Monte was having the time of his life: He’d done six dives the day before and was finishing up his third for day two, “diving his brains out,” as he liked to say. Water temperatures were in the upper 60s, and visibility was good. He was feeling great — or at least he thought he was. As Monte finished up his safety stop at 10 feet, he began feeling dizzy and his stomach started to churn. Suddenly, he wasn’t feeling so great anymore.

THE DIVER

An avid diver, Monte had made about 150 dives a year for the past 12 years. He was in good health, although he smoked a pack of cigarettes a day. At 38, he enjoyed living life. For him, that life definitely included scuba diving.

THE DIVES

Monte was diving with a group on a local liveaboard and took advantage of the unlimited diving, switching buddies when other divers didn’t want to get back in the water. Monte used 32 percent nitrox on every dive, and planned his dives based on the equivalent air depth to give himself more bottom time.

On the first day, Monte made six dives — including one at night — all between 60 and 85 feet of seawater. On day two, he planned to do exactly what he had done on the first day. Still using the 32 percent nitrox, Monte made dives to 55 feet, 70 feet and 
73 feet. Bottom times were between 33 and 43 minutes, according to his dive computer.

THE ACCIDENT

At the end of his third dive on day two, Monte’s computer warned him that he was ascending too quickly. He began dumping air from his BC and got himself under control as he swam to the anchor line to make a safety stop. A few other divers were on the line, so he settled down at 10 feet to off-gas.

Near the end of his three-minute stop, Monte noticed tingling all over his body, and his legs felt weak. On the surface, before he got out of the water, Monte threw up and needed help getting on board. He was dizzy and couldn’t get his balance or walk.

The boat crew immediately put Monte on oxygen, alerted the Coast Guard and began heading for shore. Monte’s weakness decreased, but the dizziness progressed to vertigo, and 
he remained nauseated. As his buddies helped him out of his gear, they noticed a red, marbled rash on his abdomen. It was sensitive to the touch.

A helicopter evacuated Monte to a hyperbaric facility for evaluation and treatment. Monte was diagnosed with neurological decompression illness with inner-ear involvement and skin bends. He underwent a U.S. Navy Treatment Table 6 with two extensions (more time and oxygen). After follow-up treatments, and with time, he made a full recovery.

ANALYSIS

DCI is caused by a buildup of nitrogen gas, which occurs when the body can no longer handle the gas supersaturation. Monte pushed the limits, although he may have made similar dives before without issue. Just because your dive computer says you can make a dive doesn’t mean you should, because they take into account only depth and time. They don’t analyze factors such as heart rate, breathing rate, gas uptake or other factors such as fitness, body type and hydration. Like most nitrox divers, Monte planned his dives using the equivalent air depth, instead of using the reduced-nitrogen content to give himself an added safety buffer. This gave him more bottom time on each dive, but it took away any potential safety factor. He also made dives that were increasingly deep, but not enough to be considered a factor.

Monte’s series of nine dives increased his gas load to the point that his body could no longer handle the stress. Consequently, symptoms appeared in dramatic fashion. He reported that he hadn’t noticed any problems before the last dive. While that is entirely possible, it is also possible that Monte had mild symptoms of decompression illness before the dive but didn’t notice them or connect them to diving. It’s common for divers to ignore mild symptoms such as fatigue or minor joint pain in shoulders and knees, ascribing them to the stress and work of the dive.

General fitness also plays a role in DCI. Monte was in good health, although he did smoke and had a history of asthma. He did not report difficulty on his dives, but smoking impairs the body’s ability to absorb oxygen.

To avoid a problem, Monte could have used the nitrox as if it were air. His bottom times would have been shorter, but he would have had an additional safety buffer. You can’t enjoy longer bottom times and increased safety on the same dive.

Monte did his safety stop at 10 feet instead of the more-common 15 feet. The shallower depth and lower ambient pressure didn’t help, but it probably didn’t make things worse. Safety stops are not decompression stops. They are intended to reduce your gas load and add a safety factor to your dives, but Monte’s gas load was so high that a slightly deeper safety stop wouldn’t have made a difference.

Cutting down the number of dives, and resting, hydrating and eating well in between can decrease the likelihood of a problem. So would ceasing smoking, in Monte’s case.

LESSONS FOR LIFE

1. GET AND STAY FIT

You don’t have to be a triathlete to dive, but general fitness is a must. Many dive accidents include divers who are in poor shape or are dangerously obese.

2. STOP SMOKING

Smoking impairs breathing and the body’s ability to absorb and remove waste gases from the blood.

3. DIVE CONSERVATIVELY

Don’t overload yourself with too many dives in any given day. Take a break and enjoy the sunshine.

4. UNDERSTAND NITROX

Nitrox can give you longer bottom times, or it can increase your safety margin on a dive — not both.

5. ASCEND SLOWLY

Rapid ascents can cause bubble formation as the ambient pressure exceeds the pressure of gases inside your body. Give your body the chance to remove the nitrogen naturally before it forms bubbles and causes problems.

About Lessons For Life

We're often asked if the Lessons for Life columns are based on real-life events. The answer is yes, they are. The names and locations have been removed or altered to protect identities, but these stories are meant to teach you who to handle a scuba diving emergency by learning from the mistakes other divers have made. Author Eric Douglas takes creative license for the story, but the events and, often, the communication between divers before the accident are entirely based on incident reports.