HBOT Adverse Event Management: A Canadian Clinic Guide

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TL;DR: Adverse event management is the operational backbone of a safe Canadian hyperbaric clinic. Most HBOT adverse events are minor and reversible, but clinic owners still need a written reporting framework, a trained staff response protocol, and a compliance pathway to Health Canada, the manufacturer, and provincial regulators. The goal is not zero events – it is zero undocumented events, zero missed escalations, and zero repeat incidents.

Hyperbaric oxygen therapy is a pressurised medical treatment delivered in regulated Canadian clinics, and adverse event management is the structured, written system every hyperbaric clinic uses to capture, classify, report, and learn from safety incidents inside the chamber environment. Canada Hyperbarics publishes operational guidance for clinic owners across the country, and this article sets out a complete adverse event framework built on Canadian regulatory expectations and the peer-reviewed safety literature. Clinic owners who run monoplace or multiplace chambers need this structure in place before day one of patient treatment, not after the first incident.

What counts as an adverse event in a hyperbaric clinic?

An adverse event is any unexpected medical, mechanical, or environmental occurrence during a hyperbaric session that causes harm, could have caused harm, or deviates from the planned treatment protocol. The definition is deliberately broad. It captures patient-level events like middle ear barotrauma and oxygen toxicity seizures, device-level events like chamber pressure loss, and near-misses where no harm occurred but the potential was present.

The Canadian safety picture is reassuring overall. A 2025 Canadian retrospective cohort study at Toronto General Hospital and Rouge Valley Hyperbaric Medical Centre reviewed 634 HBOT sessions delivered to 22 patients with a history of seizures and documented one seizure event across all treatments, an incidence of one in 634 sessions (Park et al., 2025). A 2025 systematic review of HBOT in rheumatic and autoimmune disease reported only mild, reversible adverse events across seven contributing studies, including barotrauma, tinnitus, headache, and claustrophobia, with no severe reactions (Fang et al., 2025).

That safety profile is a floor, not a ceiling. A clinic reaches it only through deliberate protocol design, staff training, and disciplined documentation.

Which adverse events occur most often during HBOT?

Most Canadian hyperbaric clinics see a predictable mix of minor, reversible events and a much smaller proportion of serious events. The pattern below is drawn from multiple 2021-2025 systematic reviews and Canadian safety data.

Adverse event	Approximate frequency	Severity	Primary mitigation
Middle ear barotrauma	Up to 10% of patients	Minor, reversible	Equalisation training, slow compression, screening
Sinus squeeze	2-5% of patients	Minor	Decongestant use, avoid treatment during URI
Claustrophobia and anxiety	2-5% of patients	Minor	Pre-session coaching, staff reassurance
Oxygen toxicity seizure	Approximately 1 in 634 sessions	Serious, reversible	Air breaks, pressure limits, screening
Pulmonary oxygen toxicity	Rare in clinical HBOT	Serious	Session duration limits, air breaks
Confinement anxiety withdrawal	2-6% withdraw treatment	Minor	Orientation, multiplace option if available
Hypoglycaemia in diabetic patients	Low, monitored	Minor to moderate	Pre-session glucose check, snack protocol
Fire or combustion event	Extremely rare	Catastrophic	Fire code compliance, grounding, textile rules

The frequency column reflects published meta-analysis data. A 2023 systematic review of HBOT for fibromyalgia reported adverse events in 44 of 185 patients (23.8%), with 12 patients (6.5%) withdrawing due to adverse reactions and no serious events (Chen et al., 2023). A 2024 systematic review of HBOT for diabetic foot ulcers concluded that adjunctive HBOT improved healing while maintaining a favourable safety profile (Tao and Yuan, 2024).

How should a Canadian hyperbaric clinic classify adverse events?

A classification tier is the first operational decision. Without tiers, every report lands in the same inbox and critical events do not receive priority review. Canada Hyperbarics recommends a four-tier structure modelled on international hyperbaric safety committees and adapted for Canadian reporting obligations.

Tier 1 – Near miss. No patient harm occurred, but a protocol deviation or unsafe condition was observed. Example: chamber operator spotted a restricted textile on a patient before pressurisation. Review at weekly safety huddle.
Tier 2 – Minor event. Transient harm requiring no intervention beyond routine care. Example: mild middle ear discomfort that resolved with equalisation. Review within 72 hours.
Tier 3 – Moderate event. Event requiring medical intervention, early treatment termination, or a physician call. Example: oxygen toxicity seizure managed with air break and session end. Review within 24 hours, reported to medical director.
Tier 4 – Serious event. Event involving hospitalisation, death, major injury, or a chamber malfunction with harm potential. Example: fire, chamber depressurisation, or patient cardiac arrest. Report immediately to medical director, manufacturer, Health Canada, and provincial regulator.

