The effect of hyperbaric oxygen therapy on myocardial function in post-COVID-19 syndrome patients: a randomized controlled trial.

Post-COVID-19 condition refers to a range of persisting physical, neurocognitive, and neuropsychological symptoms following SARS-CoV-2 infection. Recent evidence revealed that post-COVID-19 syndrome patients may suffer from cardiac dysfunction and are at increased risk for a broad range of cardiovascular disorders. This randomized, sham-control, double-blind trial evaluated the effect of hyperbaric oxygen therapy (HBOT) on the cardiac function of post-COVID-19 patients with ongoing symptoms for at least three months after confirmed infection. Sixty patients were randomized to receive 40 daily HBOT or sham sessions. They underwent echocardiography at baseline and 1-3 weeks after the last protocol session. Twenty-nine (48.3%) patients had reduced global longitudinal strain (GLS) at baseline. Of them, 13 (43.3%) and 16 (53.3%) were allocated to the sham and HBOT groups, respectively. Compared to the sham group, GLS significantly increased following HBOT (- 17.8 ± 1.1 to - 20.2 ± 1.0, p = 0.0001), with a significant group-by-time interaction (p = 0.041). In conclusion, post-COVID-19 syndrome patients despite normal EF often have subclinical left ventricular dysfunction that is characterized by mildly reduced GLS. HBOT promotes left ventricular systolic function recovery in patients suffering from post COVID-19 condition. Further studies are needed to optimize patient selection and evaluate long-term outcomes.This study was registered with ClinicalTrials.gov, number NCT04647656 on 01/12/2020.

Clinical and biochemical short-term effects of hyperbaric oxygen therapy on SARS-Cov-2+ hospitalized patients with hypoxemic respiratory failure.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) has been proposed to address COVID-19- associated respiratory failure. However, its biochemical effects are poorly known. METHOD: 50 patients with hypoxemic COVID-19 pneumonia were divided into C group (standard care) and H group (standard care plus HBOT). Blood was obtained at t = 0 and t = 5 days. Oxygen saturation (O2 Sat) was followed up. White blood cell (WC) count, lymphocytes (L) and platelets (P) and serum analysis (glucose, urea, creatinine, sodium, potassium, ferritin, D dimer, LDH and CRP) were carried out. Plasma levels of sVCAM, sICAM, sPselectin, SAA and MPO, and of cytokines (IL-1ß, IL-1RA, IL-6, TNFα, IFNα, IFNγ, IL-15, VEGF, MIP1α, IL-12p70, IL-2 and IP-10) were measured by multiplex assays. Angiotensin Converting Enzyme 2 (ACE-2) levels were determined by ELISA. RESULTS: The average basal O2 Sat was 85 ± 3%. The days needed to reach O2 Sat >90% were: H: 3 ± 1 and C: 5 ± 1 (P < 0,01). At term, H increased WC, L and P counts (all, H vs C: P < 0,01). Also, H diminished D dimer levels (H vs C, P < 0,001) and LDH concentration (H vs C, P < 0.01]. At term, H showed lower levels of sVCAM, sPselectin and SAA than C with respect to basal values (H vs C: ΔsVCAM: P < 0,01; ΔsPselectin: P < 0,05; ΔSAA: P < 0,01). Similarly, H showed diminished levels of TNFα (ΔTNFα: P < 0,05) and increased levels of IL-1RA and VEGF than C respect to basal values (H vs C: ΔIL-1RA and ΔVEGF: P < 0,05). CONCLUSION: Patients underwent HBOT improved O2 Sat with lower levels of severity markers (WC and platelets count, D dimer, LDH, SAA). Moreover, HBOT reduced proinflammatory agents (sVCAM, sPselectin, TNFα) and increased anti-inflammatory and pro-angiogenic ones (IL-1RA and VEGF).

Hyperbaric oxygen therapy for long COVID (HOT-LoCO), an interim safety report from a randomised controlled trial.

