Last updated: April 2026
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Quick Answer
- Hyperbaric oxygen therapy (HBOT) effectiveness depends on pressure and oxygen concentration, as higher pressure pushes more oxygen into the bloodstream and tissues.
- The Undersea & Hyperbaric Medical Society (UHMS) lists 14 approved indications for HBOT, including air or gas embolism and carbon monoxide poisoning.
- Gas embolism can occur from an ascent of as little as one meter, or through causes like accidental intravenous air injection or mechanical ventilation.
- Continuous IV infusion of oxygen at 10 mL/min has been reported as well tolerated, while 20 mL/min caused symptoms.
Understanding the different pressure settings in hyperbaric oxygen therapy is crucial for anyone considering this treatment. The effectiveness of HBOT is directly tied to both the pressure inside the chamber and the amount of oxygen a person breathes while under that pressure. When pressure increases, more oxygen gets pushed into the bloodstream and then into the body's tissues. The Undersea & Hyperbaric Medical Society (UHMS) provides clear guidelines on the approved uses for HBOT, listing 14 specific indications. These indications are the foundation for how we apply hyperbaric oxygen therapy in clinical settings. For example, pulmonary barotrauma and gas embolism can happen after an ascent of as little as one meter, highlighting the precise nature of these conditions and the need for specific treatment protocols. See the arterial gas embolism evidence atlas for the full study-by-study evidence breakdown.
Why Does Pressure Matter in Hyperbaric Oxygen Therapy?
Pressure is a critical component that makes hyperbaric oxygen therapy effective. It works together with the amount of pure oxygen a person breathes to deliver healing benefits. As the pressure inside the hyperbaric chamber increases, it physically forces more oxygen to dissolve into the bloodstream. This increased oxygen then travels to tissues throughout the body, even those that are struggling to receive enough oxygen under normal conditions.
When we consider the practical aspects of hyperbaric therapy, pressure affects several key areas. First, it influences how the treatment feels to the patient. Higher pressures can make the sensation in the ears more noticeable, similar to the feeling experienced when diving underwater or flying in an airplane. Audrey Burrell of Healing the Hyperbaric Way explained this simply, stating, "Pressure is one key factor that makes hyperbaric therapy effective. The other is the amount of oxygen you breathe while at that pressure. As pressure increases, more oxygen is driven into the bloodstream and tissues." This direct relationship between pressure and oxygen delivery is fundamental to how HBOT works.
Different pressures are used for different conditions, reflecting the specific physiological needs of each indication. For instance, some conditions might benefit from lower pressures, while others require higher pressures to achieve the desired therapeutic effect. The choice of pressure, whether 1.3, 2.0, or 2.4 ATA (Atmospheres Absolute), is based on established medical protocols and the specific goals of the treatment. The goal is always to maximize oxygen delivery to damaged or oxygen-deprived tissues while maintaining patient safety and comfort.
The Role of Oxygen Concentration
Beyond just pressure, the concentration of oxygen is equally important. In a hyperbaric chamber, patients typically breathe 100% oxygen. This high concentration, combined with increased pressure, significantly raises the amount of oxygen available to the body. Under normal atmospheric pressure, our blood carries oxygen mainly through hemoglobin in red blood cells. However, under hyperbaric conditions, the increased pressure allows a much larger amount of oxygen to dissolve directly into the plasma, the liquid part of the blood. This dissolved oxygen can then reach areas that might be poorly supplied with blood due to injury or disease.
Understanding ATA (Atmospheres Absolute)
The term ATA stands for "Atmospheres Absolute." One ATA is the average atmospheric pressure at sea level. So, 1.3 ATA means the pressure inside the chamber is 1.3 times the normal atmospheric pressure. Similarly, 2.0 ATA is twice the normal pressure, and 2.4 ATA is 2.4 times the normal pressure. To put this into perspective, being at 1.3 ATA feels like being about 10 feet underwater, while 2.0 ATA is like being roughly 33 feet underwater. At 2.4 ATA, the sensation is similar to being about 46 feet underwater. These pressure levels are carefully controlled within the hyperbaric chamber to ensure precise and consistent treatment. The higher the ATA, the greater the partial pressure of oxygen, and thus, the more oxygen is dissolved into the body's fluids.
