Hyperbaric Chamber Treatment for Divers on Koh Tao

What is decompression sickness ?

Decompression sickness happens when dissolved gas comes out of solution in the body faster than it can be breathed off, forming bubbles in tissue and blood. The everyday comparison is a bottle of fizzy water: open it slowly and the gas escapes quietly, open it fast and it foams. Ascending too quickly, diving too long or too deep, or repeating dives without adequate surface intervals all tip that balance the wrong way.

It is not exclusively a beginner problem, and that misconception causes real harm. Experienced divers and instructors get decompression illness too, sometimes on profiles they have run without incident many times before. Dehydration, fatigue, alcohol the night before, cold water and physical exertion all raise the risk on a dive that would otherwise have been uneventful.

What are the symptoms, and when do they appear ?

Most cases declare themselves within the first hour after surfacing, but symptoms can begin up to 24 hours later. That delay is precisely why cases get missed — the connection to the dive feels less obvious by evening, and a tired diver on the second beer attributes joint ache to the boat and the day.

The symptoms divers actually report

• joint pain, most commonly in the shoulders, elbows or knees
• unusual fatigue that feels disproportionate to the day
• tingling, numbness or pins and needles
• weakness in a limb
• dizziness or unsteadiness
• an itchy or mottled skin rash
• shortness of breath
• confusion, difficulty concentrating or unusual behaviour

Why they get dismissed

Nearly every symptom on that list has an innocent explanation available: a long day, a heavy tank, too much sun, not enough water. The diver reaches for the innocent one because it is more comfortable and because stopping means missing tomorrow's dives. That reasoning is the single most common contributor to a delayed presentation.

How is it treated ?

With hyperbaric oxygen therapy, also called recompression. The patient is recompressed inside a chamber while breathing oxygen, which shrinks the bubbles, drives the gas back into solution and floods the tissue with oxygen, then decompressed slowly under supervision. In a multiplace chamber a trained operator stays inside for the duration, which means the patient is monitored directly throughout rather than watched through a window.

The chamber is at our Koh Tao clinic at 1/53 Moo 2, Mae Haad, opposite Krungsri Bank — a multiplace chamber operated with the SSS Recompression Chamber Network, where hyperbaric oxygen therapy is given for decompression sickness and arterial gas embolism. Divers assessed at our Koh Phangan or Lamai clinics who need recompression are transferred to Koh Tao, and the clinic arranges that transfer. How long a session lasts, and what it costs, depend on the treatment table your case needs; both are explained before treatment starts.

Why "I only did a shallow dive" is not reassurance

Decompression illness is associated with depth and time, but it is not exclusive to deep profiles, and shallow-water cases are well recognised. Repetitive dives over several days, short surface intervals, exertion, cold and dehydration all shift the risk on profiles that look conservative on paper. A dive computer that stayed within limits describes the gas loading it modelled, not the physiology of the person carrying it.

The practical upshot is that the dive profile is one input into the assessment rather than a filter that decides whether you are worth assessing. Bring the computer, describe the week honestly, and let the examination do the rest.

What should you do before you get to the clinic ?

1. Stop diving. No further dives until you have been assessed, whatever the outcome.
2. Call the clinic. 077-423-801 — describe the dive profile and the symptom.
3. Breathe oxygen if it is available, which most dive schools carry.
4. Drink water unless you are nauseated or drowsy.
5. Do not fly, and do not book a flight. Say so if you have one booked.
6. Write down your dive profile — depths, times, surface intervals, number of days.

Your dive computer is the most useful thing you can bring. Bring it, and do not reset it.

What to tell your dive school

Tell them, and tell them early. Instructors need to know because it affects the rest of the group's profiles and because they may have equipment, oxygen and transport that gets you assessed faster than arranging it yourself. Schools on Koh Tao deal with this more often than a traveller would guess and the response is usually immediate and practical rather than defensive.

There is a social pressure here worth naming. Nobody wants to be the person who stops the day, and the diver who quietly decides to see how they feel in the morning is making that decision for social reasons rather than medical ones. Say something at the surface interval, not at the bar.

How long should you wait before flying ?

Long enough that the remaining dissolved gas has been breathed off, and the interval depends on what you have been doing. This is one of the most-searched questions on Koh Tao, and it matters because the island's visitors almost all leave by boat and plane within days of their last dive.

The interval is longer after several days of repetitive diving than after a single dive, and longer again after any decompression dive, so the honest answer comes from your dive log rather than from a single number. Bring it, or your computer, and the doctor will give you a specific interval for your week.

If you have had any symptom at all, the answer changes entirely and becomes a clinical decision rather than a rule of thumb. Ask before you book. Divers Alert Network is the standard reference for divers on this and worth knowing before your first dive, and the NHS overview of decompression sickness gives a sound plain-English summary.

How do you reduce the risk ?

• ascend slowly and always make your safety stop
• build in generous surface intervals, particularly on multi-day trips
• drink more water than feels necessary in this climate
• avoid alcohol the night before diving, and avoid it entirely between dives
• do not dive with a cold, congestion or an ear problem
• dive conservatively on the last day before flying
• declare medical history honestly on your dive medical

Should you be seen ?

• Any neurological symptom after a dive → call immediately, this is an emergency
• Joint pain, rash, unusual fatigue after diving → same day, do not sleep on it
• Ear pain or blockage after a dive → same day; it is usually barotrauma, but it needs looking at
• Feeling fine but flying tomorrow after multi-day diving → ask the clinic before you fly
• A symptom that resolved on its own → still be assessed, and say it resolved

The full scope of what our Koh Tao clinic treats covers everything else, and the practical detail on hours and costs is in our guide to seeing a doctor on Koh Tao.