(505) Use of non-invasive cardiac monitoring to guide discontinuation of postpartum magnesium sulfate in severe preeclampsia.

Objective: To determine the utility of using total peripheral systemic vascular resistance (SVR) assessed using non-invasive cardiac monitor for individualizing the duration of postpartum magnesium sulfate (PP Mg) in patients with preeclampsia (PE) with severe features.

Study Design: Single center pilot randomized controlled trial in which singleton pregnant individuals with PE with severe features were randomized to 24 hours (h) of PP Mg per standard of care (control group) or individualized duration of PP Mg based on reduction in post-delivery SVR (intervention group). SVR was assessed with non-invasive cardiac monitoring using the Cheetah® system. A 30% reduction in SVR (maintained for 1h) from baseline post-delivery SVR was used as a cutoff for discontinuation of PP Mg. Our primary outcome was duration of PP Mg use. Secondary outcomes included a composite of maternal morbidities associated with PE.

Results: Of 53 patients enrolled in the study, we excluded 6 from this analysis due to insufficient data to assess primary outcome. There were no adverse events with use of device and censors. Baseline characteristics of the control (n=26) and intervention (n=21) groups were balanced. (Table 1). Six (28.6%) patients in intervention group met the SVR criteria and had their PP Mg discontinued before 24h. The duration of PP Mg infusion was shorter in the intervention group (21.6 ±4.7 h) compared with control group (24 h, p=0.02). There was no difference in secondary outcomes between the two groups (Table 2). Among the 6 individuals from the intervention group, in whom PP Mg was discontinued earlier than 24h, there was no difference in adverse outcomes.

Conclusion: Non-invasive monitoring of SVR can be a valuable tool to individualize the duration of PP Mg for PE with severe features. 28% of patients had their PP Mg discontinued prior to 24h with no apparent increase in adverse maternal outcomes. These findings should be conformed in a larger trial.