The Application of Hyperbaric Oxygen Therapy in Non-ventilated COVID-19 Patients - Randomized Controlled Trial
Phase: PHASE4
Conditions: COVID, Coronavirus
Sponsor: Maimonides Medical Center

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 1 of 9 
TITLE The application of Hyperbaric Oxygen Therapy in Non-ventilated COVID-19 
patients – Randomized Controlled Trial 
INTRODUCTION 
The 2019-20 coronavirus disease, caused by COVID-19, is an ongoing pandemic. 
The outbreak started in Wuhan, Hubei province, China, in December 2019 and the 
World Health Organization (WHO) recognized it as a pandemic on March 11, 
2020. Up to Apr 9, 2020, there are more than 2 million confirmed cases, and over 
140,000 deaths. In Israel, COVID-19 was confirmed in more 12,000 cases and 
took the life of 140 victims. There are 323 mild admitted cases, 170 moderate 
admitted cases and 170 severe admitted cases (16.04.2020). 
Even though the general mortality rate is low (0.2-7%, country based), patients 
who develop Acute Respiratory Distress Syndrome (ARDS) have a significantly 
higher mortality rate, up to 61-90% ]1[. COVID-19 ARDS is different, causing a 
rapidly progressive disease including respiratory insufficiency and pulmonary fibrosis 
]2[. The mechanism behind isn't clear yet, but evidence points to the direction of 
an acute cytokines storm which include: IL-2, IL-7, GCSF, InterferonGamma, 
TNF-alpha, Macrophage chemoattractant protein ]3[. Poor prognosis include high 
levels of IL-6 and Ferritin ]3[. 
The SARS-CoV-2 virus is a positive RNA strand with the following structural 
proteins: Spike protein (S), Envelope protein €, Membrane protein (M) and 
nucleocapsid. In addition the virus is encoded to several other protein: orflab, 
ORF1, OR3a, ORF6, ORF7a, ORF8 [4, 5]. A recent bioinformatic study analyzed the 
pathogenic function of these proteins. The study found the ORF8 protein and 
another glycoprotein are able to bind to the Porphyrin molecule (the ring 
surrounding the iron atom in the Heme component). Parallelly, the orflab, 
ORF10, ORF3a proteins are able to harm the HEME component. Located on the 
1-beta chain of the hemoglobin molecule, unbinding the iron atom needed for the 
Porphyrin]6[.  

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 2 of 9 
More than 160 clinical trials have been registered, but as of April 2020, there is no 
proven effective treatment. In a recent randomized controlled trial including 199 
patients, anti-viral drugs (Lopinavir-Ritonavir) did not show efficacy 
[
7
]
. Moreover, 
the use of extracorporeal membrane oxygenation (ECMO) did not prove efficacy 
compared to the standard treatment on an analysis of 17 patients 
[
8
]
.  
BACKGROUND AND SIGNIFICANCE 
The use of hyperbaric oxygen therapy (HBOT) includes breathing 100% oxygen in 
pressures higher than 1 absolute atmospheres (ATA), increasing the amount of 
oxygen dissolved in the plasma and the different tissues. During the session, oxygen 
partial pressure can increase from 100mmHg to 1700-2500mmHg (according to the 
applied pressure) [9]. In the last month, Chen et al. reported a case series of 5 severe 
COVID-19 patients treated with 3-8 HBOT sessions in addition to the standard 
therapy 
[
10
]
. In all cases, they reported an increase in oxygen saturation, arterial 
oxygen content, lactate levels reduction, fibrinogen levels decrease and increase in 
lymphocytes number. In addition, the patients' chest CT showed improved signs. 
Symptomatic relief started following the 2nd session. No significant adverse events 
were reported [9]. 
These findings may be explained by the known physiological effects of HBOT, related 
to the SARS-CoV-2 virus pathogenesis: 

Increased competitive binding of oxygen to the hemoglobin molecule
– it has been postulated recently the SARS-CoV-2 bind to the heme component
in the hemoglobin molecule and reduces the oxygen affinity to hemoglobin.
During HBOT, the increased amount of available oxygen molecules increases
the binding to the hemoglobin molecules. This has shown significant beneficial
effects in cases of another competitive molecule such as carbon monoxide
intoxication, where HBOT induces carbon monoxide unbinding and release of
the red blood cells [12, 11]. If the virus indeed affects the Heme component
(as suggested above) in a competitive affinity, HBOT may significantly improve
and normalize the red blood cells oxygen carrying capability.