BACKGROUND: With ~ 50 million individuals suffering from post-COVID condition (PCC), low health related quality of life (HRQoL) is a vast problem. Common symptoms of PCC, that persists 3 months from the onset of COVID-19 are fatigue, shortness of breath and cognitive dysfunction. No effective treatment options have been widely adopted in clinical practice. Hyperbaric oxygen (HBO2) is a candidate drug. METHODS: The objective of this interim analysis is to describe our cohort and evaluate the safety of HBO2 for post covid condition. In an ongoing randomised, placebo-controlled, double blind, clinical trial, 20 previously healthy subjects with PCC were assigned to HBO2 or placebo. Primary endpoints are physical domains in RAND-36; Physical functioning (PF) and Role Physical (RP) at 13 weeks. Secondary endpoints include objective physical tests. Safety endpoints are occurrence, frequency, and seriousness of Adverse Events (AEs). An independent data safety monitoring board (DSMB) reviewed unblinded data. The trial complies with Good Clinical Practice. Safety endpoints are evaluated descriptively. Comparisons against norm data was done using t-test. RESULTS: Twenty subjects were randomised, they had very low HRQoL compared to norm data. Mean (SD) PF 31.75 (19.55) (95% Confidence interval; 22.60-40.90) vs 83.5 (23.9) p < 0.001 in Rand-36 PF and mean 0.00 (0.00) in RP. Very low physical performance compared to norm data. 6MWT 442 (180) (95% CI 358-525) vs 662 (18) meters p < 0.001. 31 AEs occurred in 60% of subjects. In 20 AEs, there were at least a possible relationship with the study drug, most commonly cough and chest pain/discomfort. CONCLUSIONS: An (unexpectedly) high frequency of AEs was observed but the DSMB assessed HBO2 to have a favourable safety profile. Our data may help other researchers in designing trials. Trial Registration ClinicalTrials.gov: NCT04842448. Registered 13 April 2021, https://clinicaltrials.gov/ct2/show/NCT04842448 . EudraCT: 2021-000764-30. Registered 21 May 2021, https://www.clinicaltrialsregister.eu/ctr-search/trial/2021-000764-30/SE.

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.

Hyperbaric oxygen therapy to treat lingering COVID-19 symptoms.

Background: SARs-Cov-2 infections can produce prolonged illness and significant disability. Patients recovering from COVID-19 can have persistent symptoms leading to long-term morbidity. Methods: Six patients with long-lasting (> 30 days) COVID-19 symptoms were treated with hyperbaric oxygen (HBO2) therapy. All patients were assessed for symptoms using the ImPACT questionnaire, a muscle and joint pain scale, and a modified Borg dyspnea scale. Patients were assessed before, during and after HBO2 treatments. Results: All patients saw improvements in the measured symptoms to levels that were the same as pre-infection levels (five of six patients) or had significant improvement in symptoms (one patient). Conclusion: The results suggest that HBO2 helped to improve symptom scores, reduce the length of time of symptoms, and improved the quality of life. More detailed and randomized studies are needed to confirm the results in this report.

Hyperbaric oxygen for COVID-19 patients with severe hypoxia prior to vaccine availability.

Introduction: Few treatments have demonstrated mortality benefits among hospitalized hypoxic COVID-19 patients. We evaluated the use of hyperbaric oxygen (HBO2) therapy as a therapeutic intervention among hospitalized patients with a high oxygen requirement prior to vaccine approval. Methods: We extracted data on patients with COVID-19 hypoxia who required oxygen supplementation ranging from a 6L nasal cannula up to a high-flow nasal cannula at 100% FiO2 at 60L/minute with a 100% non-rebreather mask at 15 L/minute and were eligible for off-label HBO2 therapy from October 2020 to February 2021. We followed the Monitored Emergency use of Unregistered and Investigational Interventions or (MEURI) in conjunction with the consistent re-evaluation of the protocol using the Plan-Do-Study-Act (PDSA) tool [1]. We compared patient characteristics and used Fisher's exact test and a survival analysis to assess the primary endpoint of inpatient death. Results: HBO2 therapy was offered to 36 patients, of which 24 received treatment and 12 did not receive treatment. Patients who did not receive treatment were significantly older (p ≺ 0.01) and had worse baseline hypoxia (p = 0.06). Three of the 24 (13%) patients who received treatment died compared to six of 12 (50%) patients who did not receive treatment (RR ratio: 0.25, p = 0.04, 95% CI: 0.08 to 0.83). In the survival analysis, there was a statistically significant reduction in inpatient mortality in the treatment group (HR: 0.19, p = 0.02, 95% CI: 0.05-0.74). However, after adjusting for age and baseline hypoxia, there was no difference in inpatient mortality (hazard ratio: 0.48, p = 0.42, 95% CI: 0.08-2.86). Conclusion: The survival benefit of HBO2 therapy observed in our unadjusted analysis suggests that there may be therapeutic benefits of HBO2 in treating COVID-19 hypoxia as an adjunct to standard care.

Can Hyperbaric Oxygen Therapy Be Used to Treat Children after COVID-19? A Bibliographic Review.

