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March 2019    Download the Entire Issue (PDF) Available to the Public Vol. 45, No. 3   RSS Feed for Undercurrent Issues
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The Fatal Effects of “Rapture of the Deep”

and how drugs and reluctant divemasters may play a big part

from the March, 2019 issue of Undercurrent   Subscribe Now

Last April, Jeff Sharp, a 64-year-old attorney from Modesto, CA, and his wife, Kathy Monday, went for a dive on the backside of Molokini, a partially submerged crater off the island of Maui, but for some reason, he made an uncontrolled ascent from around 200 feet deep. Why? We'll never know the true circumstances that led to this tragedy, but Sharp had been seen finning deeper than he should have been, so the suspected culprit is nitrogen narcosis.

First certified in 2012, Sharp had dived in the Hawaiian Islands before, but this was his and Monday's first time at Molokini. On this trip, they were part of a group of six to eight divers on a tourist dive boat, accompanied by two dive guides. Most of them descended to around 70 feet, and after a guide pointed out a group of sharks, Monday realized Sharp had disappeared from her view. She looked up to see if he'd had problems with his ears and had ascended but was shocked to discover moments later that he was swimming far below her.

She pursued him, along with one of the dive guides, who used a tank banger to try to get Sharp's attention, but the guide was obviously concerned about goingbeyond the maximum operating depth of the nitrox he was breathing. Monday almost caught him, but she became fatigued and could no longer swim hard. By that time, Sharp was at around 185 feet and slowly sinking, perpendicular with feet down.

Why Didn't the Dive Guide Go After Him?

The next thing Monday recalled was the dive guide inflating her BC and sending her to the surface; she was lucky to survive the ascent. Sharp evidently came back to his senses, but in panic, took the same action. Maybe it was the sensation of finding he was out of air at 200 feet that startled Sharp into reacting, but, if that was the case, how could he then have inflated his BC?

His cause of death was listed as rapid ascent. Nitrogen bubbles were found in his cerebral and cardiovascular systems, indicating Sharp had ascended too fast for previously absorbed nitrogen to safely escape via his lungs. Monday was hospitalized and stayed in the intensive care unit for four days. She suffered a type of heart failure known as takotsubo cardiomyopathy, a weakening of the left ventricle resulting from severe emotional and physical stress.

Sharp may have been distracted by the sharks and decided to follow one. Also, currents can affect diving conditions on the back side of Molokini, but that was never mentioned in any reports of the incident.

If Monday, a middle-aged grandmother, could reach Sharp as he descended, why not presumably a younger, fitter dive guide?

A dive guide's initial reluctance to go deeper than the maximum operating depth of the nitrox in his tank can inhibit one from trying to rescue a sinking diver, although a wise, experienced guide would know that oxygen toxicity is factored by both pressure and exposure time. Many dive guides have found it necessary to break that rule to grab an ill-disciplined diver (Read my blog post "No Computer, No Sense!" on this matter at

One could argue that a conscientious and competent dive guide should have been able to bring Sharp safely to the surface. After all, if Monday, a middle-aged grandmother, could reach him, why not a presumably younger, fitter dive guide? Sharp's descent happened at the beginning of the dive, when divers should have had plenty of air in their tanks, and even if Sharp was debilitated by narcosis, it should have been a routine matter for his guide to take control of him and make a controlled buoyant lift while he breathed off the guide's alternate air source.

The Effect of Prescription Drugs: Who Really Knows?

The mechanism of nitrogen narcosis is still not fully understood -- it affects different people in different ways and on different occasions. Some medical experts set the threshold for narcosis at 100 feet, but some divers start feeling the "rapture of the deep" as shallow as 60 feet deep. Others appear to be unaffected until much deeper. Some training agencies, such as GUE, insist their divers breathe a tri-mix containing helium if going deeper than 100 feet. Those who first dived the wrecks at Bikini Atoll did so on air, yet regularly dived twice a day down to 185 feet without any ill effects being reported. Dive industry veteran Bret Gilliam, a frequent Undercurrent contributor, has the depth record for an air-breathing dive at 452 feet done back in 1990, so he is obviously less affected by nitrogen under pressure than most of us divers.

Over-the-counter medications can intensify the narcosis effect, although no formal research has been done. Sharp had taken Dramamine before his dive, and, although he'd made many dives, this was his first one below 60 feet. Dramamine's common side effects at the surface can be dizziness or drowsiness, which doesn't augur well if you're befuddled by the effects of depth -- nitrogen under pressure can exacerbate the listed side-effects of both over-the-counter and prescription drugs.

It's still pretty surprising that there has been little to no research on the side effects of drugs while diving. Subscriber David F. Colvard (Raleigh, NC), a retired physician, told Undercurrent, "Almost 20 years ago, I contacted every drug company that made psychotropic medications for data on their meds in a hyperbaric environment. None had any data at all. I can tell you that no drug manufacturer will ever do a study on its drug in scuba divers, [although] there was a study done a decade ago on Sudafed and Benadryl used while in dry chambers."

Editor Ben Davison recalls how, after taking a half-milligram dose of Ativan (also known as Lorazepam) on a Belize dive he had done many times before, that "at 135 feet, I saw God."

So that you'll be more focused on the wonderful marine life swimming in front of you instead of having visions of the rapture, avoid diving deeper than you are used to, particularly if you're taking prescription drugs. And whatever the prescribed medication you're taking, talk to your physician before you go diving to make sure you're medically fit to do so.

-- John Bantin

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