted included number of incidents and individuals poisoned, age of those poisoned, outcomes, source of carbon monoxide, and lodging type. From January 1, 2005 to December 31, 2018, 905 guests were poisoned in 115 identified incidents, including 22 fatalities. Children represented 16% of those poisoned and 27% of fatalities. Type of lodgings were hotels, motels, and resorts of all classes and located in a majority of states. Most poisonings were caused by natural gas fueled appliances and could likely have been prevented by an in-room carbon monoxide alarm. To reduce morbidity and mortality from unintentional CO poisoning in lodging facilities, government should mandate installation of in-room CO alarms, similar to the current requirement for smoke alarms., Competing Interests: The authors have no conflicts of interest to disclose.

Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are common outcomes for service members. Abnormal connectivity within neural networks has been reported in the resting brain of mTBI and PTSD patients, respectively; however, the potential role of PTSD in changes to neural networks following injury has not been studied in detail. Using a data-driven approach, the present analysis aimed to elucidate resting state functional connectivity in the default mode network (DMN) in those with mTBI only and those with comorbid mTBI and PTSD. A secondary analysis focused on distinct contributions by the anterior and posterior DMN components. Group-level independent component analysis was used to identify the DMN, and a dual-regression method was utilized to measure connectivity within the overall network and its anterior (medial prefrontal cortex) and posterior (posterior cingulate cortex) nodes. Connectivity within the overall DMN was significantly higher for the mTBI only group (p = 0.001), as compared to controls and mTBI + PTSD. For all subjects with mTBI, network connectivity correlated inversely with PTSD checklist score (p < 0.05). Additionally, distinct associations (p < 0.05) between medial prefrontal cortex connectivity and PTSD symptoms and, separately, posterior cingulate cortex connectivity and mTBI-related cognitive deficits were found. To our knowledge, this is the first study to report a differential relationship between DMN components and both post-traumatic symptoms and cognitive outcomes., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)

Post-traumatic stress disorder (PTSD) is commonly observed in military service members with mild traumatic brain injury (mTBI); however, the relationship between mTBI and PTSD is complex and not well understood. The present study aims to elucidate a link between the degree of alteration in limbic system-related white matter tracts and PTSD symptoms in an mTBI population. Diffusion-tensor imaging (DTI) with probabilistic tractography of the fronto-limbic pathways revealed decreased white matter integrity in the uncinate fasciculus in those with co-morbid mTBI and PTSD (n = 34), relative to those with only mTBI (n = 35). Additionally, fractional anisotropy (FA) and radial diffusivity (RD) measures in the bilateral uncinate fasciculus correlated with Post-Traumatic Stress Disorder Checklist Civilian version (PCL-C) scores, and primarily within the avoidance and re-experiencing domains. Findings from this study suggest the degree of traumatic injury within the limbic system could be directly related to post-traumatic stress and post-concussive symptoms, with disrupted white matter leading to significant PTSD outcomes.

The mTOR pathway is central to most cells. How mTOR is activated in macrophages and modulates macrophage physiology remain poorly understood. The tumor suppressor Folliculin (FLCN) is a GAP for RagC/D, a regulator of mTOR. We show here that LPS potently suppresses FLCN in macrophages, allowing nuclear translocation of the transcription factor TFE3, leading to lysosome biogenesis, cytokine production, and hypersensitivity to inflammatory signals. Nuclear TFE3 additionally activates a transcriptional RagD positive feedback loop that stimulates FLCN-independent canonical mTOR signaling to S6K and increases cellular proliferation. LPS thus simultaneously suppresses the TFE3 arm and activates the S6K arm of mTOR. In vivo, mice lacking myeloid FLCN reveal chronic macrophage activation, leading to profound histiocytic infiltration and tissue disruption, with hallmarks of human histiocytic syndromes like Erdheim-Chester Disease. Our data thus identify a critical FLCN-mTOR-TFE3 axis in myeloid cells, modulated by LPS, that balances mTOR activation and curbs innate immune responses.

