How to handle a freediver suffering blackout due to hypoxia.
by: Sebastian Naslund 2008  (sebastian @ freediving.biz)

DRAFT 4

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.

4) There is no proof that a "Freediver Laryngospasm" can opened by pressing air against it. The best procedure is to start with resolute and increasing BTT for at least 15 seconds, and if there is no signs of awakening, try a gentle RB.

5) Since most Freediver Blackouts seems to 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 or RB.  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.

Introduction
The freediver community (competetive freediving) has during the last 10 years developed many procedures for adding safety to freediving. Techniques an procedures
to handle blackout accidents caused by extended breath holds leading to hypoxia.
Yet the freediving world is divided on some details. Some say: "Go for a quick blow into the lungs" (a so called rescue breath) – others say: "It is impossible to blow air (against the supposed laryngospasm) into the lungs of a blacked out freediver".

There are differences in how safety techniques are being taught. Is there one right way? Have we found the ultimate response to blackout (BO)? No one could really say. There could be similar techniques that are different, but more or less equal in efficiency.

In this text I will address two issues regarding the handling of BO victims.
1) How efficient is the laryngospasm when it comes to keeping water out of the BO victims lungs?
2) Which is the most efficient technique when it comes to retrieving and “waking up” a BO victim?

Can I come to a final conclusion on this topic? Probably not. Science and new practical experience are all the time accumulating new knowledge.

Also, humans are different, we basically function the same way, but there are variations, based on genetics, and health issues (physical and psychological). So one approach might not be the best applicable to every situation. But I will in this text aim for the approach that is most general.

Background
Hypoxia - When we hold our breath we will reduce the amount of oxygen in lung, blood and tissues. At one point we will suffer the effects of hypoxia - these effects are basically: LMC (loss of motor control) and a few more effects like loosing: the ability to think coherently, vision, memory, color perception. At one point we will lose consciousness. This is not the start of dying, this is a last phase in a series of events aimed to conserve oxygen.
Unconsciousness or blackout - A continued lack of oxygen in the brain render a victim unconscious usually around a blood partial pressure of oxygen of 25-30mmHg (Probably at higher levels in non divers). Now we must understand that when medical doctors speak of unconsciousness it is often about an anesthetics unconsciousness, apart from that, there is talk of a semi unconsciousness. Concioussness is about brain activity. It is not an ?on or of switch?. Sometimes unconscioussness is categorized in certain levels (see the ?Glasgow coma scale? that has levels 3-15).
Scientists are starting to believe that the blackout freedivers suffer is a form of semi unconsciousness. I will use the term “freediver blackout” as something that differs from the clinical term unconsciousness, since there are more and more indications that there are differences. The BO situation in freediving is not the same as a struggling drowning scenario at surface by a non freediver, or a blow to the head where a person falls unconscious into water.

Laryngospasm (LS) - In the case of a freediver extending their breath hold into hypoxia and blackout we generally will see a closure of airways. The LS is a reflex that is there to protect the victim from drowning. It is a reaction to any fluid entering the throat.
It is not clear if this is a straightforward laryngospasm involving only the larynx as observed in clinical situations such as surgery and certain illnesses. The freediver “throat closure” could involve any combination of: Larynx, vocal cords and/or epiglottis. Apnea and chilling of the face may also induce bronchoconstriction. A respected scientist (Christopher W. Dueker) claims:
“A person who /…/ loses consciousness in the water will not have protective laryngeal reflexes.” and “ a breath-hold diver who loses consciousness will not develop laryngospasm”.

Yet we freedivers know out of experience that something seals - how else can we explain hundreds of observations of dry lung surfacings after BO at depth. I will in this text use the term: “freediver laryngospasm? (FLS) to define this phenomenon. Often it seems also the soft palate seals since we have seen so many cases of deep blackouts without even water in the throat.
Of course the soft palate can not seal if the head falls back. In his case the body has to rely only on the FLS to keep water out of the lungs (or the dive buddy controlling the head).

Drowning - If water would enter the lungs even in small amounts as a couple of deciliters, there is a risk of drowning. The water in the lungs prevents oxygen uptake (gas exchange). If hypoxia is prolonged by inhibited gas exchange in the lungs - then brain damage and death will occur. This can happen even hours after leaving the water – so called “secondary drowning” - due to lung oedema caused by water in the lungs This has to do with washing out of surfactants from the alveoli, or other lung damages.

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.