The last thing you want to think about as you're soaking in the warm rays en route to your next dive is what you'd do if you or your buddy should step on a stonefish or be stung by a jellyfish. But that's exactly what should be on your mind as you prepare for your next plunge, at least until you come up with an emergency plan.

"In many emergency situations, you really don't need to do a lot. But you do need to do critical little things," says Neal Pollock, Ph.D., of Divers Alert Network and the Center for Hyperbaric Medicine and Environmental Physiology at Duke University Medical Center, Durham, N.C. First aid is about fast action, explains Pollock. It needs to happen quickly, so you can repair the damage done from an accident or at least stop things from getting worse until medical help arrives. "Walk yourself through emergency events you may encounter. What would you do if a shark came up and bit your buddy? Go through your actions step by step. If you don't know, get answers. A little mental rehearsal can save you a lot of time and anguish and improve your confidence and response time," says Pollock, co-editor of DAN Pocket Guide to First Aid for Scuba Diving.

Check, Call, Care

Your first actions after any accident should be to follow what the Red Cross, the original first-aid professionals, call the "3 Cs" — check, call, care.

Check the scene and the people or person involved (in some cases, it may be you). How serious is the accident? Is there a lot of bleeding? Is anyone unconscious or having trouble breathing? Is it safe for you to even be there? Take in as much information as you can.

Call for help if you need it. For emergencies such as serious marine animal bites or envenomation, suspected DCS, heart attack, near drowning, etc., call 911. For non-life-threatening situations, at least call for the divemaster, so you can get help in assessing the situation and providing aid. (See "Call 911 if...")

Care for the injuries, at the very least providing preliminary assistance until professional help arrives.

Close Encounters of the Injurious Kind

Scuba diving is traditionally a look, don't touch kind of sport. But even careful divers can inadvertently run into trouble, says avid diver and ER doc George Bulloch, M.D., of Redwood City, Calif., who suffered a chance encounter with a Portuguese man-of-war a few years back. Unless you know what to do, those injuries from underwater encounters can turn from bad to worse pretty quickly, he says.

Here are some quick fixes for diving's most common mishaps. Take care of the wounds and seek medical assistance as recommended. In the days following an injury watch the wound for infection. If it swells, becomes hot, reddens or a red streak appears, develops pus and/or a foul odor, is painful to the touch or you develop a fever, see a doctor ASAP.

Stings
Jellyfish (there are more than 9,000 kinds), fire coral (not actually coral but a member of the jelly family) and bristleworms are a few of the common culprits that can deliver a painful zing.

Flush the injury with plenty of seawater to remove remaining tentacles and generally clean it out. Hot water inactivates many marine venoms, so if possible, flush or immerse the injury in very hot (but not scalding) water for 30 to 90 minutes. Vinegar also helps. Neutralize the venom from any remaining nematocysts (stingers) by rinsing the wound with vinegar. (Note: Do not use vinegar for a Portuguese man-of-war; it can trigger any remaining nematocysts to fire.) Then remove remaining stingers. Tweezers work for large stingers. You can also shave the area with shaving cream and a razor. Or in the case of small bristles, apply a piece of adhesive tape and "pull" them off. Rinse with vinegar again. Take Tylenol or ibuprofen orally and apply a hydrocortisone cream for pain.

Some stings, like those from a box jellyfish, can be very toxic, even fatal. Watch for severe symptoms, like pronounced swelling, trouble breathing, muscle weakness and nausea, that require immediate attention.

Punctures
As the name implies, punctures are deeper than stings because they stab through the skin. They can be small, like those from a sea urchin, lionfish or cone snail, to very big, such as the harpoon-like jab of a stingray, but they should all be treated seriously.

Flush or immerse the wound in very hot, but not scalding water for 30 to 90 minutes. Use tweezers to remove any remaining spines. Don't struggle to remove sea urchin spines; some may need surgical removal. Scrub the area with soap and water and rinse thoroughly.

Many punctures are venomous and some can be fatal, so seek immediate medical care. For particularly toxic punctures, like those from the cone snail or stonefish, wrap the affected area snugly (but not so tight as to cut off circulation) with an ACE bandage to slow the spread of venom.

Bites
Even small bites are potentially very dangerous, not only because they may carry venom (as in sea snakes and the potentially lethal blue-ringed octopus), but also because they deliver a hefty dose of bacteria that can cause rapid, nasty infections.

For snakes and octopus bites, wrap the affected area snugly (but not so tight as to cut off circulation) with an ACE bandage to slow the spread of venom. Seek help immediately. In the case of a blue-ringed octopus bite, the person may also need rescue breathing (mouth-to-mouth).

For moderate fish bites, irrigate the wound with fresh water. Then gently scrub it with soap and water and thoroughly rinse it. Apply an antibiotic ointment and keep the area elevated. For large bites, the first step is to stop the bleeding. Apply direct pressure over the wound with a clean dressing. Snugly wrap an ACE bandage around the dressing to keep pressure on the wound. Keep the wounded area above heart level, if possible. If the bleeding stops, you can then clean the wound. For all bites, seek medical assistance immediately.

Scrapes
By far the most common diving injury is the common scrape, usually from coral. Clean all nicks and scrapes with soap and fresh, clean water. Then flush the affected area again. To drive out all remaining debris, perform a final rinse with a mixture of half hydrogen peroxide and half water. Pat it dry and apply a coating of antibiotic ointment.

DIY First-Aid Kit

Toss these 10 dive savers in your bag and you'll hopefully never need them.

• Vinegar or rubbing alcohol
• Fresh water
• ACE bandage
• Antibiotic ointment
• Over-the-counter pain reliever (ibuprofen, Tylenol)
• Tape
• Tweezers
• Shaving kit
• Gauze pads
• Soap

Call DAN if ...

Even innocent injuries can turn deadly if you have an allergic or severe reaction. After any accident, watch for severe swelling, dizziness, blurred vision, breathing difficulties, weakness, muscle pain, cold sweat and a rapid heartbeat. If any occur while you're on a dive trip, call DAN's emergency hotline 919-684-4DAN immediately. Injectible epinephrine can help calm allergic reactions. CPR may be necessary until help arrives.

Diver CPR photo courtesy of Shutterstock.com