A simplified, step-by-step, sample flow chart for hemorrhage treatment is outlined below. The clinician should keep in mind that this outline describes an attempt to treat what should be a surgical problem, medically. One can only surmise at the nature of the internal insult. Periodic evaluation of the mare without quantification of the severity of the internal blood loss and the benefit of blood pressure measurements makes this a very challenging situation.
1. Obtain initial vital signs.
2. If internal bleeding is suspected and the mare is hypovolemic, insert a large-bore (12- to 14-gauge) IV catheter into the left, or most easily accessible, jugular vein. It may be prudent to catheterize both jugular veins, as these mares change positions frequently and because violent head movement may dislodge a catheter.
3. Administer 2 to 3 L of warmed hypertonic saline. Warmed saline has been shown not only to provide plasma expansion, but also to exert some cytoprotective properties by attenuating harmful humoral cascades.
4. Follow hypertonic saline with 2 to 3 L of a warmed polyionic crystalloid such as Normosol-R or Plamalyte. These solutions contain readily available buffers such as acetate and gluconate that do not need to be converted by the liver. They are available in rigid plastic containers that can be pressurized by a hand pump. This small amount of crystalloid furnished will often calm and stabilize a mare. The goal is to volume expand just enough to deliver oxygen and nutrients to cells, yet not to elevate blood pressure so that it will dislodge what hopefully is a growing clot at the site of injury. The clinician should not become overzealous in fluid administration without reevaluating vital parameters.
5. Try to make the mare’s environment conducive to clot formation (i.e., lessen noise and distractions, create warmth with heat lamps and blankets if it is severely cold), provide water to drink at regular intervals and in appropriate amounts, and if the mare is lying down, let her continue to do so because this may provide some pressure on internal organs and help to stem hemorrhage.
6. Attempt to characterize the site and magnitude of blood loss to better assess the time and expense that may be involved in a continued resuscitative effort. If fluid is found on transabdominal ultrasound, abdominocentesis and fluid analysis is strongly advised.
7. After the initial crystalloids, 3 to 4 L of plasma are highly recommended because they will provide proteins and clotting factors. If owners are willing to spend money and the mare is valuable, plasma is probably the most important “medication” to give. This colloid can be kept in the freezer at home so that it is convenient to take to an emergency, or have it picked up by a farm employee. Thawed plasma can be kept in a refrigerator or cooler for as long as 7 days or more.
8. Reevaluate vital signs and determine if more fluids should be given. A stall-side chart to jot down the course of medications and the amounts administered is highly recommended.
9. Consider taking a peripheral blood sample for complete blood count and biochemical analysis.
10. If the mare continues to deteriorate, serious consideration should be given to a fresh whole blood transfusion (). The main purpose of the transfusion is to provide more oxygen carrying red blood cells. Even though a conservative amount of anticoagulant is prescribed in this protocol, the risk that progression of clot formation could be hindered is always present. A vaccinated, equine infectious anemia-negative gelding or nonparous mare is a suitable donor.
The additional expense of the following adjunctive medications may be deemed necessary once the mare has stabilized:
1. Aminocaproic acid — a hemostatic agent to inhibit fibrinolysis; 20 g in fluids can be given as a loading dose, followed by 10 g every 6 hours thereafter; usually started if mare is stabilized, because clot fibrinolysis should not begin until 12 hours after its formation.
2. Flunixin meglumine — -to control inflammation and endotoxin insult; follow appropriate dosage and regimen.
3. Furosemide — to promote enhanced renal blood flow in the face of aggressive resuscitation; follow appropriate dosage and regimen.
4. Various tranquilizers — to calm uncontrollable mares; this author avoids these and has not found one to be better than another. A sudden drop in blood pressure may occur in a hypovolemic mare.
5. Broad-spectrum antibiotics — sulfonamides or penicillin/gentamicin strongly encouraged if the mare is hydrated.