Rescue breaths

[x_yeti]

I was wondering what the latest sentiment in the freediving world is on rescue breaths? Most education systems seem to teach some form of rescue breath/s in the event a freediver doesn't resume breathing after a blackout (between 10 - 30 seconds). So I have 2 questions for you:

1) Should rescue breaths be used?

I've encountered 2 schools of thought here. Firstly there are those who believe rescue breaths should be used asap and that they help release a laryngospasm. Then there are those who believe that they don't help to release a laryngospasm and only CPR breaths should be used once the BO diver has been towed to land or onto a boat.

2) If rescue breaths are used, then how should they be delivered?

I personally believe in using a CPR method of delivering rescue breaths to release a laryngospasm i.e. steady, firm breath, delivered for 1 second and watching the chest to see if it rises. I've recently encountered another school of thought, where fast, hard breaths are used.

Opinions?

 

[monkeyhatfork]

don't know about the in water breaths for rescue diver in scuba they say do them- free diving was bought to blow across the face and taps on the cheek but thats assuming a proper buddy rescue were u have secured the airway. as for land based cpr when i did my emf certification they recommend not using breaths anymore that its more successful and delivers more oxygen doing just chest pumps at 100 per 60 sec the rebound flex from the compression vacuums in air(and cleaner more oxygen rich) than the dead air you are blowing into them. I mostly shore dive fairly long distances and its a long swim in at least 20 min so they are not gonna make it to cpr on land

 

[monkeyhatfork]

in trubridges "BREATH" documentary they show one his past blackouts and his safety diver grabs him immediately and gives him rescue breaths at an almost frantic pace. i've been bought both ways guess its dumb I've not put more thought into which i would use luckily not had to yet. a simple back out should revive quickly fairly quick if caught quick and airway secured

 

[hogphish]

In my opinion...so dont flame me... CPR and its frequent changes and evolution has been developed to address a pulseless victim in CARDIO/resp arrest. 99% of this population have pathological cardiovascular changes precipitating arrest. The typical freediver has a sound cardiovascular system and the primary event is hypoxia/hypercarbia, not cardiac arrest. Every blackout that I have witnessed still has a spontaneous heart beat. If the typical TTB times 3 fails to stimulate respiration then ventilation should be performed immediately in the water. If the diver can be oxygenated even at ambient 16% O2 this will often be all that is needed to overcome laryngospasm and preserve cardiac automaticity (keep the heart beating) so that compressions won't be necessary.

 

[Kars]

Nice question Yeti!

I'm looking forward to hearing the expert opinions and moreover the why do and why don'ts!

 

[Fitz-Clarke]

This is a very important topic. You should give in-water rescue breaths if there is hypoxic blackout lasting more than a few seconds. Don’t push the face underwater as you give the breaths. Statistics in drowning show that mortality increases with time to initial ventilation. Same can be expected for breath-hold diving. If you don’t have the skill to do in-water mouth-to-mouth ventilation effectively, learn it. It’s not difficult if you are wearing fins.

Start chest compressions once on the boat or deck if you cannot detect a carotid pulse within 10 seconds, and only after the initial series of ventilations. Maintain compressions and ventilations at a 30:2 ratio if alone, or ideally at 5:1 with two rescuers. If pulse is present, ventilate every 5 seconds. Positive pressure oxygen ventilation is best (bag-valve-mask connected to high flow oxygen). Don’t worry about laryngospasm. If present it can sometimes be overcome with adequate positive pressure, and will eventually relax. Laryngospasm will release if there is severe hypoxia or hypercarbia. So if laryngospasm is present, it might actually indicate potential for a favourable prognosis.

I like to keep an open mind, but so far I haven’t seen any convincing evidence that “blow-tap-talk” is effective for anything other than assessing initial level of consciousness.

