Number 4

We said farewell and thank you to two giants in dive medicine this year: Dr. Peter Bennett and Dr. Claes Lundgren. They leave the proverbial big shoes for us to fill – and a wealth of good works and fond memories. 10.22462/07.08.2022.13

Central retinal artery occlusion (CRAO) is a relatively rare emergent condition of the eye resulting in sudden painless vision loss. This vision loss is usually dramatic and permanent, and the prognosis for visual recovery is poor. A wide variety of treatment modalities have been tried over the last 100 years with little to no success, with the exception of hyperbaric oxygen therapy. The optimum number of treatments will vary depending on the severity and duration of the patient’s symptoms and the degree of response to treatment. The majority of patients will stabilize within a few days after symptom onset. Utilization review is recommended for patients treated for more than three days after clinical plateau. 10.22462/07.08.2022.12

Objective: Hyperbaric oxygen (HBO2) is used in several clinical and research fields. This study aimed to analyze the 100 most-cited hyperbaric-related publications of the past 10 years to understand the trends in HBO2 research. Methods: This was a literature review. All publication and citation data were retrieved from the Scopus database. Publications with “hyperbaric oxygen,” “hyperbaric oxygenation,” “HBO,” and “HBOT” in the title, abstract, or keywords published between January 01, 2011, and December 31, 2020, were enrolled. The 100 most-cited HBO2-focused publications were identified, and their publication title, authors’ nationality, publication journal, year, type (original or review), and application field were recorded and analyzed using descriptive statistics. Linear regression was used to evaluate the trends in publication numbers. Results: A total of 6,517 publications were enrolled. The annual rate of increase was 4.56 per year (p-value = 0.13, 95% CI: -1.62 to 10.74). The total, average, median and mode of citations were 67,726, 10.4, 4, and 0, respectively. The 100 most-cited HBO2-focused publications accounted for 1.5% (100/6,517) of all publications and 8.1% (5509/67,726) of the total number of times cited. The most cited publications originated from 17 countries and were published in 65 journals, led by the Cochrane Database of Systematic Reviews. Conclusions: The annual number of ..

Background: Early recompression therapy is suggested for a better clinical outcome of decompression sickness (DCS) patients. This study analyzed the efficacy of our 24-hour on-call system for early recompression therapy. Methods: We conducted a single-center retrospective cohort study. They were classified into DCS Type I versus Type II, duty time versus non-duty time groups based on the time of emergency department (ED) admission, and hospitalization versus discharge groups according to clinical outcomes. Baseline characteristics, diving variables, and in-hospital course were analyzed. Results: This study investigated 341 acute DCS patients. A total of 81 and 260 patients had Type I and Type II DCS, respectively. While 198 patients accessed the center during duty time, 143 presented during non-duty time. Fifty patients were admitted, and 291 patients were discharged. Total median time from symptom onset to HBO2 therapy was 259 minutes: 240 minutes for the duty group and 292 minutes for the non-duty group (p=0.16); 251 minutes for the discharged group and 291 minutes for the hospitalized group (p<0.001). The median time from ED admission to HBO2 therapy was 65 minutes: 60 minutes for the duty group and 69 minutes for the non-duty group (p=0.23); 63.4 minutes for the discharged group and 92 minutes for the ..

Introduction: We aimed to assess the efficacy and safety of a standardized hyperbaric oxygen (HBO2) therapy protocol in patients with retinal artery occlusion (RAO). Methods: A retrospective study was conducted in our tertiary care center from July 2016 to September 2019. Patients experiencing central RAO and branch RAO for less than seven days were included. Once the diagnosis was made, patients were urgently referred to the HBO2 department to receive a first 90-minute HBO2 session at a pressure of 2.5 ATA. Patients underwent two daily sessions seven days a week for at least 15 days. If no reperfusion was seen on fluorescein angiography on Day 15, treatment was continued for an additional week with an assessment on Day 21. The primary endpoint was BCVA improvement defined as a decrease by 0.3 logMAR at one month. Results: Twenty-eight patients were included during the study period. Fifty-seven percent of patients were treated more than 12 hours after the onset of the first symptoms. The mean BCVA was 1.5 logMAR at the time of referral and improved to 0.9 logMAR after HBO2 (p=0.001). A multivariate analysis identified a high blood pressure (p=0.039) and a low initial BCVA (p=0.005) as poor prognostic factors. Conclusion: Performing HBO2 sessions twice daily at ..

