Massive transfusions require the coordination of physicians, nurses, laboratory testing, and the hospital’s blood bank. Many institutions have an alert system, similar to those used in the case of trauma, that informs the necessary personnel that a massive transfusion is likely to take place or is occurring.

Healthcare professionals preparing for a massive transfusion should ensure that the patient is hooked to a monitor and there is adequate intravenous access to deliver the blood products when they become available. Notifying the blood bank will also help avoid delays in getting further deliveries of blood products if necessary.

Many institutions have created protocols for massive transfusion using knowledge from interprofessional teams. These institution-specific protocols facilitate ordering blood products and receiving them expeditiously from the blood bank. While these protocols vary between institutions, many massive transfusion protocols focus on delivering PRBCs in addition to platelets and fresh frozen plasma (FFP).[6][9][10]

While unfeasible for the general population, there is strong evidence from medical, military experience demonstrating positive outcomes when fresh whole blood is transfused to trauma patients. This has led to the concept of mimicking whole blood during massive transfusion by transfusing packed red blood cells (PRBCs), platelets, and fresh frozen plasma (FFP), with fresh frozen plasma supplying the coagulation factors. There is still controversy regarding the best ratio of these 3 components in the setting of massive transfusion. Many experts advocate for a 1:1:1 ratio of FFP, platelets, and PRBCs. Lower ratios of platelets and FFP have been used without evidence of inferiority, and the vast majority of massive transfusion protocols at trauma centers target lower ratios of plasma to PRBCs (80% trauma centers in a study of MTPs have greater than a 1:2 ratio of plasma to packed reds). The use of cryoprecipitate, fibrinogen concentrate, and recombinant factor VIIIa have been used with mixed results.

There is also strong evidence from the military that the use of tranexamic acid (TXA) can reduce coagulopathy and increase survival in patients with combat injuries, and further evidence that the addition of TXA in civilian bleeding trauma patients can reduce death. TXA works by inhibiting fibrinolysis or clot breakdown. Given its good safety profile and overwhelmingly positive results, it has been incorporated into many massive transfusion protocols.[11]

Targets of resuscitation in the setting of massive transfusion include:

• Mean arterial pressure (MAP) of 60 to 65 mm Hg
• Hemoglobin 7 to 9 g/dL
• INR less than  1.5
• Fibrinogen  greater than 1.5 to 2 g/L
• Platelets greater than 50 times 10/L
• pH 7.35 to 7.45
• Core temperature greater than 35 C

Potential complications of massive transfusion include metabolic alkalosis, hypocalcemia, hypothermia, and hyperkalemia. Non-fatal complications have been seen in more than 50% of patients when more than 5 units of blood products are transfused.[12][13][14]

Metabolic alkalosis and hypocalcemia result from sodium citrate and citric acid that is added to blood products in storage to prevent coagulation. Each unit of blood can generate a total of 23 mEq of bicarbonate as citrate is metabolized. This can result in a metabolic alkalosis if the kidneys are unable to excrete the excess bicarbonate. Additionally, the alkalosis can result in hypokalemia as hydrogen ions move out of cells to compensate for the alkalosis through an H+/K+ transporter. Citrate also binds ionized calcium, which can lead to significant free hypocalcemia. It typically does not affect calcium bound to albumin. Severe hypocalcemia can result in paresthesias and cardiac dysrhythmias.

Hypothermia can also result from the infusion of blood products. Blood products are stored at 4 C. Rapid infusion of cold blood can lead to lower core body temperatures. Given that this population is already predisposed to hypothermia, which can further worsen coagulopathy, many rapid infusers also have warmers to reduce the risk of hypothermia during massive transfusion. Hyperkalemia is also a possible complication as potassium can increase in blood during long-term storage. It is typically only seen when blood products have been stored for long periods and are infused through central access at high speeds.[4]

Additionally, the traditional complications of blood transfusion, specifically transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) can occur with massive transfusion. While the pathogenesis of TRALI is poorly understood, the incidence of TRALI increases as the number of blood products given increases. The rapid onset of hypoxemia indicates TRALI within 6 hours of a transfusion. Patients clinically will look very similar to those with acute respiratory distress syndrome (ARDS) with a PaP2/FiO2 less than 300 mm Hg, bilateral infiltrates on chest x-ray, and no signs of systolic heart failure. TACO can also be seen with overzealous transfusion.[15]

Massive transfusion is an important life-saving intervention for patients with massive acute blood loss. Massive transfusion has been used in many clinical settings including obstetrics, gastroenterology, trauma, and the operating room. Although the etiology of bleeding is different in all of the cases, the same principles of massive transfusion apply. Massive transfusion can, however, have serious complications and should be reserved for patients with hemodynamic instability as a bridge to definitive therapy.

Today, all healthcare workers should be very familiar with the healthcare institution's policy of performing checks and cross-checks before transfusing blood. This is mandatory and it applies to the laboratory technologist who prepares the blood, the nurse who receives the blood from the blood bank and the nurse who transfuses it; in short, all members of the interprofessional healthcare team. The aim is to prevent adverse reactions to blood. All patients must be educated about the potential for adverse reactions before administering the blood. Further, the nurse must tell the patient to inform her or him in cases they develop a fever, headache, rash or difficulty breathing. The nurse should also be aware that nonhemolytic febrile reactions do occur in 10-15% of patients who receive blood and hence good clinical judgment is required when to continue the transfusion and when to discontinue it. If an adverse reaction occurs, the nurse should immediately stop the transfusion, call the physician and send the blood back with all the tubing back to the laboratory. Caution should be exercised at every step because complications of blood transfusions do have the potential to kill a patient. [16][17] This is why the interprofessional approach is necessary, so that this strategy is only used when necessary, and optimally administered when in use. [Level 5] 

Outcomes

In general, when massive blood transfusions are done especially in the setting of trauma, the potential for complications is high. Some studies indicate that no more than 20-30 units of blood should be given to avoid complications. Overall, most studies reveal that such transfusions do not lead to patient survival but in fact, are associated with many adverse events.[18][19] (Level V)