Tissue oxygenation – The oxygen content in the different tissues is
multiplied by 25-30 times [13]. This effect has two therapeutic aspects: First,
overcoming pulmonary hypoxia (either shunt or VQ mismatch) by increasing
the FiO2 significantly. By increasing the pulmonary oxygen gradient, oxygen
diffusion increases and can overcome the inflammation in the alveoli and the
thickened fibrosis caused by ARDS. These effects have been demonstrated in
patients who developed ARDS after suffering a blunt chest trauma who were
treated with HBOT. In these patients, HBOT induced improvement and rapid
normalization of PaO2, PaO2/FiO2 in addition to cardiac parameters CI and SVI
[
14
]
. Second, during HBOT, the amount of oxygen dissolved in the plasma

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 3 of 9 
becomes significant and enables tissue oxygenation without the need of red 
blood cells
[
15
]
  
. 

Mitochondrial function restoration – HBOT can restore the normal function
of the mitochondria and the cellular metabolism, decrease apoptosis and
reduce the oxidative injury [16].

Anti-inflammatory – HBOT reduces the following inflammatory cytokines
both in the protein level and genes expression (mRNA): IL-2, TNF-alpha, IL-6,
IL-1beta, mediated by several transcription factors: Hypoxia induced factor
1alpha (HIF1alpha), Nrf2, NFkB [17-19] . The anti-inflammatory effect has
been shown in chronic diseases as well as models of acute infection and
massive hemorrhage [20, 21].
Apart from Chen et al. case series, no prospective study was performed on the effect 
of HBOT on COVID-19 patients. In addition to the safety report in that case series, 
there's more evidence for the level of safety of HBOT in patients with acute pulmonary 
insufficiency: 

There is an ongoing debate in regards to the use of high inhaled oxygen level
for patients with ARDS. In a recent randomized controlled trial (LUNGSAFE),
there was no association between high oxygen levels and bad prognosis 
[
22
]
.

The use of HBOT in patients with ARDS after blunt chest trauma, showed
promising results in oxygenation and cardiac function, with no safety issues
[
14
]
.
STUDY OBJECTIVES 
The purpose of the current study is to evaluate the efficacy of HBOT in moderate-
severe non ventilated COVID-19 patients.  
The primary objectives of study will be to assess the following indicators: 

Oxygenation index = PaO2/FiO2 one day after the last session.

SpO2 – room air saturation one hour before and after a session, 6 hours after
a session and one day after the last session.

NES – Early warning score, before and after each session, 6 hours after each
session and one day after the last session

Inflammatory parameters one day after the last session: WBC, Immune
profile, CRP, ESR, Procalcitonin, TNFalpha, IL1, IL2, IL6, IL10.
The secondary objectives of study will be to assess the following indicators: 

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 4 of 9 

Oxygenation index = PaO2/FiO2 one week after the last session.

SpO2 – room air saturation one week after the last session.

NES – Early warning score, one week after the last session

Inflammatory parameters one week after the last session: WBC, Immune
profile, CRP, ESR, Procalcitonin, TNFalpha, IL1, IL2, IL6, IL10.