Here is some background:

(1) David Szpilman who works with the lifeguard service in Rio de Janeiro looked at 29,000 water rescues over 6 years, of which they had good data on 46 drownings, median age 17. These folks have by far the largest volume of data on water rescues. Deaths and brain damage were less in the subgroup that received in-water rescue breathing (16 percent bad outcome) compared with those taken to shore before initiating resuscitation (84 percent bad outcome). Although the number of drownings in this data set is not high, the trend to better outcomes with IWR is significant, and makes sense.

(2) Drowning is a consequence of hypoxia. Consciousness is lost around arterial PaO2 of 30 mm Hg. Animal studies show that spontaneous breathing effort stops when PaO2 drops below about 20 mm Hg. Death follows several minutes later from secondary cardiac arrest, where heart rate and contractility drop progressively until beats are rare and there is no effective stroke volume or blood pressure. Ventricular fibrillation is uncommon in hypoxic arrest. It is generally good to have access to a defibrillator, but hypoxia tends to result in PEA, which is not a shockable rhythm. Ventilation, and chest compression if pulseless, are essential until re-oxygenation allows for cardiac recovery, manifested by increase of heart rate and blood pressure back to normal.

This is very different from sudden cardiac arrest on the street where the heart stops pumping (arrhythmia or ventricular fibrillation due to heart attack), but the lungs still contain a reasonable store of oxygen. These folks are usually over 40 or 50 years of age and have underlying heart disease. They need rapid restoration of circulation, hence benefit of immediate chest compressions. But a free-diver with hypoxic blackout would likely still have circulation for a while, but lacks oxygen.

(3) Compression-only CPR is NOT effective in hypoxic arrest. It makes no sense to circulate deoxygenated blood. Yes there is a small degree of ventilation forced by sternal compressions, but a profoundly hypoxic victim needs good ventilation as soon as possible. Even though exhaled air from the rescuer contains only 16 percent oxygen, that is much preferred over the small lung volume change induced by chest compression that probably barely exceeds dead space volume. American Heart Association and European Resuscitation Council 2010 guidelines specifically recommend against compression-only CPR for drowning:

“The first and most important treatment for drowning victim is alleviation of hypoxaemia. Prompt initiation of rescue breathing or positive pressure ventilation increases survival. Give five initial ventilations/rescue breaths as soon as possible. Rescue breathing can be initiated whilst the victim is still in shallow water provided the safety of the rescuer is not compromised… If the victim is in deep water, open their airway and if there is no spontaneous breathing start in-water rescue breathing if trained to do so… Give 10 - 15 rescue breaths over approximately 1min… If more than an estimated 5 min from land, give further rescue breaths over 1min, then bring the victim to land as quickly as possible without further attempts at ventilation.”

“Most drowning victims will have sustained cardiac arrest secondary to hypoxia. In these patients, compression-only CPR is likely to be less effective and should be avoided.”

 

[whiteminiman]

An interesting and comprehensive post, touching on key research from around the world.... Which is why I have a couple of questions....

Start chest compressions once on the boat or deck if you cannot detect a carotid pulse within 10 seconds, and only after the initial series of ventilations. Maintain compressions and ventilations at a 30:2 ratio if alone, or ideally at 5:1 with two rescuers.

The pulse check has been out for many years now, due to inaccuracies and difficulties in actually doing it. Current guidelines state to "look for signs of normal breathing" if it is not normal, start CPR.
Additionally, two person CPR is no longer recommended, nor the 5:1 ratio. Current protocol says stick with 30:2 and swap rescuers every couple of minutes to maximise effectiveness, rather than trying to synchronise working. Remember the majority of people will be lay-responders rather than health care professionals.

I like to keep an open mind, but so far I haven’t seen any convincing evidence that “blow-tap-talk” is effective for anything other than assessing initial level of consciousness.”

Yes, I've wondered about this too, and reached the same conclusion as you.

