flying before diving

[Thalassamania]

Let's look at the actual question and answer for a moment:

Q:It takes most tourists 24 hours to get to our resorts here in Thailand. I notice that many tourists begin diving immediately when they arrive and often start drinking quite a bit of alcohol. Aren't they at greater risk for decompression sickness after their long flight if they begin diving right after they arrive? Shouldn't they wait one day before they begin diving?

A:Mild dehydration can occur on long flights, especially when travelers cross several time zones; alcohol consumption can also contribute to dehydration. Generally speaking, dehydration is thought to predispose a diver to decompression illness because the washout of inert gas (nitrogen, in diving) is less effective in a dehydrated individual.

If there were a relationship between diving after flying and DCI, we would expect to see a great deal of decompression illness on the very first day of diving -- indeed, some data suggests that there are more accidents on the first day of a planned multiday dive trip. Of the 88 cases reviewed from the Caribbean for 1994, 33 -- or 37.5 percent -- occurred on the first day. The remainder occurred on days two through seven. Given that there are thousands of tourist divers who fly to Caribbean and Pacific dive sites, these numbers are far too small to establish a cause and effect.

Although no one can insist upon a 24-hour waiting period after flying, such a conservative approach to diving after flying is a reasonable idea -- it gives divers an opportunity to rehydrate, adjust to a new climate and time zone, and rest up after a long flight.

There's no question that you can dehydrate on a flight. So what to do? NO ALCOHOL or other diuretic, no coke, no coffee, no tea. Drink fruit juice or water, and lots of it.

The higher level of first day DCI is worrisome. I'd suggest that more than a third on day one vs. days two through seven (when there is more likelihood of multi-day, multi-dive problems) is statistically significant, however the causality link can clearly be questioned (e.g., was the diver's table use rusty, did they forget how to use their computer, were they ascents less under control, etc.).

 

[miketsp]

..snip..
indeed, some data suggests that there are more accidents on the first day of a planned multiday dive trip. Of the 88 cases reviewed from the Caribbean for 1994, 33 -- or 37.5 percent -- occurred on the first day.

..snip..

The higher level of first day DCI is worrisome. I'd suggest that more than a third on day one vs. days two through seven (when there is more likelihood of multi-day, multi-dive problems) is statistically significant, however the causality link can clearly be questioned (e.g., was the diver's table use rusty, did they forget how to use their computer, were they ascents less under control, etc.).[/FONT][/COLOR]

We always have to be careful with correlation data.
I'd go along with the expectation that a higher DCI incidence on the first day is much more likely to be due to rusty diving technique than residual micro-bubbles after a long-haul flight. Assuming the diver stayed hydrated.

 

[Thalassamania]

We always have to be careful with correlation data.
I'd go along with the expectation that a higher DCI incidence on the first day is much more likely to be due to rusty diving technique than residual micro-bubbles after a long-haul flight. Assuming the diver stayed hydrated.

Yes. But my problem with that is that on the first day out:

• They'd have less nitrogen (no multi-day).
• Chances are that they make less dives.
• Chances are that the dives are less challangeing.
• We're looking a DCS, not embolism or other injury (or are we?)

 

[miketsp]

Yes. But my problem with that is that on the first day out:

• They'd have less nitrogen (no multi-day).
• Chances are that they make less dives.
• Chances are that the dives are less challangeing.
• We're looking a DCS, not embolism or other injury (or are we?)

Well I looked back at my log and on several dive trips I've done quite a significant reverse profile on the first day. The op often wants to check the group out and the first dive is somewhere easy and shallow to let people get acclimatised and back into practice. The second dive was a deeper dive to the limit of the tables.

 

[Thalassamania]

I wonder if that procedure is common enough to account for the observation?