Rescue ascension

[lamont]

An unconcious diver will vent overpressure on there own as they asscend, baro trauma is not a big risk.Even if it was, they are not breathing underwater, it dosen't get much worse than that. You wont make them any more dead. Don't endanger your self.

If I'm looking directly at my buddy when he goes limp in the water, then it does actually get worse than that, and time is a critical factor in how bad it gets. In that situation, I'm going to try to balance an equation evaluating the risks to both of us. If I find someone on the bottom unconscious with a reg out of their mouth and I have no idea how long they've been there, then you're probably right that they're probably dead, probably not coming back, and i should make sure to eliminate risk to myself.

And if an unconscious diver has air in their lungs (laryngospasm will close their airway when they suck in water, their lungs will not be filled with water) and you ascend directly from 90 fsw you can cause lung barotrauma which now complicates the whole picture -- if there was any chance of CPR and defibrillation working on them, now you've added a punctured lung...

 

[Wildcard]

I was waiting for someone to come up with the no water in the lungs myth. Just wondering, how many drownings have you worked? Everyone will have water in the lungs after more than a few minutes underwater.....Think about it, what is drowning?

 

[lamont]

I was waiting for someone to come up with the no water in the lungs myth. Just wondering, how many drownings have you worked? Everyone will have water in the lungs after more than a few minutes underwater.....Think about it, what is drowning?

If they go unconscious while I'm watching them they haven't drowned yet and the lungs will not be filled with water. Some water may enter the lungs but laryngospasm due to water in the airway will close it off. Some time after the victim goes unconscious the airway relaxes and water enters the lungs and air can escape and barotrauma is no longer a concern.

 

[japan-diver]

Having a little real world experience in this matter, I'll tell you what worked in real life:

Hold the reg in the persons mouth, tilt the head back to ensure the airway is open and ascend quickly to the surface. Upon arrival at the surface clear the airway and give rescue breaths.

If we see the person pass out in front of us, the lungs are still dry and you have about 1 minute before the lungs will fill with water, possibly longer with a reg in the persons mouth. If you come upon a victim that has been underwater for an undetermined amount of time there may or may not be water in the lungs already, I would initate the same ascent procedures and hope for the best in this case.

If this is a deco/tech dive then its a completely different story and things get much more complicated.

 

[Kangy]

How fast is "ascend quickly" I can see maybe 60fpm maybe, maybe 90fpm given the situation that you saw your buddy pass out in the water and have around 1 minute to get him to the surface, personally I would rather stick with keeping the reg in his mouth, ascending at 60fpm taking 30 extra seconds, yes although that may not appear to be much of an ascent rate change.
Also wouldn't some other factors such as your time at depth, repetive dives, gas mix, etc, etc. play a part in this, lets say you are on your first dive of the day using EaN 32 on your way up from a 100ft dive with a bottom time at depth of 5 minutes shooting 60fpm to the surfae may not be that hazardous of a situation considering your buddy is unconscience. However lets say this is your 2nd dive of the day using air to 110 ft with a bottom time of 12 minutes, depending on your surface interval, tables, etc. you may be approaching your NDL and have a significant amount of nitrogen buildup. shooting to the surface even at 60fpm skipping deep stops/safety stops could pose a problem for the rescuer, on a beach dive away from the shore it won't do any good having him on the surface if your inoperable due to being bent, especially if there is not a convenient source of 02 waiting for both of you at the surface.
In this situation if you wanted to analyze it there is more to factor in than just an ascent from 90fsw with an unconscience diver, however IMO personally I would take the chance, get my buddy to the surface, although "inconvenient" I would take a trip to the chamber for mild DCS over a dead buddy anyday, that's just me though.

 

[Dr Deco]

Hello readers:

Missed Deco and Reentry

This is a frequently asked question when reentry is concerned. If one were shy only a few minutes of missed decompression – let us say up to fifteen minutes – it is probably just a well to stay on board and watch for signs and symptoms of DCS. Breathing oxygen is a good idea.

If one was very active at depth, and tissue gas loadings were known to be higher than normal, the one might anticipate a greater risk with that duration. Always remember that dive tables - and DCS – are not like an ON/OFF switch. Within the table and you are OK but beyond the table, you are assured of a “hit.” It is not that way.



