If the
victim breathes under water (if passing from a
“freediver blackout” with FLS to a stage into full
unconsciousness where the FLS releases - the lungs
will fill up with water. If the larynx relax due to
hypoxi in that muscle, we might be as low as 30%
saturation which are really serious levels.
Reviving a person that has water in their lungs is
very hard, especially if there is no oxygen
apparatus (with pump) available and hospitals are
far away. I will not pursue this scenario further
but return to the issue of laryngospasm.
How long does the laryngospasm or FSL last?
The laryngospasm (LS) is nothing but a survival mode
based on the reaction to water in the throat. There
are no secure data on how long a LS or a FLS lasts.
The estimates that have been done by doctors and
scientist are that the laryngospasm in drowning
generally can last up to 2 minutes. There are cases
where it has lasted for up to half an hour and when
the person has survived brain damage thanks to
hypothermia slowing down bodily functions and
metabolism (surely also the dive response has been
involved in this case).
We freedivers have seen FLS´s that has lasted long
after surfacing from a deep blackout, incidents of
up to a minute has been reported. There are of
course cases where the laryngospasm has lasted less
than 2 minutes.
The issue for us freedivers is: how much time do we
have to get the victim to the surface?
Time frame of rescue operations
To say
that this FLS is foul proof, and lasts for two
minutes would be inaccurate and irresponsible.
Retrieval of a BO victim back to the surface should
of course be done as fast as possible.
I would add to his that there is a point in doing
this as peaceful as possible, since the human is not
only a physical machine but a psychological machine
and that the way the body is handled can have
effects on how long the freediver stays in FLS (I
will address this more later).
In a worst case scenario if a blacked out body is
lost out of visibility, maybe sinking to the bottom
or to the bottom plate (slightly out our reach) -
our rescue operations should work towards a 60-120
second time frame. It could be worth using a few
extra seconds for suitable preparation to do a full
hearty rescue, than just zoom of unprepared and
uncoordinated with other available human resources.
It is
important to point out that it is the actual fast
retrieval of the body to the surface that is the
primary object, not the finesse of doing it. We don
not know when full unconsciousness and release of
FLS will start. It can happen at any time.
Do we have to control the position of the head
and close airways while retrieving under water?
Yes if possible we should control the position of
the head, since we want to stop the head from
falling back which would lead to the opening of the
mouth and soft palate and would let water enter the
mouth, sinuses and throat. This water can be felt by
the body and prolong the FLS and later the water in
the throat can enter the lungs creating risk of
secondary drowning. But, then again, it is the fast
retrieval that is important, not he finesse in doing
it.
As seen in baby swimming the laryngospasm and
sealing of soft palate is instant and usually very
effective if water enters the throat. In children
below 6 months of age there is also an apnea reflex
when water touches the face. The competitive
freediving community has seen many divers BO under
surface (down to 25 meters) coming up and breathing
happily after only a few seconds or in extreme cases
after a minute more or less. A few coughs and
clearings of the throat, and generally the FLS has
worked as “intended”.
I will
mention a few incidents of dry surfacings after deep
BO, out of the top of my mind: Hubert 10 m Ibiza
2002, Wolle 18m Dahab 2005, Alex 20 m Dahab 2005,
Natalia 15 m Dahab 2006, Klara 22 m Lysekil 2006,
Kiara 17m Hurghada 2006, Anabel Hurgada 2006, Enzo
25 m 1970, Simoni 18 m Sardinia 1998, Panos 24 m
Greece 2003/04, Tom 22 m Canada 2003, Mandy 15 m
Canada 2003. I assume there has been lots more since
these are the ones I have seen or heard of. I have
heard of no competitive freediver swallowing water
in a deep BO (apart from the three No limit victims
we have had, and Buyles No Limit accident).
“The deepest I have ever seen anyone black out was
25 m /…/The person recovered within 15 s of hitting
the surface”, quote Kirk Krack, freediving coach.
Water in the lungs is always a possibility at an
early stage of a freediver BO, but I will argue that
problem is actually the opposite: how to stop the
FSL and make the person start breathing again when
at surface.
Freediving is different
If reading scientific abstracts most suggest victims
release their laryngospasm when becoming unconscious
or some time after.
“In most victims the laryngospasm relaxes some time
after unconsciousness and water fills the lungs
resulting in a wet drowning”, Christopher Dueker
(MD)
I have further up in the text pointed to situations
where this has not happened, and I have argued that
both the unconsciousness and the laryngospasm is
different in the case of advanced freedivers in deep
BO´s – since we have seen so many dry surfacings and
no deep blackout victim in a competition never
releasing their FLS under water. Some have released
air, other have not. Some have had their airways
protected, others not.
So making deductions from studies of drowning
scenarios can be partially or totally wrong.
Drowning itself is common, but hard to study. No one
is there to measure the length of a laryngospasm and
exactly when it is established. Many observations
are from laryngospasm happening in clinical
situations (surgery e t c).
