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UHM Journal Ahead of Print

The UHMS now provides the Undersea and Hyperbaric Medicine Journal as an e-publication prior to print.  UHMS members and subscriber will have access to the full unedited paper once logged in. 



Renal abscess (RA) is a collection of infective fluid in or around the renal parenchyma. It typically occurs in immunocompromised patients including those with diabetes mellitus (DM), poor nutritional status, or steroid administration. We herein report a case of RA associated with DM in which hyperbaric oxygen (HBO2) therapy greatly contributed to the resolution of this disease. The patient was an 85-year-old man with poorly controlled type 2 DM. Contrast-enhanced computed tomography for postoperative follow-up of appendiceal cancer showed a mass lesion with poor contrast enhancement extending from the upper pole of the left kidney to the dorsal side. Therefore, a diagnosis of RA was established. The lesion was percutaneously punctured and a drainage tube was placed. Antibiotics following sensitivity testing was administered. The catheter was removed six days after its placement. However, pus discharge continued from the catheter removal site, with persistent redness around the wound. Therefore, lumbotomy incision for abscess drainage was performed on the 49th day. However, the pus discharge persisted, and we decided to perform HBO2 therapy, expecting decreases in bacterial proliferation, reduction in local edema, and improvement of host defense. HBO2 therapy for 90 min at two atmosphere absolute was performed 10 times. The amount of pus discharge decreased and redness improved ..
We present two cases of cricoid chondronecrosis treated with hyperbaric oxygen (HBO2) therapy. Both patients presented with biphasic stridor and dyspnea several weeks after an intubation event. Tracheostomy was ultimately performed for airway protection, followed by antibiotic treatment and outpatient HBO2 therapy. Both patients were decannulated within 6 months of presentation and after at least 20 HBO2 therapy sessions. Despite a small sample size, our findings are consistent with data supporting HBO2 therapy’s effects on tissue edema and neovascularization as well as HBO2 potentiation of antibiotic treatment and leukocyte function. We suggest HBO2 therapy may have accelerated airway decannulation by way of infection resolution as well as the revitalization of upper airway tissues, ultimately renewing the structural integrity of the larynx. Physicians should be aware of the potential benefits of HBO2 therapy when presented with this rare but significant clinical challenge. DOI: 10.22462/01.01.2023.30
Inner ear decompression sickness (IEDCS) is an uncommon diving-related injury affecting the vestibulocochlear system, with symptoms typically including vertigo, tinnitus and hearing loss, either in isolation or in combination. Classically associated with deep, mixed-gas diving, more recent case series have shown that IEDCS is indeed possible after seemingly innocuous recreational dives, and there has been one previous report of IEDCS following routine hyperbaric chamber operations. The presence of right-to-left shunt (RLS), dehydration and increases in intrathoracic pressure have been identified as risk factors for IEDCS, and previous studies have shown a predominance of vestibular rather than cochlear symptoms, with a preference for lateralization to the right side. Most importantly, rapid identification and initiation of recompression treatment are critical to preventing long-term or permanent inner ear deficits. This case reemphasizes the potential for IEDCS following uncomplicated diving and recompression chamber operations, as it is only the second reported incident of the latter, in a U.S. Navy diver with previously unidentified RLS. DOI: 10.22462/599
The hip is the most common location for avascular necrosis of the femoral head (AVN), with an estimated incidence in the United States of 10,000 to 20,000 new cases per year. The current standard of care for early disease is core decompression, with bone marrow injections becoming more commonplace. Hyperbaric oxygen enhances oxygen delivery to tissue, promotes an anti-inflammatory and pro-healing environment, and helps initiate angiogenesis. We believe that these properties of HBO2 make it a unique tool for AVN and applied it in conjunction with standard of care for our patient.   DOI: 10.22462/644
Throughout more than five decades a multitude of experimental and clinical studies has shown predominantly positive, but also controversial results on the efficacy of hyperbaric oxygen (HBO2) therapy in burns. Aim of the study was to define a common denominator or constellations, respectively, linked to the effects of HBO2 in burns with special focus on dosage parameters. Based on original work since 1965, species, number of individuals, type of study, percentage of total body surface area (TBSA), region, depth of burn, causative agent, interval between burn and first HBO2 session, pressure, duration of individual session, number of HBO2 sessions per day, cumulative number of HBO2 sessions and type of chamber were assessed. Out of 47 publications included, 32 were animal trials, four were trials in human volunteers and 11 clinical studies. They contained 94 experiments whose features were processed for statistical evaluation. 64 (67.4%) showed a positive outcome, 16 (17.9%) an ambiguous one and 14 (14.7%) a negative outcome. The only factor independently influencing the results was pressure with ATA (atmospheres absolute) lower than 3 ATA being significantly associated with better outcome (p=0.0005). There is a dire need for well-designed clinical studies in burn centers equipped with hyperbaric facilities to establish dedicated ..