Dr Deco :doctor:

 

[DandyDon]

Love it when you post with your more learned advice. (Anyone who doesn't know Dr.Deco's credentials - they're not on a sticky any longer, but he's renown for his work in decompression.)

From purely anecdotal experiences of very green newbies, my home bud and I both did 80 ft dives at 5,000 elevation as our first paper cards dives, and both experienced runaway ascents from expanding BCs and unfortunate egos - bobbing to the surface like corks. I went back down to 15 ft for 3 min, he didn't. I was fine, he ached for weeks - which I learned about only a couple of years later. Long story, but he was more into his new GF than dive buddy.

However, our experiences are yet random. Far too many variables in divers and experiences to say what will happen with those. We now practice slow ascents, deep stops, long safety stops, and hidden stops - the latter learned from our esteemed Dr.Deco.

 

[logos]

If they go unconscious while I'm watching them they haven't drowned yet and the lungs will not be filled with water. Some water may enter the lungs but laryngospasm due to water in the airway will close it off. Some time after the victim goes unconscious the airway relaxes and water enters the lungs and air can escape and barotrauma is no longer a concern.

I suspect you are over-estimating the frequency of the occurance of laryngospasm and how tight the spasm is. I suspect that laryngospasm will only occur occasionally and even then only rarely to the extent that the patients airway would be totally occluded.

I have seen only one case of laryngospasm (post extubation after general anesthetic) and the patient was ventalateable by mask, albeit not without a fair bit of pressure.


Question for those more in the know: Did they change the 60f/min thing to 30? It sounds like thats what you guys are saying. If so, when/why? (it was 60f/min last I heard...but that would have been when i did my ow...around 1996.

Seems to me that if I witnessed the event or if there were others available on the surface to care for the patient, I would be more inclined to exceed limits for ascension speed.

I dont think i've ever done a safety stop...maybe once on a dive charter boat a few years back...so I would definately skip that.

 

[DandyDon]

Question for those more in the know: Did they change the 60f/min thing to 30? It sounds like thats what you guys are saying. If so, when/why? (it was 60f/min last I heard...but that would have been when i did my ow...around 1996.

You know, 30 ft/min is so widely suggested here on SB, I really cannot tell you how many of the agencies have recently adotped it. My Oceanic computers suggest 60 ft/min to 60 ft, then 30 ft/min above that.

We have many Inst on SB, maybe some of them would like to post here on that...?

 

[TSandM]

PADI is still teaching 60 fpm in their written materials, although the instructors do say that that has been modified.

As in many resuscitation scenarios, there is no cut and dried answer. You have two issues: One diver who is unresponsive and not breathing (this is a very BAD sign). One diver who is well. Your goal is to get both divers to the surface safely. For the victim, this means pretty much as fast as possible. I'd rather deal with a pneumothorax than anoxic brain injury, and furthermore, by the time breathing efforts cease, laryngospasm, if it has existed, has virtually always relaxed. For the rescuer, this means as fast as reasonable . . . And what reasonable is depends on the situation.

If you're relatively shallow or very early in the dive and minimally loaded, as a rescuer, I'd get the victim up at at least 60 fpm, being very careful to manage my own lung volumes. This is assuming that, as lamont states, I SAW the person go unresponsive. If I encountered an unknown, unresponsive, non-breathing diver, that person's dead, and I'm not taking any major risks with my own safety at that point. 60 fpm to the surface -- this was once considered safe for ALL NDL dives. If I'd been deep or down for a significant period of time, I'd try to get on O2 at that point, and be very vigilant for DCS symptoms.

When you are facing decompression obligations, the situation becomes much more difficult. There have been long discussions of in-water recompression on this board and others. It's not something to be undertaken lightly, but neither is doing decompression stops with an unresponsive, apneic fellow diver . . . IF you know when he stopped breathing.

As I said to begin with, there are no cut and dried answers. Every situation is going to have to be quickly and accurately assessed by the functional diver, the risk-benefit ratio for victim and rescuer evaluated, and a proper course of action chosen.