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Chapter 11
10
Divers who develop air embolism after free ascent or in submarine escape training, where a
recompression chamber is available nearby, are immediately recompressed to reduce the air
bubbles from their original size and so reduce the brain damage. The depth chosen will
depend on the severity of the condition. High oxygen pressures are administered to reduce
the bubble further. Otherwise,
transport
to a chamber must be arranged urgently.
There is some controversy about the best way to
position
the patient. Divers used to be
taught to place the patient in the 30 degrees head down position, to keep the rising bubbles
away from to the brain. This caused difficulty with resuscitation and transport however, and
the increased venous pressure in the head worsened the cerebral oedema (brain swelling)
which accompanies injury. It is no longer advised.
A more reasonable approach is to place the patient
horizontally
,
on their side
(the left side
is theoretically preferable but this is probably not critical) without a pillow. This will place
the head slightly lower than the heart. The patient is likely to be unconscious or drowsy and
this position is also good for patency of the airway. This is often called the
coma position
.
The patient should
not be allowed to sit up or stand up
once this position is adopted as
there are some case reports of divers rapidly deteriorating after sitting up, even some time
after the barotrauma event. This may be due to bubbles rising to the brain.
The patient should be given
100% oxygen
to breathe. After an hour of breathing 100%
oxygen, it is probably safe to allow him to assume a more comfortable position.
If the patient is unconscious the basic life support (
BSL
) priciples take precedence and
should be followed (see Chapter 42).
The
other complications
of burst lung, such as pneumothorax or emphysema, must also be
looked for and treated, if present.
The definitive treatment is
recompression therapy
in a well equipped chamber. Urgent
transport is necessary in order to minimize brain or other essential organ injury.
Unfortunately, even in the best facilities, full recovery is not always possible.