Balestra C.,DAN Europe Research Division |
Balestra C.,Center for Hyperbaric Oxygen Therapy |
Lafere P.,DAN Europe Research Division |
Lafere P.,Center for Hyperbaric Oxygen Therapy |
And 3 more authors.
European Journal of Applied Physiology | Year: 2012
One of the possible risks incurred while diving is inert gas narcosis (IGN), yet its mechanism of action remains a matter of controversy. Although providing insights in the basic mechanisms of IGN, research has been primarily limited to animal studies. A human study, in real diving conditions, was needed. Twenty volunteers within strict biometrical criteria (male, age 30-40 years, BMI 20-23, non smoker) were selected. They performed a nodecompression dive to a depth of 33 mfw for 20 min and were assessed by the means of critical flicker fusion frequency (CFFF) measurement before the dive, during the dive upon arriving at the bottom, 5 min before the ascent, and 30 min after surfacing. After this late measurement, divers breathed oxygen for 15 min and were assessed a final time. Compared to the pre-dive value the mean value of each measurement was significantly different (p<0.001). An increase of CFFF to 104 ± 5.1 % upon arriving to the bottom is followed by a decrease to 93.5 ± 4.3 %. This impairment of CFFF persisted 30 min after surfacing, still decreased to 96.3 ± 8.2 % compared to pre-dive CFFF. Post-dive measures made after 15 min of oxygen were not different from control (without nitrogen supersaturation), 124.4 ± 10.8 versus 124.2 ± 3.9 %. This simple study suggests that IGN (at least partially) depends on gas-protein interactions and that the cerebral impairment persists for at least 30 min after surfacing. This could be an important consideration in situations where precise and accurate judgment or actions are essential. © Springer-Verlag 2012.
Peeters A.,Paul-Henri Spaak College
Safety, Reliability, Risk and Life-Cycle Performance of Structures and Infrastructures - Proceedings of the 11th International Conference on Structural Safety and Reliability, ICOSSAR 2013 | Year: 2013
In any model, a large number of uncertainties has to be taken into account and they have to be combined. The way they are combined has a large influence on the uncertainties linked to the final result but also on the possible evolutions of the studied system. The Sti imulus-Driven Theory of Probabilistic Dynamics (SDTPD) allows investigating the different possible evolutions and the probability of each evolution.Nevertheless the SDTPD leads to complex equations. Hence, a computer code - MoSt - has been developed. It combines the SDTPD approach for the occurrence (or not) of events, a computing of the process variables for the system evolution and the Monte Carlo simulation techniques for the probabilistic aspect. Through a small example, this article presents the way uncertainties can be modeled thanks to the SDTPD and the results obtained with MoSt. Indeed, with this method, it is easily possible to combine various kinds of uncertainties but also to investigate the impact of numerous uncertainties. © 2013 Taylor & Francis Group, London.
Salem W.,Free University of Colombia |
Salem W.,Paul-Henri Spaak College |
Klein P.,Free University of Colombia
Manual Therapy | Year: 2013
Segmental range of motion (ROM) during high-velocity manipulative spinal treatment is generally considered an important factor for the risk of adverse side effects, especially in the cervical spine region. Among the many techniques reported, the so-called multiple-component technique (MCT) is increasingly recommended. Such a technique is assumed to induce a relatively low three-dimensional (3D) segmental ROM compared with other techniques. The aims of our study are to quantify the 3D segmental ROM and to determine the pattern of motion between cervical vertebrae during the pre-manipulative position at the C4-C5 level. Ten healthy volunteers participated in this study. Two CT scans were conducted: one in a neutral position and the other in the pre-manipulative positioning. The manipulation using MCT was carried out by a skilled practitioner. During positioning, the head was rotated to the left and bent laterally to the right, and the upper cervical spine was rotated to the left and bent laterally to the right. In contrast, the lower cervical spine underwent right rotation and was bent laterally to the right. Segmental ROM was lower than the values obtained during active physiological rotation (P<0.05). This study provides new insight into the 3D kinematics of the cervical spine during manipulation. An unexpected mechanism of counter-rotation was identified at the lower cervical levels and could represent a valuable and convenient way for precisely focussing on the level for manipulation. © 2013 .
Cialoni D.,DAN Europe Foundation |
Pieri M.,DAN Europe Foundation |
Balestra C.,Paul-Henri Spaak College |
Marroni A.,DAN Europe Foundation
Aviation Space and Environmental Medicine | Year: 2014
Introduction: Flying after diving may increase decompression sickness risk (DCS), but strong evidence indicating minimum preflight surface intervals (PFSI) is missing. Methods: On return flights after a diving week on a live-aboard, 32 divers were examined by in-flight echocardiography with the following protocol: 1) outgoing flight, no previous dive; 2) during the diving week; 3) before the return flight after a 24-h PFSI; and 4) during the return flight. Results: All divers completed similar multiple repetitive dives during the diving week. All dives were equivalent as to inert gas load and gradient factor upon surfacing. No bubbles in the right heart were found in any diver during the outgoing flight or at the preflight control after a 24-h PFSI following the diving week. A significant increase in the number and grade of bubbles was observed during the return flight. However, bubbles were only observed in 6 of the 32 divers. These six divers were the same ones who developed bubbles after every dive. Conclusions: Having observed a 24-h preflight interval, the majority of divers did not develop bubbles during altitude exposure; however, it is intriguing to note that the same subjects who developed significant amounts of bubbles after every dive showed equally signifi- cant bubble grades during in-flight echocardiography notwithstanding a correct PFSI. This indicates a possible higher susceptibility to bubble formation in certain individuals, who may need longer PFSI before altitude exposure after scuba diving. © by the Aerospace Medical Association, Alexandria, VA.
Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-2010-ITN | Award Amount: 3.40M | Year: 2011
Decompression sickness (DCS) is caused by circulating inert gas bubble formation in blood vessels and tissues resulting from supersaturation during inadequate decompression. It is an acknowledged risk of situations involving variations in ambient pressure, such as space flight and extravehicular activity, exposure to altitude, hyperbaric tunnelling intervention, as well as recreational and commercial underwater diving. Because new industrial challenges (human space flight programs, deeper planed tunnelling interventions and offshore oil excavation) and emerging recreational demands, the range of both environmental conditions and population characteristics involved in such activities regularly widen. Thus, new interdisciplinary approaches of decompression are needed to reduce risk for DCS. To foster knowledge of decompression phenomena, the PHYPODE ITN proposes to : - Develop an educational and research framework for cross-fertilization of currently fragmented research activities on physiopathology of decompression; - Give young researchers opportunities to share research techniques and resources, benefit from the best international scientists knowledge in this field, have the advantages of strong interactions between industry, medical centres and academia; - Widen career prospectives of young researchers by embracing the whole chain of research : from fundamental research for pathophysiological understanding of decompression to applied research in the industry for management of decompression. To achieve this training programme, academic partners, non profit association with worldwide activities, hyperbaric medical centres and industrial partners, with complementary expertises will build up the common agreed program concerning education and research.