Objectives: Hyperbaric oxygen (HBO2) exposure may enhance cardiorespiratory fitness. Exercise training and HBO2 exposure stimulate mitochondrial biogenesis, increase capillary density, and induce adaptive antioxidant mechanisms. We hypothesized that an exercise regimen of sprint interval training (SIT) while breathing HBO2 would lead to a greater improvement in exercise performance compared to the same training breathing ambient air., Methods: Healthy long-term intermediate-altitude residents, ages 20-39 years, with normal spirometry and cardiorespiratory fitness were randomized to two groups: one performing six sessions of a SIT regimen over two weeks in a hyperbaric chamber (1.4 ATA [141.9 kPa], FiO2=1.0); the other performing under ambient pressure conditions (0.85 ATA [86.1 kPa], FiO2=0.21). Training effect was evaluated by comparing incremental cycle ergometry cardiopulmonary exercise testing before and after the training regimen. The primary outcome measure was peak oxygen consumption (V̇O2), while secondary outcomes included additional exercise parameters. The effect of study group on exercise parameters was assessed using two-factor repeated measures ANOVA., Results: Of 58 participants randomized, 49 completed the training program and all cardiopulmonary exercise tests (n=23 HBO2, n=26 ambient). Both groups experienced an increase in peak V̇O2: 8.1% HBO2 and 7.1% ambient; the differences were not significant (p=0.50). Secondary parameters of peak work rate and peak V̇E experienced a significantly higher change in the HBO2 group compared to the ambient group (p=0.05 and p=0.03, respectively)., Conclusion: Cardiorespiratory fitness improved after a two-week SIT regimen, but improvement in peak V̇O2 was not significantly different between ambient and HBO2 groups., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Host-commensal interactions are critical for the generation of robust inflammatory responses, yet the mechanisms leading to this effect remain poorly understood. Using a murine model of cytokine storm, we identified that host microbiota are required to sustain systemic TLR-driven immune responses. Mice treated with broad-spectrum antibiotics or raised in germ-free conditions responded normally to an initial TLR signal but failed to sustain production of proinflammatory cytokines following administration of repeated TLR signals in vivo. Mechanistically, host microbiota primed JAK signaling in myeloid progenitors to promote TLR-enhanced myelopoiesis, which is required for the accumulation of TLR-responsive monocytes. In the absence of TLR-enhanced monocytopoiesis, antibiotic-treated mice lost their ability to respond to repeated TLR stimuli and were protected from cytokine storm-induced immunopathology. These data reveal priming of TLR-enhanced myelopoiesis as a microbiota-dependent mechanism that regulates systemic inflammatory responses and highlight a role for host commensals in the pathogenesis of cytokine storm syndromes.

To date, several Department of Defense (DoD) and civilian studies have evaluated hyperbaric oxygen for mild forms of traumatic brain injury. Prior to the DoD-sponsored "Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury (mTBI) (BIMA)" trial, none included post-intervention follow-up beyond three to six months. Post-hoc attempts at long-term follow-up were complicated by low participation and potential self-selection bias. BIMA planned for follow-up through 12 months but was amended to add post-concussive and post-traumatic stress disorder, quality of life, pain, depression, anxiety, and alcohol use assessments at 24 and 36 months. A total of 42 of 71 BIMA participants consented to extendedfollow-up, and 40 and 14 completed a 24- or 36-month visit, respectively, representing an overall response rate of 59% and 20%. Participants who completed extended follow-up were similar to the study group that did not in terms of demographics, perceived intervention allocation, and initial response to intervention. There were no significant differences at 24 or 36 months between intervention groups, and group mean scores were near pre-intervention values. This return to baseline could be due to waning treatment effect, selection bias, or participant or perception effects. Though BIMA implemented several participant retention strategies, more frequent participant contact and increased compensation might improve long-term retention in future studies. clinicaltrials.gov Identifier NCT01611194., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission.

