Jenny Peng1,2, Niels Rochow1, Mohammadhossein Dabaghi3, Radenka Bozanovic4, Jan Jansen4, Dragos Predescu5, Bryon DeFrance6, Sau-Young Lee1, Gerhard Fusch1, Ponnambalam Ravi Selvaganapathy3,7, Christoph Fusch1,8. 1. 1 Division of Neonatology, Department of Pediatrics, McMaster University, Hamilton, ON, Canada. 2. 2 Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada. 3. 3 Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada. 4. 4 Department of Pathology and Molecular Medicine, Pediatric Pathology, McMaster University, Hamilton, ON, Canada. 5. 5 Division of Cardiology, Department of Pediatrics, McMaster University, Hamilton, ON, Canada. 6. 6 Division of Maternal-Fetal Medicine, Department of Obstetrics & Gynecology, McMaster University, Hamilton, ON, Canada. 7. 7 School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada. 8. 8 Department of Pediatrics, Paracelsus Medical School, General Hospital of Nuremberg, Nuremberg, Germany.
Abstract
INTRODUCTION: A lung assist device, which acts as an artificial placenta, can provide additional gas exchange for preterm and term newborns with respiratory failure. The concept of the lung assist device requires a large bore access via umbilical vessels to allow pumpless extracorporeal blood flow rates up to 30 mL/kg/min. After birth, constricted umbilical vessels need to be reopened for vascular access. The objective is to study the impact of umbilical vessel expansion on vessel integrity for achieving large bore access. METHODS: Umbilical cords from healthy term deliveries were cannulated and dilatated with percutaneous transluminal angioplasty catheters in 1 mm increments from 4 to 8 mm for umbilical artery and from 4 to 15 mm for umbilical vein, n = 6 per expansion diameter. Paraffin-embedded transverse sections of dilated and control samples were HE & Van Gieson stained. Effects of dilatation, shown by splitting, were measured. RESULTS: Umbilical vessel expansion led to concentric splitting, shown by areas devoid of extracellular matrix and nuclei in the tunica intima and media. No radial splitting was observed. Results suggest an expansion threshold of umbilical artery at 6 mm and umbilical vein at 7 mm, while maximal splitting was observed above this threshold (3.6 ± 0.8%, p = 0.043 for umbilical artery 7 mm and 6.3 ± 1.8%, p = 0.048 for umbilical vein 8 mm). Endothelial cell sloughing was present in all dilated samples but not in the control samples. CONCLUSION: The suggested thresholds for safe expansions are similar to in utero umbilical vessel diameters and demonstrate a proof of concept for attaining large bore access for the lung assist device.
INTRODUCTION: A lung assist device, which acts as an artificial placenta, can provide additional gas exchange for preterm and term newborns with respiratory failure. The concept of the lung assist device requires a large bore access via umbilical vessels to allow pumpless extracorporeal blood flow rates up to 30 mL/kg/min. After birth, constricted umbilical vessels need to be reopened for vascular access. The objective is to study the impact of umbilical vessel expansion on vessel integrity for achieving large bore access. METHODS: Umbilical cords from healthy term deliveries were cannulated and dilatated with percutaneous transluminal angioplasty catheters in 1 mm increments from 4 to 8 mm for umbilical artery and from 4 to 15 mm for umbilical vein, n = 6 per expansion diameter. Paraffin-embedded transverse sections of dilated and control samples were HE & Van Gieson stained. Effects of dilatation, shown by splitting, were measured. RESULTS: Umbilical vessel expansion led to concentric splitting, shown by areas devoid of extracellular matrix and nuclei in the tunica intima and media. No radial splitting was observed. Results suggest an expansion threshold of umbilical artery at 6 mm and umbilical vein at 7 mm, while maximal splitting was observed above this threshold (3.6 ± 0.8%, p = 0.043 for umbilical artery 7 mm and 6.3 ± 1.8%, p = 0.048 for umbilical vein 8 mm). Endothelial cell sloughing was present in all dilated samples but not in the control samples. CONCLUSION: The suggested thresholds for safe expansions are similar to in utero umbilical vessel diameters and demonstrate a proof of concept for attaining large bore access for the lung assist device.
Authors: Mohammadhossein Dabaghi; Neda Saraei; Gerhard Fusch; Niels Rochow; John L Brash; Christoph Fusch; P Ravi Selvaganapathy Journal: Biomicrofluidics Date: 2019-06-27 Impact factor: 2.800