DAN Medical Frequently Asked Questions

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Basic Instincts

DAN explores a hypothetical underwater emergency.Aboard the dive boat your dive buddy seemed relaxed and well prepared. Thirty minutes into the dive at about 50 feet / 15 meters, however, he panics and appears to be hysterical. He removes his mouthpiece. What emergency procedure should you perform?

Anytime a diver loses his regulator underwater he is at risk of drowning, loss of consciousness and, if he breath-holds on his way up, an arterial gas embolism. That?s why we spend so much time in open-water training learning what it feels like to be underwater and working on equipment-related skills: it?s to prevent the situation from occurring. Nonetheless, it does happen from time to time and for a variety of reasons.

Try to make contact with the diver. Do you know whether this diver has a history of anxiety-related issues when diving, or is he having a real problem with his regulator or air supply? For example, see if the tank is attached to the backpack. Is the regulator attached to the tank? Is the first stage leaking? Is the mouthpiece attached to the regulator? Does the regulator work? Is the regulator leaking? Does the octopus work? Can you see other equipment problems?

Consider Medical or Physical Problems

Has anything like this happened before? Does the diver have a significant medical history, such as high blood pressure or cardiovascular illness? Is there trauma ? i.e., do you see any wounds?

Many callers to the DAN Medical Information Line have said that just before they panicked, they had experienced the sensation of not getting enough air; others had noted that they felt like they were "breathing through a straw." It is difficult to communicate respiratory (breathing) distress underwater, and it very quickly turns to panic when the diver sees no real option except bolting to the surface for air.

Getting the Diver to the Surface

Time is a definite concern in a rescue like this. The panicked diver?s tissues will consume oxygen, even while he is not breathing. This means that during the ascent, as oxygen concentrations in the lung decrease and gas expands, the diver is at risk of losing consciousness (called shallow-water blackout) and perhaps in danger of an arterial gas embolism from lung overexpansion.

On the other hand, if the diver is unconscious, he may relax the pharynx and allow passive exhalation. This will allow air to vent out of the lungs without over-pressurization and barotrauma.

The diver, whether conscious or not, may also experience laryngospasm, a reflex spasm that occurs when water enters the throat. Because the spasm may completely or partially close the airway, an ascending diver experiencing this reflex risks arterial gas embolism.

Dealing With Complications

The central task in the rescue of a panicked diver involves helping him make a normal ascent without inhaling water and holding his breath. Assuming this is a standard no-decompression recreational dive, the best assistance is to hold onto the diver to help control the rate of ascent. A distressed diver in this situation will likely do everything in his power to hold his breath and not breathe in water voluntarily. Expanding lung volume usually forces some air to escape through the mouth and nose, but the risk of AGE still exists.

Drowning or near-drowning is also a possibility, but you shouldn?t have to cover both the mouth and nose during the ascent. The diver may still have his mask. If he has panicked, however, both the regulator and mask may come off, making the situation grave indeed. We have a natural protective mechanism to continue to breathe after we lose consciousness. If that were to happen underwater, however, it could result in drowning or near-drowning.

The risk of injury and even death increases once a diver loses the regulator. In the best scenario, the diver takes it back immediately or the buddy will offer it to the diver and adjust the equipment, and the diver continues to breathe. If not, the buddy or dive guide will have to help the diver to the surface in a controlled emergency ascent, one would hope, without incident. If the diver can reach the surface safely, serious injury or death may be averted.

Other reasons besides equipment trouble or panic may cause the diver to spit out a mouthpiece. Most said another diver assisted them to the surface.

Once you?ve reached the surface, establish positive buoyancy for both yourself and the panicked diver. If you haven?t already removed the diver?s weight belt, do it now. If you?re diving in warm water, you may have to inflate the diver?s BCD.

At this point, you should be able to get the diver back to the shore or the dive vessel.

A good diving buddy should be knowledgeable and skillful, should remain aware of the surroundings in the water, and should be aware of his partner?s medical and diving history. That?s what a buddy?s for.