Ear clearing is the single most common challenge in HBOT. Roughly 2% of HBOT sessions involve ear pain or mild ear injury. Almost all of this is preventable with good clearing technique.
We pulled the major diving medicine sources and UHMS clinical guidelines to summarize the topic. The FDA has cleared HBOT for 13 specific uses (FDA 2021). Ear clearing technique is the same regardless of why you are in the chamber.
This article covers the why, the techniques, and what to do when standard clearing does not work.
Why ears need clearing
The middle ear is a small air-filled space behind the eardrum. The Eustachian tube connects it to the back of the throat.
When chamber pressure rises during compression, ambient air pressure pushes the eardrum inward. The middle ear must accept new air through the Eustachian tube to keep the eardrum at neutral position.
If the tube does not open, the eardrum bows inward. This causes the pain, pressure, and fullness most people feel as "ears not popping."
The Heyboer et al. 2017 review found middle-ear injury in roughly 2% of HBOT sessions. Most cases are mild and resolve.
A small share require an ear tube to continue HBOT.
The three main clearing techniques
Several techniques open the Eustachian tube. Learn 2 or 3 because not every technique works for every person.
The Valsalva maneuver. Pinch your nose shut, close your mouth, and gently blow as if you were trying to exhale through your nose (Roydhouse 2002). The air should push the Eustachian tubes open.
Stop as soon as you feel the click.
This is the most-used technique. It works for roughly 70% of people. Do not blow hard — too much force can cause inner ear injury.
The Frenzel maneuver. Pinch your nose shut, close your mouth, and use your tongue to "swallow" air upward toward the back of your throat. This pushes air into the Eustachian tubes without raising lung pressure.
The Frenzel is gentler than Valsalva and works for some people who cannot Valsalva. It takes practice.
The Toynbee maneuver. Pinch your nose shut and swallow. The swallowing action opens the Eustachian tubes briefly.
The Toynbee is the gentlest of the three. It works less reliably than Valsalva but is good as a backup, especially if you have allergies or mild ear inflammation.
For more on what to expect in a session, see our what to bring to an HBOT session guide.
Timing matters
Clear early, clear often. Do not wait until you feel pressure.
A typical HBOT chamber compresses at about 1 foot of descent per 5-10 seconds, reaching treatment pressure in 10-15 minutes (UHMS Indications Manual 2019). Clear every 2-3 feet of pressure change in the early compression phase.
Once at treatment pressure, no clearing is needed. The pressure is constant during the 60-90 minute session.
Decompression (the return to surface pressure at session end) is automatic for the ears — air leaks out passively without active clearing.
What "the click" sounds like
Successful clearing produces a small audible click or pop. Some people feel it more than hear it. The feeling is one of pressure release.
If you cannot get the click, do not push through. Stop, signal the operator, and let them slow or pause compression.
When standard clearing does not work
If you cannot clear despite trying all three techniques, the chamber operator will pause compression. This is standard practice at any UHMS-vetted program.
Several factors make clearing harder:
- Active cold or sinus infection. Defer the session. The Eustachian tubes are swollen.
- Allergies. Loratadine or fexofenadine an hour before the session can help.
- Dehydration. Drink water steadily before HBOT. Mucus thickens with low water intake.
- Aging. Eustachian tube function declines with age. Be slower and more deliberate.
- Recent ear surgery or barotrauma. The hyperbaric doctor will evaluate.
For more on safety screening for older adults, see our HBOT for elderly patients safety considerations.
Decongestants and clearing
Many hyperbaric programs allow pseudoephedrine (Sudafed) or oxymetazoline (Afrin) before sessions for patients with mild Eustachian tube problems.
Pseudoephedrine taken 30-60 minutes before the session can ease tube clearing. Avoid it in patients with high blood pressure or heart conditions.
Oxymetazoline nasal spray works locally and is often gentler than oral decongestants. Use sparingly — repeated use can cause rebound congestion.
For drug coordination questions, see our HBOT and medication interactions to know article.
When ear tubes (myringotomy) become an option
If you have an FDA-cleared indication for HBOT — diabetic foot ulcer, radiation injury, severe burn — and cannot clear your ears despite all techniques and pre-medications, the next step is myringotomy (Capes & Tomaszewski 1996). See the late radiation tissue injury evidence atlas for the full study-by-study evidence breakdown. See the diabetic foot ulcer evidence atlas for the full study-by-study evidence breakdown.
Myringotomy is a small surgical opening in the eardrum that lets air pass freely. It is typically done by an ENT consultant attached to the hospital's hyperbaric program. Sechrist Industries and Perry Baromedical chambers at UHMS-vetted programs all coordinate with ENT for this.
The procedure takes 10-20 minutes under local anesthesia. The eardrum opening heals over 4-8 weeks after HBOT is complete.
