349: EVALUATING CONCORDANCE BETWEEN LAB HEMOGLOBIN/HEMATOCRIT AND POINT-OF-CARE TESTS IN PEDIATRIC ECMO

Abstract

Introduction: Accuracy of point-of-care (POC) hemoglobin (Hgb) and hematocrit (Hct) testing in critically ill patients on extracorporeal membrane oxygenation (ECMO) support is unknown. Advantages of POC testing include immediate results and smaller blood volume, however inaccurate results can lead to repeat testing and could contribute to increased blood transfusion. The objectives of this study were to quantify agreement between lab-based and POC tests for Hgb and Hct in critically ill pediatric patients on ECMO. Methods: A single center retrospective study from January 1, 2013 to December 31, 2021. Lab and POC results were recorded if obtained within 5 minutes of each other. A single set of values was recorded per day, using the values closest to 4AM if multiple sets were obtained, and up to 10 days of an individual ECMO course were included. POC measures included in-line hematocrit monitor and bedside blood gas analyzer. Discordance was a priori defined as > 0.5g/dL (Hgb) or > 1.5% (Hct) discrepancy. Exclusion criteria were: > 18 years of age, cannulated at outside hospital, converted to other mechanical circulatory support, ECMO support during OR only, and subsequent ECMO courses during the study. Results: 136 patients were included with an average age of 2 months. 51% were female. 66% VA ECMO and 34% VV ECMO. Diagnoses included sepsis (8.1%), trauma (2.9%), cardiac s/p CPB (29%), cardiac non-CPB (15%), congenital diaphragmatic hernia (CDH) (12%), and non-CDH respiratory (31%). The average ECMO duration included in analyses was 7 days. 279 values compared lab-based to in-line, of which 27% were discordant for Hgb and 24% for Hct. 59 values compared lab-based to blood gas analyzer, of which 32% were discordant for Hgb and 36% for Hct. All discordant results had a lower POC value. Conclusions: Lab-based hemoglobin and hematocrit values compared to both blood gas analyzer and in-line hematocrit monitor were often discordant. In all cases, POC measures were lower, raising concerns that use of POC to guide transfusions could increase transfusion burden. Further study is needed to evaluate factors predictive of discordance and to determine effects of POC hemoglobin/hematocrit measures on transfusion burden in pediatric ECMO patients.