Purpose: The aim of our study is to investigate the effects of hyperbaric oxygen (HBO2) therapy on retinal layers in healthy eyes. Method: Thirty patients who were taken to outpatient HBO2 for any indication were included in the study. All patients underwent 10 sessions of HBO2; 20 healthy patients were taken as the control group. We used the spectral-domain optical coherence tomography (SD-OCT) to obtain automated measurements of thickness for each retinal layer – i.e., the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL) and retinal pigment epithelium (RPE) – and to conduct foveal (central 1 mm), inner-ring (parafoveal 1 to 3mm), and outer-ring (perifoveal 3 to 6mm) retinal layer measurements. Retinal OCT scans were performed before HBO2, after the first and 10th sessions. All retinal layer thicknesses were assessed with SD-OCT software system and compared between each visit. Retinal thicknesses were calculated in the central, inner ring and outer ring subfields (nine quadrants). Results: In SD-OCT measurements, there were no statistically significant difference before HBO2, after the first and 10th sessions in terms of foveal, inner-ring and outer-ring thickness of RNFL, GCL, IPL, INL, OPL, ONL ..

Introduction: Several causes can lead to carbon monoxide (CO) intoxication. A first-line treatment option for such intoxications is hyperbaric oxygenation (HBO2) therapy. The COVID-19 pandemic has been changing everyday life in Germany since March 2020, mainly caused by statutory provisions. Our aim was to review whether these changes have an influence on the causes and frequency for the development of CO intoxication. 10.22462/07.08.2022.7 Methods: We retrospectively analyzed the data of patients who were treated for CO intoxication in our institution between April 2019 and March 2021. Besides demographic data, we compared the overall number and documented causes for each CO intoxication in the period of April 2020 to March 2021 with the period between April 2019 and March 2020. Results: After applying inclusion and exclusion criteria, 139 patients were included. We found a significant decrease in the overall number of patients who needed treatment since the beginning of the COVID-19 pandemic. However, the share of CO intoxication caused by the indoor use of coal stoves, coal barbecue, or suicide attempts increased. In contrast, the share of cases caused by apartment or house fire, smoking waterpipe, or gas stoves decreased. Conclusion: The COVID-19 pandemic and the associated restrictions lead to a significant reduction in the number ..

Arsenic (As) is a toxic substance that damages the human body through exposure to drinking water. This exposure damages many organs and tissues in the body, especially the liver and kidneys. Hyperbaric oxygen (HBO2) therapy is a treatment method that acts by reducing oxidative stress parameters in tissues with high-pressure oxygen. Based on this, our study aimed to investigate the effectiveness of HBO2 on liver and kidney tissues with chronic arsenic toxicity. In the study 24 male Wistar albino rats (220-300 g, two to three months old) were equally divided into four groups: Control; As; HBO2; and As+HBO2. All animals were housed in individual cages. The toxicity model was created by adding arsenic to drinking water at a dose of 5 mg/kg/day for 60 days. HBO2 was applied 2 ATA pressure for 90 minutes a day for five days. At the end of the study, liver and kidney tissues were taken and stored for analysis. In liver tissue, histopathological showed that arsenic reduced inflammatory cell infiltration, sinusoidal congestion, and hydropic degeneration, while HBO2 increased these measures. Similar results were found by TUNEL method. In kidney tissue, both histopathologic and TUNEL method examinations found similar results with the liver: The ..

Purpose: In a disabled submarine scenario, a pressurized rescue module (PRM) may be deployed to rescue survivors. If the PRM were to become disabled, conditions could become hot and humid exposing the occupants to heat stress. We tested the hypothesis that the rise in core temperature and fluid loss from sweating would increase with rising dry bulb temperature. Methods: Twelve males (age 22 ± 3 years; height 179 ± 7 cm; mass 77.4 ± 8.3 kg) completed this study. On three occasions, subjects were exposed to high humidity and either 28-, 32-, or 35˚C for six hours in a dry hyperbaric chamber pressurized to 6.1 msw. Changes in core temperature (Tc) and body mass were recorded and linear regression lines fit to estimate the predicted rise in Tc and loss of fluid from sweating. Results: Heart rate was higher in the 35˚C condition compared to the 28˚C and 32˚C conditions. Tc was higher in the 32˚C condition compared to 28˚C and higher in 35˚C compared to the 28˚C and 32˚C conditions. Projected fluid loss in all of the tested conditions could exceed 6% of body mass after 24 hours of exposure endangering the health of sailors in a DISSUB or disabled PRM. A fluid ..

