Table 2 Details of the data presented by the included studies
ID | First author (reference) | Type of study | Country | Study population | Age (year) | Male | Comorbidities | Pressure and time per day | Baseline laboratory values | Patients’ outcome | Conclusion |
|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Chen [27] | Case series | China | N = 5 Chest CT showed typical pulmonary imaging changes of COVID-19, and nucleic acid tests of SARS-CoV-2 were positive | 24–69 (mean 47.6) | Male 80% | Hypertension, coronary heart disease, acute myocardial infarction, and the coronary stent implantation | 2.0 ATA for Patient 1# 1.6ATA for the other patients 90 min in first Treatment & 60 min in the followed | Lymphocyte count and LYM%: (0.61 ± 0·35 × 109/L before vs. 1.09 ± 0·24 × 109/L after, P < 0.05) Blood CRP (before): 30.56 ± 1.15 mg/L (After):3.98 ± 1.50 mg/L WBC Before: 6.78 ± 0.39 × 109/L After: 5.64 ± 1.40 × 109/L | All the symptoms were basically relieved except for mild breathlessness (motion) complained by every patient The mean value of daily SpO2 of Patient 1# was restored 95% after 5 days, while 2# and 3# after 3 days, 4# after 2 days, and 5# after 1 day | HBOT can dramatically increase the amount of dissolved oxygen in the blood and treatment to critically ill COVID-19 patients |
2 | Gorenstein [25] | Clinical trial | USA | 1) Hyperbaric oxygen therapy, (N = 20) 18 years and older, confirmed COVID-19, SpO2 < 93% on room air 2) Controls (Propensity-matches patients), (N = 60) | 1) 58.4 (2) 60.9 | 1) Male: 18 (90%) 2) Male: 55 (92%) | NA | 2 ATA, 90 min | Positive Troponin: 1) 0%, 2) 0% All the following are mean and none are significantly different (units not reported): D-dimer: 1) 1142, 2) 1870 Ferritin: 1) 1490, 2) 1382 CRP: 1) 120, 2) 137 LDH: 1) 496, 2) 475 | Mechanical ventilation: 1) n = 2 (10%), 2) 18 (30%) Death: 1) n = 2 (10%), 2) 13 (21.7%) | The adjusted hazard ratio for time to death = 0.37 (95% CI of 0.10 to 1.37) The adjusted hazard ratio for time to mechanical ventilation = 0.37 (95% CI of 0.10 to 1.37) Few adverse events occurred in the form of epistaxis (not related to HBOT), ear pain, and claustrophobia, and all were classified as mild One severe case of hypoxic arrest that was concluded as not related to HBOT |
3 | Guo [28] | Case report | China | Symptoms of both cases: shortness of breath; respiratory rate (RR) ≥ 30 breaths/min; finger pulse oxygen saturation (SpO2) ≤ 93% at rest; and oxygen index (P/F ratio: PaO2/FiO2 ≤ 300 mmHg.N = 2 | Case 1) 57 Case 2) 64 | Case 1) male Case 2) male | Case 1) Cough, fever, fatigue, and hypertension Case 2) Cough, fever, diabetes, and coronary heart disease | 1.5 atmospheres absolute HBO2 with an oxygen concentration of more than 95% for 60 min per treatment, once a day for one week | NA | For both patients, dyspnea and shortness of breath were immediately alleviated after the first HBO2 treatment. The RR also decreased daily. The decreasing trend of SO2 and P/F ratio was immediately reversed and increased day by day. Ratio corresponding to immune function gradually recovered. D-dimer corresponding to peripheral circulation disorders and serum cholinesterase, reflecting liver function had improved. Follow-up chest CT showed that the pulmonary inflammation had clearly subsided | Hyperbaric oxygen therapy treatment may rapidly improve the progressive hypoxemia of patients with COVID-19 pneumonia |
