Incidence and Management of Umbilical Artery Flow Abnormalities during Open Fetal Surgery.

INTRODUCTION: Umbilical artery (UA) Doppler ultrasound is used to assess uteroplacental insufficiency. Absent or reversed end diastolic flow (AREDF) in the UA is associated with increased perinatal mortality in fetuses with intrauterine growth restriction. We describe the incidence of UA Doppler abnormalities during open fetal surgery.

METHODS: We conducted a retrospective review of patients undergoing open in utero myelomeningocele (MMC) repair between 2008 and 2015. Intermittent UA Dopplers were performed during key portions of all cases. Our primary outcome was the rate of any AREDF. Secondary outcomes included analysis of absent versus reversed end diastolic flow (EDF), vasopressor use, and volatile anesthetic and clinical outcomes.

RESULTS: Thirty-four of 47 fetuses developed UA Doppler abnormalities intraoperatively. Nineteen had absent EDF and 15 had reversed EDF. No AREDF was present before induction, and all AREDF resolved by postoperative day 1. Ten of 19 (52.6%) patients who received sevoflurane had reversed EDF, versus 5/28 (17.9%) for desflurane, odds ratio (95% CI) 5.11 (1.36-19.16), p = 0.02. One intraoperative fetal death occurred in the AREDF group.

DISCUSSION: AREDF is a common phenomenon during open MMC repair. Anesthetic agent choice may influence this risk. Future studies of UA flow during fetal surgery are needed to further evaluate the impact of intraoperative AREDF on fetal well-being.