In clinical management of carbon monoxide (CO) poisoning, serum cardiac enzyme biomarkers and electrocardiogram (ECG) are both highly recommended emergency check-ups to evaluate myocardial injuries. Medical imaging – including head CT or MRI – are not routine for CO poisoning emergency management. We herein report on a comatose patient who was diagnosed with cerebral infarction secondary to 24 hours previous acute CO poisoning, warned by a typical cerebral-type T waves on ECG in advance, and confirmed by a head MRI. Fortunately, the patient made a full recovery based on a timely treatment with medications and hyperbaric oxygen (HBO2) therapy. We would like to propose that a vital, stable, conscious CO poisoning patient who remains a higher risk for hemorrhagic or ischemic stroke should be closely monitored for potential neurological abnormalities, and a continuous ECG monitoring should be reinforced throughout the treatment. A head MRI or CT is a priority in evaluating the secondary cerebral stroke and should be arranged immediately in the event of an abnormal ECG or if unusual new symptoms are apparent. DOI:10.22462/630
Objective: To analyze Hyperbaric Oxygen Therapy Registry (HBOTR) data to determine physician productivity rates and understand the frequency of simultaneous patient supervision in the United States (US). Methods: Deidentified electronic health record data from all payers were prospectively collected from the HBOTR from 2013 to 2022 and retrospectively analyzed. We estimated the mean number of yearly hyperbaric oxygen therapy (HBO2) treatments per physician per workday. We analyzed physician productivity by counting the number of physicians who administered fewer than two HBO2 treatments daily on average and the ten most productive physicians. Results: There were 262,055 HBO2 sessions provided by 333 physicians at 53 facilities in 34 states from 2013 through 2022. The annual number of patients treated by all physicians, regardless of payer, increased by 51.4% from 2013 to 2019 (n = 736 vs. 1,160) before decreasing by 10.8% in 2022 (994). The mean number of treatments/workday/provider was 3.6 (SD: 3.4); 87.1% of physicians (n = 290) performed <two treatments/workday. Only two physicians (0.6%) performed an average of >8 treatments daily. Conclusions: HBO2 utilization has varied over time, but it markedly decreased in 2022, while practice patterns have remained consistent. Physicians across the US have consistently supervised ≤4 HBO2 sessions per day ..
[ RESEARCH ARTICLE [ Quantification of referrals received at two emergency-capable hyperbaric medicine centers QUANTIFICATION OF HYPERBARIC REFERRALS ABSTRACT Emergency hyperbaric oxygen treatment capability is limited in the United States, and there is little documentation of calls received by 24/7/365 centers. Our study aimed to calculate the number of calls received for urgent hyperbaric oxygen (HBO2). We logged calls from two HBO2 chambers on the East Coast of the United States that serve a densely populated region. The total number of emergency calls was 187 at the University of Maryland (UMD) and 127 at the University of Pennsylvania (UPenn). There were calls on 180 (46%) days during the study period at UMD and 239 (63%) days at UPenn. The most common indication was carbon monoxide toxicity. The peak month of calls was March. Emergency HBO2 calls are common, and more centers need to accept emergency cases. Additional data from geographically diverse centers would add generalizability to these results and capture more diving-related emergencies. Keywords: epidemiology; hyperbaric facilities; hyperbaric oxygen; intensive care medicine; medical conditions and problems Key points: A trend toward inadequate emergency hyperbaric oxygen therapy availability has recently been discussed. Calls received at two academic emergency-capable hyperbaric medicine centers were recorded for one ..