4 | Levina [14] | Clinical trial | Russia | 1) 10 patients with the diagnosis “Coronavirus infection caused by the virus SARS-CoV-2” (moderately severe patients) 2) 22 patients with the diagnosis “Coronavirus infection caused by the virus SARS-CoV-2” in serious condition | 1) 63.5 [51; 74] 2) 59 [51,75; 67] | 1) Male: 5 (50.0%) 2) Male: 10 (45.5%) | Claustrophobia ear pain | 1.4–1.6 ATA for no more than 60 min | Not available | The patients showed an increase in blood oxygen saturation in patients in both surveyed groups, as well as positive dynamics in the form of a decrease in shortness of breath, an improvement in general well-being | Inclusion of daily sessions (at least 4) of excessive oxygen delivery in "soft" states (1.4–1.6 ATA) in the complex treatment of COVID-19, safety, and its initial positive effect on the mental state of the examined patients and the dynamics of blood oxygen saturation |
5 | Liang [29] | Case report | China | Chills and a body temperature of 37.8 °C Chest CT examination multiple patchy ground-glass opacity (GGO) shadows in the S I and S II segments of the upper lobe of the right lung and the S I + II segment of the upper lobe of the left lung. N = 1 | 69 | Male | A history of coronary atherosclerotic heart disease and underwent coronary stent implantation | Total daily oxygen inhalation time of 95 min and an oxygen dose of 216 unit of pulmonary toxic dose (UPTD) | White blood cell counts 3.68 × 109/L Lymphocyte count 1.47 × 109/L C-reactive protein 22.4 mg/L D-dimer 0.28 mg/L Prothrombin time 11.3 s Partial thromboplastin activation time 28.2 s | Blood gas examination showed a PO2 of 122 mmHg, PCO2 of 37.3 mmHg, and SO2 reaching 99%. Re-examination of CT showed that the area of consolidation in bilateral lungs decreased. The patient was switched to a nasal catheter for oxygen inhalation. One month after discharge, follow-up CT examination showed diffuse GGO shadows in both lungs, while the consolidation shadows and fibrous cord shadows completely resolved | Hyperbaric oxygen therapy may directly cause persistent accumulation of oxygen debt under hypoxic tissues and organs throughout the body and subsequent damage to important oxygen-consuming tissues and organs, providing a good systemic functional basis for the body to combat viral infections |
6 | Petrikov [26] | Clinical trial | Russia | 1) Study group, (N = 57), 18 years and older, confirmed COVID-19, SpO2 = 91.3 ± 5.9% 2) Control group (N = 30) | 1) 58.8 ± 13.6 2) 64.5 ± 12.7 | 1)Male: 30 (52.6%) 2) Male: 13 (43.3%) | NA | 1.4_1.6 ATA mode for 40 min | Blood Malondialdehyde: 1) decrease from 4.34 ± 0.52 µmol/L to 3.98 ± 0.48 µmol/L | NA | The use of Hyperbaric oxygen therapy increases the effectiveness of treatment |
7 | Thibodeaux [21] | Case series | USA | Study group, (N = 5), 18 years and older, confirmed COVID-19 | 39–63 | 1) 1 (20%) | Obesity (80%) Diabetes (60%) Hypertension (80%) Viral pneumonia (40%) | 2.0 ATA for 90 min | D-dimer (pre): 1 = 12,070 mg/mL D-dimer (post): 1 = 4324 mg/mL | Recovered: n = 5 (100%) oxygen saturation of 97% on 45% FiO2 Oxygen saturation(pre): 95.5 ± 2.61% Oxygen saturation(post): 94.6 ± 2.30% Respiratory rate, breaths/min (pre): 35.4 ± 8.47 Respiratory rate, breaths/min (post): 28 ± 7.55 | HBOT can reduce the need for mechanical ventilation, and increase oxygen saturation in patients with COVID-19 |
8 | Xiao-Ling [30] | Case report | China | N = 1 coronavirus disease 2019 (COVID-19) patient with endotracheal intubation | 87 | Male | NA | NA | NA | After four times HBOT: 1. Improved function of liver and kidney 2. Improved blood coagulation | HBO2 significantly reduces CO2 retention in COVID-19 patients |