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Crossings - Obituaries: An editorial note 10.22462/03.04.2022.12

Obituary: David H. Elliott 10.22462/03.04.2022.11

ASM 2022 Abstracts Part II 10.22462/03.04.2022.10

Letter to the editors 10.22462/03.04.2022.9

Acute traumatic ischemias are an array of disorders that range from crush injuries to compartment syndromes, from burns to frostbite and from threatened flaps to compromised reimplantations. Two unifying components common to these conditions are a history of trauma be it physical, thermal, or surgical coupled with ischemia to the traumatized tissues. Their pathophysiology resolves around the self-perpetuating cycle of edema and ischemia, and their severity represents a spectrum from mild, almost non-existent, to tissue death. Since ischemia is a fundamental component of the traumatic ischemias and hypoxia is a consequence of ischemia, hyperbaric oxygen is a logical intervention for those conditions where tissue survival, infection control and healing is at risk. Unfortunately, even with mechanisms of hyperbaric oxygen that strongly support its usefulness in traumatic ischemias coupled with supportive clinical data, clinicians are disinclined to utilize it for these conditions. This focuses on the orthopedic aspects of the traumatic ischemias, namely crush injury and compartment syndrome, and show how hyperbaric oxygen treatments can mitigate their severity. 10.22462/03.04.2022.8

Introduction: This case report describes an initially overlooked Type II decompression sickness (DCS) occurrence that was confused with a cerebral vascular accident in a patient with chronic atrial fibrillation (AF). The purpose of this case report is to reinforce the maxim that DCS needs to be suspected anytime a scuba diver experiences signs or symptoms compatible with DCS after completing a scuba dive. Methods: A 71-year-old scuba diver with a history of AF and who was taking warfarin made four dives, all with maximum depths less than 60 fsw (20 msw) over a 10-hour interval. Shoulder pain developed before entering the water on the fourth dive and was worse after exiting from the fourth dive. Twenty minutes later the diver collapsed while standing and was unable to make a grip using his left hand. A literature review failed to locate any case reports of divers with AF presenting with strokelike symptoms only to find the cause was Type II DCS. Findings: Initially the patient’s findings were reviewed with a diving medicine team. The recommendation was for the patient to be managed for a stroke. The patient was transferred to a hospital for a computed tomography scan, but no recommendation was made ..

Inert gas bubbles in tissues and in blood have been historically considered as the only triggering factors for DCS, but now many other factors are considered to affect the final outcome of a decompression profile for a certain individual. In this sense, inflammation seems to play a relevant role, not only due to the physical damage of tissues by the bubbles, but as a potentiator of the process as a whole. The present study aims to put forward a mathematical model of bubble formation associated with an inflammatory process related to decompression. The model comprises four state-variables (inert gas pressure, inert gas bubbles, proinflammatory and inflammatory factors) in a set of non-linear differential equations. The model is non-extensive: inert gas transitions between liquid and gaseous phases do not change the concentration of the dissolved gas. The relationship between bubbles and inflammation is given through parameters that form a positive feedback loop. The results of the model were compared with the experimental results of echocardiography from volunteers in two dive/decompression profiles; the model shows a very good agreement with the empirical data and previews different inflammatory outcomes for different experimental profiles. We suggest that slight changes in the parameters’ values ..

Purpose: Diving in warm water increases thermal risk during exercise compared to thermoneutral waters. The purpose of this study was to evaluate exercise endurance in warm- and hot-water conditions in divers habituated to wet or dry heat. Methods: Nineteen male divers completed this study at the Navy Experimental Diving Unit. Subjects were assigned DRY or WET heat habituation groups. The DRY group (n=9) cycled at 125-150W for one hour in a non-immersed condition (34.4˚C, 50%RH), while the WET group (n=10) cycled at 50W for one hour while immersed in 34.4˚C water. Exercise time to exhaustion was tested on an underwater cycle ergometer in 35.8˚C (WARM) and 37.2˚C (HOT) water at 50W. Core temperature (Tc) was continuously recorded and for all dives. Results: Time to exhaustion was reduced in HOT compared to WARM water (p<0.01) in both DRY (92.7°æ41.6 minutes in 35.8˚C vs. 43.4°æ17.5 minutes in 37.2˚C) and WET (95.9°æ39.2 minutes in 35.8˚C vs. 53.4°æ27.5 minutes in 37.2˚C) groups, but did not differ between groups (p=0.62). Rate of Tc rise was greater with higher water temperature (p<0.01), but was not different between groups (p=0.68). Maximum Tc (p=0.94 and p=0.95) and Tc change from baseline (p=0.38 and p=0.34) was not different between water ..