Thanks for a great post.
Dan

 

[monkeyhatfork]

I was emf certified a few months ago they said to abandon breathes as part of on land cpr as well and just chest pump. In an ideal situation if no breathing u might have emergency o2 on hand and could use that in conjunction but it was thought better to not break rythem of chest pumps. whent back and reviewed some course materials. FOR free diving i was tought talk tap blow pretty much does the trick within 10 sec often sooner and only on very very rare freak accurances would u need to go any further was bought that in most cases a laryngospasm will relax on its own but if after 10 sec. it has not 2 initial breath to release it and if no breathing then one breath at every 5 seconds till land but that this is extremely rare if proper safety/buddy rescue was in place. as far as evidence of it working i think they have gerenally seen blackout recovery within the first 10sec and site medical studies in which doctors use it on non-breathing infants suffering from sleep apnea but basically to use for 10sec then fall back to standard first aid cpr procedures.

 

[Kars]

So when the BO is detected by the safety diver, After how many seconds would you suggest doing rescue breaths?

Is there a time and place for the 'blow tap talk' technique?
For instance when a static diver bo's and is brought up near instantly.
In other words for short underwater unconsciousness time bo's.

Starting strait with rescue breaths is preferable when the underwater unconscious time is more then ... seconds?

On the other hand the underwater consciousness is a bit difficult to guess, because people sometimes keep 'swimming' a bit for a few moments when they actually already passed out. So grabbing a stalled diver at 10m,may mean that he already passed out at (rough guess) 15m, so the underwater unconscious time is the time the safety needed to bring the diver from 15m to the surface, say 15 seconds. In my experience each extra second of BO time, requires an hyperbolically increasing amount of recovery time.

Anyway I'm interested in hearing true experts explain all the ins and outs and correct my fuzzy thoughts.


Thanks a lot, its really helpful to get a better understanding of the mechanics involved.

 

[x_yeti]

Ok but what about laryngospasms? A freediving blackout is different to a drowning thus the blow-tap-talk. The BTT is done to help release potential laryngospasms. Rescue breaths that go straight into the stomach because of laryngospasms only complicate recovery.

Do rescue breaths help release laryngospasms and if they do, how would one deliver this type of rescue breath compared to a CPR style rescue breath?

 

[whiteminiman]

monkeyhatfork - With regards to the differences with your previous training, that is because there are differences between the American guidelines and the European/Asian guidelines. Both based on the same science - just a subtle variation about the importance of ventilations in cardiac arrest.

People repeatedly say that "freediving black out" is different to "drowning". I do not see that at all. In a medical context, they are identical. Drowning is the process of experiencing respiratory impairment due to immersion or submersion in liquid. A freediving black out is EXACTLY a drowning - under the new (updated 2002) definition of drowning.

World Health Organisation | Definition of Drowning

Freediving is the process of deliberately experiencing respiratory impairment due to submersion in liquid. Freedivers are looking to take it as far as they can without injuring themselves.

So a freediving blackout is EXACTLY the start of the drowning process.

Not all drownings involve inhalation of water. Not all drownings involve laryngospasm. Laryngospasm is poorly understood - and certainly by the time a body is being examined by a coroner - there is no way they can tell whether the larynx was in spasm or not. There is not a lot of evidence either way for the occurence of laryngospasm in drowning.

To my mind - "blow tap talk" is the freediving equivalent of checking for responses and asking "are you allright" and checking for breathing.

http://www.resus.org.uk/pages/bls.pdf

(see page 27-28 for the drowning specific comments)

You have ten seconds to check for normal breathing. If they are not breathing normally, then CPR should be started. In the case of a drowning (which is EXACTLY what we are dealing with) the recommendations state that five rescue breaths should be done prior to starting chest compressions.

Obviously, we cannot do chest compressions in the water. I would suggest that by following the guidelines, we would attempt five rescue breaths - and then get the injured freediver out of the water as soon as possible.

If they obviously loose consciousness under the water, then I'd be happy that the act of the safety diver grabbing them, and pulling them to the surface counts as "checking for responses", and I would go straight to five rescue breaths.

A rescue breath is simply one person breathing into another person. There is nothing special about; there aren't any different types of it. You can breath through their mouth, or through their nose. You breath gently.

Too many people "blow" into their casualty. You do not need to do this. Read the guidelines. You should effectively be "breathing out" into the casualty - no greater volume and no greater force than your own *normal* breathing.