Symptoms level one day and one week after the last session

Viral load one day and one week after the last session

Chest Xray changes one day and one week after the last session

Percentage of patients with positive IgG serology one day and one week after
the last session

Percentage of patients with positive IgM serology one day and one week after
the last session

Pulmonary function test one day and one week after the last session

Time to symptoms recovery

Percentage of patients who required invasive intubation

Time to recovery (negative PCR twice) – TTCR

Mortality rate in 30 days

Safety – percentage of adverse events
STUDY DESIGN 
Subjects: Patients at Maimonides Medical Center (MMC) 
Eligibility Criteria: 
Patients who are (1) within 7 days of need of oxygen supply, (2) positive to SARS-
CoV-2 through RT-PCR, (3) have at least one risk factor for bad prognosis of COVID-
19: hypertension, diabetes mellitus, ischemic heart disease, smoking, age>50, etc., 
(4) have respiratory insufficiency: Room Air SpO2 <94% or PaO2/FiO2<300mmHg,
(5) are older than 18 years of age and (6) have ability to sign an informed consent
will be included in the study.
Patients who are (1) negative to SARS-CoV-2 through RT-PCR, (2) have a HBOT 
contraindication: pneumothorax, pneumomediastinum, claustrophobia, ear/sinus 
disease which aren't allowed in HBOT, known chronic pulmonary disease: severe 
emphysema or known pulmonary bullae, (3) have pregnancy and/or (4) have inability 
to sign an informed consent will be excluded from study. 

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 5 of 9 
Design: 
This study is a prospective randomized controlled, double blind clinical trial performed 
on laboratory confirmed COVID-19 infection admitted patients in MMC. It involves 
the use of MMC monoplace HBO chambers. The trial will include 30 patients who will 
undergo either hyperbaric oxygen therapy (HBOT) or Normobaric oxygen therapy 
(NBOT), randomized on a 2:1 ratio, within 4 days in addition to the standard 
treatment including oxygen, drugs, steroids, bronchodilators, antibiotics and others. 
The evaluation procedure includes symptom monitoring, room air saturation, vital 
signs monitoring, pulmonary function and blood tests at baseline, one day and one 
week after the last session. In addition, one hour prior to and post session saturation 
and vitals will be monitored.  
Data Collection Procedures: 
Upon signing an informed consent, the patients will be randomized 2:1 to hyperbaric 
oxygen therapy group (HBOT) and normobaric oxygen therapy group (NBOT) 
(Randomization will be performed using a computer software based on patient id). 
Following the randomization, the patients will undergo evaluation including 
symptoms, vitals, pulmonary function, blood tests.  
The patients will undergo 8 sessions of either hyperbaric/normobaric oxygen therapy, 
2 sessions per day, in 4 consecutive days. During the sessions, the symptoms and 
vitals will be monitored. 1 day and 1 week following the last session, revaluation will 
be performed. 
Protocol Day 1 
1. Baseline evaluation: blood test including: arterial blood gases, 2 CBC tubes, 2
Gel tubes (10-15 cc total), vitals (temperature, blood pressure, heart rate,
room air saturation), symptoms questionnaire, pulmonary function test.
2. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
prior to session
3. One-hour session NBO/HBO
4. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
after the session.
5. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
before the 2nd session.
6. One-hour session NBO/HBO (8 hours following the first session)
7. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
after the session.
8. Daily oxygen supply dose monitoring.
Protocol Day 2-4 

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 6 of 9 
1. Daily symptoms questionnaire
2. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
prior to session
One-hour session NBO/HBO
3. Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
after the session.
4.
Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
before the 2nd session.
5.
One-hour session NBO/HBO (8 hours following the first session)
6.
Vitals (temperature, blood pressure, heartrate, room air saturation) one hour
after the session.
7.
Daily oxygen supply dose monitoring.
Follow up Protocol 
1.
Repeat evaluations one day after the last session and one week after the last
session:
Blood test including: arterial blood gases, 2 CBC tubes, 2 Gel tubes (10-15
cc total)
Vitals (temperature, blood pressure, heart rate, room air saturation)
Symptoms questionnaire
Pulmonary function test.
2.
Oropharyngeal swab for SARS-CoV-2 RT-PCR every 3 days for 1 week
3.
Clinical monitoring for 30 days
Data Analysis: 
Continuous data will be expressed as means ± standard-deviations. Independent and 
dependent t-test with two-tail distribution will be performed to compare variables 
between and within the two groups, when a normality assumption holds according to 
Kolmogorov-Smirnov test. Categorical data will be expressed in numbers and 
percentages and compared by chi-square tests. Univariate analyses were performed 
using Chi-Square/Fisher’s exact test to identify significant variables. A value of 
p<0.05 will be considered significant.  
Data analysis will be performed with Matlab R2019b (Mathworks, Natick, MA) 
Statistics Toolbox. 
Sample Size: 30 
Based on a previous study on HBOT effect on ARDS 
[
14
]
, with 95% power and 
significance level of 5%, and a groups difference of  30 (SD 15-18) in the PaO2/FiO2 
and a 2:1 groups allocation, the sample requires 7 NBOT patients and 13 HBOT 
patients. Considering 15% dropout, we will recruit 10 NBOT patients and 20 HBOT 
patients, 30 in total. 

