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
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:
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
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
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
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: firstname.lastname@example.org
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