Background: Audiology clinics have many tools available to evaluate auditory and vestibular complaints. However, many tools lack established normative ranges across the life span. We conducted this study to establish reference ranges across the life span for audiology/vestibular measures commonly used to evaluate patients with traumatic brain injury., Materials and Methods: In this repeated measures study, 75 adults, ages 18-65 years, without a history of traumatic brain injury, underwent robust auditory/vestibular evaluations three times over six months, including rotational chair, videonystagmography, computerized dynamic posturography, vestibular evoked myogenic potentials, and retinal fundoscopy., Results: Age effect was notable for transient evoked otoacoustic emissions, pure-tone audiometry, auditory brainstem response, auditory middle latency response, and auditory-steady state response at 4000 hertz (Hz). Older participants (50-65 years) were more likely to have delayed latency horizontal saccades, positional nystagmus, slowed lower-extremity motor control responses, and delayed latency ocular vestibular evoked myogenic potentials. Low to mid-frequency horizontal (0.003-4 Hz) and mid-frequency vertical (1-3 Hz) vestibulo-ocular reflex, otolith-mediated reflexes, dynamic visual acuity and balance measures were generally not influenced by age. Females had larger static subjective visual testing offset angles, longer cervical vestibular evoked myogenic potential P1 latency, faster velocity horizontal saccades, and quicker motor control latency for large backward translations than age-matched males., Conclusion: These reference ranges can be used to discern impairment within the auditory and vestibular pathway following traumatic brain injury in young to middle-aged adults., Id: TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT01925963., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Objective: Macrophage activation syndrome (MAS) is a life-threatening cytokine storm syndrome that occurs in patients with underlying rheumatic diseases. Preclinical and clinical data suggest that interferon-γ (IFNγ) is pathogenic in MAS, but how IFNγ may be linked to disease pathogenesis remains unknown. This study was undertaken to determine whether IFNγ signals synergize with systemic innate immune responses to drive the cytokine storm in a murine model of MAS., Methods: IFNγ-deficient mice were treated with 5 doses of the Toll-like receptor 9 (TLR-9) agonist CpG 1826, IFNγ, or a combination of the 2 stimuli over the course of 10 days. Immunopathologic features of MAS, including cytopenias, hepatitis, hepatosplenomegaly, and induction of inflammatory myelopoiesis, were assessed. Mixed bone marrow chimeras were created to determine whether TLR-9- and IFNγ receptor 1 (IFNγR1)-dependent signals induce enhanced myelopoiesis in a cell-intrinsic or cell-extrinsic manner., Results: IFNγ-deficient mice did not develop features of MAS when treated with repeated doses of either the TLR-9 agonist or IFNγ alone. In contrast, IFNγ-deficient mice treated with both the TLR-9 agonist and IFNγ developed cytopenias, hepatitis, and hepatosplenomegaly, reproducing major clinical features of MAS. TLR-9- and IFNγR1-dependent signals synergized to enhance myeloid progenitor cell function and induce myelopoiesis in vivo, which occurred through cell-extrinsic mechanisms and correlated with the induction of disease., Conclusion: These findings demonstrate that TLR-9-driven signals potentiate the effects of IFNγ to initiate murine MAS, and provide evidence that induction of inflammatory myelopoiesis is a common TLR-9- and IFNγ-dependent pathway that may contribute to the pathogenesis of MAS., (© 2018, American College of Rheumatology.)

