HBOT Contraindications


HBOT may not be the ideal treatment method for all medical conditions and/or when using certain medications. If you have been diagnosed with any of the following conditions or are currently taking any of the medications listed, please ensure you discuss with the staff of Ontario HBOT prior to booking or beginning HBO treatment:



Optic neuritis

High Fever over 102

Chronic Obstructive Pulmonary Disease (COPD) / Bullous Emphysema

Recent thoracic surgery


Pregnant or suspect you might be pregnant


The following drugs have the tendency to become toxic at high pressure:

Doxorubicin (Adriamycin) – A chemotherapeutic drug.

Cisplatin – Also a chemotherapeutic drug.

Disulfiram (Antabuse) – Used in the treatment of alcoholism.

Mafenide acetate (Sulfamylon) – Suppresses bacterial infections in burn wounds

We do recommend that you eat something prior and/or immediately following your treatment, especially if you suffer from low blood sugar. Please refrain from drinking coffee prior to your treatment.

Though the following conditions and medication are not considered contraindications, they will be regarded as special circumstances and will be discussed with those involved prior to beginning treatment. We ask that you please inform the staff if you or your family member suffers from the below conditions or is taking from any of the following medications:

Upper respiratory infections – This might cause difficulties for the patient to clear their ears, which can result in what is termed sinus squeeze.

High fever

Emphysema with CO2

History of thoracic (chest) surgery

Malignant disease

Middle ear barotrauma (MEBT)



Ear or sinus surgery

A smoker

Medications for; controlling anxiety, insomnia, agitation, seizures

Side Effects & Risks of HBOT

As with any treatment and medication, potential side effects or risks are possible. There are some risks associated with hyperbaric oxygen therapy; however most of them are rare and great care is taken to prevent their possibility.

Smoking - Nicotine counteracts the attempts to deliver oxygen through hyperbaric oxygen therapy. Nicotine patches must be removed 2 hours before treatment. Nicotine can; Restricts the blood supply to fingers and toes Irritate mucous membranes and may make it difficult to equalise your ears and sinuses, which can result in damage to you middle or inner ear. Carbon monoxide from cigarettes introduces carbon monoxide into the blood steam, which reduces the oxygen carrying capacity of your haemoglobin in your red blood cells.Based on the above, it is incompatible for patients to be smoking when they are undergoing treatment. Long term smokers are strongly advised to stop smoking during treatment.

Barotrauma - During pressure change you may experience discomfort in your ears, sinuses or teeth (if you have fillings or cavities). The sensation in your ears may be relieved by several methods of equalization. Whenever a change of pressure occurs, there is the possibility of a small tear in the lung tissue and escape of air into surrounding structures outside of the lungs (pneumothorax). This can occur if the normal passage for air out of the lungs is blocked during depressurization. Slow depressurizations are used in all hyperbaric treatments to minimize this risk. Breathing normally will also aid in the minimization of pulmonary barotrauma. Do not hold your breath during you HBO treatment.

Oxygen toxicity - Breathing oxygen at increased pressure can result in central nervous system oxygen toxicity or pulmonary oxygen toxicity. In order to minimize this risk, Ontario HBOT follows very strict guidelines and tables regarding dive depth and duration. Each individual’s health and condition is considered prior to establishing a treatment protocol. Should you feel any unusual symptoms such as facial twitching, nausea, ringing of the ears, visual disturbances, or irritability of these signs please notify the hyperbaric technician.

History of seizures - HBO therapy may lower the seizure threshold and it may be appropriate to increase medication for patients treated for epilepsy. Fire risks With the use of oxygen in any form there is always an increased risk of fire. We adhere to strict safety regulations to minimize and prevent hyperbaric related fires. Please observe all Ontario HBOT’s documented rules & guidelines. Cataracts Individuals with cataracts may experience accelerated maturation of the cataract, but HBO treatment will not cause cataract formation.

Temporary changes in eye sight - Rarely, patients develop temporary changes in eyesight; these are minor and occur only in those individuals who have had large numbers of treatments. Vision should return to pre-treatment level approximately eight weeks after the cessation of therapy. We recommend that if you experience vision changes during your HBOT do not operate vehicles or other heavy machinery while the symptoms persist.

Fatigue - Some people may feel some fatigue following hyperbaric treatment, which will resolve over time.

Optic neuritis - There have been very occasional reports of patients with optic neuritis having deterioration in vision and HBOT should be used with caution in this condition.

Gas embolism - A gas embolism occurs by the expansion of respiratory gasses during a reduction in atmospheric pressure (ascent) which enters blood vessels. This risk is minimized by thorough pre-dive assessments, controlled ascent rates, and never holding your breath.