How Pressure Impacts the Body
The primary way increased pressure impacts the body in HBOT is by reducing the size of gas bubbles and increasing oxygen solubility. For conditions like air or gas embolism, higher pressure physically shrinks gas bubbles in the bloodstream, helping to clear blockages and restore blood flow. At the same time, the increased partial pressure of oxygen enhances the body's healing capabilities. It promotes the growth of new blood vessels, reduces swelling, fights certain types of infections, and helps damaged tissues recover. The combined effect of pressure and high oxygen concentration creates a powerful therapeutic environment that supports the body's natural healing processes. Without the elevated pressure, simply breathing 100% oxygen at normal atmospheric pressure would not achieve the same profound physiological changes.
What Are the Approved Uses for Hyperbaric Oxygen Therapy?
The approved uses for hyperbaric oxygen therapy are strictly defined and regularly reviewed by leading medical authorities. The primary guiding body for these indications in the United States is the Undersea and Hyperbaric Medical Society (UHMS). The UHMS meticulously evaluates scientific evidence to determine which conditions benefit from HBOT, ensuring that treatments are both safe and effective.
Our approach to hyperbaric oxygen therapy is always as an adjunctive treatment. This means it is typically used in addition to other standard medical interventions. For example, a patient receiving HBOT for a severe infection might also be on a course of antibiotics. Similarly, individuals with complex wounds often combine HBOT with surgery, nutritional support, and other therapies recommended by their primary care physicians. This integrated approach ensures comprehensive care and maximizes the potential for positive outcomes. According to UCLA Health Hyperbaric Medicine Indications, "Indications for hyperbaric oxygen therapy are based on recommendations defined by the Undersea and Hyperbaric Medical Society (UHMS)." This underscores the importance of adhering to these established guidelines when considering HBOT.
The UHMS publishes a comprehensive list of approved indications, which serves as the gold standard for hyperbaric medicine practitioners. This list is updated periodically to reflect new research and clinical understanding. Patients and healthcare providers can refer to the latest edition of the UHMS Hyperbaric Oxygen Therapy Indications document to understand the conditions for which HBOT has demonstrated clear therapeutic benefit.
The UHMS Approval Process
The UHMS follows a rigorous process for approving new indications for hyperbaric oxygen therapy. This process involves extensive review of clinical trials, research studies, and expert consensus. A dedicated committee, comprising specialists in hyperbaric medicine and related fields, evaluates the evidence to ensure that any approved indication meets high standards of efficacy and safety. This thorough vetting process is crucial for maintaining the integrity and credibility of hyperbaric medicine. It ensures that HBOT is used appropriately and for conditions where there is robust scientific support for its benefits.
HBOT as an Adjunctive Treatment
It is important to emphasize that HBOT is rarely a standalone treatment. Instead, it is integrated into a broader treatment plan. For instance, in cases of problem wounds, HBOT might accelerate healing, but it does not replace the need for wound debridement, infection control, or proper wound dressings. For conditions like carbon monoxide poisoning, HBOT is a critical intervention, but it is still part of an emergency medical response that includes supportive care and monitoring. This collaborative approach ensures that patients receive the full spectrum of care necessary for their recovery. The hyperbaric team works closely with other specialists to coordinate treatment plans and optimize patient outcomes.
The Importance of UHMS Guidelines
Following UHMS guidelines is vital for patient safety and treatment effectiveness. These guidelines provide clear protocols, including recommended pressures, treatment durations, and frequency for each approved indication. Deviating from these established protocols without strong medical justification can compromise patient safety and reduce the therapy's effectiveness. Clinics and practitioners who adhere to UHMS standards demonstrate a commitment to evidence-based medicine and high-quality patient care. The UHMS guidelines also help in standardizing care across different hyperbaric facilities, ensuring a consistent level of quality and safety for patients undergoing HBOT.
What are the UHMS-Approved Indications for HBOT?
The Undersea and Hyperbaric Medical Society (UHMS) has identified 14 specific conditions for which hyperbaric oxygen therapy is an approved treatment. These indications are based on extensive research and clinical evidence, ensuring that HBOT is used where it can provide significant therapeutic benefits. These approved uses cover a range of acute and chronic conditions, often those involving tissue damage, infection, or compromised blood flow.
