Understanding how decompression illness treatment targets nitrogen bubbles in the bloodstream

What is the primary focus of the treatment for decompression illness?

• A. Increase blood oxygen levels
• B. Relieve pressure on the joints
• C. Remove nitrogen bubbles from the bloodstream
• D. Stabilize the diver's position in the water

Answer: (C)

The primary focus of the treatment for decompression illness is to remove nitrogen bubbles from the bloodstream. When a diver ascends too quickly, nitrogen, which is absorbed by the body under pressure, can form bubbles as the pressure decreases. These bubbles can obstruct blood flow, cause tissue damage, and lead to various symptoms associated with decompression sickness. The treatment often involves administering pure oxygen to the diver in a hyperbaric chamber. This method helps in dissolving the nitrogen bubbles back into the bloodstream and facilitating their elimination from the body. The process reduces the size of the bubbles and allows for safer and more effective elimination through respiration. In contrast to other options, while increasing blood oxygen levels and relieving pressure on joints can be benefits during treatment, they are not the primary focus. Stabilizing the diver's position in the water is also not a main concern when addressing decompression illness itself, as the critical action is to safely reduce the nitrogen bubbles in the system.

Decompression illness is one of those diving legends that sounds almost mythical until you’ve heard a firsthand account. The truth is a lot simpler—and a lot more critical—than the drama makes it seem: when a diver ascends too quickly, nitrogen that’s been absorbed into the body under pressure can form bubbles as the pressure falls. And yes, those bubbles can cause real trouble, from pain in the joints to more serious neurological symptoms. The backbone of treatment is straightforward, even if the mechanics are a bit science-y: remove nitrogen bubbles from the bloodstream.

Let me explain what that really means and why it matters so much, especially for anyone who’s curious about the IANTD Open Water framework and how the medical side of diving actually works.

What goes wrong under pressure (in plain language)

• Nitrogen is your invisible passenger. Under the pressure you experience underwater, nitrogen dissolves in your tissues and blood, almost like sugar dissolving in tea as you heat it up.

• When you start to ascend, that pressure drops and the dissolved nitrogen wants to come out of solution. It forms bubbles—tiny, then bigger—just like fizz in a bottle when you open it.

• Those bubbles aren’t just annoying. They can obstruct blood flow, irritate nerves, and damage tissues. In the worst cases, they can affect the brain, spinal cord, lungs, or heart.

The primary focus of treatment: remove nitrogen bubbles from the bloodstream

• This is the key point you’ll hear echoed in medical guides and in the field. The goal isn’t just “more oxygen” or “less joint pain.” It’s getting rid of those nitrogen bubbles so they stop causing trouble and so your body can recover.

• How does that removal happen? Two big ways. First, by using oxygen therapy to speed up the washout of nitrogen. Second, by recompressing the diver in a hyperbaric environment to shrink the bubbles and promote dissolution of nitrogen back into the blood, where it can be breathed out safely.

Why oxygen matters (beyond “more oxygen sounds good”)

• Breathing pure oxygen helps because it creates a high partial pressure of oxygen in the blood. That pressure helps nitrogen dissolve back into the liquid portions of the blood more readily and get carried away through the lungs.

• In practical terms, a diver suspected of decompression illness is typically given 100% oxygen as soon as possible. This isn’t just a “helpful boost”; it’s a foundational step to accelerate bubble resolution.

• The hyperbaric chamber is where the real magic happens. By placing the patient in a chamber that’s pressurized (often at 2 to 3 atmospheres or more), the nitrogen bubbles shrink. The elevated pressure pushes dissolved nitrogen back into solution and then out of the body through respiration as the patient breathes oxygen. It’s a carefully controlled process designed to halt ongoing tissue injury and reduce symptoms quickly.

Why the other options aren’t the primary focus

• A. Increase blood oxygen levels: While oxygen therapy is essential and beneficial, increasing oxygen alone isn’t the dramatic fix. The real winner is reducing the nitrogen bubbles that caused the problem in the first place.

• B. Relieve pressure on the joints: That might help with some symptoms, like joint pain, but it doesn’t tackle the root cause. Joint relief is more of a symptom management outcome, not the central treatment goal for decompression illness.

• D. Stabilize the diver’s position in the water: Keeping someone safe and supported is important, but stabilization isn’t the central therapeutic aim for DCS. The critical action is to address the bubbles in the bloodstream, preferably in a hyperbaric environment or with high-flow oxygen on the way to a facility.

