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Decompression sickness (DCS) occurs when nitrogen gas (N2) comes out of solution too quickly, forming bubbles in the blood and tissues. These bubbles can be a serious condition; thus it is of extreme interest in the dive community to model DCS risk. Diving models use tissue compartments to calculate tissue partial pressures, often using data obtained from other mammalian species (i.e., pigs). Adipose tissue is an important compartment in these models because N2 is five times more soluble in fat than in blood; at any blood/ tissue interface N2 will diffuse into the fat and can lead to bubble ..

Background: Hyperbaric oxygen therapy has been demonstrated to lower blood glucose levels in patients with diabetes. Continuous glucose monitoring (CGM) allows glucose monitoring in real time. Battery-operated CGM transmitters have yet to be formally tested and given safety approval for use in a hyperbaric environment. Materials and Methods: We evaluated and tested commercially available Dexcom. G6 CGM transmitters under hyperbaric conditions. Each transmitter contains a 3V, 130-mAh (0.39 Wh) lithium manganese dioxide battery (IEC CR1632) and circuit board that are fully encapsulated in epoxy. Each transmitter is pressurized to 90 pounds per square inch (psi) in an autoclave at 40ÅãC for ..

Background: Acute kidney injury (AKI) as a consequence of ischemia is a common clinical event that can lead to unacceptably high morbidity and mortality. Hyperbaric oxygen (HBO2) preconditioning has been shown to prevent ischemia-reperfusion injury (IRI) in different tissues.  Objectives: The aim of our study was to compare the effects of HBO2 preconditioning on renal hemodynamics, kidney function and oxidative stress in normotensive and spontaneously hypertensive rats that suffered kidney IRI. Methods: An experiment was performed on Wistar (normotensive) and spontaneously hypertensive rats (SHR). The animals were divided into the following experimental groups: sham-operated rats and rats with or without HBO2 preconditioning 24 hours ..

Background: Hyperbaric oxygen (HBO2) therapy can have a positive effect on wound healing, angiogenesis and blood flow. No prior study has described the effects of HBO2 therapy and gene expression of this process. The goal of our research was to show the effects of HBO2 and its impact at the molecular level on angiogenesis, proliferation, differentiation, oxidative stress, inflammation, and extracellular matrix formation. Live animal subjects were used for simulating the process of wound healing under standard conditions and under the influence of HBO2. Methods: Two experimental groups were created using injured rabbits (N=24), one group (N=12) treated with hyperbaric therapy twice ..

Hyperbaric medicine is a relatively young specialty that remains in the blind spot of most doctors’ awareness. This study endeavors to identify the level of awareness of the indications for hyperbaric oxygen (HBO2) therapy among a doctor population in a developed country and factors which may improve referral rates. An anonymized questionnaire was distributed to doctors licensed to practice in Malta. Questions included physician specialty, demographics and previous exposure to diving and/or hyperbaric medicine. Moreover, two scoring systems were used to score subjects on HBO2-related topics. Binomial logistic regression models and generalized linear models were used in the statistical ..

Idiopathic sudden sensorineural hearing loss (ISSHL) is defined as unexplained hearing loss of at least 30 decibels (dB) occurring within 72 hours over at least three contiguous frequencies. ISSHL is common and has a significant effect on quality of life. Hyperbaric oxygen (HBO2) therapy is a medical treatment method that aims to increase the level of dissolved oxygen in the tissues. Correcting perilymph hypoxia is the goal of HBO2 therapy for ISSHL. In recent years, HBO2 therapy has been increasingly involved in the treatment of ISSHL. The medical records of 135 patients who had received HBO2 therapy for ISSHL ..

Purpose: Central retinal artery occlusion (CRAO) is an ophthalmic emergency with poor prognosis, despite diligent conventional treatment. According to the clinical recommendations of the Undersea and Hyperbaric Medical Society hyperbaric oxygen (HBO2) is a potentially beneficial treatment; however, the benefit of adjunctive HBO2 in patients with CRAO in Korea remains unclear. The present study aimed to evaluate the effect of adjunctive HBO2 in patients with CRAO. Methods: This registry-based observational study included adult patients who presented to the emergency department or ophthalmology outpatient department within 24 hours of the onset of CRAO symptoms. Data of patients from October 2016 to February 2019 ..

Background: Central retinal artery occlusion (CRAO) is a rare ocular-ischemic syndrome causing irreversible blindness. Its pathophysiology has not been clarified, and no targeted therapies are available yet. Hyperbaric oxygen (HBO2) therapy is an approved therapy for CRAO and has been shown to improve the visual acuity of CRAO patients safely. However, further clinical data are required to classify HBO2 therapy as a type-I general agreement for CRAO. Materials and Methods: Eleven patients with non-arteritic CRAO were enrolled. Patient demographics, medical history, detailed eye examinations, HBO2 therapy results, pre-/post- HBO2 therapy visual acuity measurements and genotypes for common thrombophilic mutations (Factor V G1691A ..