The list of approved indications is comprehensive, addressing various medical challenges. For example, the UHMS 14th Edition specifies conditions such as air or gas embolism, which can be life-threatening. It also includes carbon monoxide poisoning, where HBOT can rapidly clear toxins from the body. Decompression sickness, commonly known as "the bends" in divers, is another critical indication where immediate HBOT can prevent severe long-term complications. We rely on this authoritative list to guide our treatment protocols and ensure we are providing care that meets the highest medical standards. UHMS Hyperbaric Oxygen Therapy Indications 14th Edition provides the full details of these approved uses.
Other approved uses include complex and chronic conditions that are often difficult to treat with conventional methods alone. These involve problem wounds that resist healing, compromised grafts and flaps following surgery, and various types of infections. The therapy's ability to enhance oxygen delivery and reduce inflammation makes it a valuable tool in managing these challenging cases.
The Full List of UHMS-Approved Indications
The 14 UHMS-approved indications for hyperbaric oxygen therapy are:
- Air or Gas Embolism: This condition occurs when gas bubbles enter the arteries or veins, potentially blocking blood flow. HBOT helps to reduce the size of these bubbles and increase oxygen delivery to affected tissues. According to Richard E. Moon, "Gas embolism occurs when gas bubbles enter arteries or veins. Arterial gas embolism (AGE) was classically described during submarine escape training, in which pulmonary barotrauma occurred during free ascent after breathing compressed gas at depth. Pulmonary barotrauma and gas embolism due to breath holding can occur after an ascent of as little as one meter."
- Carbon Monoxide Poisoning: HBOT is highly effective in treating carbon monoxide poisoning by accelerating the removal of carbon monoxide from the blood and delivering vital oxygen to oxygen-starved tissues.
- Clostridial Myonecrosis (Gas Gangrene): This is a severe bacterial infection that causes tissue death. HBOT helps to kill the anaerobic bacteria responsible for the infection and promotes tissue healing.
- Decompression Sickness: This condition affects divers who ascend too quickly, causing nitrogen bubbles to form in the blood and tissues. HBOT helps to recompress these bubbles and facilitate their safe removal from the body.
- Problem Wounds (Selected): This category includes chronic wounds that have not responded to conventional treatments, such as diabetic foot ulcers, venous stasis ulcers, and pressure ulcers. HBOT improves oxygenation, promotes new blood vessel growth, and enhances wound healing.
- Compromised Grafts and Flaps: When skin grafts or surgical flaps have compromised blood supply, HBOT can improve tissue viability and increase the chances of successful integration.
- Acute Traumatic Ischemias: This includes conditions like crush injuries and compartment syndrome, where severe trauma leads to reduced blood flow and tissue damage. HBOT helps to reduce swelling, preserve tissue, and promote recovery.
- Delayed Radiation Injuries (Soft Tissue and Bony Necrosis): Radiation therapy can sometimes cause damage to healthy tissues, leading to chronic pain, non-healing wounds, and bone death. HBOT can help repair these damaged tissues by improving blood supply and stimulating healing.
- Intracranial Abscess: This is a collection of pus within the brain, often caused by bacterial infection. HBOT can be an adjunct to antibiotics and surgery, helping to fight the infection and promote healing.
- Necrotizing Soft Tissue Infections: These are aggressive, rapidly spreading bacterial infections that destroy muscle, fat, and skin. HBOT supports the body's immune response and helps to control the infection.
- Refractory Osteomyelitis: This is a persistent bone infection that has not responded to standard antibiotic treatment. HBOT enhances antibiotic effectiveness and promotes bone regeneration.
- Severe Anemia: In cases where a patient cannot receive a blood transfusion, HBOT can provide enough dissolved oxygen in the plasma to sustain life and support cellular function.
- Central Retinal Artery Occlusion: This is a blockage of the main artery supplying blood to the retina, which can cause sudden, severe vision loss. HBOT can help restore blood flow and oxygen to the retina.
- Adjunctive Hyperbaric Oxygen Therapy in the Treatment of Thermal Burns: For severe burns, HBOT can reduce swelling, improve blood flow, decrease infection risk, and promote faster healing.
