• Suelyn Van Den Helm, Natasha Letunica, Rebecca Barton, Asami Weaver, Hui Ping Yaw, Vasiliki Karlaftis, Conor McCafferty, Tengyi Cai, Fiona Newall, Stephen B Horton, Roberto Chiletti, Amy Johansen, Derek Best, Joanne McKittrick, Warwick Butt, Yves d'Udekem, Graeme MacLaren, Matthew D Linden, Vera Ignjatovic, and Paul Monagle.
• Haematology Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.
• Pediatr Crit Care Me. 2023 Apr 1; 24 (4): 268276268-276.

ObjectivesTo investigate changes in von Willebrand factor (VWF) concentration, function, and multimers during pediatric extracorporeal membrane oxygenation (ECMO) and determine whether routine monitoring of VWF during ECMO would be useful in predicting bleeding.DesignProspective observational study of pediatric ECMO patients from April 2017 to May 2019.SettingThe PICU in a large, tertiary referral pediatric ECMO center.PatientsTwenty-five neonates and children (< 18 yr) supported by venoarterial ECMO.InterventionsNone.Measurements And Main ResultsArterial blood samples were collected within 24 hours pre-ECMO, daily for the first 5 days of ECMO, every second day until decannulation, and 24 hours post-ECMO. The STA R Max analyzer was used to measure VWF antigen (VWF:Ag) and ristocetin cofactor (VWF:RCo) activity. VWF collagen binding (VWF:CB) was measured using an enzyme-linked immunosorbent assay. VWF multimers were measured using the semi-automated Hydragel 11 VWF Multimer assay. Corresponding clinical data for each patient was also recorded. A total of 25 venoarterial ECMO patients were recruited (median age, 73 d; interquartile range [IQR], 3 d to 1 yr). The median ECMO duration was 4 days (IQR, 3-8 d) and 15 patients had at least one major bleed during ECMO. The percentage of high molecular weight multimers (HMWM) decreased and intermediate molecular weight multimers increased while patients were on ECMO, irrespective of a bleeding status. VWF:Ag increased and the VWF:RCo/VWF:Ag and VWF:CB/VWF:Ag ratios decreased while patients were on ECMO compared with the baseline pre-ECMO samples and healthy children.ConclusionsNeonates and children on ECMO exhibited a loss of HMWM and lower VWF:CB/VWF:Ag and VWF:RCo/VWF:Ag ratios compared with healthy children, irrespective of major bleeding occurring. Therefore, monitoring VWF during ECMO would not be useful in predicting bleeding in these patients and changes to other hemostatic factors should be investigated to further understand bleeding during ECMO.Copyright © 2023 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.

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