The coronavirus disease (COVID-19) epidemic is a public health emergency of international concern. It was believed that SARS-CoV-2 virus was much less likely affect children. Statistics show that children account for 2-13% of all COVID-19 patients in individual countries. In the youngest population, acute respiratory failure is not as serious a problem as complications after COVID-19, mainly pediatric inflammatory multisystem syndrome (PIMS, MIS-C). This study used a bibliography review. The Medline database (using the PubMed platform) and the Cochrane Clinical Trials database were searched using the following keywords: hyperbaric oxygen therapy for children, treatment of children with COVID-19, and use of HBOT in the treatment of children following COVID-19. Thirteen publications that quantitatively and qualitatively described the efficacy of HBOT application in the treatment of pediatric diseases were eligible among the studies; those relating to the use of HBOT in the treatment of children with COVID-19 and its complications were not found. The bibliographic review showed that hyperbaric oxygen therapy can be used in the treatment of children after carbon monoxide poisoning, with soft tissue necrosis, bone necrosis, after burns, or after skin transplant. No evidence supported by research has been found in scientific journals on the effectiveness of the use of hyperbaric oxygen therapy in children with a history of COVID-19 infection. Research data are needed to develop evidence-driven strategies with regard to the use of HBOT therapy in the treatment of children and to reduce the number of pediatric patients suffering because of complications after COVID-19.

Hyperbaric oxygen for treatment of long COVID-19 syndrome (HOT-LoCO): protocol for a randomised, placebo-controlled, double-blind, phase II clinical trial.

INTRODUCTION: Long COVID-19, where symptoms persist 12 weeks after the initial SARS-CoV-2-infection, is a substantial problem for individuals and society in the surge of the pandemic. Common symptoms are fatigue, postexertional malaise and cognitive dysfunction. There is currently no effective treatment and the underlying mechanisms are unknown, although several hypotheses exist, with chronic inflammation as a common denominator. In prospective studies, hyperbaric oxygen therapy (HBOT) has been suggested to be effective for the treatment of similar syndromes such as chronic fatigue syndrome and fibromyalgia. A case series has suggested positive effects of HBOT in long COVID-19. This randomised, placebo-controlled clinical trial will explore HBOT as a potential treatment for long COVID-19. The primary objective is to evaluate if HBOT improves health-related quality of life (HRQoL) for patients with long COVID-19 compared with placebo/sham. The main secondary objective is to evaluate whether HBOT improves endothelial function, objective physical performance and short-term HRQoL. METHODS AND ANALYSIS: A randomised, placebo-controlled, double-blind, phase II clinical trial in 80 previously healthy subjects debilitated due to long COVID-19, with low HRQoL. Clinical data, HRQoL questionnaires, blood samples, objective tests and activity metre data will be collected at baseline. Subjects will be randomised to a maximum of 10 treatments with hyperbaric oxygen or sham treatment over 6 weeks. Assessments for safety and efficacy will be performed at 6, 13, 26 and 52 weeks, with the primary endpoint (physical domains in RAND 36-Item Health Survey) and main secondary endpoints defined at 13 weeks after baseline. Data will be reviewed by an independent data safety monitoring board. ETHICS AND DISSEMINATION: The trial is approved by the Swedish National Institutional Review Board (2021-02634) and the Swedish Medical Products Agency (5.1-2020-36673). Positive, negative and inconclusive results will be published in peer-reviewed scientific journals with open access. TRIAL REGISTRATION NUMBER: NCT04842448.

Hyperbaric Oxygen Improves Neurocognitive Function and Symptoms of Post-COVID Condition.

According to this study: Hyperbaric oxygen therapy can improve cognitive function, psychiatric symptoms, pain, and fatigue in patients who have post-COVID-19 condition.The beneficial effect of the therapy can be attributed to increased brain perfusion and neuroplasticity in regions associated with cognitive and emotional roles.

Hyperbaric oxygen therapy as a supportive therapy for COVID-19 patients: a narrative review.

The Coronavirus illness 2019 (COVID-19) was first observed to induce fever, dry cough, pneumonia, and dyspnea in the lower respiratory tract. Atypical manifestations, including digestive problems and cardiac symptoms, were also observed. The rate of mortality in the older population is greater than in the younger group, as well as in individuals suffering from comorbidities. Oxygen supplementation through a facemask, non-invasive ventilation, mechanical ventilation, and extracorporeal membrane oxygenation ECMO are some of the available supportive techniques. Hyperbaric oxygen treatment (HBOT) is thought to boost tissue oxygenation by increasing plasma soluble oxygen levels. HBOT also reduces inflammatory responses in COVID-19 patients, minimizing the negative impacts of the cytokine storm. Because the existing data on the efficacy of HBOT in COVID-19 patients is limited, the purpose of this article is to review the possible mechanisms of HBO, as well as data available on potential advantages, side effects and uses in the treatment of COVID-19 patients.