Effect of hyperbaric oxygen therapy on diabetes-related oral complications HYPERBARIC OXYGEN THERAPY IN DIABETES MELLITUS ABSTRACT Background: Diabetes Mellitus is a chronic disease characterized by uncontrolled blood sugar levels, which lead to end-organ damage. While the diagnosis and treatment of its complications have been extensively studied, the effect of Hyperbaric Oxygen Therapy (HBO2) on diabetes- related oral complications remains unexplored. Aim: This prospective clinical study aims to investigate the effect of HBO2 on diabetes-related oral complications. Methods: Twenty patients diagnosed with diabetic foot ulcers and scheduled for HBO2 were included in this study. We recorded stimulated and unstimulated saliva pH, buffering capacity, flow rate, and subjective symptoms such as dry mouth, halitosis, taste loss, difficulty swallowing, and clinical examination findings before HBO2 and after the 21st session. Results: Upon comparing the findings, we observed a significant decrease in dry mouth and halitosis, periodontal disease severity, and healing of candida-related stomatitis and angular cheilitis. Despite not reaching statistical significance for other saliva parameters, the unstimulated salivary flow rate increased to normal limits (0.3-0.4 ml/min) in 6 out of 8 patients with a flow rate of less than 0.25 ml/min. Conclusion: Our study investigated the effect of HBO2 on diabetes-related oral complications for the first time, highlighting symptomatic ..
 ABSTRACT A widely accepted belief is that Nathaniel Henshaw was the first practitioner of hyperbaric medicine. He is said to have constructed the first hyperbaric chamber where he treated several disorders and provided opportunities to prevent disease and optimize well-being. While there is little doubt Henshaw was the first to conceptualize this unique medical technology, careful analysis of his treatise has convinced this writer that his was nothing more than a proposal. Henshaw’s air chamber was never built. He would have failed to appreciate how its structural integrity could be maintained in the presence of enormous forces generated by envisioned changes in its internal pressure and, likewise, how its door could effectively seal the chamber during hypo-and hyperbaric use. Henshaw would have also failed to appreciate the limitations of his two proposed measuring devices and the toxic nature of one. Neither of these would provide any quantitative information. The impracticality of his proposed method of compressing and decompressing the chamber is readily apparent. So is the likely toxic accumulation of carbon dioxide within the unventilated chamber during lengthy laborious periods required to operate it. Henshaw recommended pressures up to three times atmospheric pressure and durations for acute conditions until their ..
Advanced high-pressure hyperbaric techniques in tunneling HIGH-PRESSURE TECHNIQUES IN TUNNELING   ABSTRACT Work in compressed air and diving are both occupational activities that have been around since the mid-19th century, and those undertaking their work under elevated pressure. Meeting the demand to go to “higher pressure for longer” in tunneling has lagged in diving, but both activities have found it necessary to adopt mixed gas breathing and saturation exposure techniques. This paper explains how work in hyperbaric conditions at high pressure is undertaken in tunneling and is illustrated by the hyperbaric activity likely to be involved in constructing a large-diameter road tunnel below a body of water such as an estuary. It also explores the practical differences between work in compressed air and diving. Keywords – decompression; hyperbaric; mixed gas; saturation; transfer under pressure; tunneling; Key points - the paper reviews work in compressed air in tunneling and describes the developing use of mixed gas and saturation exposure techniques in tunneling whilst highlighting important differences between the application of such techniques in tunneling and in diving. INTRODUCTION/BACKGROUND Work in compressed air is a construction technique developed in the mid-19th century in which compressed air is applied to a tunnel or shaft at a pressure equivalent ..
Acute effects of apnea bouts on hemoglobin concentration and hematocrit: a systematic review and meta-analysis APNEA AND HEMATOLOGICAL EFFECTS ABSTRACT Objective: This study aimed to systematically analyze the existing literature and conduct a meta-analysis on the acute effects of apnea on the hematological response by assessing changes in hemoglobin (Hb) concentration and hematocrit (Hct) values. Methods: Research in Pubmed, The Cochrane Library, and Web of Science was carried out for studies in which the main intervention was voluntary hypoventilation, and Hb and Hct values were measured. Risk of bias and quality assessments were performed. Results: Nine studies with data from 160 participants were included, involving both subjects experienced in breath-hold sports and physically active subjects unrelated to breath-holding activities. The GRADE scale showed a “high” confidence for Hb concentration, with a mean absolute effect of 0.57 g/dL over control interventions. “Moderate” confidence appeared for Hct, where the mean absolute effect was 2.45% higher over control interventions. Hb concentration increased to a greater extent in the apnea group compared to the control group (MD = 0.57 g/dL [95% CI 0.28, 0.86], Z = 3.81, p = 0.0001) as occurred with Hct (MD = 2.45% [95% CI 0.98, 3.93], Z = 3.26, p = 0.001). Conclusions: ..
