Recognizing DCS, giving 100% oxygen, running the 5-minute neuro check — the rescue protocols that decide between full recovery and lasting damage.
## Introduction Your buddy complains of joint pain after the dive and feels oddly tired — sore muscles or an emergency? The honest answer: any symptom that shows up in connection with a dive counts as a suspected diving accident until proven otherwise. Acting costs you nothing. Hesitating can cost everything.
Under the umbrella term DCI (decompression illness), dive medicine groups two emergencies together: decompression sickness (DCS), caused by gas bubbles in blood and tissue, and arterial gas embolism (AGE), where air bubbles enter the bloodstream directly. DCI doesn't just strike inexperienced divers — even seasoned divers sometimes underestimate small deviations from the dive plan, like a slightly too-fast final meter of ascent. That's exactly why rescue training belongs in every advanced course, not just in the textbook. As an intermediate diver at DOMISPORTS, you'll learn the protocols here that determine whether an emergency leaves lasting damage — from the first warning signs to oxygen therapy and the neuro check.
## What you need Emergency oxygen system: delivers 100% O2 at a minimum of 15 liters per minute, via demand valve or reservoir mask. Fluids: still water or isotonic drinks for rehydration. Heat protection: blankets or towels against hypothermia. Wetnotes: for documenting the neuro check and dive computer data.
### 1. Recognize the symptoms Mild cases (DCS Type I) show up as extreme fatigue, deep joint pain ("the bends"), itching, or reddish-blue skin mottling. Severe cases (DCS Type II or AGE) hit the nervous system: numbness, tingling, paralysis, dizziness, breathing trouble, unconsciousness. Symptoms can appear right after surfacing, but sometimes only hours later — stay alert even after a dive that felt completely unremarkable. Any of these signs after a dive gets treated as an emergency, immediately.
### 2. Give 100% oxygen The single most important first response: get pure oxygen into the patient right away. The high O2 fraction creates a strong concentration gradient in the lungs that accelerates the removal of trapped nitrogen. Flow rate: at least 15 liters per minute, with a tight-fitting mask or demand system.
### 3. Rehydrate carefully Almost every diver is dehydrated after a dive — dry tank air and increased urine output see to that. Blood that's too thick flows worse and clears nitrogen more slowly. Give a conscious patient 0.5 to 1 liter of still, isotonic fluid per hour, but never as a few big gulps at once.
### 4. Run the 5-minute neuro check While oxygen is flowing, test three areas: consciousness (questions about person, place, time), motor function (smile, squeeze eyes shut, raise arms, walk a straight line), and sensation (feel touches at different spots). Note the time and repeat every 15 minutes — that's how you see if things are improving or getting worse.
### 5. Call emergency services and prep for the chamber Call emergency services and explicitly say "suspected diving accident" — that gets transport to a hyperbaric-chamber clinic coordinated immediately. Secure the diver's dive computer too: the stored profiles are vital diagnostic data for the physician at the chamber.
## Common mistakes - In-water recompression: Sending the injured diver back underwater with a fresh tank is absolutely life-threatening — seizures underwater almost always end in drowning. - Downplaying symptoms: Writing off joint pain as muscle soreness burns time that, with DCS, decides between full recovery and lasting damage. - Stopping oxygen too soon: Even if symptoms improve, don't pull the mask right away — bubbles in the tissue can grow again fast (rebound effect). - No emergency plan at the dive site: Not knowing beforehand where the nearest oxygen kit is, what the emergency chain looks like, or which clinic has a chamber costs precious minutes in a real crisis.
## Safety notes If the diver is unconscious but still breathing, get them into the recovery position immediately to keep the airway clear. The head must never sit lower than the body — contrary to old myths, that only raises the risk of a dangerous brain edema.
## Pro tip Even if symptoms fully disappear after 30 minutes of pure oxygen, the emergency isn't over. Keep the oxygen going and call a dive-medicine hotline like DAN (Divers Alert Network) — they can decide over the phone whether observation in a chamber is still needed. Save the number before your next dive trip — you don't want to be searching for it mid-emergency.
### How do I tell DCS apart from ordinary muscle soreness? The biggest clue is timing: joint pain, fatigue, or skin changes within hours of a dive should always be treated as DCS until proven otherwise. Muscle soreness is usually symmetrical and explained by exertion — DCS is often one-sided and unexpected.
### Do I really need to call emergency services even for mild symptoms? Yes. Mild symptoms can develop into severe neurological damage within hours. Call and say "suspected diving accident" — that starts chamber coordination immediately, whatever happens afterward.
### Why is in-water recompression so dangerous? Because the patient can lose consciousness underwater and drown before anyone can help in time. In-water recompression is a myth from diving's early days and is strictly forbidden today — the only safe recompression happens in an actual hyperbaric chamber.
### How long do I keep giving oxygen if symptoms disappear? Longer than you'd think. Even if the patient improves after 30 minutes, keep the oxygen running and call a hotline like DAN. Bubbles in the tissue can grow again quickly once oxygen stops.
### What do I do if the diver is unconscious? Put them in the recovery position right away if they're still breathing on their own — the head should never sit lower than the body. If they're not breathing, start resuscitation and call emergency services at the same time.
Decompression Theory and Bühlmann Algorithm