SPA Annual Meeting Reviews
Session III: Rapid Pediatric Blood Transfusions
Reviewed by Elizabeth S. Yun, MD
Associate Professor (CHS)
University of Wisconsin School of Medicine and Public Health
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Dr. Yun |
Rapid Pediatric Blood Transfusions
Norma J. Klein, MD
University of California, Davis
Norma J. Klein, MD (University of California, Davis) discussed two complications of massive transfusions in pediatric patients, recommended protocols currently in the literature and provided some evidence for safe administration of massive transfusion.
Dr. Klein began by reviewing transfusion associated hyperkalemia (TAH). She noted that the Pediatric Perioperative Cardiac Arrest Registry showed that anesthesia cardiac related deaths in pediatric patients has increased over the past seven years. The registry identified hypovolemia and hyperkalemia as the most common identifiable causes that could have been prevented. Reasons for these complications included underestimation of blood loss, inadequate access, not enough help and delay in getting blood and undertreated, unrecognized hypocalcemia.
Dr. Klein then discussed the potassium content in packed red cells and the impact of that content in a rapid transfusion setting. The potassium content in RBCs at the end of its shelf life is 50-70 mEq/l. The standard neonate transfusion dose of 15ml/kg greatly exceeds a neonate’s daily potassium intake and replacement dose for hypokalemia. Additionally, the rate of the transfusion impacts how much potassium reaches the patient. Therefore, the strategy for treating TAH is prevention. Patients at high risk for hyperkalemia need to be identified (small size, renal disease preexisting hyperkalemia).
If a neonate needs a transfusion, staying ahead of the blood loss, transfusing through large bore IVs, using fresh or irradiated blood and avoiding rapid infusion are important strategies for avoiding hyperkalemia. Intraoperatively, the ECG should be monitored for peaked T waves, narrow QT and bradycardia as signs of hyperkalemia. If a PEA rhythm evolved during a transfusion, hypocalcemia should be considered as well. The treatment is to stop the transfusion immediately and support hemodynamics with vasopressors, such as epinephrine. Immediate management of hyperkalemia includes replacing calcium to reestablish the gradient between the resting membrane potential and the threshold potential. Sodium bicarbonate, hyperventilation and beta agonists should also be used since they drive potassium into the intracellular space. Insulin and glucose can then be used to maintain intracellular potassium. In conclusion, the best way to manage TAH is to prepare and prevent it, give transfusions as slowly as possible and use calcium to prevent cardiovascular collapse and hypocalcemia.
Dr. Klein then discussed the potential complication of large volume transfusions in pediatric patients. She noted that the classic teaching of 10-15 ml/kg to calculate transfusion volume has no clear supportive evidence. In contrast, a 70 kg adult receives 3-4ml/kg from one adult red blood cell unit. This increased transfusion volume in children raises the concern of transfusion associated circulatory overload (TACO). This issue has been identified as a major cause of transfusion related mortality in adult patients and may be related to both transfusion volume and rate.
The Serious Hazards of Transfusion (SHOT) organization, based in the UK, tracks adverse transfusion issues and reported five pediatric patients who were overtransfused in 2018 and 11 patients in 2019. In 2018, there was one fatality when a neonate received exchange transfusions three times the blood volume. The signs of fluid overload are difficult to diagnose in children since they are nonverbal and have baseline tachypnea. There is no international consensus for criteria in adult patients, although the UK NHS provides a simple one that includes worsening respiratory compromise or pulmonary edema within 12-24 hours of a transfusion.
At this time there is very little literature on TACO in pediatric patients and no age based criteria. At this time the best management is prevention. Identifying high risk patients (LV dysfunction, renal insufficiency, positive fluid balance, emergencies and large transfused volume) is an important first step although the criteria used is based on adults.
Management goals include not getting behind with blood loss and avoiding unnecessary transfusions. The SHOT recommendations include careful weight-based dosing, using pediatric sized red blood cell packs in massive transfusion and close bedside monitoring of patients. There needs to be more research in this field so the definition of TACO can be standardized in adults and children.
Reference
https://www.shotuk.org
