my shallow water blackout nightmare

[Mullins]

That could make for quite a dangerous balancing act for those looking for max performances. They would presumably want to push CO2 levels to a point just below that at which they would be too narked to return efficiently to the surface (unless they were going down the FRC route or similar). An element of that came through in Will's thread on his CNF attempt - he mentioned that narcosis was a sign he had done his ventilation properly.

I don't know about 'impending doom' but a definite feeling of unease has been associated with my experiences of narcosis. While I know intellectually that my body is capable of these dives, when I'm at the bottom of the descent line with sore legs and a strong urge to breathe the idea that I'll ever be able to make it back to the surface suddenly seems laughable.

Sorry, didn't mean to hijack this thread - this is sort of relevant to the general question of whether packing is a good thing or not, but this level of detail has shoved the other questions around ventilation, surface interval, safety procedures etc into the background a bit...

[SEDATE]

Originally Posted by efattah

Narcosis acts much like alcohol, affecting the NMDA receptors in your brain (NMDA = N-Methyl-D-Aspartate). By inhibiting the NMDA receptors, the brain activity is slowed down; thinking slows, and brain O2 consumption also slows.

Eric
many years, about 20-25 years taking alcohol increase apnea ability in humanbody?
i know a person he was alcolic man before and give up drinking 3-4 years ago , as far as i remember, that person i know spearfishing now and has a very good deep times 2.30min-3.30 min around 15-20m,is this strange?

[DeepThought]

PM'ed this to lungfish, hoping to put all of this behind us.
-------------
My apologies if for some reason my post has seemed ego-driven. We have had a few disagreements in the past but all seemed strictly technical from my side and none of them left me with any negative emotions towards you. I'm sorry if my previous post was accidentally percieved as a way to get back at you or an invitation for ganging up on you (which I don't think had happen, knowing the people involved). I was truely intending to voice up an opinion supporting a certain line of thought that happens to cntradict yours, none of it was personal.

You might find it as a surprise but technical issues and arguments aside, I found a kindred spirit in you when it came down to the essence of freediving. Your open invitation to your hawaii house for freedivers, your reports of animal encounters, your good eye for nature and animal behaviour, your serial recreational freediving, your drift diving in open water outside of the GBR, your pictures etc.

I hope that you will reconsider your departure from db as I think you have a lot to contribute (in technical issues as well).

Sincerely, Michael.

[SpearoPimp]

So reviewing the blackout section in Umberto's book I'm still a little unsure about what to do If a blackout victim is in spasm and has lockjaw. If taking off the mask and blowing air in the persons face does not bring them back and they are too contracted and locked up like I was for a rescue breath what should be done by the rescuer on the surface to bring that person back to breathing and consciousness as soon as possible? Tonight I am going to the CPR course but I don't think they know anything about freediving there.

[tylerz]

Anybody experienced a diver coming to consciousness while still having a laryngospasm?

Here is another elaboration on laryngospasm, the following quote being from:
http://www.muskoka.ambulance.ca/arti...php?article=21

"When a near drowning victim in the water, who can no longer keep afloat begins to submerge, they will try to take and hold one more deep breath. While the victim holds their breath, the level of CO2 in their blood increases, forcing the victim to attempt to inhale. As the victim inhales, water is both aspirated and swallowed. As the water is aspirated, it flows past the epiglottis resulting in spasm and collapse of the upper airways. This is called laryngospasm, and it seals the airway so tightly that no more than a small amount of water reaches the lungs. From this point, the victim's fate can take two paths.

The victim may quickly become unconscious due to hypoxia(too little oxygen in the cells - primarily the brain), go into a state of ventricular fibrillation(a lethal cardiac arrhythmia) and then quickly die. This is the less common of the two paths. Only ten percent of victims die from true asphyxia.

Ninety percent of victims will follow the other path. These victims will either be able to attempt a final respiration, and draw water into the lungs, or laryngospasm subsides with the onset of unconsciousness and water freely enters the lungs. What happens after this point depends on how long the victim is submerged, how cold the water is, and whether the water is salt or fresh."

[SpearoPimp]

Originally Posted by lungfish

The safety rescue I described is effective and simple. No slapping, just work with keeping the airway closed to the surface, get the mask off, gently pat them while talking loud enough to be heard and breathing on their eyes. One or two cycles of rescue breathing can release a laryngospasm. Otherwise, it releases with the terminal breath at the onset of anoxia.

