Skip to main content
ScholarsBetaWeill Cornell Medicine

Overview

My research program is focused on transforming the prevention and management of bleeding and thrombosis in critically ill children through precision transfusion medicine. Despite the widespread use of platelet transfusions in pediatric critical care, clinicians currently lack both evidence-based transfusion thresholds and biologically meaningful markers of platelet function to guide treatment decisions. As a result, platelet transfusions are frequently administered based on platelet count alone, despite growing evidence that transfusions may contribute to thrombosis, bleeding, organ dysfunction, and mortality.

To address these critical gaps, my research program integrates mechanistic discovery science with multicenter clinical trials to improve outcomes for children at high risk of bleeding. My work has included the study of platelet lipidomics in critical illness, the development and validation of definitions of bleeding specific to critically ill children and the development of evidence-based guidelines for the transfusion of platelets and plasma in the pediatric intensive care unit.

My research has focused on populations of children who frequently receive platelet transfusions - those supported by extracorporeal membrane oxygenation (ECMO), children following cardiopulmonary bypass surgery and children with oncologic diagnoses.

Highlights

  1. 1
    Pediatric critical care medicine : a journal of the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies · 2022
    MEMarianne Elizabeth NellisDDDiana DelgadoMDMichelle Demetres
    PMID: 34989711PMCID: PMC8820267DOIFirst author86 citations
  2. 2
    JAMA network open · 2026
    MEMarianne Elizabeth Nellis
    PMID: 41604154PMCID: PMC12853206DOISenior author5 citations
  3. 3
    Critical care medicine · 2025
    MEMarianne Elizabeth NellisUJUmesh Joashi
    PMID: 41432485PMCID: PMC13036739DOIeCommonsFirst author6 citations

Publications

100 publications

Funding

7 grantsView NIH portfolio on RePORTER ↗

Active

3 grants
  • Sub-PI
    Age-dependent heterogeneity in the efficacy of prophylaxis with enoxaparin against catheter-associated thrombosis in critically ill children
    Eunice Kennedy Shriver National Institute of Child Health and Human Development · 2021–2027 · via Yale University
    R01HD106326-04
  • Sub-PI
    Transfusion and Organ Dysfunction in Pediatric Septic Shock (TROPICS) study
    National Heart, Lung, and Blood Institute · 2022–2027 · via Research Institute at Nationwide Chidren'sHospital
    R01HL157208-05
  • MPI
    ECmo hemoSTAtic Transfusions In Children (ECSTATIC)
    National Heart, Lung, and Blood Institute · 2022–2026 · via Yale University· 2 renewals
    R34HL159119-03
Completed grants (4)
  • PI
    TAXI-CAB: Transfusion and Anemia eXpert Initiative - Control/Avoidance of Bleeding
    National Heart, Lung, and Blood Institute · 2020–2022
    R13HL154544-01
  • Sub-PI
    Ancillary to ABC PICU to Study MOD in Critically Ill Children
    Eunice Kennedy Shriver National Institute of Child Health and Human Development · 2017–2022 · via University of California, Los Angeles
    No publications yet
    R01HS092471-03
  • Sub-PI
    Prevention of central venous catheter-associated thrombosis in critically ill children
    Eunice Kennedy Shriver National Institute of Child Health and Human Development · 2019–2019 · via Yale University
    R21HD089131-02
  • MPI
    Age of Blood in Children in Pediatric Intensive Care Units (ABC-PICU)
    National Heart, Lung, and Blood Institute · 2014–2019 · via University of Washington, The
    U01HL116383-05

Clinical research

7 studies

Active

3 studies
  • PI
    Platelet Dysfunction and the Role of Platelet Transfusion in Extracorporeal Membrane Oxygenation (ECMO) - An -Omics Approach
    Weill Medical College of Cornell University · OPEN TO ACCRUAL (as of 2023)
  • PI
    TRansfusion and Organ Dysfunction in PediatrIC Septic shock (TROPICS)
    Nationwide Children's Hospital · OPEN TO ACCRUAL (as of 2022)
  • PI
    Age-dependent Heterogeneity in the Efficacy of Prophylaxis With Enoxaparin Against Catheter-associated Thrombosis in Critically Ill Children
    PHASE2; PHASE3 · Yale University · OPEN TO ACCRUAL (as of 2022)
    Deep Venous Thrombosis
    NCT04924322
Completed & closed trials (4)
  • PI
    ECMO Hemostatic Transfusions in Children
    PHASE4 · Yale University · IRB STUDY CLOSURE (as of 2025)
    Extracorporeal Membrane Oxygenation Complication; Hemorrhage; Thromboembolism; Transfusion Adverse Reaction
    NCT05796557
  • PI
    Current Practices in Pediatric Intensive Care Units to Improve Patient Mental Health Outcomes: A Survey
    Weill Medical College of Cornell University · IRB STUDY CLOSURE (as of 2025)
  • PI
    Assessing the Hemostatic Efficacy of Pathogen Reduced Platelets in Children Undergoing Cardiopulmonary Bypass Surgery: A Pilot Clinical Trial
    PHASE4 · Weill Medical College of Cornell University · IRB STUDY CLOSURE (as of 2024)
    Cardiopulmonary Bypass Surgery
    NCT05293106
  • PI
    Blood Utilization Among COVID-19 Hospitalized Patients in New York City: An INSPIRE Database Study
    Weill Medical College of Cornell University · IRB STUDY CLOSURE (as of 2021)

Datasets

1 dataset
  • ECMO Hemostatic Transfusions in Children
    ClinicalTrials.gov · PHASE4 · COMPLETED · registration (not microdata) · 2024 · Open access
    nct05796557

Mentoring

3 menteesAll publications with mentees →