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 7 of 9 
Expected Outcomes:  
The primary outcomes measures that will be accessed in the study are: 

Oxygenation index = PaO2/FiO2 one day after the last session.

SpO2 – room air saturation one hour before and after a session, 6 hours after
a session and one day after the last session.

NES – Early warning score, before and after each session, 6 hours after each
session and one day after the last session

Inflammatory parameters one day after the last session: WBC, Immune
profile, CRP, ESR, Procalcitonin, TNFalpha, IL1, IL2, IL6, IL10.
The secondary outcomes measures that will be accessed in the study are: 

Oxygenation index = PaO2/FiO2 one week after the last session.

SpO2 – room air saturation one week after the last session.

NES – Early warning score, one week after the last session

Inflammatory parameters one week after the last session: WBC, Immune
profile, CRP, ESR, Procalcitonin, TNFalpha, IL1, IL2, IL6, IL10.

Symptoms level one day and one week after the last session

Viral load one day and one week after the last session

Chest Xray changes one day and one week after the last session

Percentage of patients with positive IgG serology one day and one week after
the last session

Percentage of patients with positive IgM serology one day and one week after
the last session

Pulmonary function test one day and one week after the last session

Time to symptoms recovery

Percentage of patients who required invasive intubation

Time to recovery (negative PCR twice) – TTCR

Mortality rate in 30 days

Safety – percentage of adverse events
Timetable: 12 months 
Adverse Event Reporting 
Subjects will be monitored for adverse events (AEs) during the entire study and more 
particularly, during and after each treatment session by clinical inquiry, clinical 
observation and (when applicable) by clinical examination. AE information will be 
documented and all subjects will be questioned about AEs at each visit during the 
treatment period and at the follow-up visits. AEs will also be recorded whenever 
spontaneously reported by the subject. Event description, date of onset, intensity, 

Maimonides Medical Center Protocol v1.0 17APR2018 
 Page 8 of 9 
duration, treatment for AE, whether the AE was resolved and probable relationship 
to the study product will be recorded onto case report forms (CRFs).  
The investigator must record all serious adverse events regardless of treatment or 
relationship to investigational product as soon as s/he is informed of the event. 
Any serious adverse event (SAE) which occurs after a patient has entered the study 
(after signing informed consent), must be reported. The original copy of the serious 
adverse event form must be kept with the documentation at the site. 
Patients who have had an SAE during the treatment period must be followed clinically 
until all parameters (including laboratory), have either returned to normal, have 
stabilized or are otherwise explained.   
SAEs should be reported by the investigator to competent authorities and ethics 
committees according to local requirements.  
For more information, see research protocol from overall study. 
REFERENCES 
1.
Goh, K.J., et al., Rapid Progression to Acute Respiratory Distress Syndrome:
Review of Current Understanding of Critical Illness from COVID-19 Infection.
Ann Acad Med Singapore, 2020. 49(3): p. 1-9.
2.
Mehta, P., et al., COVID-19: consider cytokine storm syndromes and
immunosuppression. Lancet, 2020. 395(10229): p. 1033-1034.
3.
Ruan, Q., et al., Clinical predictors of mortality due to COVID-19 based on an
analysis of data of 150 patients from Wuhan, China. Intensive Care Med, 2020.
4.
Zhu, N., et al., A Novel Coronavirus from Patients with Pneumonia in China,
2019. N Engl J Med, 2020. 382(8): p. 727-733.
5.
Wu, F., et al., A new coronavirus associated with human respiratory disease in
China. Nature, 2020. 579(7798): p. 265-269.
6.
liu, w. and h. Li, COVID-19: Attacks the 1-Beta Chain of Hemoglobin and
Captures the Porphyrin to Inhibit Human Heme Metabolism. 2020.
7.
Cao, B., et al., A Trial of Lopinavir-Ritonavir in Adults Hospitalized with Severe
Covid-19. N Engl J Med, 2020.
8.
Henry, B.M. and G. Lippi, Poor survival with extracorporeal membrane
oxygenation in acute respiratory distress syndrome (ARDS) due to coronavirus
disease 2019 (COVID-19): Pooled analysis of early reports. J Crit Care, 2020.
58: p. 27-28.
9.
Fosen, K.M. and S.R. Thom, Hyperbaric oxygen, vasculogenic stem cells, and
wound healing. Antioxid Redox Signal, 2014. 21(11): p. 1634-47.