Purpose: Eye movements may offer a sensitive method to measure response to intervention in mild traumatic brain injury (mTBI)., Methods: The Brain Injury and Mechanisms of Action of Hyperbaric Oxygen for Persistent Post-Concussive Symptoms after Mild Traumatic Brain Injury Study (BIMA) randomized 71 participants to 40 sessions of hyperbaric oxygen or sham. A companion normative study (Normal) enrolled 75 participants. An eye tracking system measured left and right eye movements for saccadic and smooth pursuit. At baseline two smooth pursuit tasks, circular and horizontal ramp, and four saccadic tasks, horizontal and vertical step, reading, and memory guided-on tasks differentiated BIMA from Normal participants. The change from baseline in these tasks were measured and compared between interventions and against Normal participants at 13 weeks and six-month follow-up using the two-sample t-test. The Holm-Bonferroni procedure was used to adjust for multiple testing., Results: Change from baseline in eyetracker measures for participants assigned to the hyperbaric oxygen arm did not significantly differ from those assigned to the sham arm at post-randomization time points 13 weeks and six months. Consistent shifts of BIMA participant values toward Normal values at 13 weeks and six months were observed for overall fixation duration, forward saccadic duration, and number of lines read for the reading task, number of misses on the memory guided-on task, and absolute intersaccadic interval velocity and absolute saccadic amplitude on the circular task. The distributions between Normal and BIMA participants were no longer statistically significantly different at 13 weeks and six months post enrollment for these measures., Conclusion: The baseline differences between BIMA and Normal suggest potential vulnerability of the smooth pursuit system and the saccadic system. During the six-month follow-up period, improvement toward Normal was seen on some measures in both the hyperbaric oxygen and sham intervention arms without difference between intervention groups., Ids: clinicaltrials.gov Identifiers NCT01611194 and NCT01925963., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Safety monitoring and successful blinding are important features of randomized, blinded clinical trials. We report chamber- and protocol-related adverse events (AEs) for participants enrolled in two randomized, double-blind clinical trials of hyperbaric oxygen (HBO2) for persistent post-concussive symptoms clinicaltrials.gov identifiers NCT01306968, HOPPS, and NCT01611194, BIMA), as well as the success of maintaining the blind with a low-pressure sham control arm. In both studies, participants were randomized to receive HBO2 (1.5 atmospheres absolute, >99% oxygen) or sham chamber sessions (1.2 atmospheres absolute, room air). In 143 participants undergoing 4,245 chamber sessions, chamber-related adverse events were rare (1.1% in the HOPPS study, 2.2% in the BIMA study). Minor, non-limiting barotrauma was the most frequently reported. Rarely, some participants experienced headache with chamber sessions. No serious adverse events were associated with chamber sessions. An allocation questionnaire completed after intervention revealed that the sham control arm adequately protected the blind in both trials. Participants based allocation assumptions on symptom improvement or lack of symptom improvement and could not discern intervention arm by pressure, smell, taste, or gas flow., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Introduction: Carbon monoxide (CO) poisoning causes hypoxia and inflammation, which could adversely affect muscle. We could find no published information about CO poisoning causing myositis., Case Report: A 53-year-old previously healthy female semi truck driver had CO poisoning from a faulty diesel engine exhaust intermittently over three months, culminating in an episode of acute CO poisoning, with syncope after exiting the truck at the end of the three-month period. Neuropsychological symptoms immediately after the acute poisoning event were followed by the development of fatigue, weakness and myalgias within two months and a diagnosis of "polymyositis" within four months. C-reactive protein and creatine kinase were elevated. Electromyogram showed pure myopathy without sensory abnormalities. Occult malignancy was ruled out. Thigh muscle biopsy revealed severe inflammatory myopathy and myonecrosis. Muscle specialist pathologists interpreted the biopsy as toxic or viral inflammatory myopathy, not polymyositis, with CO poisoning as the likely etiology. She received steroids and mycophenolate. Nineteen months later, a repeat biopsy was negative for inflammation or myopathic process. Alternative diagnoses were ruled out by clinical investigation and her course over the next five years., Conclusion: This patient's presentation and clinical course support a diagnosis of myositis from CO poisoning, although it is possible that the myositis was either idiopathic or post-viral (without evidence of a causative virus)., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright © Undersea and Hyperbaric Medical Society.)

