The role of after-hours house-call medical service in the treatment of COVID-19 patients awaiting hospital admission: A retrospective cohort study.

ABSTRACT: Due to the increasing number of coronavirus disease 2019 (COVID-19) cases in Japan, hospitals are unable to provide admission and immediate inpatient care. The after-hours house call (AHHC) service offers telephone consultations and in-home care to patients awaiting admission. Currently, there is no report on the management of COVID-19 patients when inpatient beds are insufficient.We aimed to describe the clinical characteristics and outcomes of COVID-19 patients treated by an AHHC medical service in Osaka and Tokyo, between April and May 2021 (during the fourth wave in Japan). Patients were classified into 2 groups: Moderate I and Moderate II, according to the severity of infection under Japanese guidelines. A retrospective study of the hospital records and follow-up telephone consultations was performed.The AHHC treated a total of 55 COVID-19 patients (17 with Moderate I, 38 with Moderate II disease). The median ages (interquartile range) were 63 (49-80.5) and 64 (50.8-81), respectively. In each group, approximately 30% of AHHC patients received out-of-hospital oxygen therapy for the duration of their treatment until it was no longer required. Major symptoms, including shortness of breath or difficulty breathing (47.1% and 78.9%, respectively) and fever or chills (41.2% and 76.3%, respectively) were lower in the Moderate I group than in the Moderate II group. Overall, 16.4% of patients died, with 17.6% in the Moderate I group and 15.8% in the Moderate II group.We found the proportion of mortality in patients treated by the AHHC was slightly higher to that of patients treated in Japanese hospitals. This study will provide an alternative management of patients requiring oxygen in situations where hospital beds are in short supply.

A novel hyperbaric swimming respirometer allows the simulation of varying swimming depths in fish respirometry studies.

The understanding of swimming physiology and knowledge on the metabolic costs of swimming are important for assessing effects of environmental factors on migratory behavior. Swim tunnels are the most common experimental setups for measuring swimming performance and oxygen uptake rates in fishes; however, few can realistically simulate depth and the changes in hydrostatic pressure that many fishes experience, e.g. during diel vertical migrations. Here, we present a new hyperbaric swimming respirometer (HSR) that can simulate depths of up to 80 m. The system consists of three separate, identical swimming tunnels, each with a volume of 205 L, a control board and a storage tank with water treatment. The swimming chamber of each tunnel has a length of 1.40 m and a diameter of 20 cm. The HSR uses the principle of intermittent-flow respirometry and has here been tested with female European eels (Anguilla anguilla). Various pressure, temperature and flow velocity profiles can be programmed, and the effect on metabolic activity and oxygen consumption can be assessed. Thus, the HSR provides opportunities to study the physiology of fish during swimming in a simulated depth range that corresponds to many inland, coastal and shelf waters.

Real-world effectiveness of hyperbaric oxygen therapy for delayed neuropsychiatric sequelae after carbon monoxide poisoning.

To assess real-world effectiveness of hyperbaric oxygen therapy (HBOT) on delayed neuropsychiatric sequelae (DNS) after carbon monoxide (CO) poisoning we conducted a retrospective review of patients with CO poisoning admitted to Linkou Chang-Gung Memorial Hospital, Taiwan's largest medical center, during 2009-2015. We included patients developing DNS after CO poisoning and compared improvements in neuropsychiatric function, with and without HBOT, after 12 months post-DNS to understand differences in recovery rates. DNS improvement-associated factors were also evaluated. We used receiver operating characteristic (ROC) curve analysis to assess the role of time elapsed between DNS diagnosis and HBOT initiation in predicting DNS improvement. A total of 62 patients developed DNS, of whom 11 recovered while the rest did not. Possible factors predicting DNS improvement included receiving HBOT post-DNS (72.7% vs 25.5%; P = 0.006), and treatment with more than three HBOT sessions during acute stage CO poisoning (81.8% vs 27.5%; P = 0.003). The relevant area under the ROC curve was 0.789 (95% CI 0.603-0.974), and the best cut-off point was 3 days post-DNS diagnosis, with 87.5% sensitivity and 61.5% specificity. Early HBOT in patients who developed DNS after CO poisoning significantly improved their DNS symptoms, with treatment effects sustained for 1 year after DNS diagnosis.

