question: How do we restore missing blood after a blood donation??
comment: Taking bkood from your body lowers your blood pressure, and triggers your bone marrow to start making more. Its more complicated than that.. But..
passages: Section::::Blood salvage procedures.
  
  Several processes have been developed to assist in salvaging the patient's own whole blood in the perioperative setting. These can be categorized into three general types of salvage procedures:
  
  BULLET::::1. Cell processors and salvage devices that wash and save red blood cells, i.e. "cell washers" or RBC-savers
  
  BULLET::::2. Direct transfusion
  
  BULLET::::3. Ultrafiltration of whole blood
   Insufficient transfusion efficacy can result from red blood cell (RBC) blood product units damaged by so-called "storage lesion"—a set of biochemical and biomechanical changes which occur during storage. With red cells, this can decrease viability and ability for tissue oxygenation. Although some of the biochemical changes are reversible after the blood is transfused, the biomechanical changes are less so, and rejuvenation products are not yet able to adequately reverse this phenomenon.
   Intraoperative blood salvage
  
  Intraoperative blood salvage (IOS), also known as cell salvage, is a specific type of autologous blood transfusion. Specifically IOS is a medical procedure involving recovering blood lost during surgery and re-infusing it into the patient. It is a major form of autotransfusion.
   It has been used for many years and gained greater attention over time as risks associated with allogenic (separate-donor) blood transfusion have seen greater publicity and become more fully appreciated. Several medical devices have been developed to assist in salvaging the patient's own blood in the perioperative setting. The procedure is frequently used in cardiothoracic and vascular surgery, during which blood usage has traditionally been high. A greater effort to avoid adverse events due to transfusion has also increased the emphasis on blood conservation (see bloodless surgery).
  
  Section::::Background.
   Hemofiltration or ultrafiltration devices constitute the third major type of blood salvage in operating rooms. In general, ultrafiltration devices filter the patient's anticoagulated whole blood. The filter process removes unwanted excess non-cellular plasma water, low molecular weight solutes, platelet inhibitors and some particulate matter through hemoconcentration, including activated cytokines, anaphylatoxins, and other waste substances making concentrated whole blood available for reinfusion. 
   Research published in 2012 demonstrated that repeated blood donation is effective in reducing blood pressure, blood glucose, HbA1c, low-density lipoprotein/high-density lipoprotein ratio, and heart rate in patients with metabolic syndrome.
  
  Section::::Donor compensation.
   Blood is sometimes collected using similar methods for therapeutic phlebotomy, similar to the ancient practice of bloodletting, which is used to treat conditions such as hereditary hemochromatosis or polycythemia vera. This blood is sometimes treated as a blood donation, but may be immediately discarded if it cannot be used for transfusion or further manufacturing.
   Intraoperative blood salvage is a technique which recycles and cleans blood from a patient during an operation and redirects it into the patient's body.
  
  Postoperatively, surgeons seek to minimize further blood loss by continuing administration of medications to augment blood cell mass and minimizing the number of blood draws and the quantity of blood drawn for testing, for example, by using pediatric blood tubes for adult patients.
   BULLET::::- Baxter Healthcare Corporation (2005), in which "pinhole leaks were observed at the two-omega end of the umbilicus (multilumen tubing), causing a blood leak."
  
  BULLET::::- Fenwal Incorporated (2007), in which there were "two instances where the anticoagulant citrate dextrose (ACD) and saline lines were reversed in the assembly process. The reversed line connections may not be visually apparent in the monitor box, and could result in excessive ACD infusion and severe injury, including death, to the donor."
  
