18 November, 2001
Dr. Neal Pollock, The "Dive Safety Officer" on Dr. Bowser's research team, is a research scientist with the Center for Hyperbaric Medicine and Environmental Physiology at Duke University Medical Center. 'Environmental Physiology' is the study of how the body responds to environmental conditions of pressure, temperature, and other factors. 'Hyperbaric Medicine' concerns the clinical application of pressure for the treatment of specific diseases (for example, wounds that heal poorly and carbon monoxide poisoning). Doctors use the hyperbaric chambers (Duke has seven available for humans) to treat patients. The Applied Studies group that Dr. Pollock works with is concerned with how humans respond to extreme environments underwater, in high altitude, and in space.
Dr. Pollock has been diving for 23 years. He was born in Edmonton, Alberta where he began his study of marine biology. His background in marine science led him to pursue a masters in exercise physiology (with a focus on diving physiology) and a doctorate in exercise and environmental physiology. Dr. Pollock's scientific diving history and cold water diving experience was instrumental in bringing him to the extreme conditions of diving in the cold Antarctic waters. He began diving in Antarctica in 1990, then continued in 1993, 1994, 1999, and 2001.
Dr. Pollock's work at Duke University involves studying the effects of high and low pressure on the bodies of people working in extreme environments, whether they are diving underwater or working in space. The Applied Studies group conducts research to optimize decompression procedures for those with special needs - divers, high altitude parachutists, and astronauts. The following describes pressure effects. As a diver descends (goes down) in the ocean, the pressure surrounding the body increases and additional gas from the lung flows into the body. When the diver returns to the surface, the ascent must be made slowly enough to allow the excess gas in the body to be removed from the lung safely. According to Dr. Pollock, if a diver ascends too quickly, the nitrogen gas can make the blood and tissues "fizz like a coke bottle opened after being shaken" (other gases may be involved, but nitrogen is the typical culprit). This is known as decompression sickness or the 'bends.' One variation of these studies has Dr. Pollock and his colleagues determining how long divers should wait between diving and flying in order to avoid decompression sickness (since flying reduces the pressure surrounding the body and increases the decompression stress of the dive).
Another variation of their studies is funded by NASA. Astronauts must decompress to work outside in spacesuits (extravehicular activity - EVA - or spacewalking). The spacesuits hold a reduced pressure to allow the astronaut to move more easily. The project goal is to help astronauts decompress safely and as fast as possible. Efficiency is becoming more important now with the numerous spacewalks required for the construction and maintenance of the new International Space Station. The group that Dr. Pollock works with is trying to find the best combination of oxygen-breathing and exercise to remove nitrogen from the body prior to decompression and thereby reduce the risk of decompression sickness. Exercise increases both blood flow and breathing. When exercise is combined with oxygen breathing, nitrogen rapidly leaves the body.
Dr. Pollock's diving and research in Antarctica gives him the opportunity to experience extreme conditions firsthand in order to guide his research. He is also collecting data in Antarctica for Project Dive Exploration (PDE), a study developed by the Divers Alert Network (DAN). The long term objective of the project is to collect computerized records from one million actual scuba dives. Volunteer divers wear small computers that monitor their activity. An accurate record of the profile of each dive is measured. Ultimately, this data will provide an indication of the true risk of decompression sickness and help to identify factors that may affect individual risk.
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