The effect of total compression time and rate (slope) of compression on the incidence of symptomatic Eustachian tube dysfunction and middle ear barotrauma: a Phase II prospective study.

Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are common reported complications during hyperbaric oxygen treatment. Our Phase I study data was the first to demonstrate a statistically significant decrease in the occurrence of symptomatic ETD and MEB. The Phase I Trial suggested the total time interval and rate (slope) of compression (ROC) may be a determining factor in ETD and MEB. This Phase II study investigates an optimal rate of compression to reduce ETD and MEB when considering each multiplace treatment (with multiple patients) as the unit of observation as a group, rather than for each individual patient. Data were collected prospectively on 1,244 group patient-treatment exposures, collectively including 5,072 individual patient-treatment/exposures. We randomly assigned patient-treatment group exposures to four different time interval and rate (slope) of compression. These compression rates and slopes were identical to those used in the Phase I trial. All patients experiencing symptoms of MEB requiring compression stops were evaluated post treatment for the presence of ETD and MEB using the O'Neill Grading System (OGS) for ETD. Data were analyzed using the IBM-SPSS statistical software program. A statistically significant decrease in the number of compression holds was observed in the 15-minute compression schedule, correlating to the results observed in the Phase I trial. The 15-minute linear compression profile continues to demonstrate the decreased need for patient symptomatic compression stops (as in the Phase I trial) using a USN TT9 during elective hyperbaric oxygen treatments in a Class A multiplace hyperbaric chamber. Trial Registration: ClinicalTrials.gov Identifier: NCT04776967.

Multiple and early hyperbaric oxygen treatments enhance muscle healing after muscle contusion injury: a pilot study.

BACKGROUND: The optimal timing of hyperbaric oxygen (HBO2) treatments for the best recovery following muscle injury has yet to be determined. Thus, the optimal number and timing of HBO2 treatments for maximal muscle regeneration were explored. METHODS: The HBO2 treatment protocol consisted of 2.5 ATA 100% oxygen for 120 minutes. Muscle-injured rats were randomized to one of 10 groups: single HBO2 treatment immediately after injury (HBO 1T day 0), one day (HBO 1T day 1), three days (HBO 1T day 3) and five days (HBO 1T day 5) after injury; three HBO2 treatments from immediately after injury to two days after injury (HBO 3T day 0-2), from one to three days after injury (HBO 3T day 1-3), from three to five days after injury (HBO 3T day 3-5), from five to seven days after injury (HBO 3T day 5-7); five daily HBO2 treatments (HBO 5T); and no treatment (NT). RESULTS: HBO 5T and HBO 3T day 0-2, days 1-3 and days 3-5 significantly promoted CD206-positive cell infiltration, satellite cell differentiation and muscle regeneration compared to the NT group. CONCLUSION: Five HBO2 treatments and three HBO2 treatments within three days of injury promote muscle regeneration.

Hyperbaric oxygen for refractory osteomyelitis.