Hyperbaric oxygen (HBO2) therapy is a UHMS-approved treatment for radiation cystitis and has been used for other causes of cystitis such as cyclophosphamide-induced hemorrhagic cystitis and interstitial cystitis, among others. Immunotherapy with Bacillus Calmette-Gu.rin (BCG) is the most effective treatment of non-muscle invasive bladder cancer. BCG acts as a non-specific stimulant of the reticuloendothelial system, causing a local inflammatory response. BCG attaches to bladder tumor cells as well as urothelial cells which then stimulates an immune response involving a multitude of cytokines and local migration of polymorphonuclear cells that leads to death of the cancer cells. The typical protocol of a single six-week course has been shown to provide long-term protection from tumor recurrence and to reduce disease progression. Irritative bladder side effects are common, but serious side effects are uncommon. Two cases of severe BCG-cystitis treated with HBO2 are presented. Two male patients with bladder cancer were treated with intravesicular BCG. Each developed complications of pain, spasms, urinary frequency and nocturia; one developed gross hematuria. Cystoscopy showed friable mucosa. They failed standard medical therapy and were referred for HBO2. They were treated in a multiplace chamber at 2.2-2.4 ATA. One patient received 60 and the other 40 treatments. ..

Objectives: This is the first nationwide survey to obtain baseline information on the clinical application of hyperbaric oxygen (HBO2) therapy in China. The findings provide a reference for future management and policy formulation research. Methods: This questionnaire-based survey was implemented using an online survey tool. The survey assessed six aspects related to HBO2 practice: characteristics of institutions, departments/units, chambers, practitioners, treatment capacity, and scientific research. Results: Subjects were 1,924 institutions (2,699 HBO2 chambers and 11,266 practitioners) from 31 provinces, municipalities, and autonomous regions in mainland China. The findings showed that most institutions (86.9%) were public hospitals and 70.0% of chambers were air pressurized. The numbers of newly built HBO2 departments/units and chambers have gradually increased over the last five decades. We found that 70.8% of HBO2 departments/units were independent, most non-independent HBO2 units were affiliated to rehabilitation departments, and 88.1% of institutions had 24-hour emergency treatment capacity. Most institutions (44.5%) had 1,001 to 5,000 annual therapy sessions. In 2019, three conditions most frequently treated across the institutions were cerebrovascular diseases, carbon monoxide poisoning, and central nervous system injury. We identified the following shortcomings: shortage of doctors and (particularly) technicians; imbalances in emergency capacity, treatment facilities, and staff composition among institutions of ..

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 ..

Objective: The objective of the study was to compare pulmonary function tests results of hyperbaric chamber inside attendants (HCIAs) working in a hyperbaric chamber before and after sessions. Methods: A total of 68 health care personnel working as HCIAs in the hyperbaric oxygen therapy unit between June 2019 and September 2019 were included in the study. All participants experienced the pressure chamber for the first time. In spirometric evaluation, we measured forced vital capacity (FVC), forced expiratory volume at one second (FEV1), forced expiratory flow at 25%-75% of FVC (FEF25-75) and peak expiratory flow (PEF). In addition, FEV1/FVC ratio (FEV1%) was also calculated. Results: The mean FVC was found as 3.56 ± 0.66 (min-max: 2.17-5.63) before hyperbaric exposure and 3.44 ± 0.62 (min-max: 2.30-5.28) after the exposure (3.4%) (p<0.05). The mean FEV1 was found as 3.37 ± 0.63 (2.13-5.39) before the session and 3.24 ± 0.59 (min-max: 2.3-5.28) after the session (3.9%) (p<0.05). There was no statistically significant difference between the mean FEV1/FVC ratio, PEF and FEF25-75 measured before and after hyperbaric exposure. Conclusion: The results of this study indicated that among pulmonary function test parameters, decreases were found in FEV1, FVC, FEF25-75, PEF, but clinical significance has not been established. 10.22462/03.04.2022.1