Category Archives: 2021 DAN Health and Safety

Benjamin Kistler

Diving into the DAN Internship

The second half of my internship here at DAN has been packed to the brim with events. I have been able to complete my pilot study on the hydration status of scuba divers. In this observational study, I collected urine samples from divers pre- and post-dive and compared them to control samples with no dive in between. I then analyzed these samples for urine-specific gravity and osmolality in order to see how hydrated divers are entering and exiting a dive. I compared these changes to any changes that would normally occur during the day. I obtained great data from divers here at DAN, but the majority of the data came from our trip to West Palm Beach, Florida, for Lobster Mini Season. Here, we joined charters to take measurements on divers including urine samples, neurocognitive performance, subjective fatigue, skin conductivity, electrocardiograms, and more.

Here is a picture of me on the Pura Vida charter analyzing pre-dive urine samples while the divers are in the water.

We not only took measurements during this trip, but we also got to dive! Our first day on the road consisted of stopping in Charleston, South Carolina, to dive the Cooper River, where we hunted for prehistoric shark teeth and fossils. Our next stop we didn’t dive at, but we got to take a behind-the-scenes tour of the Georgia Aquarium in Atlanta. We then stopped in Blue Grotto in North Florida to dive the crystal-clear cavern on our way down. Finally, we also dove on the beautiful reefs in West Palm, which are some of the best that the Atlantic side of Florida has to offer.

Shark teeth I found in the Cooper River.

Above the Voyager pool at the Georgia Aquarium that houses whale sharks, manta rays, and many more species of fish and aquatic life.

At the bottom of the 100-foot cavern of Blue Grotto.

Myself and two other interns descending on the reefs of West Palm Beach.

Another project that I have been involved with recently is serving as a research subject at the Duke Hyperbaric Medical Center. I am involved in a study that is looking to see if a ketogenic diet is protective against oxygen toxicity in divers. For this study, I will enter their hyperbaric chamber two times; one time on a ketogenic diet and one time on a normal diet. For each round, I will be breathing 100% oxygen at a depth of 35 feet of sea water while hooked up to an electroencephalogram, electrocardiogram, IV line, electrodermal activity sensors, and expired gas monitors while peddling on an underwater ergometer and playing a flight simulation game. I will do this task for two hours each round, or until I show symptoms of oxygen toxicity. Another study that I have already completed is looking to see how we can automate the detection of venous gas emboli in divers. For this study, a Doppler device was used to listen to my heart sounds and the information is being used to train a device to listen for bubbles in the vasculature.

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Divers Alert Network Research Internship Kick-Off

My time here at Divers Alert Network started with meeting and learning about the different departments including research, medical, marketing, and operations. We spent a few days taking a research field operator workshop, learning how to operate the various devices we use in data collection. The other interns and I then got briefed on the projects we would be working on over the summer and began doing literature review on them.

One project we started for the summer includes a neurocognitive battery test designed to measure mental fatigue in divers. This test involves a series of 10 “brain” games designed to test working memory, reaction time, dexterity, etc. Another project involves assessing the hydration status of divers by collecting urine samples pre- and post-dive and measuring markers such as specific gravity and osmolality.

Some of DAN’s ongoing projects that we jumped in on include an ultrasound comparison study where we take ultrasounds of divers with three devices to see if they all give comparable results. One is a larger ultrasound device with a computer, one a smaller ultrasound device that can hook up to an iPad or iPhone, and one a small doppler device that records sounds. Another project we jumped in on is the cardiac study where ECG leads are hooked up to divers to measure the electrical activity of their heart before, during, and after a dive.

We decided to clean out the DAN library as we try to make all of the diving-related literature virtually accessible.

This is a picture from our field operator workshop when David Le from UNC came to talk to us about the physics of ultrasound and how we can use it to manipulate microbubbles.

Here is a picture of my heart under the Vivid q ultrasound computer after a dive. We were able to see small venous gas emboli flowing through the right side of my heart. These bubbles are produced when inert gas comes out of solution during a high to low pressure change and can get lodged in the body and produce symptoms of decompression sickness. Most of the time they are benign. These gas bubbles are the reason divers do safety stops at shallow depths so they can decompress.

This picture is from our first ultrasound comparison weekend at Mystery Lake in NC (credit Dr. David Charash).

We have also done some fun dives at quarries around the area including Fantasy Lake and Blue Stone Quarry.

Over Memorial Day Weekend, we found an old American flag during a dive under a bunch of silt and thought it was only right to haul it back to the surface.

We have gotten to tour two hyperbaric chambers so far where divers become patients when they are struck with decompression illnesses. These chambers are used to treat a variety of other diseases and conditions, too. During the Undersea and Hyperbaric Medical Society annual conference, we learned about how these chambers operate and recompress divers to various depths and on various gas mixes.

Duke University’s hyperbaric chambers. There are 7 chambers here that house patients, hyperbaric technicians, and research participants.

Smaller chamber at Bluestone Quarry.

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