Refractory osteomyelitis is defined as a chronic osteomyelitis that persists or recurs after appropriate interventions have been performed or where acute osteomyelitis has not responded to accepted management techniques [1]. To date, no randomized clinical trials examining the effects of hyperbaric oxygen (HBO2) therapy on refractory osteomyelitis exist, and the number of new osteomyelitis clinical trials conducted over the past decade has been limited. However, based on a comprehensive review of the scientific literature, the addition of HBO2 therapy to routine surgical and antibiotic treatment of previously refractory osteomyelitis appears to be both safe and ultimately improves infection resolution rates. In most cases, the best clinical results are obtained when HBO2 treatment is administered in conjunction with culture-directed antibiotics and initiated soon after clinically indicated surgical debridement. Where extensive surgical debridement or removal of fixation hardware is relatively contraindicated (e.g., cranial, spinal, sternal, or pediatric osteomyelitis), a trial of culture-directed antibiotics and HBO2 therapy prior to undertaking more than limited surgical interventions provides a reasonable prospect for osteomyelitis cure. HBO2 therapy is ordinarily delivered on a once daily basis, five-seven days per week, for 90-120 minutes using 2.0-3.0 atmospheres absolute (ATA) pressure. Where prompt clinical improvement is seen, the existing regimen of antibiotics and HBO2 therapy should be continued for approximately four to six weeks. Typically, 20-40 HBO2 sessions are required to achieve sustained therapeutic benefit. In contrast, if prompt clinical response is not noted or osteomyelitis recurs after this initial treatment period, then continuation of the current antibiotic and HBO2 treatment regimen is unlikely to be effective. Instead, clinical management strategies should be reassessed and additional surgical debridement and/or modification of antibiotic therapy considered. Subsequent reinstitution of HBO2 therapy will again help maximize the overall chances for treatment success in these persistently refractory patients.

Effect of Hyperbaric Oxygen Therapy Initiation Time in Acute Carbon Monoxide Poisoning.

OBJECTIVES: Hyperbaric oxygen therapy (HBO2) is recommended for symptomatic patients within 24-hour postcarbon monoxide poisoning. Previous studies have reported significantly better outcomes with treatment administered within 6 hours after carbon monoxide poisoning. Thus, we aimed to compare the neurocognitive outcomes according to HBO2 delay intervals. DESIGN: Retrospective analysis of data from our prospectively collected carbon monoxide poisoning registry. SETTING: A single academic medical center in Wonju, Republic of Korea. PATIENTS: We analyzed the data of 706 patients older than 16 years treated with HBO2 with propensity score matching. Based on carbon monoxide exposure-to-HBO2 delay intervals, we classified patients into the early (control, less than or equal to 6 hr) and late (case, 6-24 hr) groups. The late group was further divided into Case-1 (6-12 hr) and Case-2 (12-24 hr) groups. We also compared mild (nonintubated) and severe (intubated) groups. INTERVENTIONS: HBO2. MEASUREMENTS AND MAIN RESULTS: After propensity score matching, Global Deterioration Scale scores at 6 months postcarbon monoxide exposure showed significantly fewer poor outcome patients in the early than in the late group (p = 0.027). The early group had significantly fewer patients with poor outcomes than the Case-2 group (p = 0.035) at 1 month and than the Case-1 (p = 0.033) and Case-2 (p = 0.004) groups at 6 months. There were significantly more patients with poor prognoses at 6 months as treatment interval increased (p = 0.008). In the mild cohort, the early group had significantly fewer patients with poor 6-month outcomes than the late group (p = 0.033). CONCLUSIONS: Patients who received HBO2 within 6 hours of carbon monoxide exposure had a better 6-month neurocognitive prognosis than those treated within 6-24 hours. An increase in the interval to treatment led to an increase in poor outcomes.

Clinical characteristics, treatment, and prognosis of 74 2019 novel coronavirus disease patients in Hefei: A single-center retrospective study.

ABSTRACT: Since December 2019, pneumonia caused by a novel coronavirus (SARS-CoV-2), namely 2019 novel coronavirus disease (COVID-19), has rapidly spread from Wuhan city to other cities across China. The present study was designed to describe the epidemiology, clinical characteristics, treatment, and prognosis of 74 hospitalized patients with COVID-19.Clinical data of 74 COVID-19 patients were collected to analyze the epidemiological, demographic, laboratory, radiological, and treatment data. Thirty-two patients were followed up and tested for the presence of the viral nucleic acid and by pulmonary computed tomography (CT) scan at 7 and 14 days after they were discharged.Among all COVID-19 patients, the median incubation period for patients and the median period from symptom onset to admission was all 6 days; the median length of hospitalization was 13 days. Fever symptoms were presented in 83.78% of the patients, and the second most common symptom was cough (74.32%), followed by fatigue and expectoration (27.03%). Inflammatory indicators, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) of the intensive care unit (ICU) patients were significantly higher than that of the non-ICU patients (P < .05). However, 50.00% of the ICU patients had their the ratio of T helper cells to cytotoxic T cells (CD4/CD8) ratio lower than 1.1, whose proportion is much higher than that in non-ICU patients (P < .01).Compared with patients in Wuhan, COVID-19 patients in Anhui Province seemed to have milder symptoms of infection, suggesting that there may be some regional differences in the transmission of SARS-CoV-2 between different cities.

