The Naval Sea Systems Command (NAVSEA) has awarded Duke Anesthesiology’s Richard Moon, MD, a five-year $1,991,019 grant for his project titled, “Perfluoromethane as a Decompression Gas for Human Diving.”
Moon’s research focuses on reducing decompression risk following dives by utilizing an alternative breathing gas (perfluoromethane, CF4) during decompression from heliox dives. Confirming that CF4 breathing during decompression after heliox dives reduces decompression stress would be beneficial in one or both of two ways: (1) reduction of decompression sickness (DCS) risk for a given depth-time exposure; (2) increasing allowable bottom time for a given DCS risk.
The aims of this project encompass a comprehensive investigation into the safety and efficacy of utilizing CF4 as a breathing gas in both animal models and human volunteers.
“The anticipated product is a safe method of reducing decompression time after heliox dives, which can then be tested at scale to produce new decompression tables for both helium and air/nitrox diving,” says Moon, professor of anesthesiology and director of Duke’s Center for Hyperbaric Medicine and Environmental Physiology.“ Our research is expected to produce new data and new techniques that will advance decompression practice.”
In the study, several hypotheses will be investigated to provide valuable insights into the safety and efficacy of utilizing CF4-O2 in different scenarios. These hypotheses include examining histological analysis in rats previously exposed to CF4-O2 at 8 ATA to ascertain the presence of any abnormalities. Additionally, the research aims to establish the safety of human exposure to breathing CF4-O2 (80-20) at pressures of up to 6 ATA, while also determining the tolerability of narcosis levels experienced by divers at 6 ATA when inhaling 80% CF4. Moreover, the study will explore the potential benefits of transitioning from He-O2 to CF4-O2 before and during decompression from a dive to 160 fsw for 40 minutes with moderate exercise, with a specific focus on reducing decompression stress through assessments of venous gas emboli (VGE) and associated symptoms. Furthermore, the investigation will assess the tolerability of dyspnea and arterial PCO2 levels during CF4-O2 exposure in conjunction with submersed exercise at specific oxygen consumption rates, ensuring that all respiratory parameters remain within safe limits for human divers.