Acute aortic dissection during scuba diving RUNNING HEAD: ACUTE AORTIC DISSECTION DURING SCUBA DIVING   ABSTRACT A 60-year-old man with hypertension and dyslipidemia complained of chest pain upon ascending from a maximum depth of 27 meters while diving.  After reaching the shore, his chest pain persisted, and he called an ambulance.  When a physician checked him on the doctor’s helicopter, his electrocardiogram (ECG) was normal, and there were no bubbles in his inferior vena cava or heart on a portable ultrasound examination.  The physician still suspected that he had acute coronary syndrome instead of decompression illness; therefore, he was transported to our hospital.  After arrival at the hospital, standard cardiac echography showed a flap in the ascending aorta.  Immediate enhanced computed tomography revealed Stanford type A aortic dissection.  The patient obtained a survival outcome after emergency surgery.  To our knowledge, this is the first reported case of aortic dissection potentially associated with scuba diving.  It highlights the importance of considering aortic dissection in patients with sudden-onset chest pain during physical activity. In addition, this serves as a reminder that symptoms during scuba diving are not always related to decompression. This report also suggests the usefulness of on-site ultrasound for the differential diagnosis of ..
Cardiovascular effects of breath-hold diving at altitude RUNNING HEAD: BREATH-HOLD DIVING AT ALTITUDE   ABSTRACT Hypoxia, centralization of blood in pulmonary vessels, and increased cardiac output during physical exertion are the pathogenetic pathways of acute pulmonary edema observed during exposure to extraordinary environments. This study aimed to evaluate the effects of breath-hold diving at altitude, which exposes simultaneously to several of the stimuli mentioned above. To this aim, 11 healthy male experienced divers (age 18-52y) were evaluated (by Doppler echocardiography, lung echography to evaluate ultrasound lung B-lines (BL), hemoglobin saturation, arterial blood pressure, fractional NO (Nitrous Oxide) exhalation) in basal condition (altitude 300m asl), at altitude (2507m asl) and after breath-hold diving at altitude. A significant increase in E/e’ ratio (a Doppler-echocardiographic index of left atrial pressure) was observed at altitude, with no further change after the diving session. The number of BL significantly increased after diving at altitude as compared to basal conditions. Finally, fractional exhaled nitrous oxide was significantly reduced by altitude; no further change was observed after diving. Our results suggest that exposure to hypoxia may increase left ventricular filling pressure and, in turn, pulmonary capillary pressure. Breath-hold diving at altitude may contribute to interstitial edema (as evaluated by BL score), possibly because ..
  Hyperbaric Oxygen Therapy Regimens, Treated Conditions, and Adverse Effect Profile RUNNING TITLE:  AN UNDERSEA AND HYPERBARIC MEDICAL SOCIETY SURVEY STUDY ABSTRACT Introduction: When administering HBO2, pressures can range from 1.4 atmospheres absolute (ATA) to 3 ATA. While different treatment modalities have been proposed, there is a paucity of literature comparing the effectiveness and risk profile associated with different pressures treating the same condition. Considering the therapeutic divergence, this study aims to survey Undersea and Hyperbaric Medical Society (UHMS) members on pressure modalities and their use in different clinical conditions. Methods: The study was a voluntary cross-sectional survey administered online and open to healthcare providers who were members of the Undersea and Hyperbaric Medical Society. UHMS itself distributed the survey link. The survey period lasted from November 2022 until January 2023. Data were collected utilizing the Qualtrics platform and analyzed through Microsoft Excel.  Results: A total of 265 responses were recorded. The majority responded utilizing 2.4 ATA (35.2%) as the pressure of choice, followed by 2.0 ATA only (27.1%), and those who changed therapeutic pressure according to the treated condition (26.4%). The overwhelming choice for treatment of osteoradionecrosis (ORN) of the jaw, radiation proctitis/cystitis, diabetic foot ulcer, and chronic osteomyelitis was 2.0 ATA (68.0- 74.9%).  Among listed ..