I stand by my entire post.

Can some one please explain what is meant by the release of the laryngospasm at the onset of anoxia. when does this happen if the release is not triggered byh the rescuer?

[SpearoPimp]

In one of lungfish's original posts on page 2 he says as you are bringing someone to the surface to keep the chin tucked in to keep the airways closed while underwater. but in section 9.4 of umberto's book it illustrates that the chin is to by hyperextended (up) while bringing the diver to the surface. so my question is what is the best way to bring a diver up so that they do not take in any water in the process?"

[tylerz]

Without finding, or being offered any references to alternative treatments of laryngospasm, everything seems to suggest it releases when it is inclined to, or if the victim is conscious (generally because water was inhaled during a normal non-hypoxic state), possibly with the assistance of holding their breath, relaxing, and panting.

On top of trying the other techniques suggested in this thread, as soon as possible get the diver out of the water, turn them on their side with their face leaning towards the ground, allowing liquid in their mouth to drain and/or be directed away from their trachea. Get them to a hospital as soon as possible.

Has anybody heard of a freediver/spearo who sufficated due to a laryngospasm or had one that did not release until reaching the hospital? If there was any significant chance that this could happen, it would seem warranted to create or have a device for emergency response intubation, such that buddies could apply ventilation. Obviously, this would be controversial in terms of application, but if you are out in the middle of nowhere on a boat or what have you, the process may warrant the risk.

[tylerz]

Originally Posted by SpearoPimp

In one of lungfish's original posts on page 2 he says as you are bringing someone to the surface to keep the chin tucked in to keep the airways closed while underwater. but in section 9.4 of umberto's book it illustrates that the chin is to by hyperextended (up) while bringing the diver to the surface. so my question is what is the best way to bring a diver up so that they do not take in any water in the process?"

The way I was taught, find makes sense, have seen in action, and been subjected to , is that you hold the back of the divers head with one hand, and the other, you put your palm under the chin, finger pushing in and down on the diver's mask, or if goggles then on the facial part of the maxilla (upper jaw) above teeth. The importance is on keeping the jaw closed, which in terms of grip at the jaw, can best be achieved with chin somewhat hyperextended. With the chin tucked in too much, you may lose the grip due to loss of surface area for the palm and angle required to get your arm past the chest. Your wrist may not flex well enough to maintain thorough surface coverage if the chin is tucked in.

[efattah]

I have done numerous BO rescues and the procedure I used was:

1. Close the jaw and pinch the nose
2. Drag them to the surface
3. Take off the mask, blow on their face, and tell them to breathe -- they would normally have a laryngospasm at this point
4. At this point one of two things happen:

A) they start sniffing, and partially wake up, the laryngospasm (presumably) releases, they start breathing again and wake up

B) They do not wake up and the laryngospasm remains

In case B, I have always handed off the BO victim to another more qualified person. Artificial respiration is attempted, but usually the laryngospasm blocks the air. Sometimes the rescuer can force air past the throat, but sometimes not. In the case of one BO at 2003 Nationals, the blacked out diver was out for 3 minutes while rescuers could not get air into his lungs. Finally after about 3 minutes the laryngospasm (presumably) released on its own, allowing air to be forced into the lungs. Then he woke up.

Everything I have heard of in freediving seems to say that once you black out, your throat closes shut, and it remains closed for approximately 2-3 minutes into the blackout, at which point it relaxes and if you are underwater (as in Audrey's case) water floods the lungs at that point.

I have never heard of a conscious diver still having a closed throat.

[DeepThought]

This might add a little.
Question about getting a blackoutee to the...

[SpearoPimp]

Thank you everybody for all of the helpful input. I'm wondering how you would know if the BO'ed diver has taken in any water into thier throat or lungs (can this even happen shortly after a victim blacks out before the spasm releases?), and should this happen what do you do different when you get them to the surface?

[Mano]

I Want To Have Exceptional Exposure Tables For Air Diving Deeper Than 66m (po2>1.6) Can Any One Help Me

[Mano]

I Am Serchin For Exeptional Exposure Tables For Air Diving Deeper Than 66m (po2>1.6) Can Any One Help Me

[Fondueset]

Wow; just reread quite a bit of this. What an AMAZING thread!