Each of these indications has specific treatment protocols, including recommended pressures and treatment schedules, designed to optimize outcomes for patients. The efficacy of HBOT in these areas has been thoroughly documented and continues to be supported by ongoing research.
How Does Hyperbaric Oxygen Therapy Address Air or Gas Embolism?
Hyperbaric oxygen therapy plays a crucial role in treating air or gas embolism, a serious condition where gas bubbles enter the arteries or veins and can obstruct blood flow. This can lead to a range of symptoms, from mild discomfort to life-threatening complications, depending on where the bubbles travel and their volume. HBOT works by physically shrinking these gas bubbles and by delivering a massive amount of oxygen to tissues that may have been deprived due to the blockage.
Gas embolism can occur in various ways, often associated with rapid changes in pressure or medical procedures. For instance, Richard E. Moon, in "Hyperbaric Oxygen Therapy Indications: Air or Gas Embolism," explains that "Gas embolism occurs when gas bubbles enter arteries or veins. Arterial gas embolism (AGE) was classically described during submarine escape training, in which pulmonary barotrauma occurred during free ascent after breathing compressed gas at depth. Pulmonary barotrauma and gas embolism due to breath holding can occur after an ascent of as little as one meter." This highlights how even a small pressure change can trigger the condition in susceptible individuals.
Venous gas embolism (VGE) is frequently observed after compressed gas diving. In most cases, these bubbles are small and are effectively filtered out and trapped by the pulmonary capillaries in the lungs, preventing them from causing any noticeable symptoms. However, when the volume of VGE is large, it can overwhelm the capacity of these pulmonary capillaries. This allows the bubbles to bypass the lungs and enter the arterial circulation, where they can cause significant problems. Large volumes of VGE can lead to symptoms such as coughing, difficulty breathing (dyspnea), and pulmonary edema.
Mechanisms of Action Against Gas Embolism
When a patient with gas embolism undergoes HBOT, they are placed in a chamber where the pressure is significantly increased, often to 2.8 ATA or higher for acute cases, as per standard recompression tables. This increased pressure directly reduces the size of the gas bubbles in the bloodstream, following Boyle's Law. As the bubbles shrink, they are less likely to block small blood vessels, allowing blood flow to resume.
Simultaneously, the patient breathes 100% oxygen. This high partial pressure of oxygen creates a steep gradient that helps to "wash out" the inert gas (like nitrogen in divers) from the bubbles. The oxygen effectively replaces the inert gas within the bubbles, making them more soluble in the blood and facilitating their removal from the body. This dual action of bubble reduction and inert gas washout is critical for resolving gas embolism.
The Severity of Gas Embolism
The clinical deficits caused by gas embolism can vary widely depending on the amount and location of air injected. Even small volumes of air injected into arteries can lead to significant problems. While intravenous injection is often asymptomatic, larger volumes can be dangerous. Research shows that continuous IV infusion of oxygen at 10 mL/min has been reported as well tolerated in humans, but an increase to 20 mL/min caused symptoms. This indicates a threshold for the body's ability to manage gas in the bloodstream. Compared with constant infusions, sudden injections of air are more likely to cause immediate clinical abnormalities because the body has less time to adapt and filter the bubbles. In experimental animals, intravenous injection of up to 0.5-1 mL/kg has been tolerated, but these are controlled experimental settings and not directly transferable to human clinical tolerance without careful consideration. The precise application of HBOT pressures, such as 2.0 ATA or 2.4 ATA, is crucial for effectively managing these complex and often time-sensitive conditions.
Causes Beyond Diving
While diving is a well-known cause, gas embolism can also arise from numerous medical and non-medical situations. These include accidental intravenous air injection during medical procedures, complications during cardiopulmonary bypass surgery, and even less common incidents like hydrogen peroxide irrigation. The wide range of potential causes underscores the importance of having HBOT readily available as a treatment option. Understanding the various ways gas embolism can occur helps us to identify patients who may benefit from hyperbaric oxygen therapy.
What Other Conditions Can Lead to Gas Embolism?
Gas embolism is not exclusively a diving-related issue; it can arise from a wide array of medical procedures, injuries, and even accidental occurrences. Understanding these diverse origins is crucial for recognizing when hyperbaric oxygen therapy might be necessary. Beyond the classic diving scenarios, the causes range from routine medical interventions to more unusual circumstances.