CMS Data Demonstrates a Cost and Clinical Advantage for Hyperbaric Oxygen for Radiation Cystitis, A Controlled Study John J. Feldmeier DO 1, John P. Kirby MD 2, Helen B. Gelly MD3 Marc Robins DO 4, John Peters FACHE 5 Peter Gruhn, MA6, Sarmistha Pal, PhD6 1. Professor Emeritus and Past Chairman, Radiation Oncology, University of Toledo Medical Center. 2. Associate Professor of Surgery, Washington University School of Medicine in St Louis, MO 3. President, Regenerative and Hyperbaric Medicine, Marietta, Georgia 4. Marc Robins, DO, MPH, FUHM, FAACP 5. John S. Peters, FACHE, ED UHMS 6. Peter Gruhn, M.A., Dobson DaVanzo and Associates, LLC 6. Sarmistha Pal, Ph.D., Dobson DaVanzo and Associates, LLC Key Words: controlled study; cost-effectiveness; clinical effectiveness; hyperbaric oxygen; radiation cystitis Running Title: Hyperbaric Oxygen for Radiation Cystitis Acknowledgments: 1. The Project was supported by an unrestricted grant from Healogics, LLC 2. The authors also wish to express their thanks to the following individuals for input and editorial review: a. Joan E. DaVanzo, Ph.D., M.S.W., Chief Executive Officer Dobson DaVanzo and Associates, LLC (deceased) b. John A. Gelly, MD, Retired Physician, Marietta, GA c. Costantino Balestra Ph.D., Professor of Physiology, Vrije Universiteit Brussel (V.U.B.) VP. Research & Education DAN Europe d. Renee Duncan, BA, UHMS Consulting Copy Editor CMS Data Demonstrates a Cost and Clinical Advantage for Hyperbaric ..
Title Optimizing the hyperbaric chamber pressurization profile during standard hyperbaric oxygen therapy SHORT, RUNNING TITLE: OPTIMIZING THE HYPERBARIC CHAMBER PRESSURIZATION PROFILE Authors Lyubisa Matity¹, Francois Burman², Frans Cronje3 Hyperbaric and Tissue Viability Unit, Gozo General Hospital, Victoria VCT 2520, Malta Divers Alert Network, Durham, NC, USA King Hamad American Mission Hospital, A’ali, Kingdom of Bahrain   ABSTRACT Middle ear barotrauma (MEBT) is the most common complication in providing hyperbaric oxygen therapy (HBOT). This study explored the impact of altering the shape of the time-pressure curve to reduce the occurrence of MEBT and optimize the HBOT experience during the pressurization process. Four distinct mathematically derived protocols—Constant Pressure Difference (CPD), Constant Volume Difference (CVD), Constant Ratio (CR), and Inverted Constant Ratio (ICR)—were investigated using computer simulations on a simple ear model. Results indicated varying levels of ear strain during pressurization. The CR pressurization demonstrated balanced ear strain levels and outperformed other modalities in several measures, including the impact on the simulated ear cavity volume. The potential for enhanced patient comfort through the application of sophisticated pressurization protocols warrants further research to validate and extend the findings of this study in real-world HBOT settings.  
Position change during hyperbaric oxygen therapy for arterial gas embolism Naoto Jingami, MD 1,2, Takayuki Nitta 1,2, Yoshitaka Ishiguro, MD 1, Yudai Takatani, MD 1, Tomoyuki Yunoki, MD 1, Shigeru Ohtsuru, MD 1,2 Department of Primary Care and Emergency Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan Hyperbaric Oxygen Therapy Center, Kyoto University Hospital, Kyoto, Japan Running title: Position change during hyperbaric oxygen therapy Arterial gas embolism can be fatal and should be treated with care. Typically, the patient is placed in the supine position during treatment. However, we present a case where the patient’s position was changed to facilitate treatment. A 78-year-old man with severely reduced heart function underwent cryoablation for chronic atrial fibrillation. During the procedure, he accidentally inhaled rapidly. Subsequently, he presented with stroke symptoms. Computed tomography (CT) revealed air in the brain and left ventricle, leading to a diagnosis of arterial gas embolism. He underwent hyperbaric oxygen (HBO2) therapy as per the US NAVY Table 6 protocol. The air embolism in the brain reduced, but that in the apex of the left ventricle persisted. Subsequently, HBO2, as per the US NAVY Table 5 protocol, was performed along with a position change to the right lateral and manual vibration. The ..
