Offshore saturation divers: vascular function and the effect of Vitamin C and E supplementation

The first blood and data sampling campaign held on the dive support vessel Skandi Arctic in 2015 (renamed Deep Arctic in 2016) resulted in the conclusion that no changes were found in the saturation divers post-saturation plasma levels of vascular health bio-markers after daily intake of vitamin C and E. However, a decrease in blood red cells; a down-regulation in the expression of genes involved in oxygen transport and up-regulation of endogenous antioxidants factors were found in the divers immediately post-saturation. These changes indicated an acclimatization to the elevated ppO2. The results were described in a paper published the 18th of July 2018 in the open access journal Frontiers in Physiology, section Environmental, Aviation and Space Physiology; titled: Blood Gene Expression and Vascular Function Biomarkers in Professional Saturation Diving. The project and results were also presented in the European Underwater Baromedical Society (EUBS) conference held in Geneva in 2016 and in a poster during the EUBS in Ravenna in 2017. The finding in the first Paper resulted in the organization of another blood and data sampling campaign, held on the same vessel in 2016 to investigate the hematological changes after saturation. In 2017, the candidate spent three months in Brussels (from early September to early December) under the Overseas Research Grant, for a collaboration with professor Costantino Balestra to work on the results. The collaboration resulted in a second paper, that concluded that the divers' blood erythropoietin (Epo) and hemoglobin (Hb) levels were reduced after decompression from commercial saturation diving, indicating a successful acclimatization to the hyperbaric hyperoxia (or high oxygen levels) experienced during saturation. Also, that the marked rebound of Epo levels 24 hours after decompression suggests fast re-acclimatization back to breathing normobaric air post-saturation. This paper was submitted to the same journal as the first, and was published the 21st of August 2018 under the title: Hemoglobin and Erythropoietin After Commercial Saturation Diving. The findings were presented during the Tri-continental Conference of Diving and Underwater Medicine in Durban, South Africa in September 2018. Professor Costantino Balestra and Mr. Jean Pierre Imbert also conducted parallel research activities funded by former Technip Norge (currently TechnipFMC) onboard the same vessel, in the same period. The Overseas Research collaboration permitted the researchers to work with the PhD candidate and produce a third paper, combining the finding of their respective researches. This paper is focused on the acclimatization of the saturation divers to hyperoxia and the subjective description of the divers of its effects on them through questionnaires distributed during the 2015 and 2016 offshore campaigns. This paper is published at Frontiers in Psychology journal, section Movement Science and Sport Psychology, and titled: Commercial divers' subjective evaluation of saturation. The thesis preparation started in November 2017, and the finalized version was submitted to NTNU's Medicine and Health Sciences Faculty for review in October 2018; titled: Commercial Saturation Divers: Blood biochemistry and perceptions of acclimatization to oxygen and oxidative stress; in saturation and back to surface. The thesis is currently under evaluation by the committee composed of: - Associate Professor Jacek Kot, Medical University of Gdansk - Research Director Frauke Tillmans, Divers Alter Network (DAN), Duke University - Associate Professor May-Britt Tessem, Norwegian University of Science and Technology The trial lecture topic "Controversial aspects of the normobaric oxygen paradox - pro and con" was received the 3rd of January 2019. The candidate defended her PhD thesis January 17th, 2019.

The results have been of relative importance to the discipline of diving medicine in general. It lay a basis for more future cooperation projects between the hyperbaric research group at NTNU and TechnipFMC. More research is being discussed with other Dive Contracting companies and operators, interested in deepening our understanding of the effects of saturation, and especially deeper dives. This would allow to control the conditions in a way to avoid any adverse effects on the divers, even when the depths exceed what is currently allowed in Norway.

Diving activities are of the utmost important parts of Technip Norway work. Given the role of the divers in the offshore oil industry, it is essential to establish safe hyperbaric exposure limits to avoid adverse impacts on their health and safety. Offsh ore saturation divers work and live in closed hyperbaric chamber systems for consecutive periods of approximately 3 weeks. The work consists of 6-8 hour shifts in the water, and the rest of the time is spent inside the dry hyperbaric chamber. The divers a re faced with elevated ambient pressure and frequent pressure changes as well as exposure to higher partial pressure of oxygen (ppO2 ) than in normobaric air. The underwater workers need to be physically fit and in good health to live and work under hyper baric conditions. A Norwegian study has shown that saturation divers who have experienced decompression sickness (DCS) during their working career have significant reduction in health related quality of life. DCS is however a rare event, but the developm ent of inflammatory biomarkers can be used as an index to evaluate physiological stress associated with asymptomatic (non-DCS) saturation diving. Reductions in ambient pressure cause the formation of vascular bubbles in the blood stream, these have advers e effects on the endothelial lining in the circulatory system. Omega-3 Fatty Acids have the ability to lower cardiovascular inflammation. The endogenous production of protective proteins triggered by omega-3 FAs may contribute to the cardiovascular defen sive action. The project will contribute to meet Technip objective to be a reference company in HSE and ensure that one of our most strategic activities are conducted in the safest manner. The outcome of this research will constitute a source of informat ion to the ongoing Fitness to Dive project run by NTNU under PETROMAKS program and the Offshore Diving industry in general.