Hematopoietic system topics that are most frequently encountered in surgical critical illness are listed in Table 10.1.
SUBMASSIVE TRANSFUSION
The most common reason for the administration of blood products is the submassive loss of red blood cells (RBCs) or the reversal of a hypocoagulopathy that may be either disease- or therapy-induced. The potential adverse effects of RBC transfusion are listed in Table 10.2 (1, 2, 3, 4, 5, 6, 7). Many of the adverse effects appear to be linked to the presence of leukocytes in the RBC transfusion, and several may be ameliorated by processing that results in a more effective leukoreduction (1, 3, 6). Whether or not such a strategy will diminish the incidence of mortality and multisystem organ failure following submassive RBC transfusion remains to be determined.
The recognition of these adverse effects has accompanied the almost simultaneous realization that blood oxygen content can be reduced to nearly 50% of normal (decreased hemoglobin concentration from 14 to 7 g/dl) without a measurable decreased in tissue oxygenation parameters during surgical critical illness in the Flow Phase of shock. The important issue in this realization is that achievement of the Flow Phase of shock with augmented oxygen delivery and consumption must then depend upon an enhanced circulation, i.e., increased cardiac output, rather than more blood oxygen content (see chaps. 2 and 3) (5).
Clinical practice guidelines for the transfusion of red cells in adult trauma and critical care have been well described (Table 10.3) (8). Most controversial is the use of RBC administration during early goal-directed resuscitation of sepsis where the published protocol included RBC transfusion if the venous oxygen saturation end point was not achieved through crystalloid infusion alone (9). Two-thirds of the goal-directed group received an RBC transfusion as compared to 44% of the control group, and there was a survival advantage to the goal-directed strategy (5). This advantage does not appear to continue after resuscitation endpoints are achieved (8).
Table 10.4 has a listing of potential adverse reactions to fresh frozen plasma (FFP), cryo-precipitate, and platelet (PLT) transfusion (10, 11, 12, 13, 14, 15). FFP that is ABO-compatible rather than ABO-identical appears to augment risk, suggesting that when feasible, the ABO-identical FFP be selected (16).
Traumatic brain injury is the most common indication for FFP and/or PLT transfusion in submassive transfusion, and, typically, in the setting of drugs that cause coagulopathy (warfarin and/or anti-platelet agents). As noted in the chapter 9, the administration of FFP and PLT under these circumstances is beneficial (17, 18). However, as the adverse possibilities of FFP and PLT administration are noted, the submassive application of these products demands caution and well-delineated indications, like those developed for RBC transfusion.
MASSIVE TRANSFUSION IN TRAUMA
Massive transfusion (MT) in trauma is most often defined as the administration of >10 units of RBCs in the first 24 hours after injury. Some authors restrict MT to patients who receive this volume in the first six hours (16, 19). As expected, MT is associated with higher injury severity, hypotension (<70 gm Hg systolic), hypothermia (<34°C), and metabolic acidosis (pH <7.1) (19, 20, 21). While in the past, coagulopathy was considered dilutional and/or a consequence of fluid and RBC administration, more recent data demonstrate that coagulopathy (especially an international normalized ratio >1.5) is usually present shortly after injury in patients who will receive MT (19, 20).
Therefore, the MT patient often exhibits the “triangle of death” at the time of or shortly after Emergency Department admission. While efforts to control hemorrhage are the mainstay of management (see chap. 5), anticipation of coagulopathy, and early and aggressive administration of coagulation factors (FFP, PLT) in a 1:1:1 ratio with RBC is associated with decreased mortality from early exsanguination as well as that extending out to 48 hours (20, 22, 23).
Table 10.2 Potential Adverse Effects of Red Cell Transfusion
Fever
Alloimmunization from transfused leukocytes
ABO incompatibility—rare
Contamination—rare
Leukocytosis—reduced by filtration of leukocytes
Immunosuppression and new infection (especially blood >12 days old)
Transfusion associated acute lung injury (TRALI)
Multisystem organ malfunction
Table 10.3 Guidelines for Red Cell Transfusion
General critical illness
Hemorrhagic shock (active bleeding and Ebb phase)
Restrictive strategy (transfuse for hemoglobin (Hgb) <7 g/dl) is indicated for flow phase patients. May transfuse for Hgb >7, <10 g/dl for acute myocardial ischemia and/or new onset sepsis, especially in Ebb phase
Do not use Hgb only as the trigger—use overall assessment of oxygen delivery and consumption
Can use single unit transfusion
Sepsis
First six hours—if central venous oxygen saturation is not 70% or greater after fluid infusion, then RBC transfusion to a hematocrit of 30% is acceptable (patient remains in the Ebb phase).
Later sepsis—transfuse if Hgb < 7 g/dl
Risk or presence of acute lung injury and/or ARDS
Avoid transfusion
Report possible TRALI event
Traumatic brain injury
No benefit for transfusion for Hgb 7-10 g/dl range
Only gold members can continue reading. Log In or Register to continue