Definition of delayed-onset neurologic sequelae: A review article Alik Dakessian, MD1,2, Zachary Hagen, MD1, Eugenio R Rocksmith, MD3, Kinjal N Sethuraman, MD, MPH1,2,* 1Department of Emergency Medicine, University of Maryland School of Medicine, Baltimore, MD, United States of America 2Hyperbaric and Dive Medicine, University of Maryland Medical Center, Baltimore, MD, United States of America 3Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America   Background: Delayed-onset neurologic sequelae (DNS) is a devastating complication of carbon monoxide poisoning. Despite the abundance of research studies on DNS, the definition remains unclear, with a wide range of symptoms. The aim of this review is to identify the different symptoms and definitions that have been associated with DNS in available research.Methods: For this review, searches were conducted in both PubMed and Scopus. Research studies were screened by abstract and title by two authors and conflicts were resolved by a third. After the full-text review, data was extracted by one author. Only original full-text research studies in English with a clear definition of DNS were included.Results: A total of 127 studies were included in this review. Signs and symptoms associated with DNS were categorized into twelve groups. The most commonly used symptom categories to ..
  Hadrien Pique 2, Sigrid Theunissen 2, Costantino Balestra 1,2,3,4,5, Juani Valdivia 1, Oleg Melikhov 1 1 Association Internationnale pour le Développement de l'Apnée, AIDA International, Rue de l'Athénée 4, C/O Mentha Avocats, CH-1211 Genève 12, Switzerland 2           Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1160 Brussels 3           Anatomical Research and Clinical Studies, Vrije Universiteit Brussels (VUB), 1090 Brussels, Belgium 4           DAN Europe Research Division (Roseto-Brussels), Brussels, Belgium 5           Motor Sciences Department, Physical Activity Teaching Unit, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium   ABSTRACT Introduction Preterm birth may significantly impair the functional and anatomical development of the respiratory system and could be a background for various life-long medical sequelae. Prematurity has been recently connected to changes in hypercapnic reactions at adult age. Altered reactions to pCO2 in premature-born subjects may impact breath-hold underwater exercises (freediving) results. Methods AIDA International provided the list of top-100 rankings freediving athletes for the years 2016-2021 with their personal best results. Data was collected using a subject questionnaire developed for the study (subject-reporting outcomes). Period of data collection: from March 2022 to June 2022. Results Within the sample of divers (n=146), 17.1% (n=25) were born prematurely. 13.7% (n=20) were moderate to late preterm, and 3.4% (n=6) were very preterm. The proportion of the athletes whose birth was premature was 18.1% for females and 16.2% for males. ..
Author names and affiliations: Bin Zhang1, Hongjie Yi1, Yue Jiang1, Chenggang Zheng Department of Hyperbaric Oxygen, Changhai Hospital, Naval Medical University, 168 Changhai Rd, Shanghai, 200433, China. The authors contributed equally to this work.   Objective: To investigate the effect of 6 ATA air/ oxygen treatment schemes and 2.8 ATA oxygen inhalation schemes on cerebral gas embolism.  Methods: 29 patients with cerebral gas embolisms admitted from January 2014 to June 2022 were retrospectively included. The patients were divided into 6 ATA air/ oxygen treatment scheme groups (14 cases) and 2.8 ATA oxygen inhalation therapy scheme groups (15 cases). The Glasgow Coma Scale (GCS) was used to evaluate the therapeutic effect before and after treatment. The effective standard of treatment was the recovery of consciousness (a GCS score>8).  Results: There was no significant difference between the two groups regarding gender, age, cause of disease, time of onset, and GCS score before treatment (P>0.05). The two groups had no significant difference regarding GCS scores after one day and one week of treatment (P>0.05). After one week of treatment, 78.6% (11 of 14) of patients in the 6 ATA group and 80.0% (12 of 15) in the 2.8 ATA group improved by reaching primary end point of GCS >8.  Conclusion: The 2.8 ATA oxygen inhalation scheme can effectively treat cerebral gas ..