5 Clinical Trials for Various Conditions
The investigators hypothesize that membrane microparticles (MPs) are liberated into the blood stream in response to decompression stress and that certain MPs characteristics initiate inflammatory responses that contribute to the clinical syndrome the investigators call decompression sickness. The research goal is to evaluate the number, type and time-course for elevations in MPs in sport SCUBA divers who present for treatment of decompression sickness. Blood samples are to be taken from consenting patients before and after they undergo treatment for decompression sickness and at a follow-up clinic visit from 1 to 3 weeks later (three samples total).
This study will validate the experimental method and chamber facility at the Duke Center for Hyperbaric Medicine \& Environmental Physiology and test team capabilities to support NASA decompression sickness (DCS) studies. This project is related to development of protocols for extravehicular activity (EVA, "spacewalks") to minimize the risk of decompression sickness. Duke will perform four test days, collecting and recording data each day. Each test day will involve 3 volunteer subjects ages 18-50 years, who will breathe 100% oxygen for 6 hours. This will be followed by 6 hours in the hypobaric chamber at 1/3 atmosphere, during which subjects will perform various tasks, including arm and leg exercises, and undergo ultrasound testing to detect vascular bubbles. End-points will include bubble scores, and decompression sickness (DCS). If subjects develop DCS symptoms they will immediately be recompressed to ambient pressure and be assessed and treated.
The aims of this proposal are to test current USN procedures for adjusting decompression procedures during air diving at 8,000 and 10,000 ft altitude and to provide a decompression algorithm for no-stop dives to 100 feet of sea water (fsw) at 10,000 and 12,000 ft altitude using enriched O2 (PO2=1.3 ATM). Additionally, the experiments will determine whether a period of hyperbaric hyperoxia, such as would be experienced during a dive at altitude, reverses altitude acclimatization, resulting in a return of acute mountain sickness (AMS) symptoms.
SCUBA diving frequently involves repetitive exposures over multiple days. The goal of this study was to see how exercise impacts microparticles (MPs), endothelial function, and venous gas emboli (VGE) over a series of dives. 16 divers in 2 groups each completed 6 dives. One group completed 3 control dives followed by 5 days rest then 3 dives preceded by exercise. The other group completed the opposite protocol. Flow-mediated dilation (FMD) data and blood for MP analysis was collected before and after each dive. VGE were monitored via transthoracic echocardiography 30, 60, and 90 min after surfacing. Exercise before diving consisted of 60 min running outdoors including 8x4 min intervals at 90% VO2max effort.
The purpose of this study is to determine the impact of high intensity,anaerobic exercise, in the form of cycling, on SCUBA diving. Outcomes are determined by the quantification and subtype of circulating microparticles, complete blood counts, and the quantification of venous gas emboli, measured via transthoracic echocardiography, in the cardiac cavities.