The ideal material for use in hemorrhagic shock would be disease-free, body-temperature, fresh, whole blood, with identical blood type and major and minor blood groups.
This blood has excellent oxygen-carrying capacity, platelets, coagulation factors, volume and colloid, and would be totally non-reactive within the victim’s bloodstream. Unfortunately, this ideal material does not exist (at least not when quickly needed), so we usually compromise, using various other blood products, depending on the needs of the patient.
In an extreme emergency, you can give the patient type O negative packed RBCs from the blood bank.
For someone whose blood type is unknown and there is no time for cross-matching, this is the best approach. If type O negative blood is not available, type O positive can be substituted with good results, but there is a fair chance that the patient (if Rh negative) will become sensitized against the Rh factor. Still, that may be preferable to losing the patient because they weren’t transfused quickly enough.
If the patient’s blood type is known, you can give type specific blood to her. If she is type B positive, you can give type B positive blood to her. In either case, it is best to draw a plain tube of blood just before giving the non-crossmatched blood to help in figuring out her native blood type. The danger to this approach outside of a hospital blood bank setting is that you run the risk of one or both of the blood type labels being wrong. If you try to pair blood types, you run that risk of misidentification twice.
If you have more time, it is better to give cross-matched blood. Cross-matched means the type (A, B, AB, or O) will match, and the major factors (Rh, Kell, etc.) will match. There will undoubtedly be some minor factors that do not match, and the degree of a match hinges, in part, on the size of your blood bank and the available time.
Transfusions are usually with packed RBCs (following removal of much of the serum, coagulation factors, platelets and fibrinogen). This works well enough and is very effective at restoring oxygen carrying capacity. Give enough units so the kidney function is normal (>30 cc/hour) and the patient has no more than mild symptoms of hypovolemia. There is no specific hemoglobin concentration that should be a target.
Following transfusion, the per-unit risk of developing:
- Hepatitis C is about 1 in 3300
- Hepatitis B is about 1 in 200,000
- HIV is about 1 in 500,000
In some cases of severe hemorrhage, a coagulopathy develops as a consequence of loss of platelets and/or clotting factors. This situation can be determined through lab tests (PT, PTT, fibrinogen, platelet count, bleeding time, and others), or clinically by observing multiple bleeding sites from the mouth, gums, needle puncture sites or surgical sites. A crude estimate may be obtained by taping a red-top tube of blood to the wall. A clot should form within about 5 minutes. If it doesn’t, a coagulopathy of some form can be presumed. Coagulopathy can be suspected in anyone with massive blood loss (requiring 4 or more units of RBCs to correct).
Fresh frozen plasma (FFP) contains plasma proteins and clotting factors. For patients who are actively bleeding and have a demonstrated coagulopathy with prolonged PT and PTT, FFP will help restore hemostasis. For those not actively bleeding, FFP is not often needed if the PT and PTT are prolonged no more than 1.5 times normal. FFP need not be given prophylactically with RBC transfusions in the absence of coagulopathy. However, if the total blood volume has been replaced in an individual, FFP is sometimes given.
If the only missing factor is fibrinogen (sometimes the case with placental abruptions and often the case with long-standing missed abortions), then cryoprecipitate can be given to replace the fibrinogen. Cryoprecipitate also contains von Willebrand’s factor and is useful in treating bleeding patients with this particular deficiency.
Platelets are given if the platelet count falls below 50,000 and the patient continues to bleed. In the absence of bleeding, platelet counts between 10,000 and 50,000 are worrisome, but usually not an indication for platelet transfusion. If the platelets fall below 10,000, the patient should be transfused as the risk for CNS and GI bleeding rises significantly. Pre-operatively, those with platelet counts below 50,000 may be transfused.
Transfusion Without a Blood Bank
In civilian settings, banked blood is usually given. In many operational settings, standard blood banking procedures may not be applicable or available. In these cases, direct donor to victim transfusion can be life-saving.
Use a donor with O negative blood (“Universal Donor”). Don’t try to match, for example, a B+ victim to a B+ donor. While the accuracy of blood type records has improved, there is still a significant inaccuracy rate (as high as 5%) in the medical record laboratory reports, identification cards, and dog tags. If you try to match a B+ victim to a B+ donor (type-specific blood transfusion), you are twice taking a 5% risk of a mismatch. It is safer to take that risk only once.
If the only available blood for a Rh negative victim is Rh positive blood, Rhogam may be used, in very large doses of 25-30, full-size, 300 microgram ampoules, IV, per unit of blood, to neutralize the Rh sensitizing effects of the Rh positive blood.
Arrange IV tubing so that there is a large-bore needle at each end. This is facilitated by use of a 3-way stopcock. If this is not available, you can simply cut off the tubing at the end and insert it into the hub of a needle. Sterile petroleum jelly can provide a seal and the needle is held tightly to the IV tubing with adhesive tape.
Position the donor about 3 feet higher than the victim. With the victim in a lower bunk, the donor would be in an upper bunk. With the victim on the floor or on the deck, the donor would be on a cot or packing crate.
Insert the IV into the donor and let the blood flow downhill through the tube until it reaches the other end. Clamp the tubing just long enough to insert the other end into the victims IV or vein.
Unclamp the tubing and allow time for about 1 unit (500 cc) of blood to flow into the victim. The exact amount of time would depend on the caliber of the tubing and needle, length of the tubing, height of the donor above the victim and doubtless other factors. In practice, allow about 10 minutes, but be prepared to stop it earlier if the donor becomes light-headed or dizzy.
Because fresh, whole blood has better oxygen-carrying capacity than banked units of packed RBCs, and it is prewarmed, and because it contains platelets, clotting factors and serum proteins, each unit has about twice the clinical impact of a unit of packed cells from the bank. If, based on your clinical experience, you believe a patient would benefit from two units of PRBCs from a blood bank, they will generally do well with a single unit of fresh, whole blood.
After the patient is transferred to a definitive care facility, it will be easier for them to identify the true, native blood type (major and minor blood groups) if they have a sample of blood taken from the patient prior to any transfusions. If time permits and the tactical situation allows for it, try to draw a single red-topped tube of the victim’s blood prior to transfusion that you can send along with the MEDEVAC for use by blood banks further up the line.