Before Your First Session
Preparing for your first HBOT session is straightforward but requires some specific precautions related to the oxygen-enriched environment inside the chamber and the pressure changes you'll experience. Your hyperbaric facility will give you a specific pre-treatment briefing; this guide covers the general principles that apply at virtually every UHMS-accredited facility.
Clothing: Cotton Only
Wear 100% cotton clothing for every HBOT session. The oxygen-enriched chamber environment dramatically accelerates combustion, and synthetic fabrics (polyester, nylon, acrylic) can accumulate static charge or burn far more readily than cotton. Most facilities provide cotton gowns if you prefer not to bring your own. Avoid wool as well — it can also pose static risks in some chamber environments.
Skincare: No Petroleum Products
On the day of your session, skip lotions, hair products, deodorants (unless specifically rated for HBOT use), perfumes, aftershave, nail polish, and any petroleum-based skincare. These products are flammable in oxygen-enriched environments. If you need skincare, use only water-based products specifically approved by the facility. Hair spray is a particular concern — avoid it on treatment days.
What to Bring
- Water bottle for use before and after your session (not inside the chamber in most facilities).
- A snack for after the session, particularly if you have diabetes (HBOT lowers blood glucose).
- Entertainment: some facilities provide audio/video; most allow you to bring a book. Electronic devices (phones, tablets, e-readers with batteries) are typically prohibited inside the chamber.
- Your medication list and relevant medical history on your first session.
- Insurance card and ID for your first visit.
What to Leave at Home (or in the Locker)
- Phones, hearing aids with lithium batteries, insulin pumps (unless specifically HBOT-rated), e-cigarettes, watches with batteries.
- Jewellery, hair accessories with metal, metal hair clips.
- Contact lenses (some facilities require removal; glasses are allowed in most monoplace chambers).
- Any item not explicitly approved for HBOT use.
Ear Equalisation: Learn Before Your First Session
The most common minor side effect of HBOT is middle-ear discomfort during the compression phase (when the chamber pressure increases). You can prevent this by equalising your ears — the same technique used by scuba divers and air travellers. Three methods, from gentlest to most forceful:
- Swallowing or yawning: often sufficient for mild pressure changes.
- Toynbee manoeuvre: pinch your nose and swallow at the same time.
- Valsalva manoeuvre: pinch your nose, close your mouth, and gently try to blow out. Use gentle pressure — forceful Valsalva can injure the inner ear.
Practise these before your first session. If you have a cold, sinus congestion, or recent ear infection, let your hyperbaric team know — they may defer the session or recommend a decongestant. Patients who consistently cannot equalise may benefit from myringotomy tubes (small ear-drum tubes placed by an ENT) that bypass the equalisation requirement.
Medications and Supplements
Continue your regular medications unless specifically told otherwise. Flag the following with your hyperbaric physician:
- Insulin or diabetic medications — doses may need adjustment during a course.
- Chemotherapy — bleomycin is a lifetime contraindication to HBOT; doxorubicin requires physician review during active therapy.
- Disulfiram, mafenide acetate, cisplatin — specific HBOT interactions.
- Any medication that lowers seizure threshold — adjustment may be needed.
- Supplements and over-the-counter medications — mention them all; some antioxidants (high-dose vitamin C, E, selenium) may theoretically reduce HBOT efficacy, though evidence is thin.
Food and Drink
- Eat a light meal 1–2 hours before your session. Avoid heavy, greasy, or very large meals immediately before.
- Avoid carbonated beverages immediately before (gas expansion during decompression can cause discomfort).
- Alcohol — avoid on treatment days.
- Caffeine — your normal intake is fine, though excessive caffeine may increase anxiety during pressurisation for some patients.
What to Expect Inside the Chamber
Monoplace Chamber (Single-Patient)
You lie supine on a padded stretcher inside a clear acrylic cylinder. The chamber is enclosed but transparent — you can see out, and the technologist can see you. Audio and sometimes video entertainment is typically available. You communicate with the technologist via intercom throughout the session.
Multiplace Chamber (Multi-Patient)
You sit upright or recline in a small room-like chamber with other patients and an attendant. You wear a hood or oronasal mask connected to the oxygen delivery system. Movement is limited by the breathing apparatus but you're not confined to a cylinder.
Sensations During the Session
- Compression (first 10–15 minutes): ear fullness similar to an aircraft descending. Equalise your ears actively. Mild chamber warming.
- At depth (60–90 minutes): mostly uneventful. Many patients sleep or relax. You may feel subtle differences in voice resonance due to the pressurised environment.
- Air breaks (every 20–30 minutes at 2.0+ ATA): brief 5-minute pause from oxygen breathing. In multiplace, you remove your hood; in monoplace, the chamber environment is briefly switched to room air.
- Decompression (last 10–15 minutes): mild cooling and reverse ear-fullness. Breathe normally — do not hold your breath.
Signs to Report to the Technologist
- Ear pain not relieved by equalisation
- Visual disturbance (tunnel vision, flashing lights)
- Twitching of the face, lips, or limbs
- Nausea
- Severe anxiety or panic
- Chest pain or shortness of breath
These may be early signs of CNS oxygen toxicity (very rare) or other issues. The technologist will manage any symptoms immediately — typically by switching to air breathing and continuing or ending the session as clinically appropriate.
During a 40-Session Course
Standard neurological and wound-care courses run 20–40 sessions over 4–8 weeks. Daily attendance Monday through Friday is typical. Many patients find that:
- The routine becomes automatic by week 2.
- Energy levels may dip briefly in weeks 2–3 before improving.
- Clinical improvement often becomes clearer in weeks 5–8.
- Benefits can continue to accumulate for 1–3 months after the course ends.
- Mild transient myopia (nearsightedness) sometimes develops over extended courses and resolves 2–6 weeks after course completion.
Common Concerns
- Claustrophobia: most patients adjust by session 3–5. Options include anxiolysis medication, choosing a multiplace facility, or gradual exposure sessions.
- Barotrauma: about 2–15% of patients experience some ear discomfort during the course. Most resolve with better equalisation technique; a small number need myringotomy tubes.
- Fatigue during the course: common and typically improves by mid-course.
- Travel burden: plan carefully — daily attendance for 8 weeks is a significant commitment.
Educational use only: This guide is a general reference. Your specific hyperbaric facility will provide detailed pre-treatment instructions tailored to your treatment protocol and medical history. Follow facility-specific guidance over general information.