Delivered by Ingenta to: Guest User IP: 193.191.134.1 On: Thu, 02 Jun 2016 12:27:52 Copyright: Aerospace Medical Association RESEARCH ARTICLE 1044 Aviation, Space, and Environmental Medicine x Vol. 80, No. 12 x December 2009 G ERMONPRE P, PONTIER J-M, GEMPP E, BLATTEAU J-E, DENEWETH S, LAFÉRE P, MARRONI A, BALESTRA C. Pre-dive vibration effect on bubble formation after a 30-m dive requiring a decompression stop. Aviat Space Environ Med 2010; 81:1044–8. Introduction: The preconditioning of divers to reduce post-dive de- compression sickness (DCS) has gained increased interest in diving med- ical research over the last few years. The beneficial effects of physical exercise, oxygen breathing, hyperbaric exposure, heat exposure, hyper- hydration, or nitroglycerin administration before the dive are only a few examples of ongoing research. In this work, we investigated the effects of pre-dive whole-body vibration on post-dive bubble formation. Meth- ods: Following French Navy standard dive procedures, 14 healthy male military divers performed 2 identical dives 1 wk apart to 30 m of seawa- ter (msw) for 30 min. One of the dives was randomly preceded by a 30-min whole-body vibration session (frequencies 35-40 Hz) 1 h before the dive. Post-dive bubbles were measured precordially 30, 60, and 90 min after the dive and were graded according to the Kissman Integrated Severity Score (KISS) protocol, with and without knee flexing. Arterial endothelial function was measured before and after vibration using flow mediated dilation (FMD) measurement. Results: A significant reduction in bubble scores was observed after the “vibration” dive. Conclusion: As there was no observed change in FMD after vibration, we do not believe a nitric oxide mediated mechanism is involved; rather, a mechanical dislodgement or enhanced lymphatic elimination of gas nuclei is hypothesized. Keywords: scuba diving, decompression sickness prevention, bubble formation, whole-body vibration. T HE PREVENTION OF decompression sickness (DCS) in scuba diving is a matter of ongoing re- search. Although currently available decompression tables and algorithms are capable of reducing the risk of DCS, they cannot eliminate it completely (16). A substantial proportion of DCS cases are classified “un- explained” when the diver has complied with the proce- dures imposed by the chosen decompression model (dive computer or dive table). Because of this, a large body of research is currently directed at reducing the in- cidence of (micro) gas bubbles during decompression. However, research into the optimization of decompres- sion procedures is hampered by the large inter- (and even intra-) individual variability of post-dive decom- pression bubble formation (4). Another approach to reducing bubble formation after a dive is to “pre-condition” the diver prior to immer- sion. The general idea behind this approach is that post-dive decompression bubbles originate from the en- dothelial surface. Reports have been published on the From the Centre for Hyperbaric Oxygen Therapy, Military Hospital, Brussels, Belgium. This manuscript was received for review in June 2009. It was accepted for publication in September 2009. Address reprint requests to: Dr. Peter Germonpré, M.D., Centre for Hyperbaric Oxygen Therapy, Military Hospital Brussels, Rue Bruyn, 1 B-1120 Brussels, Belgium; peter.germonpre@mil.be. Reprint & Copyright © by the Aerospace Medical Association, Alexandria, VA. DOI: 10.3357/ASEM.2588.2010 Pre-Dive Vibration Effect on Bubble Formation After a 30-m Dive Requiring a Decompression Stop Peter Germonpré, Jean-Michel Pontier, Emmanuel Gempp, Jean-Eric Blatteau, Stefaan Deneweth, Pierre Lafère, Alessandro Marroni, and Costantino Balestra beneficial effects of pre-dive exercise (5,14), oxygen breathing (9), pre-dive hyperbaric sessions (19,24), heat preconditioning (6), hydration (15), and nitric oxide (NO) donor administration (13). Most of these experi- ments try to influence bubble formation by modifying biophysical or chemical properties of the endothelial surface, on which gas bubbles or nuclei are presumed to be forming. In this paper, we report the possibility of reducing post-dive bubble formation by a short bout of mechanical low-frequency vibrations of the whole body 1 h before the dive. METHODS The study protocol was approved by the Academic Ethical Committee of the Brussels Free University and by the French Navy Experimental Ethical Committee. After consent, 14 healthy male military divers (age range: 23-44, mean 29 yr, height: 177 6 6 cm, weight: 79.44 6 10.7 kg) participated in this prospective study. All divers were in good health, did not take any medica- tion, and had never suffered from DCS. They performed two identical dives 1 wk apart. Each dive was made in open (sea) water, to a depth of 30 m, for 30 min on the bottom with a calibrated effort during the dive (fin swimming at a determined leg frequency and speed). A 9-min decompression stop was made at a depth of 3 msw according to the French Navy standard diving procedures (MN90 diving tables). All subjects abstained from diving, smoking, or physical exercise for 48 h be- fore each dive. In a randomized fashion, one of the dives was pre- ceded by a whole-body vibration session of 30 min du- ration using a commercially available vibration mattress