Is Hyperbaric Oxygen Therapy (HBOT) Safe?

A comprehensive guide to the clinical safety of hyperbaric medicine, including common side effects, absolute contraindications, and risk mitigation.

Intro: Prioritizing Patient Safety through Medical Transparency

Hyperbaric Oxygen Therapy (HBOT) is recognized globally as a remarkably safe medical intervention when performed in a certified clinical facility under professional oversight. However, like any medical treatment that involves physiological change—in this case, changes in atmospheric pressure and systemic oxygen levels—there are specific risks, side effects, and contraindications that every patient must understand.

At TorontoHyperbaric.ca, we believe that transparency is the foundation of patient safety. This guide provides an exhaustive review of the safety standards practiced in clinical hyperbarics, the common side effects you may encounter, and the absolute conditions that would prevent a patient from undergoing treatment.

1. Common Side Effects and How We Manage Them

For the vast majority of patients, the side effects of HBOT are minor, temporary, and easily managed by our clinical team.

Middle Ear Barotrauma (Ear Squeezing)

The most common side effect of hyperbaric therapy is “ear squeezing,” or barotrauma. This occurs during the compression phase (when the pressure in the chamber is increasing) if the patient cannot equalize the pressure in their middle ear.

The Sensation: It feels similar to the “popping” sensation you experience when an airplane is landing.
Management: Our technicians are experts in teaching patients several equalization techniques (such as the Valsalva maneuver or the Toynbee maneuver). If a patient cannot equalize, we slow down the compression rate or pause the session immediately to prevent discomfort.

Temporary Vision Changes (Myopic Shift)

Some patients who undergo a long series of treatments (typically more than 20 sessions) may experience a temporary change in their vision, specifically a “myopic shift” (nearsightedness).

The Cause: This is thought to be a result of the high-pressure oxygen affecting the lens of the eye.
Management: This change is almost always temporary and typically reverses within 4-6 weeks after the completion of the treatment protocol. We recommend that patients do not change their prescription eyewear during their course of HBOT.

Fatigue and Lightheadedness

Post-session fatigue or a sense of “mental tiredness” can occur as the body adjusts to the localized metabolic changes stimulated by the oxygen surge. This is a normal physiological response and usually resolves with simple hydration and rest.

2. Absolute Contraindications: Who Should NOT Have HBOT?

There are a few specific medical conditions and medications that are “absolute contraindications,” meaning the risk of treatment outweighs the potential benefits.

Untreated Pneumothorax

An untreated pneumothorax (a collapsed lung) is the only absolute contraindication for HBOT that is universal across all clinical standards. Because the air in the pleural cavity expands and contracts with the changing pressure of the chamber, an untreated collapsed lung could lead to a tension pneumothorax, a life-threatening emergency.

Specific Medications (Chemotherapy & Disulfiram)

Certain drugs can react with high concentrations of oxygen and become toxic to the body. These include:

Doxorubicin (Adriamycin): A chemotherapy drug that can become significantly more toxic to the heart when combined with HBOT.
Cisplatin: Another chemotherapy agent that can interfere with wound healing when used during hyperbaric treatment.
Disulfiram (Antabuse): Used to treat alcohol dependence, this drug can inhibit the body’s natural antioxidant defenses.
Mafenide Acetate (Sulfamylon): A topical antibiotic used for burns that can suppress the normal healing process under hyperbaric conditions.

3. Relative Contraindications: When Caution is Required

Many other conditions are considered “relative contraindications,” where treatment can be performed safely if specific protocols are followed or if the underlying issue is managed beforehand.

History of Seizures

While rare, very high concentrations of oxygen can lower the “seizure threshold” in some individuals (Oxygen Toxicity). If a patient has a known history of epilepsy or seizures, our clinical team will adjust the treatment pressure and include “air breaks” (brief periods of breathing normal air) to significantly reduce this risk.

Upper Respiratory Infections & Sinus Issues

If you have a severe cold, sinus infection, or hay fever, it may be difficult to equalize the pressure in your ears. We often recommend postponing sessions until the infection clears to prevent uncomfortable ear barotrauma.

Claustrophobia Management

For patients who feel anxious in enclosed spaces, our clinical hub at 525 Markham Rd offers specialized support. Our monoplace chambers are constructed of clear acrylic, allowing for a full 360-degree view of the room and constant visual contact with the technician. We also provide entertainment options (movies/music) and can integrate relaxation techniques during the session.

4. The Difference in Safety: Clinical Hard-Shell vs. Wellness Soft-Shell

One of the most important safety considerations for patients is the construction of the hyperbaric chamber itself.

Hard-Shell (Clinical) Chambers: These are built to rigorous ASME-PVHO (Pressure Vessel for Human Occupancy) standards. They feature precise pressure controls, specialized medical-grade oxygen delivery systems, and fire-suppression safety features.
Soft-Shell (Wellness) Chambers: Because these units are typically not designed to exceed 1.3 ATA, they often lack the sophisticated safety monitoring systems found in clinical hubs. While the risk of barotrauma is lower at these “mild” pressures, the risk of technical failure or fire (if using an oxygen concentrator improperly) can be higher in unregulated environments.

5. Our Safety Protocols at the Revivo Clinical Hub

At the Revivo Neurology Treatment Centre, your safety is our first priority. Every patient undergoes a multi-step safety screening before entering the chamber:

Pre-Session Medical Audit: A review of all current medications and recent surgeries.
Vitals Check: Ensuring blood pressure and (for diabetics) blood sugar levels are within a safe range for treatment.
Ear Equalization Training: Teaching and verifying your ability to clear your ears safely.
Constant Technician Monitoring: You are never alone. A certified technician is in constant visual and audio communication with you throughout the entire 60-90 minute session.

Integrated Clinical Oversight

Because our facility is an integrated neurology hub, we have the specialized medical expertise to manage complex neurological and vascular patients with a higher degree of safety than a standalone “wellness” studio.

To review safety and preparation in more detail, visit our patient journey pages or reach out through our contact page.