Is 24hr SI sufficient before flying after a liveaboard trip?

[livetodive]

My wife and I are schedule to go on a liveaboard (ca. 15 dives within 3-4 days) and we have a long-haul flight just over 24 hours after we return from the liveaboard. Does anyone have an idea if the risk of DCS is increased with mulitiple dives, and if there is a greater risk of allowing 'just' 24 hours as a surface interval?

We'd really appreciate any information you can provide!

Livetodive

 

[scubasean]

I've been taught that 24 hours is fine, and my conservative Suunto computer seems to agree....

Your mileage may vary...

 

[Saturation]

The FAD issue is dependent of depth and time, not simply the dives.

Search scubaboard for the US Navy FAD table for some ideas.

24 hours is adequate time based on existing recreational data.

 

[Dr Deco]

Dear livetodive:

Table

The US Navy Fly/Dive Table can give you information based on your final tissue partial pressures. This is a reasonable table-based method of determining your place on the “partial pressure map.” It is generally very effective.

Nuclei

The other action you can take is not table based. The first is to avoid all activities that will lead to the growth/formation of tissue nuclei while on the surface after diving. This would include such activities as volleyball, probably easy to pass up on a small boat. Struggling with heavy gear in the first few hours back to shore is probably a pathway to nuclei formation, also.

The other method is to maximize gas washout by mild activity. The best idea is to not fall asleep right after surfacing, as this will reduce tissue blood flow to the absolute minimum. :nono: While not so bad with a 24-hour interval, people rest and then get up and engage in heavy work moving bags and gear.

Having done these two things, in addition to waiting as indicated by the table, will assure that your tissues will have released as much nitrogen as possible short of breathing oxygen (which is not necessary).

Dr Deco :doctor:

Readers, please note the next class in Decompression Physiology :grad:
http://wrigley.usc.edu/hyperbaric/advdeco.htm

 

[pasley]

Enjoy your live aboard trip. By the way, I am available for adoption.

In addition to the good docotrs post above, I would also add the following advice from DAN as a seldom thought of precaution.
http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=56

Please note the 2nd half of the 2nd paragraph under the answer. There may be an increased risk on the first day of diving if you are not well rested and still dehydrated from the flight. More research on this subject is needed. But when you arrive, rest, hydrate and enjoy the sights.

Iwould also encourage a light day of diving on the final day, perhaps not thrying to set a record on the number or depth of dives, but doing fewer and more shallow dives.

Not a doctor or other expert that has a clue, just my $0.02.

Enjoy the trip. I note your trip is to my neck of the woods, California. The Great Escape being one of the more popular boats.

 

[Saturation]

Hi:

Here's the link from a previous discussion on FAD. Its very detailed. It also includes a link to the US Navy FAD table.

http://www.scubaboard.com/showthread.php?s=&threadid=24631&highlight=FAD

PS: "Exceptional Exposure" is a full decompression dive.

 

[Tropics Diver]

Saturation once bubbled...
"Exceptional Exposure" is a full decompression dive.

A typical deco dive is not necessarily, and probably isn't an exceptional exposure.

Exceptional exposure is a dive "below the black line" of the USN Standard Air Tables.

80', 40 minutes is no deco.

80' 40-150 minutes is a deco dive for which the NOAA time to fly table is valid.

80', more than 150 minute dive is "exceptional exposure" and you need to wait longer than 24 hours.

At 120', a dive goes into exceptional exposure at 100 minutes.

NOAA and USN Tables

 

[livetodive]

Hi everyone,

Thanks for the great responses. I've check out other threads, and they're all very helpful as well.

One more question though: are long-haul flights any different? I mean, we'll be flying from Oz to Singapore, then to mainland Europe with a 5 hour break inbetween (total of around 24 hours! ). I know that exhaustion/stress is a contributor to DCS, but assuming we're well hydrated and don't drink any alcohol prior to the flight, is it still low risk to fly around 24 hours after our last liveaboard dive, assuming our last day of diving is 2 dives less than 50 feet? My wife is concerned about this one....

If the risk is truly negligible (ie. one in a million), then we'll do it. Otherwise, we'll have to take a shorter trip earlier in the week.

Thanks again!

Livetodive

 

[Saturation]

Tropics Diver once bubbled...
A typical deco dive is not necessarily, and probably isn't an exceptional exposure.

Exceptional exposure is a dive "below the black line" of the USN Standard Air Tables.

80', 40 minutes is no deco.

80' 40-150 minutes is a deco dive for which the NOAA time to fly table is valid.

80', more than 150 minute dive is "exceptional exposure" and you need to wait longer than 24 hours.

At 120', a dive goes into exceptional exposure at 100 minutes.

NOAA and USN Tables

Hello All:

Tropics diver is correct.

Exceptional Exposure is extreme depth-time by USN air decompression Tables. The recommended FAD is then >= 48 hours.

A decompression dive has a FAD >= 24h.

These descriptions are not included in the FAD Table found at the link but are described in the USN Diving Manual (c)2000.

Please note the limitations on how the USN table was created and that it uses USN no-stop air tables.

 

[pasley]

livetodive once bubbled...
...One more question though: are long-haul flights any different? I mean, we'll be flying from Oz to Singapore, then to mainland Europe with a 5 hour break inbetween (total of around 24 hours! )....Livetodive

For DCI risk on the return flight, probably no difference in risk. The circulation in your lower body may be impaired due to sitting so long and that may be a factor to consider. You have had several good answers about the return flight and 24 hours is the conventional wisdom, and longer is better.

I also would hope you consider the flight to the dive site.as this is potentially an increased risk of DCI if you arrive and dive soon after arriving.

I assume you read the DAN article on flying and diving. "...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..." http://www.diversalertnetwork.org/medical/faq/faq.asp?faqid=56

Dehydration and fatigue are increased risk factors for DCI.

Admittedly it is too small a sampling to determine cause and effect. But 37%, that is a good argument to me to not dive the same day I arrive, but to rest and re-hydrate.

Been there done that. Los Angeles to Kobe Japan via Alaska, 14 hours total trip. My sinus tells me that the air on planes is Sahara Desert Dry. By the end of the flight you will most likely have a very dry nose. (Ocean Spray helps). Avoid sugared, caffeinated or alcohol beverages as they all dehydrate you. H20 is the beverage of choice. But you most likely will be dehydrated to some degree, and plain wore out.