One significant category of causes includes accidental intravenous air injection during various medical procedures. This can happen during central venous catheter placement or disconnection, a common procedure for administering fluids or medications. Similarly, hemodialysis and needle biopsy of the lung are other medical contexts where air can inadvertently enter the bloodstream. Even cardiopulmonary bypass accidents, though rare, can lead to gas embolism. These incidents highlight the vigilance required in clinical settings to prevent such complications. Hyperbaric Chamber Pressures Explained emphasizes that pressure is a key factor in hyperbaric therapy's effectiveness.
Surgical procedures, especially those where the surgical site is under pressure or elevated above the heart, pose another risk. For example, procedures like laparoscopy, transurethral surgery, vitrectomy, endoscopic vein harvesting, and hysteroscopy can create conditions where air embolism might occur. In these situations, the surgical field might be pressurized or exposed to air in a way that allows gas bubbles to enter the circulatory system.
Surgical and Procedural Risks
Massive venous gas embolism (VGE) can occur when air passively enters surgical wounds that are elevated above the level of the heart. This creates a pressure gradient where the pressure in adjacent veins becomes subatmospheric, essentially sucking air into the veins. This phenomenon has been classically described in sitting craniotomy, a neurosurgical procedure where the patient is positioned upright. However, it has also been reported during other surgeries such as cesarean section, prostatectomy (both radical perineal and retropubic approaches), spine surgery, hip replacement, liver resection, liver transplantation, and even during the insertion of dental implants. These diverse surgical contexts demonstrate how varied the risk factors for gas embolism can be, impacting a wide range of medical specialties.
Other less common but documented causes of gas embolism include gastrointestinal endoscopy, hydrogen peroxide irrigation or ingestion, arthroscopy, and even cardiopulmonary resuscitation. In some extremely rare cases, blowing air into the vagina during orogenital sex or sexual intercourse after childbirth has been linked to air embolism. These varied scenarios underscore the importance of considering gas embolism in a broad differential diagnosis, especially in cases of unexplained neurological or cardiopulmonary symptoms following a medical procedure or specific event.
Understanding Bubble Tolerance
The body's tolerance for gas in the bloodstream varies. Small volumes of air injected into arteries can cause clinical deficits. In contrast, intravenous injection is often asymptomatic, especially with small amounts. Experimental animals have tolerated intravenous injection of up to 0.5-1 mL/kg of air. In humans, continuous intravenous infusion of oxygen at 10 mL/min has been well-tolerated, but 20 mL/min caused symptoms. This difference highlights that the rate and volume of gas entry, as well as the specific location (arterial vs. venous), significantly influence the clinical outcome. Injections of air are more likely to cause clinical abnormalities compared to constant infusions, likely due to the sudden impact of a bolus of gas on the circulatory system. This understanding guides the urgency and specific pressure protocols, such as those involving 2.0 ATA or 2.4 ATA, used in HBOT for treating gas embolism.
What Are the Specific UHMS Indications?
The Undersea and Hyperbaric Medical Society (UHMS) has meticulously outlined 14 specific conditions for which hyperbaric oxygen therapy (HBOT) is an approved and recommended treatment. These indications are the bedrock of clinical hyperbaric medicine, ensuring that the therapy is applied in scenarios where its benefits are scientifically proven and clinically significant. Each indication addresses unique physiological challenges that HBOT is uniquely suited to overcome, primarily through enhanced oxygen delivery and the physical effects of increased pressure.
We adhere strictly to these guidelines, recognizing that they represent the consensus of experts in hyperbaric medicine. For instance, the UHMS recognizes Central Retinal Artery Occlusion as an approved indication. This condition involves a blockage of the main artery supplying blood to the retina, leading to sudden and often severe vision loss. HBOT aims to restore blood flow and oxygen to the deprived retinal tissues, potentially preserving sight. Similarly, Selected Problem Wounds, such as diabetic foot ulcers that fail to heal, are also on the list. In these cases, HBOT can stimulate new blood vessel growth, fight infection, and accelerate the healing process.
