Hyperbaric Oxygen Therapy is generally considered very safe when delivered by trained staff under physician supervision. It has been in mainstream clinical use for more than five decades. Serious complications are uncommon. The most frequent side effects are mild and transient.
Every Evolve patient undergoes a physician-led pre-treatment assessment specifically to identify contraindications and modifiable risk factors before treatment begins.
The most common side effect. As the chamber pressurizes, the air pressure inside the middle ear must equalize with the outside pressure — the same equalization required during airplane descent. Most patients learn equalization techniques (yawning, swallowing, gentle Valsalva) within their first one or two sessions. Our technicians coach you through this. If equalization is difficult, pressurization can be slowed.
Significant middle ear injury is uncommon. In patients who cannot equalize, an ENT consultation can be arranged, and ventilation tubes (myringotomy tubes) are sometimes placed to allow treatment to continue safely.
Some patients experience a temporary mild shift in vision toward near-sightedness during a course of HBOT. This is caused by transient changes in the shape of the eye’s lens under repeated high-oxygen exposure. The effect is reversible — vision typically returns to baseline within six to eight weeks of completing treatment. Patients are advised not to update their eyeglass prescription during treatment.
Some patients feel mildly tired after a session, particularly early in the treatment course. This typically resolves on its own and does not require any intervention.
Similar to ear pressure, sinuses must equalize during pressure change. Patients with an existing upper respiratory infection or significant sinusitis may experience discomfort; in those cases, sessions are postponed until symptoms resolve.
Rarely, prolonged high-oxygen exposure can produce neurologic symptoms — most notably a brief seizure. These are uncommon at the pressures and durations used in standard HBOT, but the risk is recognized. Patients are monitored throughout each session, and any concerning symptoms are addressed by immediately reducing pressure.
Extremely rare. Includes pneumothorax (collapsed lung) due to rapid pressure change in patients with pre-existing lung disease. Our pre-treatment assessment screens for risk factors, and pressurization protocols are gradual to minimize barotrauma risk.
Patients on insulin should monitor blood glucose before and after sessions; HBOT can lower blood sugar in some patients. Our team reviews diabetes management with each insulin-treated patient before starting treatment.
Untreated pneumothorax (collapsed lung). Any unresolved pneumothorax must be treated before HBOT can be considered.
Patients are advised to:
Our chambers have entertainment screens and audio that allow video and music during sessions — bringing personal devices into the chamber is not permitted, but everything you need is provided.
Dr. Vik Agarwal MD CCFP FRCPC CAQ-HP — President, Evolve Medical Group
Dr. Seema Agarwal MD CCFP CAQ-HP — Chief Medical Officer, Evolve Hyperbarics
Last reviewed: May 2026 · Next: May 2027
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Evolve Hyperbarics is the parent brand of Brampton Hyperbarics & Wound Care, Champagne Hyperbarics, York Hyperbarics, Sudbury Hyperbarics & Wound Care, Simcoe Hyperbarics, and Durham Hyperbarics.