Associations of cephalad drainage in neonatal veno-venous ECMO – A mixed-effects, propensity score adjusted retrospective analysis of 20 years of ELSO data

Background: Neurologic complications can occur during neonatal Veno-Venous (VV) ECMO. The addition of a cephalad drainage cannula (i.e., VVDL+V) to dual lumen cannulation (i.e., VVDL) has been advocated to reduce such complications, but previous studies have presented mixed results. Methods: Data from the ECMO Registry of the Extracorporeal Life Support Organization was used to extract all neonates (≤28 days old) who underwent VV ECMO for respiratory support between 2000 and 2019. Primary outcomes were mortality, conversion to Veno-Arterial (VA) ECMO, pump flows, and complications. A mixed-effects, propensity score adjusted analysis was performed. Results: 4,275 neonates underwent VV ECMO, 581 (13.6%) via VVDL+V cannulation, and 3,694 (86.4%) via VVDL. On unadjusted analyses, VVDL+V patients had higher rates of mortality (25.5% vs 19.0%, p<0.001), conversion to VA ECMO (14.5% vs 4.1%, p<0.001), and higher pump flows at 4 h from ECMO initiation (112.7 vs 105.5 mL/Kg/min, p<0.001), but lower at 24 h (100.3 vs 104.0 mL/Kg/min, p = 0.004), and a higher proportion of them experienced hemorrhagic (29.3% vs 18.3%, p<0.001), cardiovascular (60.8% vs 45.8%, p<0.001), and mechanical (42.5% vs 32.6%, p<0.001) complications compared to VVDL patients. After adjusting for propensity scores and the multi-level nature of ELSO data, there were no differences in neurologic outcomes, pump flows, or mortality. Rather, VVDL+V cannulation was associated with higher rates of conversion to VA ECMO (adjusted odds ratio [AOR] 43.3, 95% CI 24.3 – 77.4, p<0.001), and increased mechanical (AOR 2.2, 95% CI 1.6 – 3.0, p<0.001) and hemorrhagic (AOR 2.0, 95% CI 1.4 – 3.0, p<0.001) complications. Conclusions: In this analysis, VVDL+V cannulation was not associated with any improvement in neurologic outcomes, pump flows, or mortality, but was rather associated with higher rates of conversion to Veno-Arterial ECMO, mechanical, and hemorrhagic complications.