This may or may not release the laryngospasm (which may or may not be there), but if you are gentle - then minimal air will enter the stomach.

I refer to the Utstein Guidelines for the reporting of drowning incidents... available here:
Recommended Guidelines for Uniform Reporting of Data From Drowning

This is the important part of the text:

The drowning process is a continuum that begins when the victim’s airway lies below the surface of the liquid, usually water, at which time the victim voluntarily holds his or her breath. Breathholding is usually followed by an involuntary period of laryngospasm secondary to the presence of liquid in the oropharynx or larynx.31 During this period of breathholding and laryngospasm, the victim is unable to breathe gas. This results in oxygen being depleted and carbon dioxide not being eliminated. The victim then becomes hypercarbic, hypoxemic, and acidotic.27 During this time the victim will frequently swallow large quantities of water.32 The victim’s respiratory movements may become very active, but there is no exchange of air because of the obstruction at the level of the larynx. As the victim’s arterial oxygen tension drops further, laryngospasm abates, and the victim actively breathes liquid.33 The amount of liquid inhaled varies considerably from victim to victim. Changes occur in the lungs, body fluids, blood-gas tensions, acid-base balance, and electrolyte concentrations, which are dependent on the composition and volume of the liquid aspirated and duration of submersion.27,33,34 Surfactant washout, pulmonary hypertension, and shunting also contribute to development of hypoxemia.35,36 Additional physiological derangements, such as the cold shock response, may occur in victims immersed in cold water. Water that is 10°C or colder has pronounced cardiovascular effects, including increased blood pressure and ectopic tachyarrhythmias. The response may also trigger a gasp reflex followed by hyperventilation, which may occur while the victim is underwater.37

A victim can be rescued at any time during the drowning process and may not require an intervention or may receive appropriate resuscitative measures, in which case the drowning process is interrupted. The victim may recover from the initial resuscitation efforts, with or without subsequent therapy to eliminate hypoxia, hypercarbia, and acidosis and restore normal organ function. If the victim is not ventilated soon enough, or does not start to breathe on his or her own, circulatory arrest will ensue, and in the absence of effective resuscitative efforts, multiple organ dysfunction and death will result, primarily because of tissue hypoxia. It should be noted that the heart and brain are the 2 organs at greatest risk for permanent, detrimental changes from relatively brief periods of hypoxia. The development of posthypoxic encephalopathy with or without cerebral edema is the most common cause of death in hospitalized drowning victims.38,39

That to me... pretty much describes freediving when it goes wrong... so why do we keep saying "it's different"?

Regards,
Dan

 

[Fitz-Clarke]

You are correct about maintaining the 30:2 ratio. Disregard my comment on the 5:1 ratio. The main point is to keep it simple and consistent in the field.

The recent change to 30:2 ratio for basic life support was made for several reasons:
(1) cardiac output during CPR is at best about 20 percent of normal, so the necessary ventilation rate under low-flow conditions was decreased accordingly, since a higher rate does not add to gas exchange.
(2) rescuers were pausing or interrupting chest compressions for the ventilation, which is very bad because it takes 10 seconds or more to restore blood flow after compressions are paused, due to the mass effect of blood inertia.
(3) overly frequent or excessive positive pressure ventilations increase intrathoracic pressure, and have been shown to impede venous return of blood to the heart during chest compressions.

So keep 30:2 going, don’t pause or interrupt compressions and, as you say, swap rescuers often because maintaining hard fast chest compression is tiring, and effectiveness tends to drop after a minute or two.

The pulse check after initial ventilation was eliminated because it can be difficult and unreliable for the average non-professional rescuer. CPR standards are based on the far more common “man on the street” who typically collapses from cardiac arrest. I would still do a pulse check for a relatively fresh hypoxic arrest because there is still likely to be circulation. But if in doubt, start compressions. If you find a decent reliable pulse, you are good. Just keep ventilating to reverse hypoxia.