The list extends to severe infections and conditions resulting from trauma or radiation. The 14th Edition of the UHMS Indications document details conditions like Carbon Monoxide Poisoning, which requires rapid intervention to prevent neurological damage. It also covers Necrotizing Soft Tissue Infections, aggressive bacterial infections that destroy tissue, where HBOT helps to stop the spread of infection and support tissue repair. See the necrotizing soft tissue infections evidence atlas for the full study-by-study evidence breakdown.
Breakdown of Key UHMS Indications
- Central Retinal Artery Occlusion (CRAO): This is an ophthalmic emergency. The primary goal of HBOT in CRAO is to rapidly increase the partial pressure of oxygen in the arterial blood, which can then diffuse into the ischemic retina, potentially restoring function before irreversible damage occurs. The increased pressure can also help to reduce any edema that may be present, further aiding blood flow.
- Selected Problem Wounds: This category encompasses chronic, non-healing wounds, often seen in patients with diabetes, peripheral vascular disease, or those who are immunocompromised. HBOT improves oxygen supply to the wound bed, which is crucial for collagen synthesis, angiogenesis (new blood vessel formation), and the activity of white blood cells that fight infection. This direct oxygenation helps to move the wound from a chronic, stalled state to an active healing phase.
- Clostridial Myonecrosis (Gas Gangrene): This severe bacterial infection thrives in low-oxygen environments. HBOT directly inhibits the growth of the anaerobic Clostridium bacteria and inactivates the toxins they produce. The high oxygen levels also enhance the effectiveness of antibiotics and support the body's immune response, making it a vital adjunctive treatment to surgical debridement and antibiotics.
- Acute Traumatic Ischemias: Conditions like crush injuries or compartment syndrome involve severe trauma that compromises blood flow to tissues. HBOT helps by reducing swelling (edema), which in turn can improve blood flow. The increased oxygen supply also helps to preserve marginal tissues that are at risk of dying due to lack of oxygen, potentially preventing the need for amputation.
- Delayed Radiation Injuries (Soft Tissue and Bony Necrosis): Radiation therapy, while effective against cancer, can damage healthy tissues, leading to chronic non-healing wounds or osteoradionecrosis (bone death). HBOT promotes neovascularization (formation of new blood vessels) in the irradiated tissues, improving blood supply and oxygenation. This helps to repair the damaged tissue, reduce pain, and facilitate healing.
- Sudden Sensorineural Hearing Loss (SSNHL): This condition involves sudden, unexplained hearing loss. While the exact mechanism of SSNHL is not always clear, it is often thought to involve compromised blood flow or oxygen supply to the inner ear. HBOT can increase oxygen delivery to the cochlea, potentially helping to recover hearing function.
- Intracranial Abscess: This is a serious infection within the brain. HBOT enhances the killing power of certain antibiotics against anaerobic bacteria often found in brain abscesses. It also improves oxygen delivery to the infected area, supporting the immune response and aiding in the resolution of the infection alongside surgical drainage and antibiotics.
- Refractory Osteomyelitis: This is a chronic bone infection that has not responded to traditional treatments. HBOT improves oxygen penetration into infected bone, which can be poorly vascularized. This enhanced oxygenation directly fights anaerobic bacteria, improves antibiotic transport to the site of infection, and stimulates osteogenesis (new bone formation), contributing to bone healing.
- Severe Anemia: In rare cases where a patient cannot receive a blood transfusion (e.g., due to religious beliefs or severe blood shortages), HBOT can be life-saving. The massively increased dissolved oxygen in the plasma can deliver enough oxygen to the tissues to sustain life, even with very low hemoglobin levels, buying time for the body to produce new red blood cells.
- Adjunctive Hyperbaric Oxygen Therapy in the Treatment of Thermal Burns: For severe burns, HBOT can reduce the extent of tissue damage, decrease fluid loss, diminish the risk of infection, and accelerate wound healing. It helps to preserve the viability of tissue that is partially damaged (the zone of stasis) and promotes faster recovery by enhancing oxygen delivery to the injured areas.
Each of these conditions benefits from the unique physiological effects of hyperbaric oxygen, making it an invaluable tool in modern medicine. The specific pressures, such as 2.0 ATA or 2.4 ATA, and treatment protocols are tailored to each indication to achieve the most effective outcome.
Frequently Asked Questions
What is the difference between 1.3 ATA, 2.0 ATA, and 2.4 ATA in hyperbaric oxygen therapy?
