Water in regulator at depth causing panic

[boulderjohn]

We have very few of the old time divers here on ScubaBoard--and I am not one of them myself. I am old, but I started late. I do, however, have nearly two decades of ScubaBoard experience, and I remember well some of the old threads with some of those old time divers, and I specifically remember them talking about CESA.

I am talking about the days before pressure gauges were common, the days when the J-valve was the common safety device in scuba. The idea of the J-valve was that you would dive until you were out of air, at which point you would pull a lever and get a reserve of air, enough to get you to the surface safely. One problem was they had to be filled properly, and sometimes they weren't. A second problem was that it was possible in some environments, like kelp forests, for the lever to be tripped accidently. In either case, when the diver pulled the lever, they got nothing.

And that was the time for a CESA. As I understood those old posts, divers "back in the day" had been through many CESAs, and they knew it was not a serious problem.

 

[FishWatcher747]

I was on a dive boat when I was a very new diver. It was a large boat with up to 16 divers out of Key Largo divided into 2 groups of largely green divers with a guide for each group.

A diver in my group was clearly not like the rest of us, in perfect trim and would come back to the boat with over 2000 psi in his tank. Turns out he was an instructor with thousands of dives. Why he was diving with newbies that day I do not know.

We got talking and we started talking about CESAs. He said you don't need to exhale for the whole ascent but you need to open your airway.

When I did my simulated CESA with an instructor from about 25 feet in OW in 2020 (with a regulator in my mouth and a half full tank) I exhaled all I had and hummed in the first 10 seconds. After a pause of maybe 10 seconds I was then able to exhale more, and hum as instructed for the final few seconds to the surface.

 

[johndiver999]

I was on a dive boat when I was a very new diver. It was a large boat with up to 16 divers out of Key Largo divided into 2 groups of largely green divers with a guide for each group.

A diver in my group was clearly not like the rest of us, in perfect trim and would come back to the boat with over 2000 psi in his tank. Turns out he was an instructor with thousands of dives. Why he was diving with newbies that day I do not know.

We got talking and we started talking about CESAs. He said you don't need to exhale for the whole ascent but you need to open your airway.

When I did my simulated CESA with an instructor from about 25 feet in OW in 2020 (with a regulator in my mouth and a half full tank) I exhaled all I had and hummed in the first 10 seconds. After a pause of maybe 10 seconds I was then able to exhale more, and hum as instructed for the final few seconds to the surface.

If you retain the ability to SLOWLY exhale and release a tiny stream of bubbles, almost by definition, you are still calm and of course this keeps your airway open and the diver feels (and is) remaining in control of the situation.

At the start of the ascent the expansion rate is slow, so the exhalation rate is slow, plus in the most serious of situations, you are going to really want to keep your lungs close to full so you can ride the buoyancy of the air in the lungs and also a larger volume keeps the percentage of CO2 down and this will also make you feel much better.

If the ascent is "less serious", maybe it is shallow or (most likely) the tank pressure has just dropped very low, but the regulator is still functional, then you are definitely going to want to STOP exhaling and try to inhale from the regulator on a CESA.

Of course, if you can suck a slow inhalation off the tank, you will need to be exhaling soon after as the ascent proceeds, but this fact should be obvious.

The difficulty of a CESA is going to vary based on many factors including:
if the tank can deliver any air on the ascent,
the buoyancy status of the diver,
the metabolic state of the diver,
the psychological state of the diver
the depth

 

[FishWatcher747]

A trained vocalist may do a CESA with a sustained exhale better than most of us but even in this video Juice Newton singing Angel of the Morning at 3:45 "only" holds a note for about 20 seconds.


Most of us with training can hold our breaths for 45 seconds without difficulty but we can't exhale for 45 seconds. I plan to exhale when I can and keep my airway open when I can't.

 

[inquis]

we can't exhale for 45 seconds

You'll be able to exhale far longer during a CESA since the air is expanding in your lungs.

 

[John C. Ratliff]

A trained vocalist may do a CESA with a sustained exhale better than most of us but even in this video Juice Newton singing Angel of the Morning at 3:45 "only" holds a note for about 20 seconds.


