Purpose Data regarding decompression stress after deep closed-circuit rebreather (CCR) dives are scarce. This study aimed to monitor technical divers during a wreck diving expedition and provide an insight in venous gas emboli (VGE) dynamics. Methods Diving practices of ten technical divers were observed. They performed a series of three consecutive daily dives around 100 m.

INTRODUCTION: The preconditioning of divers to reduce post-dive decompression sickness (DCS) has gained increased interest in diving medical research over the last few years. The beneficial effects of physical exercise, oxygen breathing, hyperbaric exposure, heat exposure, hyperhydration, 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.

Purpose: Since non-provocative dive profiles are no guarantor of protection against decompression sickness, novel means including pre-dive “preconditioning” interventions, are proposed for its prevention. This study investigated and compared the effect of pre-dive oxygenation, pre-dive whole body vibration or a combination of both on post-dive bubble formation.

Vascular gas bubbles are considered the principal element in decompression sickness (DCS) development. Traditionally these bubbles were called VGE (venous gas emboli), however scientific knowledge indicates that similar bubbles may also be present in the arterial circulation, therefore we propose to use “VGE” for “Vascular Gas Emboli”, and we will do so throughout the text. Reduction of VGE production represents an interesting endpoint to decrease decompression stress and DCS risk. Here we will discuss state of the art pre-dive techniques and approaches, commonly known as preconditioning, used to reduce post-dive VGE load and decompression stress. Evidence based approaches clearly show that some types of preconditioning are more potent in VGE reduction, some indecompression stress reduction and there are some with a positive impact on both. Nevertheless, further research is required to investigate the mechanisms underlying these positive effects.

BACKGROUND: Using ultrasound imaging, vascular gas emboli (VGE) are observed after asymptomatic scuba dives and are considered a key element in the potential development of decompression sickness (DCS). Diving is also accompanied with vascular dysfunction, as measured by flow-mediated dilation (FMD). Previous studies showed significant intersubject variability to VGE for the same diving exposure and demonstrated that VGE can be reduced with even a single pre-dive intervention. Several preconditioning methods have been reported recently, seemingly acting either on VGE quantity or on endothelial inflammatory markers.