Critical Care Support in Infants Post-Allogeneic HCT: Large Single-Center Cohort Experience
Authors: Cacace Fabiana , Alqahtani Shaikha , McMichael Taylor , Bonfim Carmem , Bauchat Andrea , Driscoll Timothy A. , Martin Paul L. , Kurtzberg Joanne , Mahadeo Kris Michael 
Published: December 2024

Introduction
Allogeneic hematopoietic cell transplantation (HCT) is a potentially life-saving treatment for various diseases observed in childhood but may be associated with significant transplant-related morbidity/mortality. Approximately 10% of pediatric patients undergoing HCT may require critical care (CC) support at some point during their transplant course (Zinter, 2020). This study aimed to characterize the indication for and extent of critical care support in infants (&lt;12months) undergoing HCT.
Methods
This retrospective IRB-exempt study included complications of all infants who underwent allogeneic HCT from 2003-2023 at our center. Data was extracted from the electronic medical record. Descriptive statistics were used. A p value if &lt;0.05 was considered statistically significant.
Results
A total of 107 infants (60.7% male) underwent allogeneic HCT primarily for non-malignant diseases (90.6%). Median age at time of HCT was 6 (range 1.2-11.4) months. Graft sources (90% unrelated) included umbilical cord blood (90%) and bone marrow (10 %) and 87% received myeloablative conditioning. Absolute neutrophil count (ANC) recovery occurred in 94.5% of patients at a median of 18 (range 11-75) days post-HCT. In the first 100 days post-HCT, veno-occlusive disease (12%), &gt; grade II graft-versus-host disease (15%), diffuse alveolar hemorrhage (5.6%), gastrointestinal bleeding (2%), central nervous system bleeding (3%), pericardial effusion (12.7%), severe sepsis (16.4%) and primary graft failure (5.6%) were observed.
Almost half (43.9%) of patients required CC support within 100 days of HCT (median time to CC admission was 33 (range 0-131) days), primarily due to respiratory distress (75.6%), with 47.2% of these patients having received prior non-invasive ventilation (NIV) via simple nasal cannula/blow-by oxygen (38.9%), non-invasive positive-pressure ventilation (NIPPV) (5.5%) and high-flow nasal cannula (HFNC) (2.7%). Among all patients, 26% ultimately required invasive mechanical ventilation (IMV). Among patients who received prior NIV, median time from NIV to IMV was 9.5 (range 1-89) days. There was no significant difference in outcome between patients who received NIV or NIPPV prior to IMV versus those that did not. Similarly, ANC recovery pre- or post-initiation of IMV was not statistically associated with survival. More than half (53%) of patients who received IMV support survived to CC discharge.
Other CC support in this cohort included continuous renal replacement therapy (17%). No patients received Extracorporeal Membrane Oxygenation.
With a median CC admission of 9 (range 1-105) days, 75% of patients that required CC admission, survived to CC discharge. The leading cause of CC mortality among patients requiring CC support was multi-organ dysfunction syndrome (69%). ANC recovery pre- or post-CC admission was not associated with CC survival.
Conclusion
Infants undergoing HCT may be at disproportionately higher risk of requiring CC support, yet, they may have high rates of CC survival. Similarly, more than half of infants undergoing allogeneic HCT who require IMV within the first 100 days post-HCT may survive to CC discharge. ANC recovery prior to CC admission or IMV initiation was not associated with survival, suggesting that this should not be considered when determining outcome prognostication.
F.C & S.A have contributed equally to this work.