Hyperbaric oxygen therapy improves neurocognitive functions and symptoms of post-COVID condition: randomized controlled trial.

Post-COVID-19 condition refers to a range of persisting physical, neurocognitive, and neuropsychological symptoms after SARS-CoV-2 infection. The mechanism can be related to brain tissue pathology caused by virus invasion or indirectly by neuroinflammation and hypercoagulability. This randomized, sham-control, double blind trial evaluated the effect of hyperbaric oxygen therapy (HBOT or HBO2 therapy) on post-COVID-19 patients with ongoing symptoms for at least 3 months after confirmed infection. Seventy-three patients were randomized to receive daily 40 session of HBOT (n = 37) or sham (n = 36). Follow-up assessments were performed at baseline and 1-3 weeks after the last treatment session. Following HBOT, there was a significant group-by-time interaction in global cognitive function, attention and executive function (d = 0.495, p = 0.038; d = 0.477, p = 0.04 and d = 0.463, p = 0.05 respectively). Significant improvement was also demonstrated in the energy domain (d = 0.522, p = 0.029), sleep (d = - 0.48, p = 0.042), psychiatric symptoms (d = 0.636, p = 0.008), and pain interference (d = 0.737, p = 0.001). Clinical outcomes were associated with significant improvement in brain MRI perfusion and microstructural changes in the supramarginal gyrus, left supplementary motor area, right insula, left frontal precentral gyrus, right middle frontal gyrus, and superior corona radiate. These results indicate that HBOT can induce neuroplasticity and improve cognitive, psychiatric, fatigue, sleep and pain symptoms of patients suffering from post-COVID-19 condition. HBOT's beneficial effect may be attributed to increased brain perfusion and neuroplasticity in regions associated with cognitive and emotional roles.

Efficacy and safety of hyperbaric oxygen treatment to treat COVID-19 pneumonia: a living systematic review update.

INTRODUCTION: As the COVID-19 pandemic evolves, new effective treatment options are essential for reducing morbidity and mortality as well as the strain placed on the healthcare system. Since publication of our initial review on hyperbaric oxygen treatment (HBOT) for hypoxaemic COVID-19 patients, interest in HBOT for COVID-19 has grown and additional studies have been published. METHODS: For this living systematic review update the previously published search strategy (excluding Google Scholar) was adopted with an extension from 01 February 2021 to 01 April 2022. Study inclusion criteria, data extraction, risk of bias estimation and dispute resolution methods were repeated. RESULTS: Two new studies enrolling 127 patients were included in this update, taking the total to eight studies with 224 patients. Both new studies were randomised controlled trials, one at moderate and one at high risk of bias. Across these eight studies, 114 patients were treated with HBOT. All reported improved clinical outcomes without observation of any serious adverse events. Meta-analysis remained unjustified given the high heterogeneity between studies and incomplete reporting. CONCLUSIONS: This updated living systematic review provides further evidence on the safety and effectiveness of HBOT to treat acute hypoxaemic COVID-19 patients.

A COVID-19 infection incidentally detected during hyperbaric oxygen treatment and preventive measures for COVID-19 transmission in a multiplace hyperbaric chamber.

INTRODUCTION: SARS-CoV-2 (COVID-19) was declared a global pandemic on 11 March 2020 and has become a serious threat to public health. As it can easily be transmitted through droplets and aerosols, there is an increased risk of transmission in enclosed environments such as hyperbaric oxygen treatment (HBOT) units if preventive measures are not taken. CASE REPORT: A 16-year-old female tested positive for SARS-CoV-2 during HBOT for idiopathic sudden sensorineural hearing loss. The other patients and the inside attendant who attended the sessions with her were regarded as contacts, tested for SARS-CoV-2, and quarantined until the test results were available. Ultimately, none of them tested positive. DISCUSSION: As HBOT in multiplace chambers entails a high risk of SARS-CoV-2 transmission, we strictly adapted our practice to consider that every patient could be a potential asymptomatic carrier. Therefore, the negative results of all contacts in this case and the fact that no confirmed cases of COVID-19 were reported suggests that these measures successfully prevented SARS-CoV-2 transmission in our HBOT clinic. SARS-CoV-2 transmission can be prevented if sufficient protective measures are taken.

Hyperbaric oxygen treatment for long coronavirus disease-19: a case report.