 Page 9 of 9 
10.
Ruiyong Chen 1*, X.Z., Yanchao Tang 3*, Yi Liang 4, Bujun Li 5, Xiaolan Tao
2, Changbo Liao 1., The Outcomes of Hyperbaric Oxygen Therapy to severe
and critically ill patients with COVID-19 pneumonia.
11.
Ernst, A. and J.D. Zibrak, Carbon monoxide poisoning. N Engl J Med, 1998.
339(22): p. 1603-8.
12.
Weaver, L.K., et al., Hyperbaric oxygen for acute carbon monoxide poisoning.
N Engl J Med, 2002. 347(14): p. 1057-67.
13.
Rockswold, S.B., et al., A prospective, randomized clinical trial to compare the
effect of hyperbaric to normobaric hyperoxia on cerebral metabolism,
intracranial pressure, and oxygen toxicity in severe traumatic brain injury. J
Neurosurg, 2010. 112(5): p. 1080-94.
14.
Rogatsky, G.G. and A. Mayevsky, The life-saving effect of hyperbaric
oxygenation during early-phase severe blunt chest injuries. Undersea Hyperb
Med, 2007. 34(2): p. 75-81.
15.
Boerema, I., et al., [Life without blood]. Ned Tijdschr Geneeskd, 1960. 104:
p. 949-54.
16.
Palzur, E., et al., Neuroprotective effect of hyperbaric oxygen therapy in brain
injury is mediated by preservation of mitochondrial membrane properties.
Brain Res, 2008. 1221: p. 126-33.
17.
Novak, S., et al., Anti-Inflammatory Effects of Hyperbaric Oxygenation during
DSS-Induced Colitis in BALB/c Mice Include Changes in Gene Expression of
HIF-1alpha, Proinflammatory Cytokines, and Antioxidative Enzymes. Mediators
Inflamm, 2016. 2016: p. 7141430.
18.
Aricigil, M., et al., Anti-inflammatory effects of hyperbaric oxygen on irradiated
laryngeal tissues. Braz J Otorhinolaryngol, 2018. 84(2): p. 206-211.
19.
Benson, 
R.M., 
et 
al., 
Hyperbaric 
oxygen 
inhibits 
stimulus-induced
proinflammatory cytokine synthesis by human blood-derived monocyte-
macrophages. Clin Exp Immunol, 2003. 134(1): p. 57-62.
20.
Halbach, J.L., et al., Early hyperbaric oxygen therapy improves survival in a
model of severe sepsis. Am J Physiol Regul Integr Comp Physiol, 2019.
317(1): p. R160-R168.
21.
Yamashita, M. and M. Yamashita, Hyperbaric oxygen treatment attenuates
cytokine induction after massive hemorrhage. Am J Physiol Endocrinol Metab,
2000. 278(5): p. E811-6.
22.
Madotto, F., et al., Hyperoxemia and excess oxygen use in early acute
respiratory distress syndrome: insights from the LUNG SAFE study. Crit Care,
2020. 24(1): p. 125.
Maimonides Medical Center Protocol v1.0 17APR2018