Scubadoc’s Ten Foot Stop

May 5, 2009

Blood Donations and Diving

Filed under: Uncategorized — admin @ 4:48 pm

Divers often donate blood and need to know when to resume diving. This article is meant to provide information to help answer those questions. This information should apply to any type of diving since the effect depends on the hemoglobin in the red blood cell mass rather than the partial pressures of gases.

How long must a diver wait after blood donation before diving?

The donor’s body replenishes the fluid lost from donation in 24 hours. If not anemic (Hgb<12 Gm/dl)a person can dive in 24 hours after blood donation. It may take up to two months to replace the lost red blood cells. Whole blood can be donated once every eight weeks. The most important part of the blood to the diver is the red blood cell, responsible for the transport of oxygen to the tissues. The fluid part of blood is replenished in about one day. If the diver waits 24 hours and has a normal hematocrit, then diving should be allowed.

Red blood cells are perhaps the most recognizable component of whole blood. Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color. The percentage of blood volume composed of red blood cells is called the “hematocrit.” The average hematocrit in an adult male is 47 percent. There are about one billion red blood cells in two to three drops of blood, and, for every 600 red blood cells, there are about 40 platelets and one white cell. Manufactured in the bone marrow, red blood cells are continuously being produced and broken down. They live for approximately 120 days in the circulatory system and are eventually removed by the spleen.

Is there a way to donate blood products and still be able to dive immediately?

Yes, through apheresis. This is the process of removing a specific component of the blood, such as platelets, and returning the remaining components, such as red blood cells and plasma, to the donor. This process allows more of one particular part of the blood to be collected than could be separated from a unit of whole blood. Apheresis is also performed to collect plasma (liquid part of the blood) and granulocytes (white blood cells).

Is there a way to shorten the time interval before red blood cell replenishment after blood donation?

Yes – Approximately 10 percent of body iron stores are removed with each donation. When appropriate, iron supplements can be prescribed for patients making donations to help increase red blood cell count. Erythropoietin, a hormone, can also be given to stimulate the bone marrow into producing more red blood cells.

Undercurrent Online Update

Filed under: News, Publication — admin @ 11:03 am

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Dive News

May 4, 2009

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Updates on Swine Flu In Mexico: Since it has shown up on the Yucatan peninsula, divers with Mexican travel plans need to stay current. Two good sites to check for the latest information: the U.S. State Department has created a “Swine Flu Alert” page ( — if this link doesn’t work,follow the link at to give up-to-the-minute travel information, and the Centers for Disease Control is doing the same regarding health and medical information ( By the way, if you buy travel insurance early on in your trip planning, you’ll find many policies will allow you to back out for epidemics. If you try to add it later in your plans, you’ll probably be out of luck.

Recall On Mares Drysuit Hoses: Swedish dive gear maker Si Tech is recalling its low pressure inflation hoses that are used in Mares drysuits. The plastic flow-restricting insert (colored blue, black or green) in the hose may dislodge from the connection valve, potentially obstructing the air flow. Affected hoses were sold between 2006 and 2009 in 15 types of Mares drysuits, including the Dryfit, Icefit and Polarfit models. Send the recalled inflator hoses back to the dealer you purchased your drysuit from, or to a Mares’ service center, so the insert can be removed free of charge. For more information, contact Mares Customer Service at 203-855-0631 or e-mail

Diving Southeast Asia: This just-published, 302-page, soft-bound guide by Beth and Shaun Tierney, is a must for anyone contemplating diving in Indonesia, Malaysia or Thailand. Where is Sipadan? Raja Ampat? Komodo? Richeliu Rock? Maps make it easy to pinpoint dive destinations and travel routes. Destination and 250 dive site descriptions (with tables on depth, visibility and currents) help you determine whether you’ll see big fish in the blue or pygmy seahorses in the muck. There’s a lot of supplemental information such as travel tips, health tips, and resorts and liveaboard descriptions. Order at Undercurrent, get the best price Amazon has to offer and our profit will go to preserving coral reefs.