Every tier has a written reporting path, a named owner, and a maximum review window. A blank incident report form with check-box tier selection forces the team to categorise on the spot rather than debating it after the fact.

Who must a Canadian clinic owner notify after a serious adverse event?

Reporting obligations are layered. A single serious event can trigger up to five separate notification channels. Missing any one of them is the most common compliance failure Canada Hyperbarics sees in clinic audits.

Medical director. Immediate verbal notification. The hyperbaric physician decides on continued treatment, follow-up, and whether the patient requires hospital transfer.
Chamber manufacturer. Any event involving a device malfunction, unexpected pressure behaviour, or suspected equipment fault is reported to the manufacturer under Canada’s Medical Device Regulations. Manufacturers have their own incident reporting obligations to Health Canada.
Health Canada. Serious medical device incidents are reported to Health Canada’s Medical Devices Directorate. Canada Hyperbarics recommends maintaining a direct contact and reference number for the clinic’s chamber model on file.
Provincial regulator. Depending on the province, the clinic may report to the College of Physicians and Surgeons, the provincial health authority, or a hospital accreditation body. Ontario clinics dealing with independent health facility rules, for instance, have additional reporting under provincial licensing. Check with the clinic’s legal counsel before a serious event, not after.
Patient and family. Canadian standards of care and privacy law require prompt, factual disclosure of any adverse event that caused or could cause harm. This is distinct from legal liability admission and should be scripted in advance.

Clinic owners should assume that the time between event recognition and formal reporting is under 24 hours for serious events. Draft templates for each channel in advance so staff are not writing from scratch during a crisis.

What belongs in a hyperbaric clinic incident report?

A complete incident report captures both the clinical and the operational dimensions of the event. A report that only describes the patient’s symptoms misses the root cause. A report that only describes the equipment misses the patient context. Both are needed.

Date, time, and session number. Exact chamber pressurisation, treatment, and depressurisation times.
Patient identifiers and indication. De-identified for external reporting, full identifiers for internal chart.
Chamber and operator. Chamber ID, last maintenance date, operator on shift, physician on call.
Event description. Chronological narrative from first observation to resolution.
Vital signs and monitoring data. SpO2, heart rate, blood pressure, relevant monitor alarms.
Interventions applied. Air breaks, pressure changes, oxygen adjustments, emergency medications.
Disposition. Treatment completed, early termination, transfer, follow-up appointment.
Tier classification and reporting path. Which external channels were notified and when.
Root cause and corrective action. Drafted within 72 hours, reviewed by medical director.

Canadian clinics should retain incident reports for a minimum of ten years, aligned with medical records retention in most provinces. Electronic capture with tamper-evident logs is the modern standard.

How do written protocols reduce adverse event rates?

Written, regularly reviewed protocols are the single strongest lever a clinic owner has for reducing adverse events. A 2020 Geneva hyperbaric unit report describing an integrated somatic-psychiatric protocol for urgent carbon monoxide cases demonstrated that a standardised procedure algorithm reduced both patient risk and staff stress in acute situations (Costanza et al., 2020). The principle generalises. When staff know the exact sequence of actions for seizure, claustrophobia, fire, or pressure loss, response times fall and outcomes improve.

Canada Hyperbarics recommends a protocol library with the following minimum set of written procedures.

Patient screening and contraindication checklist
Pre-treatment safety briefing for patient and family
Chamber pre-flight inspection
Compression and equalisation protocol
Air break schedule by pressure and indication
Oxygen toxicity recognition and response
Middle ear barotrauma response
Fire response and evacuation
Chamber depressurisation and patient extraction
Medical emergency escalation
Incident report workflow
Post-event staff debrief

Every protocol should have a named owner, a review date no more than 12 months old, and a version control log. Outdated protocols are worse than no protocols because they create a false sense of safety.

How often should hyperbaric staff run emergency drills?

Drill frequency is where many clinics fall short. A written protocol that is never practised is just paper. Canada Hyperbarics recommends the following drill cadence for operational clinics.