There is also a confusion regarding what kind of
closure is happening and what parts are involved:
vocal cords, larynx, epiglottis.
The word hypoxia is used in a sloppy way, no
distinct values are mentioned in most cases.
Advanced freediving is unique.
1) Freedivers are trained to function during
hypoxia.
2) In some cases a freediver can have lack of oxygen
in the brain but less so in the body, or vice versa
(since freedivers fiddle with techniques
controlling: vasoconstriction, vasodilution, PH
values, hemoglobin values e t c).
3) Freedivers out of habit use their epiglottis
while holding their breath.
4) There is much less struggle when a freediver is
closing in on a blackout compared to most drowning
situations.
5) Freedivers are also used to resist the breathing
reflexes for extended periods of time.
6) Their mammalian dive response is also stronger
than in normal people. One can guess that generally
freedivers save more oxygen before and possibly
during blackout (more oxygen is directed towards
the brain.
Further more: scientist uses terminology that is
somewhat confusing: unconscious, semi-unconscious,
blackout. Is there a difference? Yes.
Unconscious but partially aware
Even
the word unconscious is misdirecting since there is
consciousness in the unconscioussness of a blacked
out freediver: we hear, we feel, we dream (the brain
is not a shut down computer).
The adverse effects of rescue breaths
Today many instructors and safety freedivers are
using a so called rescue breath nearly directly when
the victim comes to the surface. A technique that
comes from CPR. Most clinical literature advice
rescue breaths on unconscious non breathing
patients. A term used is often: "a slight pressure
will open a laryngospasm". But as stated above, this
advice is not with a freediver blackout in mind, and
we do not know if it is an airway obstructed by what
is normally considered a laryngospasm or how deep
the unconsciousness is.
I will argue that:
1) Every rescue breath in water is risky since you
might make water enter the mouth and throat and this
will prolong a FSL.
2) Every rescue breath also has a risk of pushing
the possible water in the mouth/nose/sinuses further
into the lungs.
3) Every rescue breath also has a risk of pushing
air into the stomach triggering a vomit - a vomit
that can end in the lungs causing secondary
drowning.
4) Getting air blown into you might feel like an
“attack”, creating a stress that prolongs the FSL.
The laryngospasm is a biological reflex created by
evolution to stop the opening between lung and the
outside world when submersed. Maybe it is not
sensitive to if the pressure on the larynx/vocal
cord/epiglottis comes from water or from an inblow
of air. It is most likely the mechanism of FLS was
not evolved taking CPR/ auxiliary breathing and
in-blows into consideration.
How to open/release the Laryngospasm
It is my belief that a laryngospasm CAN NOT be
opened by a rescue breath and pushing air against
the epiglottis/vocalcord/larynx. These small muscles
are far too strong to be controlled/broken by an
inblow. Surgeons commonly uses different
medicine injected into the larynx area to loosen up
the muscle.
During Nordic Deep Competition 2006: Johan Andersson
(a biologist specializing on diving mammals/humans),
a hyperbardoctor/ Anesthesiadoctor and scientist
(Mats Linér) and a first aid medic (Daniel Fjöjt) -
explained to us that it is difficult to blow passed
a laryngospasm (that blocks the airway). Air is
likely to end up in the stomach. Experienced
freediver Wolle Neugebauer had investigated the
subject and claimed the same.
This
strong muscle will only release:
1) When the oxygen for that muscle has run out.
2) When hypoxia (unconsciousness) is so deep that
the autonomous nerve system stops functioning.
3) By any strong alerting stimulus from the outside
convincing the victim that breathing is safe.
Remember: the unconscious brain is not a shut down
computer; several functions are working during BO,
such as touch and sound sense perception.
Since there is also dreaming during BO, the brains
conceptual functions are to some degree functional –
just as we can be aroused from sleep – we can be
aroused from a freediver “black out”. People can
hear during mild unconsciousness, just as they can
hear during sleep or in many reported cases when
they have been put to sleep during surgery.
There may be vivid and strong dreams in a freediving
blackout competing for the attention, but you can
get through and communicate with the subconscious of
an unconscious mind.
So why does a rescue breath (RB) sometimes work?
Easy answer: because it resembles a technique called
BTT. Touch stimuli and air around the nose/mouth.
But the RB is a cruder less sophisticated way. BTT
is more refined and efficient at the early stages of
a blackout.
The BTT (blow tap talk).
This is BTT:
1) Expose the face to air - remove all facial
equipment (mask, noseclip, goggles).
2) Stimulate the breathing by blowing hard and close
to the face (nose, eyes).
3) Talk to the subconscious (make the victim feel
safe, use their name, tell them where they are and
that they are safe and that they can start
breathing).
4) Contact the subconscious by touch. Tap cheeks,
squeeze arm, even stroke and caress, it is about
making the victim feel safe, safe enough that they
“by themselves” (subconsciously) releases the FSL (laryngospasm).