Mechanistic Rationale and Clinical Efficacy of Hyperbaric Oxygen Therapy in Chronic Neuropathic Pain: An Evidence-Based Narrative Review.

Background: Chronic neuropathic pain is a condition affecting an increasing proportion of the general population and its management requires a comprehensive, multidisciplinary program. A growing body of evidence supports the use of hyperbaric oxygen therapy (HBOT) in several chronic neuropathic pain conditions; however, its role and efficacy remain unclear. Purpose: To summarize current evidence for the mechanistic rationale of HBOT in chronic neuropathic pain conditions and to evaluate its clinical efficacy. Methods: This narrative review was conducted after searching the following databases (Medline, Embase, Cochrane, PsycINFO, the Web of Science, Scopus, ClinicalTrials. gov, WHO ICTRP, and ProQuest Digital Dissertation) from January 1946 to March 2020. Articles published in English that involved either animal or human studies with acute or chronic neuropathic pain evaluating any HBOT-related intervention were included. Results: A total of 2971 citations were identified. A total of 29 studies were included in this review. The mechanisms of action for HBOT use in neuropathic conditions included the primary effects of hyperoxia and edema resolution, as well as the secondary effects pertinent to the production of oxygen and nitrogen reactive species (serving as pain signaling molecules), nitric oxide-dependent release of opioid peptides, and reduction of inflammatory mediators. A robust evidence for HBOT use in the clinical setting was associated with chronic regional pain syndrome and chronic primary bladder pain syndrome. Some evidence supported its use for chronic secondary (peripheral) neuropathic pain including radiation-induced plexus neuropathies, postherpetic neuralgia, and trigeminal neuralgia. Conclusions: HBOT has been shown to have antinociceptive and analgesic effects in animal models of inflammatory, neuropathic, and chronic pain. Human studies demonstrated beneficial effects of HBOT in improving clinical outcomes such as pain scores, pain-related symptoms, and quality of life. A systematic methodology of HBOT application is necessary to confirm its safety and efficacy.

Hyperbaric oxygen therapy for chronic diabetic foot ulcers: An overview of systematic reviews.

OBJECTIVES: Hyperbaric oxygen therapy in the treatment of diabetic foot ulcer has been widely used in medical practice, but its clinical effect is not clear. The purpose of this overview of systematic reviews is to evaluate the clinical evidence of hyperbaric oxygen therapy in the treatment of diabetic foot ulcers. METHODS: PubMed, Cochrane Library, Web of Knowledge, Embase, MEDLINE, Chinese National Knowledge Infrastructure Database, the Chongqing VIP Database, Chinese Biomedical Database, and Wanfang Database were searched in 1st December 2020. Systematic reviews (SRs) evaluating the effects of Hyperbaric oxygen therapy in people with diabetic foot ulcer were included. Methodological quality of the included SRs was assessed using the AMSTAR-2 tool. The quality of evidence of the primary studies was assessed using GRADE. The integrity of the included SRs was assessed using PRISMA. The bias risk of each SR was assessed using ROBIS evaluation tool. RESULTS: Eleven SRs/MAs met all inclusion criteria. According to the results of the AMSTAR-2, only 1 included review were rated critically as being of high quality, 6 included review were rated critically as being of medium quality. With PRISMA, the reporting checklist was relatively complete, but some reporting weaknesses remained in the topics of the protocol and registration, search strategy, and additional analyses. Based on the ROBIS tool, only five SRs/MAs had a low risk of bias. With the GRADE system, no high-quality evidence was found, and only 13 outcomes provided moderate-quality evidence. CONCLUSIONS: There is limited clinical evidence to support hyperbaric oxygen therapy in the treatment of diabetic foot ulcers, it is not recommended to routinely apply hyperbaric oxygen therapy to all patients with diabetic foot ulcers, especially those with non-ischemic diabetic foot ulcers. Hyperbaric oxygen therapy has certain potential to promote ulcer healing and reduce amputation rate in patients with ischemic diabetic foot ulcers, but due to the low quality and small quantity of the SRs/MAs supporting these results, high-quality studies with rigorous study designs and larger samples are needed before widespread recommendations can be made.