Monthly: Chamber-specific emergency drill. Rotate through seizure response, fire response, and depressurisation scenarios.
Quarterly: Full-team coded emergency simulation with timing, documentation, and debrief.
Annually: External audit of emergency readiness, ideally by an accredited hyperbaric safety consultant.
Before each new staff member treats patients independently: Supervised emergency drill with the clinic’s safety director as observer.

Drill logs form part of the clinic’s accreditation evidence and are routinely requested by insurers and provincial regulators. A drill that was not logged effectively did not happen.

What does the research say about reducing oxygen toxicity seizure risk?

Oxygen toxicity seizures are the most feared acute HBOT complication. The Canadian cohort study at Toronto General and Rouge Valley found one seizure in 634 sessions across 22 patients with pre-existing seizure disorders, with treatment delivered at 1.8 to 2.4 ATA using five-minute air breaks (Park et al., 2025). Fifteen patients were on oral antiseizure medications during the HBOT course. The key operational lessons transfer directly.

Use air breaks. Five-minute air breaks at defined intervals reduce central nervous system oxygen exposure.
Set pressure limits by indication. Not every protocol requires 2.4 ATA. Lower pressures reduce seizure risk and remain effective for many indications.
Screen pre-existing seizure disorders individually. A seizure history is a relative contraindication, not automatic exclusion. Clinical judgment plus patient preference, supported by written protocol, is the path.
Plan for the seizure anyway. Every operator should know the immediate response sequence even if the clinic has never had a seizure.

The rheumatic disease safety review found that adverse events including mild barotrauma, tinnitus, headache, and claustrophobia resolved on discontinuation of HBOT with no severe reactions documented (Fang et al., 2025). A disciplined clinic replicates these outcomes by operating within proven pressure and duration limits.

How should clinic owners handle patient disclosure after an adverse event?

Disclosure is both a legal and a relational process in Canada. Canadian Medical Protective Association guidance and provincial college standards require prompt, factual disclosure of adverse events without speculation about cause or liability. The clinic owner’s job is to make that disclosure easy for staff and clear for patients.

Confirm the patient is medically stable and comfortable before disclosure.
Schedule a dedicated conversation with the patient and support person, separate from treatment.
State what happened in factual terms, without speculation about cause.
Describe the next clinical steps, follow-up plan, and monitoring.
Document the disclosure in the patient chart with date, time, participants, and content.
Provide a written summary to the patient within five business days.
Arrange a follow-up call within two weeks.

Apologies are permitted and encouraged in Canada. The Apology Act in provinces including Ontario, British Columbia, and Alberta provides that an apology is not an admission of legal liability. Clinic owners should script apology language into their disclosure protocol so staff feel supported rather than legally exposed.

What role does a safety committee play in a hyperbaric clinic?

A safety committee is the group that owns the adverse event process on an ongoing basis. In small clinics, the committee may be two people meeting monthly. In larger clinics, it is a formal multidisciplinary group. Either way, it is the body that reviews every incident, sets corrective action, and updates protocols.

Membership. Medical director, safety director, lead operator, nursing representative, and clinic owner or designate.
Meeting cadence. Monthly for routine review. Ad hoc within 24 hours of any Tier 3 or 4 event.
Standing agenda. Incident review, protocol updates, drill results, regulatory updates, staff training status.
Outputs. Signed minutes, corrective action log, protocol version updates, training assignments.

Accreditation reviewers routinely request two years of safety committee minutes. A clinic that can produce them has a clear competitive advantage in referral discussions with hospital systems and hospitals and regulated facilities across Canada.

How do you build an adverse event management system from scratch?

A new clinic can stand up a working adverse event system in 60 days. The sequence is linear and the milestones are concrete.

Days 1-10. Draft the incident report form and tier classification. Name the safety director and medical director.
Days 11-25. Write the top six emergency response protocols (seizure, barotrauma, claustrophobia, fire, depressurisation, medical escalation).
Days 26-35. Train all staff on the incident report form and emergency response protocols.
Days 36-45. Run three drills covering the highest-risk scenarios. Capture timing and lessons learned.
Days 46-55. Set up the external reporting playbook (Health Canada, manufacturer, provincial regulator, insurer).
Days 56-60. Convene the first safety committee meeting. Sign off on the system. Set the 12-month review schedule.

Clinics that invest in this groundwork before opening experience fewer first-year incidents and pass accreditation reviews more smoothly. Retrofitting a safety culture after an incident is expensive and risk-loaded.

Frequently asked questions about hyperbaric adverse event management

Do minor barotrauma events need formal reporting?

