Comparison of Erythrocytapheresis and Simple Transfusion for the Treatment of Children with Sickle Cell Disease Acute Chest Syndrome
Authors: Watkins Benjamin , Saylors Robert L , Saccente Suzanne , Tang Xinyu 
Published: October 2019

Abstract
Abstract 4765

Introduction:
Therapy for acute chest syndrome (ACS) in our hospital includes IV hydration, pain control, antibiotic therapy, incentive spirometry, and an inhaled bronchodilator in patients who are wheezing or who have a history of asthma. Patients also receive red blood cells as either a simple transfusion (ST) or an exchange transfusion using automated erythrocytapheresis (RCE). Here we present clinical and laboratory data from patients with ACS who were treated with RCE and compare these results to a contemporaneous control group of patients with ACS who were treated with ST.

Methods:
This was a retrospective study of all patients who presented to Arkansas Children's Hospital from 1996 through 2010 for the treatment of newly diagnosed ACS. Episodes of ACS were separated into a control group who were treated with ST and a RCE group. Patients were referred to the apheresis service by the treating hematologist for RCE when they presented with severe ACS and impending respiratory failure (n=20) or when they failed to improve, or deteriorated, following ST (n=29). Summary statistics were described as mean ± standard deviation for continuous data and frequency and percentage for categorical data. Because there were patients with multiple episodes, repeated measures analyses were performed to evaluate the clinical differences between the RCE and ST episodes.

Results:
We identified a total of 81 patients who were diagnosed with a total of 119 episodes of ACS. The average age at presentation was 8.5 years (range 5 months to 20 years), 64% were male, and 78% had SS disease. Twelve patients (accounting for 11 episodes each in the RCE and ST groups) had a previous history of asthma and 23 patients had multiple episodes of ACS (median 2, range 2–6). Episodes treated with RCE were significantly more likely to present with tachypnea, retractions, nasal flaring, and decreased air movement but episodes treated with ST were significantly more likely to present with cough and wheezing, even though a previous history of asthma was not more common in the ST group than in the RCE group. The RCE group spent significantly more time on oxygen, eight episodes required BiPAP, and 3 episodes required mechanical ventilation but no ST episodes required either BiPAP or mechanical ventilation. The median WBC at diagnosis was significantly higher in the RCE group but there were no significant differences in hemoglobin level or platelet count between the groups. As expected, blood product utilization was significantly higher in the RCE group. There were no procedural or catheter-related complications in the RCE group. Mean length of stay was not significantly longer in the RCE group but total hospital costs were significantly higher as expected in the RCE group due to the expense of RCE and the need for ICU care, BiPAP, and mechanical ventilation. There were no deaths from ACS during the study period.
Additional variables that were studied but did not differ significantly between the groups included fever, sites of pain, vomiting, grunting, accessory muscle use, crackles, decreased breath sounds, color, oxygen saturation, chest radiograph findings, initial hemoglobin and platelet count, and post-treatment blood counts.

Discussion:
We found that children treated with RCE were sicker than those treated with ST, as determined by tachypnea, retractions, nasal flaring, decreased air movement, duration of oxygen therapy, need for BiPAP, and need for mechanical ventilation. We also found that children with ACS who present with cough and wheezing are significantly less likely to require RCE. We conclude that RCE is an effective therapy for sicker patients with ACS but that further work is required to develop a predictive scoring system to discriminate prospectively between children with ACS who will benefit from RCE and those who can be treated successfully with ST.

Disclosures:
No relevant conflicts of interest to declare.