Comparison of the efficacy of multiple antioxidant and hyperbaric oxygen treatments in the prevention of ischemia and necrosis of local random McFarlane skin flap.

OBJECTIVE: The aim of this study was to compare the efficacy of multiple antioxidant (Proxeed Plus (PP) with Carnitine, Selenium, Zinc, Coenzyme Q10, Vitamin C, Folic Acid, Vitamin B12) on local random skin flap healing with the hyperbaric oxygen (HBO) therapy. METHODS: Fourty rats were equally divided into five groups (Control, PP, HBO, HBO + PP, PP + HBO + PP). Local random McFarlane skin flap was applied to all rats. Following the applications, evaluations were made biochemical (TAS, TOS, OSI, IL-1ß, IL-6, TNF-α, TGF-ß, VEGF) and histopathological parameters. RESULTS: Necrosis percentage was found to be lower in the PP + HBO + PP group than all other groups whereas the necrosis percentages of PP and HBO groups were similar. Oxidative stress rates were significantly higher in the control group compared to the other groups whereas it was lower in the PP + HBO + PP group than all other groups. The inflammation parameters were the highest in the control group and the lowest in the PP + HBO + PP group. Growth factors were higher in the PP + HBO + PP group than all other groups. Epithelialization and wound healing were better in the HBO and PP groups than in the control group. The greatest healing, epithelialization and vascularization was seen in the PP + HBO + PP group. The histopathological findings in the PP + HBO + PP group were better in each inner region than in the other groups. CONCLUSION: Biochemical and histopathological parameters have shown that PP reduces ischemia and necrosis and increases oxygenation in flap healing by providing significant improvement thanks to the multiple molecular structures in its content.

Seizure during hyperbaric oxygen therapy: experience at a single academic hospital in Korea.

Background: Hyperbaric oxygen (HBO2) therapy is a safe and well-tolerated treatment modality. Seizures, one of the most severe central nervous system side effects of HBO2 therapy, can occur. Episodes of seizures during HBO2 therapy have not yet been reported in countries such as Korea, where hyperbaric medicine is still in the developmental stage. Methods: The registry data of all patients treated with HBO2 therapy in a tertiary academic hospital in Korea were prospectively collected, and patients who developed seizures during HBO2 therapy between October 2016 and December 2019 were evaluated. In addition, we reviewed previous studies on occurrence of seizures during HBO2 therapy. Results: During the study period, a total of 10,425 treatments were provided to 1,308 patients. The most frequently treated indication was carbon monoxide (CO) poisoning ABSTRACT (n=547, 41.8%). During the HBO2 therapy sessions (total: 10,425), five seizure episodes occurred (patients with CO poisoning: n=4; patients with arterial gas embolism [AGE]: n=1). The frequency of seizures in patients with CO poisoning (0.148%) and AGE (3.448%) was significantly higher than that in patients with all indications (0.048%) (p=0.001). None of the patients had lasting effects due to the seizures. Conclusion: Our study revealed a similar frequency rate in terms of all indications and CO poisoning, and a slightly higher rate in AGE. Seizures were observed in patients with CO poisoning and AGE. Therefore, if clinicians plan to operate a hyperbaric center in a country like Korea, where there are several patients with acute CO poisoning, they should be prepared to handle seizures that may occur during HBO2 therapy.

