15. Transfusion Strategies In The ICU

Large-Volume Blood Loss in the ICU 

  • Access: large-bore (≥16g) PIVs are best. Consider Cordis (9 fr) or Rapid Infusion Catheter (7 fr) for more access. Triple-lumen lines/central venous catheters and PICCs are too slow because they are long and thin. 
  • Prepare: communicate with your blood bank (At UCSF: you have to pick up the phone and call the blood bank in addition to placing the order in Apex). Activate massive transfusion protocol early if you anticipate more than 8 pRBCs in 24 hours or more than 4 units in 1 hour. Consider calling early for a Level-1 rapid infuser from Anesthesia and an ICU fellow/attending can help operate the device. 
  • Transfuse: 
    • RBCs: transfuse as needed for hemodynamic support and oxygen-carrying capacity in hypotensive patients with acute blood loss. 
    • FFP and platelets: massive transfusion of RBCs can have dilutional effect on coagulation factors. Various ratios have been studied, trials are ongoing so no consensus. Data from trauma literature suggest 1:1:1 ratio of pRBC:FFP:platelets for massive transfusion but this is due to acute traumatic coagulopathy. UCSF massive transfusion protocol gives 4 RBC:4 FFP:1 unit platelets. 
    • Cryoprecipitate: remember to check fibrinogen levels, transfuse cryoprecipitate when fibrinogen <100. 
  • Complications: monitor for hypocalcemia (pRBCs are stored with citrate which binds calcium), hypothermia (although you can warm the blood as you give it), hyperkalemia and acid-base derangements. 
  • Stop the bleeding (GI for endoscopy, Minnesota tube, IR for embolization or TIPS, surgery). 

Subacute Anemia in the ICU 

  • Anemia is prevalent in the ICU: approximately 2/3 of all patients. 
  • Anemia occurs even in the absence of active bleeding: etiology likely multifactorial secondary to phlebotomy, minor procedures, nutritional deficiency, and decreased production due to illness. 
  • Both anemia and transfusions have been associated with worse outcomes. 
  • Large RCTs in MICU patients show that erythropoietin does not reduce mortality and can increase thrombotic risk. 

Caring wisely: be mindful about what daily labs patients in the ICU actually need to minimize iatrogenic anemia. Patients don’t need a full set of labs every day just because they are in the ICU! 

Restrictive vs. Liberal Transfusion Strategies 

  • TRICC trial (1999): compared restrictive (Hb <7) and liberal (Hb <10) RBC transfusion strategies in euvolemic ICU patients without evidence of active hemorrhage. Decreased in-hospital mortality in restrictive group and decreased 30-day mortality in subgroup analysis (age <55 or less acutely ill w/ APACHE Score <20). 
  • GI bleeding: RCT in 2013 showed that in patients with acute severe upper GI bleeding, transfusion threshold of Hb <7 improved 6-week survival, lowered rebleeding, and resulted in fewer complications compared to Hb <9. 
  • TRISS Trial (2014): compared transfusion threshold of Hb <7 vs Hb <9 in patients with septic shock. Found no difference in 90-day mortality, ischemic events or use of life support between groups. 

Conclusions

  • Reduce unnecessary transfusions to reduce associated risks (e.g. TRALI, infections, volume overload) and conserve blood products. Goal hemoglobin of 7 is acceptable in most patients. 
  • Exceptions are patients with active myocardial ischemia (excluded from most studies), cyanotic heart disease, or severe hypoxemia. 

Keywords: TRICC, transfusion, RBC, anemia, hemoglobin 

Hebert HC, Wells G, Blajchman MA.  A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care.  N Engl J Med 1999; 340:409-417. 

Marik PE, Corwin HL. Efficacy of red blood cell transfusion in the critically ill: a systematic review of the literature. Crit Care Med. 2008;36(9):2667-74. 

PROPPR Study Group. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: the PROPPR randomized clinical trial. JAMA. 2015;313(5):471. 

Snyder CW, Weinberg JA. The relationship of blood product ratio to mortality: survival benefit or survival bias? J Trauma 2009; 66:358-62. 

TRISS Study Group. Lower versus Higher Hemoglobin Threshold for Transfusion in Septic Shock. N Engl J Med 2014; 371:1381-1391. 

Villanueva C, et al. Transfusion Strategies for Acute Upper Gastrointestinal Bleeding. N Engl J Med 2013; 368:11-21.