Yes. Minor barotrauma should be logged on the incident form even when the patient completes treatment. Tracking minor events over time reveals patterns such as equalisation technique gaps or compression rate issues that a single event would not show.

Is Health Canada notification required for all adverse events?

No. Health Canada’s Medical Device Regulations require reporting of serious incidents, which are events that resulted in or could have resulted in death, serious injury, or serious deterioration of a person’s state of health. Minor, resolved events do not trigger Health Canada reporting, but the clinic still reports them internally and to the manufacturer if a device is involved.

What is the difference between an adverse event and an adverse drug reaction?

An adverse event is any unwanted occurrence during treatment. An adverse drug reaction is specifically linked to a medication. HBOT is a physical treatment, not a drug, so the primary framework is adverse event reporting under medical device rules rather than drug reaction reporting. Medications given during the chamber session, such as rescue medications, follow standard drug reaction reporting.

Does accreditation require an adverse event management system?

Yes. All major hyperbaric accreditation frameworks, including those referenced by the Undersea and Hyperbaric Medical Society and the Canadian Undersea and Hyperbaric Medical Association, require a written safety and incident management programme. Accreditation reviewers ask for the incident log, drill records, and safety committee minutes as part of every survey.

How does adverse event reporting interact with patient privacy?

External reports to Health Canada and manufacturers use de-identified data. Patient identifiers remain in the clinic chart under the applicable provincial privacy law, such as PHIPA in Ontario or PIPA in British Columbia. The clinic’s privacy officer should review the reporting templates before use to confirm compliance.

Should near misses be reported externally?

Usually no, but always internally. Near misses are among the most valuable data a clinic collects because they reveal system weaknesses before harm occurs. A near miss log reviewed monthly at the safety committee is standard practice.

What training records do regulators expect?

Regulators and accreditation surveyors typically ask for each operator’s orientation record, annual competency assessment, drill participation log, and certification evidence. Canada Hyperbarics recommends keeping these in a single digital training file per staff member.

Where can clinic owners find research on HBOT safety?

Clinic owners can search PubMed directly or consult the Canada Hyperbarics research library, which indexes over 14,000 HBOT studies with filters for indication, study type, and date. The cancer treatment safety evaluation study page is a good starting point for clinic owners reviewing oncology-focused safety data.

Next step for Canadian clinic owners

Start with the incident report form and tier classification. A two-page form and a four-tier system give the clinic an operational baseline within a week. From there, work outward to protocols, drills, and the safety committee. Referring physicians and accreditation bodies respond strongly to clinics that can articulate their adverse event process in a single conversation, and it is the foundation of a sustainable Canadian hyperbaric practice.

Clinic owners looking to connect patients with accredited Canadian hyperbaric care can direct referrals to hospitals and regulated facilities through the Canada Hyperbarics directory, and keep current on regulatory expectations through the regulatory updates page.

Research citations

Park S, Marinov A, Clarke H, et al. Safety of hyperbaric oxygen therapy in non-emergent patients with a history of seizures: A retrospective cohort study. PLoS One. 2025;20(1):e0317586. doi:10.1371/journal.pone.0317586
Fang J, Li W, Liu C, et al. Clinical efficacy and mechanisms of hyperbaric oxygen therapy in the treatment of rheumatic and immune diseases. Front Med (Lausanne). 2025;12:1706637. doi:10.3389/fmed.2025.1706637
Chen X, You J, Ma H, Zhou M, Huang C. Efficacy and safety of hyperbaric oxygen therapy for fibromyalgia: a systematic review and meta-analysis. BMJ Open. 2023;13(1):e062322. doi:10.1136/bmjopen-2022-062322
Tao L, Yuan X. Efficacy and safety of hyperbaric oxygen therapy in the management of diabetic foot ulcers: A systematic review and meta-analysis. Int Wound J. 2024;21(3):e14507. doi:10.1111/iwj.14507
Costanza A, Ambrosetti J, Spagnoli P, et al. Urgent hyperbaric oxygen therapy for suicidal carbon monoxide poisoning: from a preliminary survey to a proposal for an integrated somatic-psychiatric protocol. Int J Emerg Med. 2020;13(1):61. doi:10.1186/s12245-020-00321-w

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice. Adverse event management protocols must be developed in consultation with qualified clinical, regulatory, and legal advisors appropriate to each clinic’s jurisdiction. Clinic owners are responsible for compliance with Health Canada regulations, provincial health authority requirements, and applicable accreditation standards. Always consult qualified professionals before implementing operational protocols in a Canadian hyperbaric clinic.