Secondary drowning

[reidfish]

How much risk is there of secondary drowning for apneists with attentive buddies etc? (Note, I am not talking about finding someone unconscious in the local pool or at the beach here).:naughty

Is a laryngiospasm usually sufficient to stop water entering lungs and damage occurring?

Is a little bit (say 30 ml) of fresh water in the lungs going to be a problem (fresh water absorbs into bloodstream and dilutes the blood)

Is, say, 30ml of salt water sufficient to aggravate the lungs enough to cause secondary drowning (salt water draws water into the lungs due to osmosis)?

Just curious, as I would like to know more about the risks of secondary drowning than I do

 

[reidfish]

OK, so nobody knows much then.

Has anybody EVER had a problem with secondary drowning from freediving? What about with Spearfishing?

 

[fpernett]

Hi Reid,
The secondary drowning is the pulmonary oedema, after drowning or near drowning. It could be from the effect of water (Fresh = Intersticial Oedema, Salt = Alveolar Oedema) or from the high negative pressure after inspiratory efforts against a closed glotis (laryngospasm). Of course larynspasm prevents water from enter the lungs, but this is only 15% of cases, and with severe hypoxia it stops.
To have a real lung injury you need a lot of water in the lungs, I don't know exact volume in humans experiment (hope I never heard of a experiment like that), but in young pigs, some researches uses 12.5-15 ml/Kg of body weight, if I translated to me I'll need 938-1125 mL to have a problem.
I think the best way to avoid that problems is to avoid immersion of airways after a BO, if BO is underwater, try to keep airways closed, and do not delay reanimation if after a BO, the freediver, do not start spontaneous breathing after 10-15 secs.

 

[reidfish]

Thanks Frank, so what you are saying is that you really need to inhale a heap of water, or your layngiospasm has to relax, for this to be a problem, so it is unlikely for most freedivers to have a problem, unless not attended by a buddy in a short time?

 

[fpernett]

Yes and No,
The laryngospasm could be a problem too, if you want to ventilate the unconscious freediver. And yes, a quick assistance is the key to avoid further problems.
Safe apneas.