Hyperbaric oxygen therapy for hypoxic-ischemic encephalopathy in non-fatal drowning.

Paroxysmal autonomic instability syndrome with dystonia (PAISD) is a possible complication that worsens the prognosis of hypoxic-ischemic encephalopathy related to non-fatal drowning. There are case reports of hyperbaric oxygen (HBO2) therapy enhancing recovery in such cases. We report a case of a 5-year-old boy admitted to the Pediatric Intensive Care Unit after a non-fatal drowning. He was transferred under mechanical ventilation and sedation, with hemodynamic instability and hypothermia. On admission he had a Glasgow Coma Score of 6. On the fifth day of admission he presented episodes of dystonia with decerebration posture, diaphoresis, tachycardia and hypertension, sometimes with identified triggers, suggesting PAISD. The episodes were difficult to control; multiple drugs were needed. Electroencephalography showed diffuse slow wave activity, and cranioencephalic magnetic resonance imaging showed hypoxia-related lesions, suggesting hypoxic-ischemic encephalopathy. Early after admission the patient started physiotherapy combined with normobaric oxygen therapy. Subsequently he started HBO2 therapy at 2 atmospheres, with a total of 66 sessions. Dystonia progressively subsided, with gradual discontinuation of therapy. He also showed improvement in spasticity, non-verbal communication and cephalic control. This case highlights the diagnostic and therapeutic challenges of PAISD and the potential benefit of HBO2 therapy, even in the subacute phase, in recovery of hypoxic-ischemic encephalopathy.

Clinical efficacy of adjuvant therapy with hyperbaric oxygen in diabetic nephropathy.

Background and objective: Diabetic kidney disease (DKD) is the most common microvascular chronic complication of diabetes mellitus. Hyperbaric oxygen (HBO2) therapy will increase the partial pressure of oxygen (PaO2) and may improve cell repair processes, which can lead to better renal function. The objective of this study was to quantify the efficacy of adjuvant HBO2 to increase the glomerular filtration rate and urinary albumin excretion in diabetic patients, as well as determine its effectiveness to modify the clinical course of DKD. Materials and methods: An experimental study was performed on patients with stage 3 and 4 DKD. Twenty sessions of HBO2 or ambient air in a hyperbaric chamber were administered. Estimated glomerular filtration rate, urine albumin:creatinine ratio calculation and clinical stage stratification were made prior to and after HBO2 administration. A descriptive, inferential and clinical efficacy analysis was performed. Results: Urinary albumin/creatinine (UACR) mean values prior to HBO2 were 1452.9 ± 644.3 mg/g and decreased to 876.1 ± 504.0 mg/g at the end of the study (p=0.06). The patients in the control group showed a UACR mean of 2784.5 ± 2128.6 mg/g and 2861.4 ± 2424.2 mg/g at baseline and at the end of the study, respectively (p=0.82). Patients in the experimental/HBO2 group showed an estimated GFR of 27.3 ± 9.5 mL/min /1.73m2 before HBO2, with a 34.4 ± 6.9 mL/min/1.73m2 after treatment (p=0.017); control group eGFR was 30.1 ± 9.2 mL/min/1.73m2, decreasing to 22.2 ± 6.8 mL/min/1.73m2 (p=0.004). Relative risk 0.00, relative risk reduction -100%, absolute risk reduction -71.4%, 95% CI (-104.9% to -38.0%), NNT 1, 95% CI (1 to 3). Conclusions: Management with HBO2 for DKD was associated with decreased excretion urinary albumin, improved GFR and clinical stage of patients in stages 3 and 4 of kidney damage unlike those receiving ambient air..

A Multistep Iter for Functional Reconstruction in Mangled Upper Limb: A Retrospective Analysis of Integrated Surgical and Medical Approach.