Introduction: 122,129 dives by 10,358 recreational divers were recorded by dive computers from 11 manufacturers in an exploratory study of how dive profile, breathing gas (air or nitrox [N2/O2] mixes), repetitive diving, gender, age, and dive site conditions influenced observed decompression sickness (DCSobs). Thirty-eight reports were judged as DCS. Overall DCSobs was 3.1 cases/104 dives.  Methods: Three dive groups were studied: Basic (live-aboard and shore/dayboat), Cozumel Dive Guides, and Scapa Flow wreck divers. A probabilistic decompression model, BVM(3), controlled dive profile variability. Chi-squared test, t-test, logistic regression, and log-rank tests evaluated statistical associations. Results: (a) DCSobs was 0.7/104 (Basic), 7.6/104 (Guides), and 17.3/104 (Scapa) ..

The purpose of this study was to investigate the effects of a single bout of heliox non-saturation diving on the cardiovascular system and cognitive function. Ten recreational scuba divers (10 males, ~35 years old) participated in this study. These subjects made two pool dives within a one-week interval, alternating gases with compressed air (21% O2, 79% N2) and with heliox (21% O2 and 79% He). The depth was to 26 meters over a 20-minute duration. The results showed that heliox diving significantly increased blood O2 saturation by 1.15% and significantly decreased blood lactate levels by ~57% when compared with ..

Aim: The aim of this study was to examine first aid measures applied in a large series of Australian dive-related fatalities to better determine where improvements can be made. Methods: The National Coronial Information System was searched to identify scuba diving and snorkeling-related cases reported to various Australian Coroners for the years 2001-2013 inclusive. Coronial documents examined included witness statements, police reports and ambulance and medical reports where available. Information relating to the recovery, rescue and/or resuscitation of the victims was extracted, compiled and analyzed. Results: 126 scuba diving and 175 snorkeling-related fatalities were identified during the study period, with airway management complications reported ..

Background: Calcific uremic arteriolopathy (calciphylaxis) is a rare and highly lethal vascular disease. Vascular calcification with calcium depositions lead to ischemic ulcers associated with gangrene, severe pain and poor healing. Although hyperbaric oxygen (HBO2) therapy has been used in the treatment of calciphylaxis, evidence of its effectiveness is limited. Objective: To determine whether HBO2 therapy has a beneficial effect in the healing of calciphylaxis ulcers.  Methods: A search was made in PubMed using a comprehensive strategy to identify the effect of HBO2 on calciphylaxis wounds. Included in the analysis were studies published up to October 2018 involving a minimum of four patients receiving HBO2 ..

Hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (AHSCT) in both children and adults has been associated with significant morbidity and mortality. Early HC can occur within 48 hours of completing the chemotherapy conditioning regimen, is usually associated with agents such as cyclophosphamide, and generally resolves promptly. Late HC is commonly associated with BK and other viruses and can prove refractory to antiviral and supportive therapy. There are limited reports of hyperbaric oxygen (HBO2) therapy showing benefit for refractory HC cases. We describe our experience with salvage HBO2 for a 15-yearold male with refractory HC beginning one month ..

Introduction: Altitude chamber exposures are used for training to allow aircrew to experience their hypoxia and pressure effect symptoms. Decompression illness (DCI) can occur subsequent to altitude chamber training or in operational aircraft when the cabin altitude is at least 18,000 feet. Definitive emergent treatment is hyperbaric oxygen (HBO2) to decrease bubble size, dissipate excess nitrogen hyperoxygenate tissue and reduce inflammation. Case report: A 27-year-old female underwent altitude chamber training to 25,000 feet. She developed tingling in both legs and left arm, headache, dizziness, malaise, then difficulty talking. She underwent two HBO2 treatments. Over the next 12 months she had paresthesia, decreased ..

Carbon monoxide (CO) poisoning presents with many different cardiac effects, but one important presentation is its effect as a CO stress test to reveal underlying coronary artery disease (CAD). There are a limited number of publications detailing this phenomenon, but after CO intoxication it is important to suspect CAD in association with mild troponin leak or non-ST segment elevation myocardial infarction (NSTEMI) shown on electrocardiogram (EKG). We recently treated three patients with CO poisoning who had underlying CAD. In the first case a man presented to the emergency department with CO toxicity and an ST segment elevation myocardial infarction ..

Carbon monoxide (CO) exposure is a prevalent cause of poisoning worldwide. The cardiac effects of CO poisoning are well described and can manifest as angina, myocardial ischemia or infarction, cardiogenic shock, and/or life-threatening arrhythmias. Atrial fibrillation has been associated with severe CO poisoning; however, few cases have described atrial fibrillation in acute CO poisoning with regard to hyperbaric oxygen (HBO2) therapy. Herein, we describe a case of severe CO poisoning that caused atrial fibrillation with successful conversion to sinus rhythm following HBO2 therapy and discuss implications for further research. DOI: 10.22462/01.03.2020.16

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, ..

[ Letters ] DOI: 10.22462/01.03.2020.18

[ Letters} DOI: 10.22462/01.03.2020.19

Correction/Erratum: In the fourth quarter issue 2020 of the UHM Journal (46-5) we represented the NNT number (number-needed-to-treat) as “three (3)” rather than simply “3.” This appeared on Page 727 in the letter from Richard Clarke, CHT, National Baromedical Services, entitled “HBO2 for radiation cystitis.” The corrected section should have read: “Although not reported, the ‘Number Needed to Treat’ (NNT, an epidemiological measure used to communicate effectiveness of an intervention, and representing the average number of patients needed to be treated in order to produce one favorable outcome) was computed as an encouraging 3. This value was the same for the subjective Expanded Prostate Index ..