The difference lies in the level of pressure applied during the therapy. ATA stands for "Atmospheres Absolute," with 1 ATA being normal atmospheric pressure at sea level. So, 1.3 ATA means the chamber pressure is 1.3 times normal, while 2.0 ATA is twice normal, and 2.4 ATA is 2.4 times normal pressure. Higher pressures, like 2.0 ATA and 2.4 ATA, drive significantly more oxygen into the bloodstream and tissues, making them suitable for UHMS-approved medical indications such as gas embolism and carbon monoxide poisoning. Richard E. Moon notes that pulmonary barotrauma and gas embolism can occur after an ascent of as little as one meter, highlighting the sensitivity to pressure changes.
How does pressure affect how a hyperbaric chamber feels?
As the pressure inside a hyperbaric chamber increases, it can feel more noticeable in your ears. This sensation is similar to what you experience when diving underwater or during an airplane takeoff or landing. Audrey Burrell from Healing the Hyperbaric Way states, "Pressure is one key factor that makes hyperbaric therapy effective. The other is the amount of oxygen you breathe while at that pressure. As pressure increases, more oxygen is driven into the bloodstream and tissues." Patients are often taught techniques to equalize the pressure in their ears, such as yawning or swallowing, to ensure comfort during the compression phase of the treatment.
Are all hyperbaric oxygen therapy indications approved by the UHMS?
No, not all uses of hyperbaric oxygen therapy are approved by the Undersea and Hyperbaric Medical Society (UHMS). The UHMS rigorously reviews scientific evidence to define a specific list of 14 approved indications for HBOT. These approved uses are based on robust clinical data demonstrating efficacy and safety. UCLA Health Hyperbaric Medicine Indications confirms that indications for hyperbaric oxygen therapy are based on recommendations defined by the UHMS. Any use outside of these approved indications is considered off-label and lacks the same level of scientific support.
Can hyperbaric oxygen therapy help with conditions not listed by the UHMS?
While hyperbaric oxygen therapy may be explored for conditions not on the UHMS-approved list, these uses are considered investigational or off-label and do not have the same level of scientific evidence or consensus. The UHMS 14th Edition lists 14 specific indications, such as problem wounds and delayed radiation injuries, where HBOT has demonstrated clear therapeutic benefit. Patients interested in HBOT for non-UHMS approved conditions should discuss the potential benefits and risks thoroughly with a qualified medical professional, understanding that these treatments may not be covered by insurance and lack broad medical endorsement.
What are some common causes of gas embolism that HBOT can address?
Gas embolism can arise from various causes, including diving-related incidents like pulmonary barotrauma from breath holding during ascent, even from an ascent of as little as one meter. Beyond diving, causes include accidental intravenous air injection during medical procedures, complications during cardiopulmonary bypass, needle biopsy of the lung, and central venous catheter placement. Procedures where the surgical site is under pressure, such as laparoscopy or hysteroscopy, can also lead to air embolism. In experimental animals, intravenous injection of up to 0.5-1 mL/kg has been tolerated, but in humans, continuous IV infusion of oxygen at 20 mL/min caused symptoms, indicating a threshold for tolerance. HBOT is crucial for treating these conditions by reducing bubble size and increasing oxygen delivery.
Sources
- https://www.uhms.org/resources/featured-resources/hbo-indications.html
- https://www.uhms.org/images/UHMS-Reference-Material.pdf
- https://www.uclahealth.org/medical-services/hyperbaric/indications
- https://healingthehyperbaricway.com/blogs/news/hyperbaric-chamber-pressures-explained-1-3-2-0-ata?srsltid=AfmBOop2rzs_jggtPAZ4ppT6puzHI8dOSvbNIGhd8iaYW1e3_aFb47EE
Related Reading
- UHMS Approved HBOT Indications: The 14 Evidence-Backed Uses
- Does Insurance Cover Hyperbaric Oxygen Therapy?
- Medicare HBOT Coverage: The 14 Approved Indications
- Hyperbaric Oxygen Therapy for Pets: A Guide to Veterinary HBOT
- 15 Questions to Ask Before Starting Hyperbaric Oxygen Therapy [2026]
— The HBOT Finder Team