Hct = hematocrit; RBCs = red blood cells.
or treatment of hypovolemia rom catastrophic hemorrhage. It has a shelf life of 40 days, and 70 percent of the transfused red cells function for at least 24 hours following transfusion. One unit raises the hematocrit by 3 to 4 volume percent. Important for obstetrical hemorrhage, whole blood replaces many coagulation factors in obstetrics-especially fibrinogen-and its plasma treats hypovolemia. A collateral derivative is that women with severe hemorrhage are resuscitated with fewer blood donor exposures than with packed red cells and components (Shaz, 2009).
Evidence supports the preferable use of whole blood for massive hemorrhage, including our experiences at Parkland Hospital (Alexander, 2009; Hernandez, 2012). Of more than 66,000 deliveries, women with obstetrical hemorrhage treated with whole blood had signiicantly lower incidences of renal failure, acute respiratory distress syndrome, pulmonary edema, hypoibrinogenemia, intensive care unit admissions, and maternal death compared with those given packed red cells and component therapy. Freshly donated whole blood has also been used successfully for life-threatening massive hemorrhage at combat support hospitals (Murdock, 2014; Stubbs, 2016).
In most institutions today, however, whole blood is rarely available. hus, most women with obstetrical hemorrhage and ongoing massive blood loss are given packed red cells and crystalloid. In these instances, no data support a 1: 1 plasma: red cell transfusion ratio. As subsequently discussed, many institutions use massive tranfusion protocols designed to anticipate all facets of massive obstetrical hemorrhage. These "recipes" commonly contain a combination of red cells, plasma, cryoprecipitate, and platelets (Cunningham, 2015; Pacheco, 2011; Shields, 201l).
Several studies have assessed plasma:red cell ratio with massive transfusion protocols used in civilian trauma units and military combat hospitals (Borgman, 2007; Gonzalez, 2007; Hardin, 2014; Johansson, 2007). Patients undergoing massive transfusion-deined as 10 or more units of blood-had much higher survival rates as the ratio of plasma to red cell units neared 1: 1.4, that is, one unit of plasma given for each 1.4 units of packed red cells. By way of contrast, the highest mortality group had a ratio of 1 :8. Most of these studies ound that component replacement is rarey necessay with acute replacement of 5 to 10 units of packed red cels.
F rom the foregoing, when red cell replacement exceeds five units or so, evaluation of platelet count, clotting studies, and plasma fibrinogen concentration is reasonable. In the woman with obstetrical hemorrhage, the platelet count should be maintained > 50,000/�L by the infusion of platelet concentrates. A fibrinogen level < 150 mg/dL or a suiciently prolonged PT or PTT in a woman with surgical bleeding is an indication for replacement. Fresh-frozen plasma is administered in doses of 10 to 15 mLlkg, or alternatively, cryoprecipitate is infused (see Table 41-8).