Continuous Platelet Infusion Is an Effective Alternative to Conventional Transfusion in Reducing Platelet Transfusions in Critically Ill Pediatric Patients with Refractory Thrombocytopenia

Background: Thrombocytopenia is often seen in critically ill children and platelet transfusions are needed to prevent or treat bleeding. However, some patients can exhibit platelet refractoriness (PR), characterized as a suboptimal rise in platelet count after platelet transfusion resulting in increased platelet transfusion to maintain the desired platelet target. Repeat platelet transfusions can increase the risk of transfusion-associated circulatory overload (TACO), allergic transfusion reaction and human leukocyte antigen (HLA) alloimmunization. To reduce the total platelet requirement and maintain platelet target, continuous platelet infusion (CPI), which involves transfusion of small volumes of platelets over an extended period of time, is utilized. However, data comparing the total platelet usage between CPI and conventional platelet transfusion (CPT) in critically ill children with PR are lacking.

Objectives: Compare total platelet usage per day and peak platelet count between CPI and CPT in pediatric patients with PR.

Methods: A retrospective cohort study was performed on all children who received CPI from February 2014 through December 2021 at a tertiary pediatric hospital. CPI was defined as: 1) for children weighing ≤35kg, transfusion of 5ml/kg apheresis platelets over 4 hours every 4-8 hours or 2) for children weighing >35kg, transfusion of 0.5 unit of apheresis platelet over 4 hours every 4-8 hours. Data collection included patient demographics, reason for admission, and bleeding history. A two-tailed paired sample t-test was used to compare platelet count trough and peak, and total platelet volume transfused per day, between CPT (before initiating CPI or pre-CPI) and during CPI (CPI). A P<0.05 was defined as statistically significant. This study was approved by the Institutional Review Board.

Results: Sixteen children with PR received CPI with demographics summarized in Table 1. Median age at time of study was 6.1 years (IQR: 0.4-14). Patients were initiated on CPI by the Transfusion Medicine service due to suspected PR. All patients were admitted to the intensive care unit (ICU) when CPI was initiated. Prior to CPI, 10 (62.5%) children had bleeding symptoms, including 6 major bleeds (intracranial hemorrhage) and 4 clinically relevant non-major bleeds (1 post-surgical, 1 pulmonary, 1 mucocutaneous, and 1 gastrointestinal bleeding event). There was a no difference in the mean platelet trough with CPI (m= 20x10⁹/L, s= 16.2) versus pre-CPI (m= 26x10⁹/L, s= 22.4), (t(15) =-1.705, P=0.109). There was no difference in the platelet peak in the pre-CPI (m= 80x10⁹/L, s= 44.6) versus CPI (m= 98x10⁹/L, s= 56.1), (t(15) =-1.185, P=0.254). There was a statistically significant difference in the mean total volume of transfused platelets per day in patients receiving CPT, pre-CPI (m= 158.4 mL/day, s= 68.5) versus CPI (m= 132.6 mL/day, s= 67.1); there was less volume infused daily when patients received CPI (t(15) =2.530, p=0.023). Overall, both transfusion strategies achieved a similar platelet peak, but the CPI required significantly less platelet transfusion by volume per day compared to CPT (Figure 1).

Conclusion: Our study demonstrated that those on CPI received a statistically significantly lower volume of platelet transfusion per day compared to CPT to maintain similar platelet counts. While a small sample size and wide variation in platelet counts likely limited the comparison of platelet peak and trough values, there was a trend towards higher platelet counts with CPI. This study suggests that CPI should be considered as alternative to CPT in critically ill children with PR, especially those at risk of TACO.

No relevant conflicts of interest to declare.