We tested the hypothesis that thermal discomfort will be greater, mood will be worse, and physical symptoms of heat illness will be exacerbated with elevations in dry bulb temperature during exposure to >95% relative humidity disabled pressurized rescue module simulation. On three occasions, 15 healthy males (23 ± 3 years) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C or 35.0 ± 0.1°C, and 95 ± 2% relative humidity normobaric environments for eight hours. Thermal discomfort (visual analog scale), mood (profile of mood states), and physical symptoms of heat illness, ear-nose-throat, and muscle discomfort (environmental symptoms questionnaire) were assessed before and following each hour of exposure. Thermal discomfort was greater throughout the exposure in 35°C versus both 32°C and 33°C (p ≥ 0.03) and did not differ between the latter conditions (p ≥ 0.07). Mood worsened over time in all trials (p < 0.01) and was worse in 35°C compared to 32°C and 33°C after five hours of exposure (p ≤ 0.05). Heat illness symptoms increased over time in all trials and was greater in 35°C versus 32°C and 33°C throughout the exposure (p ≤ 0.04). Ear-nose-throat and muscle discomfort symptoms increased over time in all trials (p < 0.01) and were higher in 35°C versus 32°C and 33°C after ..

Introduction: This is the first study to examine population medication prescription rates among U.S. submariners by common therapeutic classifications. Methods: Individual-level pharmacy records during the years 2007 to 2018 were extracted from the Military Health System’s Pharmacy Data Transaction Service (PDTS) file. Demographic and military factors captured from Navy personnel files were linked to PDTS records. Logistic regression models were used to identify characteristics and trends associated with prevalence. Published total rates for other active-duty components were compared to submariner rates. Results: There were data for 50,720 submariners, among whom 576,782 prescriptions were filled. Prevalence rates decreased significantly from 2007-2018 among most drug classes. Central nervous system agents accounted for 31% of the total prescriptions, followed by 12% for eye, ear, nose, and throat preparations, and 10% for anti-infective agents. Higher prescription rates were associated with being enlisted, younger, a woman, lower-ranked, or Hispanic. The mean yearly prescription rate was 2.7 per submariner, less than half of the overall rate of all military components. Conclusions: Central nervous system agents were the most common drug class for submariners and all military components. Future work at the drug level is warranted to better understand the temporal declines in submariner rates and if submariner rates are lower than overall ..

Background: In the current study, we investigated the effect of atmospheric pressure change on the microtensile bond strength of direct and indirect composite restorations to the teeth. Materials and Methods: A total of 16 extracted teeth were prepared after crown cutting and randomly divided into four groups. The study groups included: 1) direct restoration (Filtek™ Z250 Universal Composite Restorative System, 3M, United States) at constant pressure (control); 2) direct restoration in variable pressure; 3) indirect restoration (Z250 composite) at constant pressure (control); and 4) indirect restoration at variable pressure. Then, samples were subjected to thermal cycles. Variable pressure groups were pressurized to 0 to 5 atmospheres for 96 cycles inside the hyperbaric chamber, followed by measuring the microtensile bond strength of the specimens. Results: The mean of microtensile bond strength in both direct and indirect variable-pressure groups was significantly lower than their counterpart control groups. There was no significant difference between direct and indirect restorations in constant and variable pressure. The failure mode of the samples in the control groups was often mixed, while in the pressure groups, it was dominated by adhesive. Also, microscopic examination of restoration interfaces showed that the number and volume of voids in variable pressure groups were much more ..

Depending on pO2 and exposure time hyperoxic breathing gas may cause injury in many organs including the lungs. Pulmonary oxygen toxicity (POT) may be asymptomatic, but will initially present as a tracheobronchitis in symptomatic subjects. A number of objective measurements of POT have been investigated, but the decrement in vital capacity (VC) has remained the most accepted outcome measure. The unit pulmonary toxic dose (UPTD) has been established as the most common exposure index for POT in diving. UPTD is calculated based on the pO2 and exposure time. A literature search identified five models predicting POT, but no model would accurately predict VC change for the full range of pO2 variation and exposure time relevant for surface-oriented diving. Nevertheless, compared to UPTD, the K-index(K = t2*pO24.57, where t = time (hours) and pO2 = inspired pO2 (atm)) suggested by Arieli performed better for pO2 > 150 kPa and allowed estimation of recovery. We recommend that the Arieli K-index should replace UPTD as the POT exposure index for all surface-oriented diving. Based on the limited data available we suggest a daily threshold of K = 120 for a maximum of two diving days followed by two days of recovery. For five consecutive days of diving, we recommend that the threshold should ..