First steps if you suspect decompression illness (on the surface and in the field)

• Get the person out of the water calmly and as safely as possible. Heat, vibration, or exertion can worsen symptoms, so avoid unnecessary movement.

• Call for emergency medical help. Decompression illness is a medical emergency, and time matters.

• Administer 100% oxygen if you’re trained to do so and have the equipment. A tight-fitting mask is ideal; ensure a steady supply and monitor the patient.

• Keep the diver still and comfortable. If there’s no contraindication, place them in a position that’s comfortable and stable—often on their back with the head slightly elevated, unless there’s a head or neck injury.

• Do not give food or drink if the patient might need anesthesia or a procedure later—medical teams will decide what’s appropriate when they arrive.

• If transport to a hyperbaric facility is available, arrange it promptly. If not, oxygen and rapid medical transfer are still critical to buy time for the patient’s recovery.

What happens inside the hyperbaric chamber (the more technical part, kept digestible)

• The chamber is a controlled environment where air pressure is deliberately increased. The diver breathes 100% oxygen, which isn’t just about more oxygen in the blood; it creates the pressure gradient that encourages nitrogen to leave the bubbles and dissolve back into the bloodstream.

• The bubbles shrink in size under higher pressure, and the dissolved nitrogen is carried away through the lungs as the patient continues to breathe oxygen.

• Treatments are typically scheduled in multiple sessions rather than a single, one-off hit. The exact number of sessions and the pressures used depend on symptoms, timing, and how the patient responds to therapy. The goal is to restore normal tissue function and prevent lasting injury.

Prevention: small habits with big payoff

• Slow, controlled ascents save lives. A standard rule of thumb—often taught in entry-level courses—is to ascend no faster than about 9 to 18 meters (30 to 60 feet) per minute, with a safety stop at around 5 meters (15 feet) for several minutes. It’s not a law of physics you feel every time, but it’s the kind of discipline that prevents many cases of DCS.

• Stay conservative after deep or long dives. If you’ve done a deeper dive or pushed close to limits, add more conservative ascent plans and longer safety stops.

• Hydration and rest aren’t a cure-all, but they aren’t useless either. Being well-hydrated helps circulation, and a rested body handles pressure changes more predictably.

• Quick-checks before you go under: verify equipment, buddies, and plan. A simple, solid plan reduces risk and buys peace of mind in more ways than one.

A brief look at real-world nuance

• Sometimes, symptoms show up hours after a dive. The late-developing symptoms make it even more important to take any new neurological symptoms, numbness, weakness, or dizziness seriously—especially after a recent ascent.

• Not all symptoms scream “nitrogen bubbles.” DCS can mimic innocuous issues like fatigue or arthritis flare-ups, which is why a medical assessment is essential if symptoms appear after a dive—better to err on the side of caution.

• The historical thread matters, too. The development of hyperbaric medicine was a turning point for divers. Before recompression therapy became standard, decompression illness was far more dangerous. Today, the best outcomes come from rapid recognition, oxygen administration, and timely access to hyperbaric care.

How this topic fits into the broader world of scuba safety

• You don’t study decompression illness in a vacuum. It sits alongside other core safety pillars: buddy checks, gas management, ascent rates, and emergency response planning.

• Understanding the math behind gas behavior—who absorbs nitrogen, who releases it when pressure changes, and how oxygen interacts with bubbles—translates into smarter decisions under water.

• This knowledge isn’t just for tests or certifications; it’s practical wisdom you carry into every dive. The more you know, the more confident you’ll be when a real situation arises, and the more you’ll protect your gear, your buddy, and yourself.

A closing thought that sticks

Think of nitrogen bubbles as the uninvited guests at a party. They show up because of pressure and disappear when the room gets the right temperature and the right drink—oxygen, in this case. The primary goal of treatment is to get those guests out of the bloodstream as quickly and safely as possible, so the party can continue without interruption. Hyperbaric therapy isn’t a gimmick; it’s a proven path back to health when those bubbles decide to crash the scene.

If you’re curious about the science behind this, you’ll find the same principles echoed in standard diver safety guidelines and emergency response protocols. And if you ever find yourself explaining this to someone new to the sport, you’ll have a clear, human way to convey why the nitrogen bubbles matter—and why the response is so focused on dissolving and removing them.

In short: Treat decompression illness with urgency, focus on removing nitrogen bubbles, and lean on oxygen therapy and recompression to guide the body back to normal function. It’s a straightforward objective, but it makes all the difference between a concerning episode and a story of a safe return to the surface.