BACKGROUND: The coronavirus disease 2019 pandemic has resulted in a growing population of individuals who experience a wide range of persistent symptoms referred to as "long COVID." Symptoms include neurocognitive impairment and fatigue. Two potential mechanisms could be responsible for these long-term unremitting symptoms: hypercoagulability, which increases the risk of blood vessel occlusion, and an uncontrolled continuous inflammatory response. Currently, no known treatment is available for long COVID. One of the options to reverse hypoxia, reduce neuroinflammation, and induce neuroplasticity is hyperbaric oxygen therapy. In this article, we present the first case report of a previously healthy athletic individual who suffered from long COVID syndrome treated successfully with hyperbaric oxygen therapy. CASE PRESENTATION: A previously healthy 55-year-old Caucasian man presented 3 months after severe coronavirus disease 2019 infection with long COVID syndrome. His symptoms included a decline in memory, multitasking abilities, energy, breathing, and physical fitness. After evaluation that included brain perfusion magnetic resonance imaging, diffusion tensor imaging, computerized cognitive tests, and cardiopulmonary test, he was treated with hyperbaric oxygen therapy. Each session included exposure to 90 minutes of 100% oxygen at 2 atmosphere absolute pressure with 5-minute air breaks every 20 minutes for 60 sessions, 5 days per week. Evaluation after completing the treatment showed significant improvements in brain perfusion and microstructure by magnetic resonance imaging and significant improvement in memory with the most dominant effect being on nonverbal memory, executive functions, attention, information procession speed, cognitive flexibility, and multitasking. The improved cognitive functions correlated with the increased cerebral blood flow in brain regions as measured by perfusion magnetic resonance imaging. With regard to physical capacity, there was a 34% increase in the maximum rate of oxygen consumed during exercise and a 44% improvement in forced vital capacity. The improved physical measurements correlated with the regain of his pre-COVID physical capacity. CONCLUSIONS: We report the first case of successfully treated long COVID symptoms with hyperbaric oxygen therapy with improvements in cognition and cardiopulmonary function. The beneficial effects of hyperbaric oxygen shed additional light on the pathophysiology of long COVID. As this is a single case report, further prospective randomized control studies are needed.

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.

[Hyperbaric oxygenation in outpatient rehabilitation of COVID-19 convalescents]. / Primenenie giperbaricheskoi oksigenatsii v ambulatornoi reabilitatsii patsientov, perenesshikh COVID-19.

Searching for drug and non-drug modalities for the rehabilitation of patients with the post-COVID syndrome is an urgent public health challenge during the COVID-19 pandemic. Hyperbaric oxygenation is a promising method as a part of complex rehabilitation after COVID-19 due to its antihypoxic, anti-inflammatory, antioxidant and anticoagulant effects. OBJECTIVE: To study the effect of hyperbaric oxygenation as a part of comprehensive outpatient rehabilitation on clinical and functional parameters in COVID-19 convalescents. MATERIAL AND METHODS: The effect of hyperbaric oxygenation on clinical and functional parameters of 45 COVID-19 convalescents was studied: 22 males and 23 females aged 40-60 years. Patients were divided into three groups of 15 subjects each, depending on the CT stage of COVID-associated pneumonia (CT-0, CT-1, and CT-2-3). RESULTS: Patients in group 3 (CT-2-3) were on average in the older age group, had a higher body weight and a higher percentage of fat mass according to bioimpedance measurements, compared to the other groups. Most clinical-functional and laboratory parameters in this group were within normal or subnormal ranges. In addition, high cholesterol levels (total cholesterol 6.5±1.2 mmol/L) and subnormal levels of C-reactive protein (9.3 mg/L) were noted in group 3 patients. After comprehensive rehabilitation, an increase in the distance walked in the 6-minute walking test with a significant trend in the CT-0 (467.9±37.7→531.5±44.3 m; p<0.01) and CT-1 (533.9±74.3→570.1±57.8 m; p<0.05) groups was observed. A significant decrease in norepinephrine level in the group of COVID-19 convalescents with CT-2-3 (Δ 13%), and a decrease in glutathione peroxidase in all three groups (6465.0±1637.3→5101.0±1353.3, 6587.8±1919.3→5418.1±1289.7, 7699.5±1747.9→6620.1±1702.1 units/L in groups 1, 2 and 3, respectively; p<0.05) were recorded. CONCLUSION: The use of hyperbaric oxygenation in comprehensive outpatient rehabilitation of COVID-19 convalescents was associated with benefits, given the improvement of functional parameters, laboratory signs of limiting low-grade inflammation, sympathoadrenal activity, and oxidative stress.