Background and objectives: Complex limb wounds with multiple tissue involvement are commonly due to high energy trauma. Tissue damage is a dynamic entity and the exact extent of the injury is rarely instantly perceptible. Hence, reconstruction frequently involves a multi-stage procedure concluding with tissue replacement. Materials and Methods: A retrospective study was conducted between 2006 and 2018 and included 179 patients with contaminated multi-tissue injuries treated with hyperbaric oxygen therapy, negative pressure therapy, physiotherapy and drug treatment associated with multiple surgical time in a multistep approach, focusing on pain levels and wound closure rates. Results: Despite the long-term response to traumatic events, a combined approach of delayed surgical reconstructive time in mangled upper limb yielded satisfactory functional outcomes. Conclusions: The complex upper limb wound with deep tissue exposure may be treated with a multi-stage procedure alternatively to immediate reconstruction. The integrated technique enables the preservation of existing healthy tissue and concurrent radical debridement, reducing the risk of infection, as well as avoiding the loss of free flaps and dehiscence due to incorrect wound estimation.

Impact of oxygen therapy algorithm on oxygen usage in the emergency department.

BACKGROUND: Although oxygen is one of the oldest drugs available, it is still one of the most inappropriately administered drugs leading to over utilization of this very expensive resource. MATERIALS AND METHODS: This prospective observational study was done in a large emergency department (ED) in India. The pattern of oxygen usage was studied before and after the strict implementation of an oxygen treatment algorithm. The algorithm was taught to all doctors and nurses and its implementation was monitored regularly. The main outcome measures were proportion of patients receiving oxygen therapy, inappropriate usage, and avoidable direct medical cost to the patient. RESULTS: The 3-week pre-protocol observation phase in April 2016 included 3769 patients and the 3-week post-protocol observation phase in April 2017 included 4608 patients. The baseline demographic pattern was similar in both the pre-protocol and post-protocol groups. After the strict implementation of the algorithm, the number of patients receiving oxygen therapy decreased from 9.63% to 4.82%, a relative decrease of 51.4%. The average amount of total oxygen used decreased from 55.4 liters per person in pre-protocol group to 42.1 liters per person in the post-protocol group with a mean difference of 13.28 (95% CI 5.30-21.26; P = 0.001). Inappropriate oxygen usage decreased from 37.2% to 8.6%. There was a significant decrease in inappropriate oxygen use for indications like low sensorium (60.8% vs 21.7%) and trauma (88.5% vs 15.8%). The mortality rate in the pre-protocol phase was 2.7% as compared with 3.2% in the post-protocol phase. The total duration of inappropriate oxygen usage significantly decreased from 987 h to 89 h over the 21-day study period. CONCLUSION: The implementation of an oxygen therapy algorithm significantly reduces inappropriate oxygen use and decreases treatment cost to the patient with no additional mortality risk.

Middle-ear barotrauma after hyperbaric oxygen therapy: a five-year retrospective analysis on 2,610 patients.

Introduction: Hyperbaric oxygen (HBO2) therapy is the use of oxygen or gas mixtures at a pressure above atmospheric pressure for therapeutic purposes. This treatment is used in numerous pathological processes. Its main side effect is middle ear barotrauma (MEB), which represents a great concern for iatrogenic HBO2 therapy. The aim of this work is to describe this adverse event in order to highlight clinical elements that can contribute to its prevention and management. Methods: We conducted a five-year retrospective study from January 2013 to December 2017, where 2,610 patients were selected, in the Hyperbaric Medicine Centre, Sainte- Marguerite Hospital of Marseille, France. Results: 262 patients experienced MEB after HBO2, representing a prevalence of 10.04% and incidence of 0.587%. Their average age was 55 ± 19 years. Women were more affected than men. We have not highlighted a seasonality to this condition. Risk factors were: age older than 55 years, female gender, ear, nose and throat history (cancer, radiotherapy, infections or allergies, malformations or benign tumors), general history (smoking, obstructive breathing disorders, thyroid disorders and obesity), HBO2-approved indications of sudden deafness and delayed wound healing, and altered tympanic mobility on initial examination. Although the benign stages of Haines-Harris classification were the most encountered in our study, MEB was responsible for premature discontinuation of HBO2. Conclusion: MEB is a common condition responsible for many premature discontinuations of HBO2. Its origin is multifactorial, associating non-modifiable and modifiable factors. Better management of this affection will further contribute to making HBO2 a low-risk treatment.

