What to do if you ascend too quickly?

[The Chairman]

NetDoc:

<As this is the "Basic Scuba Discussions" forum>

This is what I teach to my "Basic" Open Water Class.

1. Avoid going into required decompression.
2. Be sure to complete any decompression obligation you may incur as long as gas and conditions permit.
3. If you miss any part or all of your required stop, provide oxygen for 3 times the missed decompression obligation or 20 minutes whichever is longer! Monitor for any signs of discomfort or DCS.
4. In case of discomfort or any sign of DCS: Call DAN at 1-919-684-4DAN (4326) and seek immediate medical help.

There is no need to seek medical attention if there are no symptoms present.

 

[Bubbletrubble]

Upon further reflection, I recall hearing that a diver should not be put on O2 unless they are exhibiting signs of DCS. Use of oxygen can mask or delay the onset of symptoms. Rather, they should be monitored for symptoms and if any are exhibited, then they should be placed on oxygen and seek immediate medical attention.

If they are asymptomatic and choose to go straight on to O2, then they should seek immediate medical attention to ensure they have not masked any symptoms.

This notion of treatment potentially "masking" or delaying symptoms is one that applies to certain kinds of medical intervention (pain management, in particular). For example, patient-reported pain will aid the medical team in taking a complete history, arriving at a diagnosis, and determining appropriate treatment for the condition.

I do not think oxygen should be withheld from an asymptomatic diver whose dive profile indicates an increased risk of DCS for fear of "masking" DCI symptoms. Early oxygen treatment is important and may reduce symptoms substantially...yet it should not change the overall treatment plan. In symptoms of serious AGE or DCS, there are many reported cases of symptoms completely disappearing upon initial oxygen treatment. My point is that oxygen can only help here.

That being said, it would be prudent to follow through with observing for DCI signs/symptoms regardless of whether oxygen is administered. As others have suggested, the diver should consider contacting DAN and/or reporting to the nearest hyperbaric chamber for medical evaluation. Keep in mind that 50% of divers with Type II DCS hits develop symptoms within one hour of surfacing and 90% report symptoms within 6 hours of surfacing.

FYI, neurological symptoms of DCS that present most frequently consist of numbness (59%), pain (55%), dizziness (27%), headache (24%), weakness (23%), gait abnormality (12%), and hypoesthesia (10%; statistics reproduced from "Neurologic Complications of Scuba Diving," June 1, 2001 issue of American Family Physician).

 

[Cave Diver]

In symptoms of serious AGE or DCS, there are many reported cases of symptoms completely disappearing upon initial oxygen treatment. My point is that oxygen can only help here.

I'm not disagreeing with this. Even if a diver shows symptoms and Oxygen alleviates them, I still think they should be checked out.

Likewise, if they show no symptoms and decide to go on Oxygen, my recommendation was that they be checked just to make sure nothing was missed.

 

[The Chairman]

I'm not disagreeing with this. Even if a diver shows symptoms and Oxygen alleviates them, I still think they should be checked out.

ANY symptoms! Even an itchy eye brow.

Likewise, if they show no symptoms and decide to go on Oxygen, my recommendation was that they be checked just to make sure nothing was missed.

Yeah, this I just can't see. If the person seems like they might be in denial, then sure. I have seen this on too many dive boats where they tell you that if you TOUCH oxygen that they will be initiating 911. All that does is to initiate denial from the beginning. I just don't see that as healthy.

 

[lowviz]

This is what I teach to my "Basic" Open Water Class.

1. Avoid going into required decompression.
2. Be sure to complete any decompression obligation you may incur as long as gas and conditions permit.
3. If you miss any part or all of your required stop, provide oxygen for 3 times the missed decompression obligation or 20 minutes whichever is longer! Monitor for any signs of discomfort or DCS.
4. In case of discomfort or any sign of DCS: Call DAN at 1-919-684-4DAN (4326) and seek immediate medical help.

There is no need to seek medical attention if there are no symptoms present.

Seaduced asked: If there is a deco obligation, use O2 and seek medical attention immediately?

Pretty much by definition: If there was a deco obligation, you do not have direct access to the surface because there is now a significant statistical risk of DCS.

So you are saying that for a rapid ascent through a deco ceiling, wait to see what happens? You make your choices, I'll make mine.

We are way further apart on this than I first thought. Neither of us is about to change, I've said all I have...

 

[Bubbletrubble]

OK. I think it might be helpful to post a pic of Table 21-3 in the US Navy Diving Manual.

 

[Bubbletrubble]

Likewise, if they show no symptoms and decide to go on Oxygen, my recommendation was that they be checked just to make sure nothing was missed.

Yeah, this I just can't see. If the person seems like they might be in denial, then sure. I have seen this on too many dive boats where they tell you that if you TOUCH oxygen that they will be initiating 911. All that does is to initiate denial from the beginning. I just don't see that as healthy.

@NetDoc: I think you're reading too much into Cave Diver's statement. He phrased seeking further medical evaluation as a "recommendation" rather than a mandatory course of action.

I can see how mandatory initiation of a 911 response might discourage oxygen use in cases when DCS symptomatology is in question. I agree with you that divers should not be discouraged from breathing oxygen if they feel like doing so. However, I think that's an issue with the boat op. Without a doubt, issues of legal liability weigh heavily on the formulation of their standard emergency procedures. Sad but true.

 

[Scott L]

Side note:
The rapid ascent. He had a faulty BCD? and returned to 90ft
or was having issues with the rig in some way? If he was using a faulty BCD and returned to 90ft and this happened again, im sure we would be discussing an incident here instead of this topic.

I am sure he had the good sence to signal his buddies of his issues and ascend with their assistance without injecting any gas into the BCD...

 

[Scott L]

There has not been any discussion on the divers ability to hold a constant depth to complete any of the myriad of IWR and/or safety stops mentioned with his faulty BCD . Perhaps this why he met up with his buddies at 90ft. The image of Wile E Coyote and the canyon floor comes to mind.

 

[The Chairman]

So you are saying that for a rapid ascent through a deco ceiling, wait to see what happens? You make your choices, I'll make mine.

That's precisely what I didn't say. The diver should be put on Oxygen immediately for 3X the missed decompression or 20 minutes whichever is longer. They also need to be monitored for signs of DCS.

Just as you can suffer from DCS if you do not exceed NDL, you have a very good chance of NOT suffering from DCS if you do and also miss your obligatory stops (with or without Oxygen). If you are not clear on what these symptoms are, then by all means initiate 911. If you know them and they are not present then we don't need additional drama.

Look at the variations within PDCs. I dove two different PDCs this past Sunday. On the same dive, one was fine while the other told me I needed 12 more minutes of deco. The plethora of vicious jelly fish from 20 FSW to the surface made my decision for me! Twelve minutes is a huge difference. However, I KNEW going into the dive that the one was far more conservative because it came from cold, cold Scandinavia. Charles' Law needs to be observed in those conditions and the company is releasing a new PDC that will be the first to have a negative conservation factor built in. Still, I was way OK with listening to the other PDC for deco. No symptoms either.

Remember, the PDC is not measuring your Nitrogen content: it can't! It's making a SWAG (Scientific Wild Arse Guess) about what it thinks you should have accumulated.