ROPE - I have not heard of this snorkeling problem

[Trilobite]

Yeah, I read this elsewhere and was curious what the actual incidence is that you'd be warning people of. Based on those lose numbers it would be around 1/200,000. People can still get this even after acclimating a fews days. If you told me about ROPE and it was 1/200,000 risk the day I arrived or 1/500,000 if I waited a few days I'd still go day 1.

Of course, it is highly unlikely that it strikes randomly; so you wouldn't decide what to do based on the simple ratios you cite (assuming the figures are accurate--personally I'm skeptical half the visitors do significant snorkeling). The Hawaii study lists several risk factors:

RISK FACTORS​

• EQUIPMENT: Snorkels with a higher degree of resistance to inhalation​

increase the risk of ROPE​

• HEALTH: Heart conditions are significant risk factors., in particular diastolic​

dysfunction, which is an asymptomatic condition common in middle age​

people. A medical history of high blood pressure may be an indication of​

diastolic dysfunction.​

• EXERTION: Increased exertion can precipitate or accelerate ROPE.​

• RECENT EXTENDED AIR TRAVEL: It is possible that recent prolonged air​

travel may be a risk factor.​

• BOATS: When jumping into the water from a boat there is little time to​

acclimate to the equipment, temperature, and conditions, and, once in, the​

snorkeler can’t touch bottom so must exert extra effort. These are all risk​

factors so extra caution is advised.​

Many visiting snorkelers are likely kids who may have little risk of this condition. And many who snorkel won't be doing it shortly after air travel. So eliminating those two big chunks likely significantly increases the incidence right off the bat for those in the victim's position.

 

[smashweights]

Of course, it is highly unlikely that it strikes randomly; so you wouldn't decide what to do based on the simple ratios you cite (assuming the figures are accurate--personally I'm skeptical half the visitors do significant snorkeling). The Hawaii study lists several risk factors:

RISK FACTORS​

• EQUIPMENT: Snorkels with a higher degree of resistance to inhalation​

increase the risk of ROPE​

• HEALTH: Heart conditions are significant risk factors., in particular diastolic​

dysfunction, which is an asymptomatic condition common in middle age​

people. A medical history of high blood pressure may be an indication of​

diastolic dysfunction.​

• EXERTION: Increased exertion can precipitate or accelerate ROPE.​

• RECENT EXTENDED AIR TRAVEL: It is possible that recent prolonged air​

travel may be a risk factor.​

• BOATS: When jumping into the water from a boat there is little time to​

acclimate to the equipment, temperature, and conditions, and, once in, the​

snorkeler can’t touch bottom so must exert extra effort. These are all risk​

factors so extra caution is advised.​

Many visiting snorkelers are likely kids who may have little risk of this condition. And many who snorkel won't be doing it shortly after air travel. So eliminating those two big chunks likely significantly increases the incidence right off the bat for those in the victim's position.

Right, my point is not the exact odds but rather the odds being high enough that if people were warned they would feel confident taking the risk.

 

[Trilobite]

Right, my point is not the exact odds but rather the odds being high enough that if people were warned they would feel confident taking the risk.

My point is not the exact odds either; it's that the odds can easily be dramatically increased if you actually read the proposed warning (rather than make calculations based on dubious data) and see that risk factors apply to you, so the victim in this case may well have decided to wait a few days if he had known of the warning. (Just as people don't go running around in open fields during thunderstorms even though the risk of being hit by lightning is quite small on an absolute basis.)

 

[Gene]

I can tell you first-hand, it's not a good feeling when you can't get enough O2 into your body, despite how much huffing and puffing breathing you're doing. Unless you have a deco tank with you, (with 100 percent O2 in it), which I had, but didn't even have the wits to use it at that point, your vision starts to get dim and you'll more than likely pass out. Lucky for me, I had cave diver buddies that swam me back to the shore, got me on O2 asap and within minutes I felt better, and the ambulance was there. (A week in the hospital after a helicopter ride to Orlando -- no chamber needed they determined.) An IPE incident caused by a weakened heart muscle, which is now chronic congestive heart failure and an aortic valve stenosis along with a low ejection fraction. On the day of this incident in April of 2019, thank God I didn't keep swimming towards July Springs through the short-cut. I had a cough that was persistent (that was not present pre-dive), and I felt that I needed to call the dive. I hate to think what would have happened if I didn't.

 

[Dr Simon Mitchell]

Hello,

ROPE is immersion pulmonary edema (IPE) by another name. IPE is a better name because it links the problem to its key contributor (immersion) whereas rapid onset pulmonary edema can occur in a variety of medical contexts that have nothing to do with snorkeling, swimming or diving.

Full face snorkel masks have been raised in this thread several times. You may be interested in a study we recently published exploring their propensity for generating hypoxia or hypercapnia in comparison to a normal snorkel. See attached or https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10735670/pdf/DHM-53-313.pdf

I am do not believe that the recent air-travel-as-a risk-factor hypothesis has been proven by the Hawaii group. Indeed, there is massive potential for a form of selection bias in looking at the data. Probably hundreds of thousands of holidaymakers worldwide swim, dive or snorkel soon after arrival at their destination so it is no surprise to find a substantial proportion of IPE victims have travelled recently. I am not dismissing it, but would not consider it proven and certainly not something I would warn people about. I can just imagine the response if I told a group of divers arriving at Truk Lagoon that they had to wait for 5 (pick a number!) days before they can dive because of concerns about IPE.

Simon M

 

[lowwall]

Hello,

ROPE is immersion pulmonary edema (IPE) by another name. IPE is a better name because it links the problem to its key contributor (immersion) whereas rapid onset pulmonary edema can occur in a variety of medical contexts that have nothing to do with snorkeling, swimming or diving.

Full face snorkel masks have been raised in this thread several times. You may be interested in a study we recently published exploring their propensity for generating hypoxia or hypercapnia in comparison to a normal snorkel. See attached or https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10735670/pdf/DHM-53-313.pdf

Simon M

Thanks for clarifying the ROPE vs. IPE nomenclature.

And for the article which is further evidence of the unsuitability of full face snorkel masks. If nothing else, it puts to rest the claim that the inclusion of one way valves completely prevents rebreathing of exhaled gases. Further, your test may well be a best case scenario for these things in that your subjects were experienced snorkelers, the testing was done in the dry so anxiety induced shortened breathing cycles were not an issue, and the testing was cut off as soon as subjects hit a threshold oxygenation level which prevented discovery of just how bad things could get. Even so, the increase in CO2 and decrease in blood O2 saturation when using these masks was alarming.

And this would just be the triggering effect in an incident. What happens next is what I feel is the real culprit. People using standard snorkels normally respond to breathing or O2/CO2 issues like shortness of breath by removing the snorkel. This is trivially simple with a snorkel, you just spit it out. But it can be a major undertaking with a snorkel mask, requiring at least one hand and typically two. Worse, a major reason people chose these masks is they are afraid of immersing their faces in water. These people are going to be loathe to even attempt removal until it's too late.

I have no particular insight on the hypothesis that air travel by itself is a risk factor for snorkelers. But IMO, these full face masks are dangerous and defective when used for their intended purpose.