In the document “Static Metabolic Bubbles as Precursors of Vascular Gas Emboli During Divers’ Decompression: A Hypothesis Explaining Bubbling Variability”, the authors Jean-Pierre Imbert, Salih Murat Egi, Peter Germonpré, and Costantino Balestra say that the risk for decompression sickness (DCS) after hyperbaric exposures has been linked to the presence and quantity of vascular gas emboli (VGE) after surfacing from the dive. These VGE can be semi-quantified by ultrasound Doppler and quantified via precordial echocardiography. For a long time, equipment such as ultrasound dopplers and precordial echocardiography machines were cumbersome and extremely expensive. Also, operating them required a specific formation. Recent devices have been miniaturized so that their size is today comparable to the size of a laptop. Their prices have also been proportionally lowered, making them more accessible. Thus the main problem with these machines is that they cannot be operated by people who have not been taught to use them. However, this problem can be partially solved with the system O'Dive PRO, which is a portable doppler designed to be used by divers, that can contribute to increasing dive safety by making divers aware of the potential consequences of certain types of diving behaviour, according to doctors Peter Germonpré, Paul Van der Eecken, Elke Van Renterghem, Faye-Lisa Germonpré, & Costantino Balestra, who published a report entitled "First impressions: Use of the Azoth Systems O'Dive subclavian bubble monitor on a live aboard dive vessel". This paper is available on our website at this address: (scient-c_265-first-impressions_use-azoth-systems-o’dive- subclavian-bubble-monitor). It must be taken into account that the authors of the two documents above say that there is evidence that bubbles are present in most, if not all, decompressions without necessarily representing a threat to the diver. However, they also say that low VGE grades or the absence of VGE after a dive are statistically associated with a safe decompression. Based on this principle, the manufacturer proposes a service that analyses the number of VGE collected and provides a detailed report of the decompression quality.

The system comprises the doppler sensor, bottles with specific contact gel, and a data logger watch. The sensor operates with the O’Dive application, which can be installed on a tablet or a smartphone. Depending on the Operational System (OS), this application is available on Apple Store and Google Play. The doppler communicates with the tablet through wifi signals. The measurements are taken on the left and right subclavian veins 30 and 60 minutes after surfacing. The duration of these measurements is 20 seconds each, starting on the left side. During these periods, the diver is seated and instructed not to move and speak. the ultrasound gel is to be on the sensor before being positioned.

Before taking the measurement, the operator ensures that the tablet is paired with the sensor. When the sensor is positioned, the software displays an undulating yellow-red signal indicating the breathing rhythm to be followed and the signal quality. The 20 seconds recording can start when the sensor's positioning and the signal's quality are correct. If the recording quality is incorrect, the system indicates that the measurement must be repeated.

A presentation with embedded videos that shows these steps in detail can be downloaded and opened through this button.

To perform the second series of measurements (30 minutes after the first one), the operator selects “ New measurement” and press. Then, he selects “Current dive” in the menu so that all measurements are related to the same dive. Using the menu “My dive” the operator enters the dive’s parameters and store the data in the machine’s memory. The dives can be stored there as long as an internet connection with the O’Dive server is not possible. The operator also use the menu “My dive” to send the dives to the O’Dive server through the function “synchronize”. The server answers by sending a notification message indicating that the dive(s) has/have been analysed. The operator can access the analysis through the command “my results”. The report indicates elements such as the number of interventions, the bubble grades per intervention that are ranked from G0 (low) to G4 (high), bubble grade distribution, signals quality, and an overall evaluation of the quality of the decompression(s).

We consider that the data from this awesome tool are to be interpreted only by people recognized to have knowledge in decompression and familiar with the latest research in this domain. Of course, the diving medical specialist of the company should be involved, and a direct contact with O’Dive should be enabled to discuss these reports if necessary. Also, the implementation of this tool should be paired with the creation of a company database that could be consulted and evaluated by scientists. Of course, the diving teams should be involved, and a presentation of this tool is necessary to make it understood and accepted by the divers. Regarding this point, it must be noted that several diving and tunneling companies have successfully put its usage into force. Regarding the limitations of this tool, note that in the documents taken as a reference at the beginning of this discussion, it is said that VGE can be only semi-quantified by ultrasound doppler, which is why scientists often use precordial echocardiography, which is reputed more accurate. However, such a machine is not designed to be handled by non-specialists. Contact AZOTH: contact@azoth-systems.com Website: https://www.azoth-systems.com/en/home/