The essential point is that free divers experience hypoxic respiratory arrest. Cardiac arrest may follow a few minutes later if there is untreated apnea after blackout. So our situation is not “man on the street”, but falls into the category of drowning resuscitation. That approach is different as quoted in the earlier posts.

 

[Fitz-Clarke]

I’m not saying that blow-tap-talk is useless. Just that I haven’t seen anything scientific that would support it. I never heard of it until I got involved in free diving. I would call it anecdotal. I’m not sure where the idea comes from. If someone responds after BTT, you would never know if they could have recovered anyway. It would be difficult to do a randomized study comparing response with and without it. But first I would want to see the evidence, or at least evaluate stories, if at least it appears to work somehow. I would be interested to hear more.

In my limited experience, free divers either start breathing after a few seconds on the surface owing to the lag time from lung to brain, or they have a prolonged blackout from complete loss of respiratory drive, usually from a deeper underwater blackout involving more severe hypoxia. There doesn’t seem to be much middle ground.

Physiologically, I think of it in terms the respiratory drive curve as PaO2 is lowered. Consciousness is lost when PaO2 drop below 25-30 mmHg. Ventilatory drive increases and reaches a peak around PaO2 of 20 mmHg, at least in animals. Then there is a fairly rapid drop to complete apnea somewhere around 15 mmHg. Below that, agonal breathing kicks in with infrequent gasps. This is a primitive brainstem response seen most clearly in newborn animals, where it is called “autoresuscitation”. We see it in the late stages of patients dying when life support is discontinued in the hospital. Agonal breaths can in rare cases be life saving, but are marginal at best. It’s like sitting on a knife edge between life and death. These people still need resuscitation.

An agonal breath could in theory account for some free divers responding spontaneously after a bad blackout without rescue breathing.

 

[monkeyhatfork]

I wouldn't say its anecdotal its a technique borrowed from hospitals as to how much sooner it wakes someone that would likely come out of the blackout after x amount of seconds anyway who knows

 

[Fitz-Clarke]

Okay. What I mean is tap and talk make sense. It might encourage someone to breathe sooner if there is a few seconds of delerium during recovery. Like yelling it might get attention. It also allows you to assess level of consciousness.

But it’s blowing on the face that doesn’t make sense to me. If you blow on a baby’s face, it will stop breathing for a few seconds. That’s part of the diving response. It seems counterproductive as a means to stimulate breathing. I still think the blowing part is anecdotal. There's no harm as long as it doesn't result in delay to resuscitation, but I'm skeptical that blowing on the face would have a significant effect on an adult.

 

[cebaztian]

On the issue of rescue breath, I am an agnostic until proven wrong.

A freediver blackout is something else than a drowning scenario.
I believe that we shouldn´t even be talking about drowning or comparing to drowning. You can find arguments for that in the link below,

Once the freediver laryngospasm is gone, breathing will start and CPR breaths are not needed.

I believe that the freediver laryngospasm is something extremely strong that can not be removed by the physical pressure of air against epiglottis/vocal cords.

I believe that doing rescue breaths in water has a BIG risk of making water drip down the throat and prolong freediver laryngospasm.

When a freediver starts breathing directly after a rescue breath (RB) I believe it is not because of the rescue breath per se, it is because rescue breaths does similar things as BTT.
Time, sound, talk, touch, air - affects consciousness and consciousness decides to let go of freediver laryngospasm.

I believe that a black out freediver can not be awaken in a second or five. I believe that TIME is an issue, that whatever we do, there has to pass a certain time, depending the level of BO.

Use that time wisely - avoid pressing air or risking water in the throat during that time.

My suggestions on what to do you can find in the link:

In short:
How to handle a freediver suffering from blackout

Sebastian

 

[whiteminiman]

Hello Sebastian,

On the issue of rescue breath, I am an agnostic until proven wrong.

I read the text at the link with interest. The only difference between a freediving blackout and a drowning is the motivation of the individual. A freediver is choosing to "balance on a knife edge", and the drowning individual wants to get out. There is no comparison to drowning. It is drowning.