For elective off-label HBOT, the decision to do myringotomy should weigh more carefully. The HBOT evidence base outside the FDA-cleared indications is generally weaker.
Chamber-specific notes
Hard-shell monoplace chambers (Sechrist Industries, Perry Baromedical) compress at controlled rates set by the operator. Communicate by intercom; the operator can pause or slow compression.
Multiplace chambers have a hyperbaric staff member inside. They can directly observe and help with clearing technique.
Soft-shell wellness chambers (OxyHealth, Summit to Sea) reach only 1.3 ATA. The pressure change is smaller and ear clearing is easier.
Restore Hyper Wellness sites commonly use these. The biological effect at 1.3 ATA is smaller, which is a separate issue covered in our mild vs medical HBOT comparison.
Aviv Clinics and similar premium off-label programs use hard-shell chambers at 2.0 ATA. The clearing requirements are similar to hospital chambers.
Pediatric ear clearing
Children may struggle with active clearing techniques. The Valsalva maneuver requires breath control that very young children do not have.
Common pediatric approaches:
- Bottle feeding (for infants) during compression — swallowing opens tubes
- Letting older children practice clearing techniques before the chamber
- Considering myringotomy for FDA-cleared pediatric HBOT cases
For more on pediatric HBOT, see our pediatric HBOT chambers overview.
What ear injury feels like
Mild ear injury feels like pressure, fullness, or muffled hearing. Most cases resolve within hours to days.
Moderate ear injury can cause sharp pain during compression, ringing, or temporary hearing change.
Severe ear injury — eardrum rupture — is rare and usually preceded by escalating pain. Tell the operator at the first sign of pain. Never push through.
How to practice clearing before your first session
Many hospital wound programs recommend practicing clearing techniques at home before the first HBOT session.
Try Valsalva, Frenzel, and Toynbee in front of a mirror. Note which technique gives you the most reliable click.
Sit upright with good head and neck position — slouching makes clearing harder. Keep your jaw relaxed.
Practice 3-4 times per day for a few days before the first session. The Eustachian tube musculature improves with practice.
Special considerations
Recent flight or scuba dive within 24 hours — defer the HBOT session. The ears need recovery time.
Active jaw or TMJ problems — let the team know. TMJ pain can mimic ear clearing pain.
Recent dental work — discuss with the hyperbaric doctor. Dental abscess in particular is a concern.
Pregnancy — Eustachian tube function may be altered. Routine HBOT in pregnancy is not standard; talk to your OB-GYN.
When to stop a session
Several scenarios warrant stopping mid-session:
- Severe ear pain that persists despite clearing attempts
- Sudden hearing loss
- Severe dizziness or nausea
- Visible blood from the ear
The operator will decompress slowly. Decompression is not the time for new clearing techniques; the air leaks out passively.
Bottom line
Learn Valsalva, Frenzel, and Toynbee. Practice before your first session.
Clear early and often during compression. Stop if anything hurts.
Most ear clearing problems resolve with technique adjustment, hydration, and a pre-session decongestant when appropriate. Persistent problems can be solved with ear tube placement for FDA-cleared HBOT indications.
For more practical session guidance, see our what to bring to an HBOT session guide.
Related Reading
- What to bring to an HBOT session
- HBOT side effects and safety
- HBOT and medication interactions to know
- HBOT for elderly patients: safety considerations
- HBOT and nutrition pre-session guidelines
Frequently asked questions
How do I clear my ears in HBOT?
Use Valsalva (pinch nose, gently blow), Frenzel (pinch nose, tongue push), or Toynbee (pinch nose, swallow). Learn 2-3 because not every technique works for every person.
When should I clear during compression?
Clear early and clear often. Do not wait until you feel pressure. Every 2-3 feet of pressure change during the 10-15 minute compression phase is a good cadence.
What if I cannot clear my ears?
Signal the operator. The chamber will pause compression. Try other techniques. If standard clearing fails repeatedly, the hyperbaric doctor may recommend ear tubes (myringotomy) for FDA-cleared HBOT cases.
Can I take Sudafed before HBOT?
Many programs allow pseudoephedrine 30-60 minutes before sessions for patients with mild ear-clearing trouble. Discuss with the hyperbaric doctor first — pseudoephedrine is not appropriate for patients with high blood pressure or heart issues.
Should I cancel a session if I have a cold?
Yes, in most cases. Active upper respiratory infection makes Eustachian tube clearing very difficult and increases ear injury risk. Defer the session until you recover.
Medical disclaimer: This article is informational and does not constitute medical advice. HBOT carries real risks including ear barotrauma, oxygen toxicity, and chamber fire. Discuss any HBOT plan with a doctor trained in undersea and hyperbaric medicine before starting. Tell the chamber operator at the first sign of ear pain; never push through pain during compression.
-- The HBOT Finder Team