Most of us with training can hold our breaths for 45 seconds without difficulty but we can't exhale for 45 seconds. I plan to exhale when I can and keep my airway open when I can't.

Holding one's breath on land, at one atmosphere pressure without any pressure change, is much different than exhaling through a CESA. There, you are exhaling excess air as it expands inside your lungs. This is not an extreme exhalation, but rather blowing out the excess air so as not to over expand the lungs, and get an air embolism. This can be done all the way up. Here's some information from DAN (Diver's Alert Network):

...
Let’s say you do everything right and you still find yourself in a situation that requires an emergency ascent. What’s the best way to proceed?

First, don’t panic. You received training on how to do emergency ascents in your original certification course. Remember the preferred order of options:

1. Make a normal controlled ascent, with your regulator in your mouth.
2. Find your buddy and obtain his secondary air source (or his primary if he will be taking the secondary, depending on the configuration of his gear). The goal in this scenario is for both divers to have a continuous air source, enabling you both to make a slow, controlled ascent to the surface.
3. If you cannot reach your buddy or another diver, or if your buddy is also out of air, complete a controlled emergency ascent on your own. But again, don’t panic. Remember, you likely have enough air in your lungs to sustain you to the surface. Follow the procedures you learned in training: Keep your regulator in your mouth at all times; sometimes air expands and gives you one more quick breath. Exhale slowly and continuously all the way to the surface, and keep your ascent slow...
   
   

   Emergency Ascents: Managing the Risks

   Emergency ascents are used to avoid any adverse events during a dive. Divers are trained in standard emergency ascent procedures. Read more.

   dan.org

SeaRat

 

[FishWatcher747]

What I am saying is I was given incomplete information. The student was supposed to hum during the simulated CESA from 25 feet with the instructor right next to the student. The student was supposed to hum loud enough for the instructor to hear the hum the whole ascent.

Try humming loudly after a complete exhale.

 

[BoltSnap]

What I am saying is I was given incomplete information. The student was supposed to hum during the simulated CESA from 25 feet with the instructor right next to the student. The student was supposed to hum loud enough for the instructor to hear the hum the whole ascent.

Try humming loudly after a complete exhale.

I am not sure that "humming" or making any sound while doing a CESA is a good idea. There maybe potential issues doing that. Best source for proper answer is DAN.

 

[OMyMyOHellYes]

I am not sure that "humming" or making any sound while doing a CESA is a good idea. There maybe potential issues doing that. Best source for proper answer is DAN.

It is just a teachable audible clue to the diver that their airway is open and they are exhaling constantly. In my class I was taught to say "Ahhhhhhh..." out the side of my mouth. It is slow, it is metered, it keeps the airway open, it is a checklist activity to incorporate in the CESA process and ingrain. It is actually easier than telling the diver to "exhale". Just telling a diver to exhale on the way up, does not really cover it - that would be a slow controlled exhalation that keeps the airway open and freely allows expanding gas to escape. Just exhale could be blowing everything you think you got and holding your breath from that point. Not good that would be.

I think it is a good idea because if you just told students to "exhale" chances are a lot of folks will forget to do it, being contrary to the normal reflex to close the airway and hold breath underwater.

 

[BoltSnap]

It is just a teachable audible clue to the diver that their airway is open and they are exhaling constantly. In my class I was taught to say "Ahhhhhhh..." out the side of my mouth. It is slow, it is metered, it keeps the airway open, it is a checklist activity to incorporate in the CESA process and ingrain. It is actually easier than telling the diver to "exhale". Just telling a diver to exhale on the way up, does not really cover it - that would be a slow controlled exhalation that keeps the airway open and freely allows expanding gas to escape. Just exhale could be blowing everything you think you got and holding your breath from that point. Not good that would be.

I think it is a good idea because if you just told students to "exhale" chances are a lot of folks will forget to do it, being contrary to the normal reflex to close the airway and hold breath underwater.

"Humms" "Ahhhs" etc. may not be a good idea for safety of the skill. It will be a good idea to check with a specialist organization, DAN for example. I am a specialist in this matter and I may not remember all of the technical details so I am not getting more involved but it will be prudent to check with subject matter experts first.