(998) Differences in Sedation Between Patients on VA Versus VV Extracorporeal Membrane Oxygenation (ECMO)

Introduction: VA and VV ECMO are both means of mechanical circulatory support, yet differentiated in how they support the cardiopulmonary system. While these modalities have been around for some time, there is minimal literature assessing the differences in sedation requirements between them. The pharmacokinetics of medications in patients on ECMO is altered due to sequestration by the ECMO circuit. These alterations are most common with highly lipophilic and highly protein bound medications, such as sedatives.

Methods: This retrospective chart review included patients admitted to Texas Health Presbyterian Hospital Dallas or Texas Health Harris Hospital Fort Worth from January 2022 to October 2023. Patients included were 18 years or older and on VA or VV ECMO for greater than 24 hours. Exclusion criteria consisted of patients who lacked information on RASS scores and/or dosing of sedatives, patients with history of IV drug use, patients in acute alcohol withdrawal, patients who died within 24 hours from cannulation, patients cannulated at an outside hospital, or patients who switched from VA to VV ECMO or vice versa. The primary outcome was median daily doses of intravenous sedatives between VA and VV ECMO patients. Secondary outcomes included survival to discharge, time from de-cannulation to discharge, and patients requiring rescue agitation medications following de-cannulation.

Results: A total of 30 patients were included in the final analysis, 18 of which were on VA ECMO and 12 on VV ECMO. Mean RASS score in the VV group was -3.6, and the mean RASS score in the VA group was -3.5 (P-value: 0.6). Ten patients in the VV group and 11 patients in the VA group received fentanyl. The median dose in the VV group was 250 mcg/hr compared to 162.5 mcg/hr in the VA group (P-value: 0.05). Ten patients in the VV group and 9 patients in the VA group were on midazolam. The median dose in the VV group was 8.8 mg/hr while it was 4.5 mg/hr in the VA group (P-value: 0.005).

Conclusions: Patients on VV ECMO required higher doses of intravenous sedatives than patients on VA ECMO to maintain similar levels of sedation. Patients on VV ECMO were found to be on ECMO for longer durations, had higher initial RASS scores, and received intravenous paralytics which could have all contributed to higher doses of intravenous sedatives.