Some
parents of infants in danger of “sudden infant death
syndrome” are advised to blow on the face of infants
that goes into “apnea state”. The effect is usually
instant, such as in many BO freediver cases – the
victim feels the air and starts breathing.
We as safety divers can not open the FLS, we can
stimulate the victim to do it by themselves.
If BTT is done thoroughly and repeatedly it does
work. If it does not work immediately the RB will
neither (it might not be the airpressure that opens
the FLS, but the similarity to BTT). If no signs of
breathing is detected it is a question of increasing
the BTT stimuli and more communicating with the
subconscious mind of the victim, by touching and
talking.
If BTT does not work?
If BTT does not work during the first 20-30
seconds after surfacing, it is a good idea to do
something else (since every case is not a general
one). A rescue breath could be the kind of new
stimuli that will get through to the victim.
The right rescue breath
A slow blow with your lips around the victim´s nose
and your hand firmly over the closed mouth, balanced
with a hand under the neck. A grip under the neck
that makes the head fall backwards and open up the
soft palate. This is important.
Blowing through the mouth also works, but if done in
water, then the nose is a more controlled area where
water can be kept out. The sinuses also gives more
friction for the airflow which slows it down and
reduces the risk of the airflow to take the turn to
the stomach.
If you feel you can blow air into the victim and the
victim is still unconscious then we have a CPR case
(which is not discussed in this text).
Conclusions
1) The general freediver blackout is not as deep as
the unconsciousness talked about in drowning
scenarios e t c. And it does not mean the the BO
victim is a non perceiving shut down machine.
2) The “freediver laryngospasm” is a reflex
that is there to protect the victim from drowning.
It has repeatedly been seen lasting longer than
stated in many scientific texts regarding drowning.
3) The main problem with a deep freediver BO is not
the risk of water in the lungs. The main challenge
is making the diver breath again when at surface.
3) The FLS might not be opened by pressing air
against it. The best procedure is to start with BTT
at least for 20 seconds, and if there is no signs of
awakening, try a gentle RB.
The
conclusions above are not supported by clinical data
or laboratory tests. But neither are the opposite
ideas about reviving freediver BO victims with so
called rescue breaths copied from the CPR procedure.
The idea of a quick rescue breath directly is
appealing: it is action, you as a rescuer feel that
you are doing something very professional. You come
a cross as a decisive person. It sounds good: a
rescue breath - it will rescue. It also resembles
what we have seen “millions of times” in TV-dramas
(which is not a good source of accurate
information).
BTT on the other hand is slower, more gentle.
Talking and touching a person that is unconscious
just comes across as silly. They don´t feel/hear do
they? Blowing in the face even sillier, do you
think that air will enter the lungs if you just
blow?
So far
there has been little interest in understanding, or
resources to explore the laryngospasm in trained
freedivers. We as thinking freedivers are the ones
in a position to pose hypothesis. To our help we
have the hands-on experience of seeing/hearing about
hundreds of shallow- and deepwater blackouts where
close to all are taken to the surface with dry
lungs.
Further ideas on improving the revival situation of
a BO freediver.
1) An
apneadoctor suggest that in a FBO situation it might
be more rewarding increase pressure on the inside:
thorax compression. Heimlich maneuvre? This has not
been tried.
2) An
other creative suggestion is that unconsciousness
could be broken by pain stimuli. Doctors may I
clinical situations "inflict" pain on a patient to
see how deep the unconsciousness is. If this
approach is useful in freediving or not, is not
known.
3) One of the most interesting propositions comes from swedish doctor/freediver Sven Grauman. Since most Blackout freedivers do not "wake up" within 10-15 seconds - whatever we do - we could use those seconds to MOVE the victim to safer ground where more actions can be taken. In practice: haul the body onto a low platform instead of BTT. Maybe the TIME itself and the moving of the victim is as effective as BTT. The body is touched, there are sounds, there is wind - stimuli that might work nearly as well as direct BTT. And if there is no natural wake up we now have the body out of water on stable ground and several actions can be taken that are either impossible or risky in water:
1)
Check heart rate.
2) Breathing movements.
3) Eye movement.
4) Level of consciousness
5) Do intra-thoric pressure instead of outer.
6) Or a rescue breath far away from water.
7) Oxygen apparatus is also close by.
This text is a hypothesis that has been commented by:
Erika
Schagatay (Professor in Animal Physiology,
specialized in human apneic diving, Mid Sweden
University)
Peter Lindholm (Scientist/doctor at Karolinska
Institutet)
Sven Grauman (MD)
References have been made to:
Johan Andersson (PHD scientist at Lund university)
Mats Liner (Anesthesia doctor at Lunds university
hospital)
Daniel Flöjt (first aid medic instructor, Åland
Sweden)
Christopher Dueker (MD)
Facts on drowning, hypoxia, laryngospasm have been
picked from:
Wikipedia and scientific abstracts found on
internet.