Successful use of hyperbaric oxygen therapy for limb salvage of acute limb ischemia as a complication of acute carbon monoxide poisoning.

Acute limb ischemia (ALI) as a complication of acute carbon monoxide (CO) poisoning is rare. Several reports have utilized hyperbaric oxygen therapy (HBO2) as an adjunctive therapy for peripheral arterial diseases. However, no study has yet described the use of HBO2 for ALI precipitated by CO poisoning. Herein we report successful limb salvage achieved with adjunctive HBO2 and conventional therapies in a patient with CO-induced ALI. A 69-year-old man was admitted with acute CO poisoning; ALI of both lower extremities occurred on hospitalization day 3. Pre-existing risk factors for ALI other than CO were not definite. After conventional treatments including catheter-directed thrombolysis and endovascular thrombectomy, the right-side lesion remained and a left-side lesion was newly developed. In addition to prior therapies, 47 sessions of serial HBO2 were administered as adjunctive therapy, resulting in limb salvage. Acute CO poisoning can cause ALI as a rare complication. HBO2 may be utilized as an adjunctive treatment in ALI.

An explicitly multi-component arterial gas embolus dissolves much more slowly than its one-component approximation.

We worked out the growth and dissolution rates of an arterial gas embolism (AGE), to illustrate the evolution over time of its size and composition, and the time required for its total dissolution. We did this for a variety of breathing gases including air, pure oxygen, Nitrox and Heliox (each over a range of oxygen mole fractions), in order to assess how the breathing gas influenced the evolution of the AGE. The calculations were done by numerically integrating the underlying rate equations for explicitly multi-component AGEs, that contained a minimum of three (water, carbon dioxide and oxygen) and a maximum of five components (water, carbon dioxide, oxygen, nitrogen and helium). The rate equations were straight-forward extensions of those for a one-component gas bubble. They were derived by using the Young-Laplace equation and Dalton's law for the pressure in the AGE, the Laplace equation for the dissolved solute concentration gradients in solution, Henry's law for gas solubilities, and Fick's law for diffusion rates across the AGE/arterial blood interface. We found that the 1-component approximation, under which the contents of the AGE are approximated by its dominant component, greatly overestimates the dissolution rate and underestimates the total dissolution time of an AGE. This is because the 1-component approximation manifestly precludes equilibration between the AGE and arterial blood of the inspired volatile solutes (O2, N2, He) in arterial blood. Our calculations uncovered an important practical result, namely that the administration of Heliox, as an adjunct to recompression therapy for treating a suspected N2-rich AGE must be done with care. While Helium is useful for preventing nitrogen narcosis which can arise in aggressive recompression therapy wherein the N2 partial pressure can be quite high (e.g.∼5 atm), it also temporarily expands the AGE, beyond the expansion arising from the use of Oxygen-rich Nitrox. For less aggressive recompression therapy wherein nitrogen narcosis is not a significant concern, Oxygen-rich Nitrox is to be preferred, both because it does not temporarily expand the AGE as much as Heliox, and because it is much cheaper and more conservation-minded.

Hyperbaric oxygen therapy awareness within a doctor population.

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 analysis. A total of 152 full replies were obtained and analyzed. Respondents who had visited a hyperbaric unit (HBU) (p=0.002) or attended a lecture on HBO2 (p=0.006) scored better than their counterparts, indicating better awareness of HBO2 indications and local chamber location. A previous HBU visit (p=0.001), being a hospital-based doctor (p=0.027) and a history of scuba diving (p=0.03) were associated with willingness to refer patients for HBO2 in the future. Encouraging visits to an HBU has been shown to be associated with multiple factors, which are expected to result in improved referral rates. Targeted educational sessions to doctors and medical students are likely to be beneficial in improving correct referral of patients for HBO2. The findings from this study may prove useful in improving appropriate referral rates of patients who may benefit from this useful treatment modality.