Donating Blood & Diving

[large_diver]

I went to donate blood last night after work (just one more donation to hit the 4 gallon mark), and although I don't have any diving planned for the next few weeks it got me to thinking -- is there a big risk if you dive immediately after giving blood? Is there a recommended time period I should wait between blood donation and diving -- perhaps the same 24 hour period the Red Cross advises you wait before enagaging in strenuous exercise/lifting?

Thanks, as always.

 

[DocVikingo]

Hey large,

Given that you have an adequate hemoglobin level (which is routinely assessed at the time of donation), a wait of 24 hours prior to diving should be sufficient provided you feel up to it. Be sure to drink plenty of fluids.

Donate & dive often.

DocVikingo

 

[Dr Deco]

Hello large:

From the viewpoint of decompression physiology, the governing factor is the local perfusion (= blood flow) in the tissue capillaries. That local flow is important in removing the dissolved nitrogen during the off gassing portion of the dive. Fluid replacement is the key.

Since inert gases are not specifically transported in the red blood cells (oxygen is), the missing RBCs will not affect the decompression characteristics. Fitness to dive is another question as alluded to above by DocVikingo.
Four gallons is commendable amount!
My Congratulations! :royal:

Dr. Deco

 

[scubadoc]

Hi large:

I'll just chime in with some information on my web site to agree with the above. Divers often donate blood and need to know when to resume diving. 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 about 24 hours. If there is no anemia (<12 Gm/dl), the diver can return to diving whenever the fluid component is replenished. However, 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.

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 blood 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 that stimulates red blood cell formation, can also be given to stimulate the bone marrow into producing more red blood cells. It is possible that the time interval before red cell replenishment can thus be shortened to 4 - six weeks after blood donation, depending on the hemoglobin level.

 

[large_diver]

Thanks for the responses guys.

Some follow-up questions for Scubadoc (and anyone else who wants to chime in) --

You started out your note by saying you wanted to add some information that would basically agree with the posts by DocV and Dr. Deco....after reading your post, I'm not sure if you are agreeing with them or not. Their point seemed to be that assuming adequate fluid replenishment, 1-2 days should be an adequate wait time before diving again. Dr. Deco even states that the missing RBCs will not result in increased risk of DCS. Your note focuses on the 8 week replenishment time for the lost RBCs...but you never come out and say that the lower RBC count is a risk (reduced oxygen carrying capacity appears to be the main issue).

Can you try and clarify this for me? I obviously have donated a lot of blood in my life, but I realized after looking at my donation card that this is my first donation since I started diving last spring. I usually feel fine after donating as long as I wait 48 hours before doing any hard core exercising.

Thanks again for your help on this issue. I will contact DAN as well to see what they have to say.

 

[large_diver]

FYI -- Here is the e-mail response I received from DAN regarding blood donation and scuba diving:

"Although blood volume will return to normal shortly following blood donation, a lower red blood cell count may contribute to undesirable signs and symptoms such as fatigue and dehydration. Such conditions are well known to increase one's risk for a dive accident or possible decompression sickness. Medical standards for divers, as defined in a clinical by the Undersea Hyperbaric and Medical Society, states divers should not dive for at least 48 to 72 hours after blood donation. DAN routinely recommends 72 hours."

Fatigue -- yeah, I got a nice reminder of that yesterday morning when I tried to do my normal mile swim at 6AM after donating blood at 6:30 PM the night before.......

 

[scubadoc]

Hi large:

We are not at all at odds with the other answers. Please note my sentence in the second paragraph: "The donor’s body replenishes the fluid lost from donation in about 24 hours. If there is no anemia (<12 Gm/dl), the diver can return to diving whenever the fluid component is replenished."

Hemoglobin is focused on because the oxygen-carrying potential is basically the only thing important to the diver in the process of blood loss (donation). Go to this link for more 'brain-swelling' information about anemia and diving.

Some interesting facts:

• DCS causes aggregation of the blood platelets but apparently does not affect the red blood cells. Nitrogen is not thought to participate with the hemoglobin molecules in the red cell.
  
• Serum, the liquid in blood, can take up large quantities of oxygen under pressure.
  
• Once oxygen enters the red blood cell and combines with the hemoglobin molecule - it does not exert any partial pressure.

 

[large_diver]

Thanks scubadoc -- I appreciate the follow-up and the link.

By the way, I have tried apheresis before (in response to an ill friend) -- I have to admit that the "chilling" effect of having your blood removed and then put back into your body was more than I could take. I think I'll stick to normal blood donation.

 

[DocVikingo]

Hi large,

You absolutely should listen to UHMS & DAN, but I am unable to discern the basis for those recommendations. We all seem to be in agreement that fluid replacement is the critical matter following donation, and if one's intake of liquids is appropriate in type & quantity this should be a non-issue after 24 hours. Continued appropriate fluid intake during a post-donation dive trip should preclude any increased risk of DCS due to dehydration.

This leaves the RBC situation. As I understand it, the drop in RBCs from a routine donation is quite small. In my limited appreciation of hematology, it would seem an individual going in with a normal hematocrit & hemoglobin level should at 24 hours post-donation have sufficient oxygen carrying/waste gas removal capacity to engage in reasonably vigorous physical activity without fatigue. If they do not, I am not sure that the replacement of RBCs that occurs within the recommended 72-hour wait would be sufficient to significantly attenuate the problem.

I have not researched this & am just shooting from the hip. No doubt some of our true experts will be able to shed additional light.

DocVikingo

 

[large_diver]

My first dive of the season probably won't be until about 3-4 weeks after this donation....I think I'll be safe.

Bottom line, I will likely restrict future donations to the off-season just to be safe.

Thanks again to all for the thoughtful responses.

-LD