Save Lots On A Trip To The Caymans: From June 1 to September 7, Cayman Airways is letting kids under age 11 fly free on flights from Miami, New York or Tampa. More than 25 hotels and condos will give a free fifth night to families who book four nights, and 14 dive operators offer free diving for kids ages 12-17 and discounts on dive packages or above-the-water attractions. Go to Other deals: The posh Westin Casuarina Resort on Grand Cayman is dropping its rates by 40 percent between June 1 and September 6; room rates start at $159.

Check This Video: Londoners were bewildered when 30 people in full dive gear were spotted walking around the city — in flippers — in late April. They were “frogmen” hired by British TV studio Sky to congregate in “flash mobs” throughout London to raise awareness of Earth Day and what people, even non-divers, can do to reduce climate change. Here’s the YouTube video of the frogmen giving eco-friendly advice (although they probably should have taken the snorkels out of their mouths before speaking):

Dive Operators and Instructors, We Need Your Help: Reader Mike Boom suggested an interesting spin on our Reader Reports — ask the dive operators for reviews. “One of my favorite conversations with a dive boat or dive resort manager is to ask about the worst or weirdest customers they’ve had. That’s when the really funny stories come trotting out, like the nudist dive charters, the Russian mafiosos with prostitutes in tow, animal pesterers who get bitten in return.” So, dive operators and instructors, turn the tables and tell us your entertaining stories that would amuse and inform our readers. E-mail me at, and we’ll compile the tales for an upcoming issue.

Florida’s Breakers Reef Recovering Nicely: In our December e-mail, we reported how a tugboat line caused extensive damage to Palm Beach’s popular Breakers Reef. Marine experts thought it would take 100 years for corals to grow back but just a few months later, they announced the corals are recovering much faster than expected. That’s because the reef corals were scrapped clean off, making it easier for a group of volunteer divers from local engineering and environmental firms to re-attach over 130 hard corals and other organisms back in place, and they expect close to 100 percent survival. The West Palm Beach Fishing Club is taking donations to support these efforts; get details by phone at 561-832-6780 or send an e-mail to Bill Fay, the diver leading the restoration, at

Lobsters and Crabs Do Feel Pain: A study to be published in the journal Animal Behavior says crustaceans do feel pain and stress, adding to growing evidence that all animals, even shellfish, can suffer. Lead author Robert Elwood collected hermit crabs from rock pools in Northern Ireland and gave some of them small electric shocks. When he provided vacant shells, only the shocked ones left their old homes for them, showing stress-related behaviors like grooming their abdomens and rapping them against the shell. “Grooming is a protective motor reaction, like licking a burnt finger, and viewed as a sign of pain in vertebrates,” Elwood wrote. The fact that they showed signs of physical distress at the same time they changed a behavior — moving into another shell — suggests they feel pain, too. All the crabs survived and were put back in the rock pools.

Send Me Your Reader Reports: Filing one gives you a chance to relate your experience, address your fellow divers, air a complaint, give deserving operators a pat on the back, and hit the highlights of a recent trip. And of course, your comments will be posted on our website and in our 2010 Travelin’ Diver’s Chapbook. Complete the online form on Undercurrent by clicking on “Submit a Reader Report.” Or send you report in an e-mail or as an attachment to us at Submit reports for trips you’ve taken after July 2008, and don’t forget to put your name on the report.

Coming Up In Undercurrent: Wananavu Beach Resort, Fiji: an updated report on this divers’ favorite . . .why travel insurance is so important for your next dive trip overseas . . . . . should you sauna before a dive? . . .a new study shows what’s lurking in that rinse tank . . . where Hawaii’s fish have gone – it’s not just the fishermen taking them . . . how and where you can recycle used scuba gear . . . a double fatality in Cocos Island leads to a major lawsuit ruling for the dive industry . . . and much more

Ben Davison, editor/publisher
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