I believe that we shouldn´t even be talking about drowning....

I believe that a black out freediver can not be awaken in a second.....

I believe that the freediver laryngospasm is something extremely strong....

I believe that doing rescue breaths in water has a BIG risk of making water drip down the throat and prolong freediver laryngospasm.

There is some very good scientific evidence based on thousands of in-water resuscitation attempts that says it is a good thing to do IF you have buoyant support and fins. Have a look at the scientific evidence (not belief) here:

[ame="http://www.slideshare.net/ILS/03-21-ppt-david-szpilman-in-water-resuscitation"]In-water resuscitiation: What are the highlights and pitfalls?[/ame]

http://www.sobrasa.org/campeonato/matosinhos_2007/apresenta/in-water_drowning_portugal_2007.pdf

Those two links above are the same content - just different formats, and are from the presentations that Szpilman & Handley gave at the 2007 World Conference on Drowning Prevention in Portugal. Those two guys are the best in the world on this topic.

Here is the paper that sits behind that presentation.

http://telagakura.net/web/resources/medical/szpilman.pdf

This is one of the most interesting things that I find about freediving. There are many people on this forum who are expert freedivers with deeply entrenched views on "freediving science". When we start to dig into the science we find that is down to anecdotal evidence, based on a couple of things that happened to a couple of divers.

There are undoubtedly different things happening to the body when we freedive, and things that are very hard to test. But the "it's different" argument is too easy to put up, without any evidence.

How to handle a freediver suffering from blackout

So some questions to the conclusions that you reach in your article. The questions are numbered in the same way your conclusions area.

1) What evidence do you have for this statement?

2) Where is the evidence to show the "repeated examples"?

4) Is there any proof that it cannot be opened by air pressure against it?

I don't think we should see BTT as some magical technique that makes anything happen. I wouldn't be surprised if we could apply a sternal rub, or supra-orbital pressure and achieve the same results. We should see the BTT as the freediving version of the normal "checking for responses" that we do in normal land based CPR.

Great thread, with some really interesting contributions.

 

[x_yeti]

Great contributions so far!

One last point that I'd like to debate. The nature of the rescue breath. Everyone so far seems to have described CPR style rescue breaths i.e. natural breathing pressure for short duration. Any idea where the hard, fast breaths to release a laryngospasm school of thought originated?

I found this article (Laryngospasm | voicedoctor.net) that describes The Bernoulli principle. As far as my limited brain can make out it would seem that hard, fast rescue breaths will actually strengthen a laryngospasm.

 

[Mullins]

One big difference: drowning victims will have been under water a lot longer, on average, than freedivers. If the laryngospasm only endures for a short time, it would be much more relevant to freediving recoveries than drowning recoveries.

 

[Fitz-Clarke]

Sebastian, your article is very interesting and thought provoking. It’s probably the most comprehensive discussion of the topic, and proposes a paradigm shift in rescue philosophy. I would like to know where your information and conclusions come from. I assume from personal experience.

A good point was made that many drowning victims are found late, having perhaps already passed through these stages. We rarely have the luxury of observing distressed swimmers to this degree. Whereas witnessed free diving blackouts provide a unique window into this physiology, particularly episodes that are prolonged.

You suggest:
(1) laryngospasm is common in free diving blackout
(2) allow it to relax and wait for spontaneous breathing

I appreciate that you might be comfortable waiting a little while to intervene, but the medical and scientific community will not accept this without reliable evidence. There is a burden of proof. For your approach to become mainstream and supercede present standards for in-water resuscitation described earlier, we would really need to formally document many cases and address some issues with some statistics:

- what percentage of diver blackouts involve laryngospasm
- who gets laryngospasm and what are the triggers
- how long does it take to relax in the free diver
- how often does adequate spontaneous breathing resume
- how do these recovery events correlate with O2 and CO2 levels
- do free diver responses to severe hypoxia differ from untrained individuals
- how much time can pass after BO until brain injury or cardiac arrest

I would say that there is presently little or no quantitative human data to provide these answers.