Introduction: We evaluated magnetic resonance spectroscopy (MRS) in United States military personnel with persistent symptoms after mild traumatic brain injury (mTBI), comparing over time two groups randomized to receive hyperbaric oxygen or sham chamber sessions and a third group of normative controls., Methods: Active-duty or veteran military personnel and normative controls underwent MRS outcome measures at baseline, 13 weeks (mTBI group only), and six months. Participants received 3.0 Tesla brain MRS for analysis of water-suppressed two-dimensional (2D) multivoxel 1H-MRS of the brain using point resolved spectroscopy (PRESS) with volume selection localized above the lateral ventricles and within the brain parenchyma, of which one voxel was chosen in each hemisphere without artifact. Script-based automatic data processing was used to assess N-acetylaspartate (NAA), creatine (Cr), and choline (Cho). Metabolite ratios for white matter were then calculated for NAA/Cr (Area), Cho/Cr (Area), and Cho/NAA (Area). These ratios were compared using standard analysis methodology., Results: There were no observable differences between participants with mTBI and normative controls nor any observable changes over time in the NAA/Cr (area), Cho/Cr (area), and Cho/NAA (area) ratios. Similarly, the control and injured participants were indistinguishable., Discussion: While participants with mild TBI showed no difference in MRS compared to normative controls, our results are limited by the few voxels chosen and potentially by less sensitive MRS markers., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Purpose: Military service members often report both affective and vestibular complaints after mild traumatic brain injury (mTBI), but associations between symptoms and vestibular deficits can be subtle and inconsistent., Methods: From two complementary studies, one of military service members with persistent post-concussive symptoms after mTBI (NCT01611194) and the other of adult volunteers with no history of brain injury (NCT01925963), affective symptoms were compared to postural control, gait, otolith and visuospatial function., Results: The studies enrolled 71 participants with mTBI and 75 normative controls. Participants with mTBI had significantly reduced postural equilibrium on the sensory organization test (SOT), and more so in those with high anxiety or post-traumatic stress. Cervical and ocular vestibular evoked myogenic potentials (cVEMP; oVEMP) showed prolonged latencies in mTBI participants compared to controls; oVEMPs were significantly delayed in mTBI participants with high anxiety, post-traumatic stress or depression. A subset of the mTBI group had abnormal tandem gait and high anxiety. Anxiety, post-traumatic stress, and depression did not correlate with performance on the 6-Minute Walk Test, visuospatial neuropsychological measures, and the Satisfaction with Life Scale in the mTBI group., Conclusion: In this study military service members with mTBI reported affective symptoms, concurrently with vestibular-balance concerns. Worse scores on affective measures were associated with abnormal findings on measures of postural control, gait and otolith function., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Background: Dizziness and imbalance are common after mild traumatic brain injury (mTBI). Hyperbaric oxygen (HBO2) has been proposed for persistent post-concussive symptoms after mTBI, but its effect on vestibular function is unknown., Objective: To describe balance function in military service-members before and after intervention, and to explore the influence of post-traumatic stress disorder (PTSD), anxiety, and depression on vestibular outcomes., Methods: Seventy-one participants with mTBI and seventy-five healthy adults without brain injury were enrolled (NCT01611194 and NCT01925963). mTBI participants were randomized to 40 HBO2 sessions or 40 sham chamber sessions over 12 weeks. Normative controls received no intervention. Balance and neuropsychological function were measured at baseline, 13 weeks, and 6 months., Results: The mTBI cohort performed worse than healthy controls on balance and gait measures and reported more affective symptoms. Some within-group improvements were noted at 13 weeks and 6 months. Significant between-intervention differences on balance measures were minimal but effects on postural control generally favored HBO2. Those with affective symptoms, particularly PTSD, had the most improvement in postural control and otolith function following 13 weeks of HBO2., Conclusion: HBO2 may influence balance function after mTBI, particularly in those with affective symptoms.