  Section::::Types.:Donation.:Donor safety.:Plasticizer exposure.
   Thus far, there are no available "oxygen-carrying" blood substitutes, which is the typical objective of a blood (RBC) transfusion; however, there are widely available non-blood "volume expanders" for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of Jehovah's Witnesses and others who have religious objections to receiving transfused blood.
   Donated plasma is replaced after 2–3 days. Red blood cells are replaced by bone marrow into the circulatory system at a slower rate, on average 36 days in healthy adult males. In one study, the range was 20 to 59 days for recovery. These replacement rates are the basis of how frequently a donor can donate blood.
   Autologous blood cell salvage is a therapeutic approach to recover the blood during cardiac surgery. Today, it is also widely used in many other high risk of surgeries around the world. Some reports suggest that if autologous blood cell salvage is routinely used in open heart surgeries, the requirements for blood transfusions can be effectively reduced. Moreover, the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists guidelines argued that the routine use of intraoperative blood salvage is beneficial to blood conservation during CPB. However, it is not available to patients who have infection or malignancy.
   The amount of blood drawn and the methods vary. The collection can be done manually or with automated equipment that takes only specific components of the blood. Most of the components of blood used for transfusions have a short shelf life, and maintaining a constant supply is a persistent problem. This has led to some increased interest in autotransfusion, whereby a patient's blood is salvaged during surgery for continuous reinfusion—or alternatively, is "self-donated" "prior" to when it will be needed. (Generally, the notion of "donation" does not refer to giving to one's "self", though in this context it has become somewhat acceptably idiomatic.)
   Blood donations are divided into groups based on who will receive the collected blood. An 'allogeneic' (also called 'homologous') donation is when a donor gives blood for storage at a blood bank for transfusion to an unknown recipient. A 'directed' donation is when a person, often a family member, donates blood for transfusion to a specific individual. Directed donations are relatively rare when an established supply exists. A 'replacement donor' donation is a hybrid of the two and is common in developing countries such as Ghana. In this case, a friend or family member of the recipient donates blood to replace the stored blood used in a transfusion, ensuring a consistent supply. When a person has blood stored that will be transfused back to the donor at a later date, usually after surgery, that is called an 'autologous' donation. Blood that is used to make medications can be made from allogeneic donations or from donations exclusively used for manufacturing.
   Hemofilter devices return the patient's whole blood with all the blood elements and fractions including platelets, clotting factors, and plasma proteins with a substantial Hb level. Presently, the only whole blood ultrafiltration device in clinical use is the Hemobag. These devices do not totally remove potentially harmful contaminants that can be washed away by most RBC-savers. However, the contaminants that are potentially reduced by using RBC-savers, as shown by data from in vitro laboratory tests, are transient and reversible in vivo with hemostatic profiles returning to baselines within hours. The key is that coagulation and homeostasis are immediately improved with the return of concentrated autologous whole blood.
   During surgery, techniques are utilized to reduce or eliminate exposure to allogeneic blood. For example, electrocautery, which is a technique utilized for surgical dissection, removal of soft tissue and sealing blood vessels, can be applied to a variety of procedures. During surgical procedures that are expected to have significant blood loss, blood that is lost during surgery can be collected, filtered, washed and given back to the patient. This procedure is known as "Intraoperative Blood Salvage." Pharmacologic agents, for example tranexamic acid, can also be utilized to minimize blood loss. Another technique, acute normovolemic hemodilution" involves the collection of a selected calculated volume of autologous blood in collection bags prior to the start of surgery with the simultaneous replacement of an equal volume of asanguinous fluid. Since the patient's blood is now diluted, blood lost during the surgical procedure, i.e. by hemorrhage, contains smaller amounts of red blood cells. The collected autologous blood product, which contains red blood cells, platelets and coagulation factors, is reinfused at the end of the surgery. When all of these therapies are combined, blood loss is greatly reduced which correspondingly reduces or averts the potential for allogeneic blood transfusion. 
   Section::::Other blood conservation techniques.:Autologous blood cell salvage.
   After the exchange transfusion, catheters may be left in place in case the procedure needs to be repeated.
  
  In diseases such as sickle cell anemia, blood is removed and replaced with donor blood.
  
  In conditions such as neonatal polycythemia, a specific amount of the child’s blood is removed and replaced with normal saline, plasma (the clear liquid portion of blood), or an albumin solution. This decreases the total number of red blood cells in the body and makes it easier for blood to flow through the body.
  
  Section::::Medical Uses.
  
  Section::::Medical Uses.:Sickle Cell Disease.
   Donors are usually kept at the donation site for 10–15 minutes after donating since most adverse reactions take place during or immediately after the donation. Blood centers typically provide light refreshments, such as orange juice and cookies, or a lunch allowance to help the donor recover. The needle site is covered with a bandage and the donor is directed to keep the bandage on for several hours. In hot climates, donors are advised to avoid dehydration (strenuous exercise and games, alcohol) until a few hours after donation.
   In three small studies of 1-2 patients suffering from recurrent CSF leaks where repeated blood patches failed to form clots and relieve symptoms, the patients received temporary but complete resolution of symptoms with an epidural saline infusion. The saline infusion temporarily restores the volume necessary for a patient to avoid SIH until the leak can be repaired properly. Intrathecal saline infusion is used in urgent cases such as intractable pain or decreased consciousness.
   Hypovolemic reactions can occur because of a rapid change in blood pressure. Fainting is generally the worst problem encountered.
  
  The process has similar risks to other forms of phlebotomy. Bruising of the arm from the needle insertion is the most common concern. One study found that less than 1% of donors had this problem. A number of less common complications of blood donation are known to occur. These include arterial puncture, delayed bleeding, nerve irritation, nerve injury, tendon injury, thrombophlebitis, and allergic reactions.
   Section::::Rugby union.
  
  In rugby union, blood replacements are provided for by Law 3.10 of the International Rugby Board.
   Regardless of manufacturer, there are many types of cell processors. Cell processors are red cell washing devices that collect anticoagulated shed or recovered blood, wash and separate the red blood cells (RBC) by centrifugation, and reinfuse the RBC. RBC washing devices can help remove byproducts in salvaged blood such as activated cytokines, anaphylatoxins, and other waste substances that may have been collected in the reservoir suctioned from the surgical field. However, they also remove viable platelets, clotting factors, and other plasma proteins essential to whole blood and homeostasis. The various RBC-savers also yield RBC concentrates with different characteristics and quality.
   The type of treatment depends on the severity of the patient’s bone marrow failure disease. Blood transfusion is one treatment. Blood is collected from volunteer donors who agree to let doctors draw blood stem cells from their blood or bone marrow for transplantation. Blood that is taken straight from collected blood stem cells is known as peripheral blood stem cell donation. A peripheral stem cell donor must have the same blood type as the patient receiving the blood cells. Once the stem cells are in the patient’s body through an IV, the cells mature and become blood cells. Before donation, a drug is injected into the donor, which increases the number of stem cells into their body. Feeling cold and lightheaded, having numbness around the mouth and cramping in the hands are common symptoms during the donation process. After the donation, the amount of time for recovery varies for every donor, “But most stem cell donors are able to return to their usual activities within a few days to a week after donation”.
   If a significant amount of red blood cells cannot be returned, the donor may not donate for 56 days, just as if they had donated a unit of blood. Depending on the collection system and the operation, the removed plasma may be replaced by saline. The body typically replaces the collected volume within 24 hours, and donors typically donate up to twice a week, though this varies by country.
  