25: Access Insufficiency in ECMO: a Retrospective Observational Study of a Femoral Bicaval Access Cannulation Strategy

Background: Bicaval access cannulation is a practice that attempts to reduce the issue of access insufficiency, but its efficacy and safety have not been adequately evaluated. Method: A single centre retrospective observational study was conducted of all V-V and V-A ECMO patients over a 3-year period. They were assessed for successful bicaval access cannulation and rates of access insufficiency as well as other complications such as recirculation and haemolysis. Cannula, console and patient-related aspects were also analysed for potential benefits. Results: 21 patients with conventional femoral ECMO cannulation were compared to 13 patients with femoral bicaval access cannulation. Femoral bicaval access cannulation was associated with a reduction in access insufficiency (100% vs 62%, p=0.007) and achieved higher average flow rates (4.5L vs 3.6L, p=0.004), RPMs (3471 vs 2950, p=0.000), and more negative access pressures (-69mmHg vs -47mmHg, p=0.007) without evidence of haemolysis or recirculation. Femoral bicaval access cannulation achieved a reduction in fluid balance at Day 3 (642mls vs 2859mls, p=0.056) and decannulation (-624mls vs 4495mls, p=0.054) but was not statistically significant. Femoral bicaval access cannulation achieved a higher GCS (12 vs 6, p=0.044) but there was no difference in RASS (-1 vs -3, p=0.096) or use of neuromuscular blockade (38.5% vs 33.3%, p=1). Conclusion: Femoral bicaval access cannulation has the potential to significantly reduce access insufficiency in bifemoral cannulation and the associated need for its management with fluid and sedation boluses. There was no evidence of harm and it could be a potentially useful strategy to reduce instability associated with access insufficiency and avoid high-risk cannula reconfiguration.