Fetal heart rate monitoring during fetoscopic repair of open spinal neural tube defects: a single-centre observational cohort study

Fetal cardiovascular changes during open and fetoscopic in-utero spina bifida closure

OBJECTIVE

Fetoscopic closure of spina bifida using heated and humidified carbon dioxide gas (hhCO2) has been associated with lower maternal morbidity compared with open closure. Fetal cardiovascular changes during these surgical interventions are poorly defined. Our objective was to compare fetal bradycardia (defined as fetal heart rate (FHR) < 110 bpm for 10 min) and changes in umbilical artery (UA) Doppler parameters during open vs fetoscopic closure.

METHODS

This was a prospective cohort study of 22 open and 46 fetoscopic consecutive in-utero closures conducted between 2019 and 2023. Both cohorts had similar preoperative counseling and clinical management. FHR and UA Doppler velocimetry were obtained systematically during preoperative assessment, every 5 min during the intraoperative period, and during the postoperative assessment. FHR, UA pulsatility index (PI) and UA end-diastolic flow (EDF) were segmented into hourly periods during surgery, and the lowest values were averaged for analysis. Umbilical vein maximum velocity was measured in the fetoscopic cohort. At each timepoint at which FHR was recorded, maternal heart rate and systolic and diastolic blood pressure were measured.

RESULTS

Fetal bradycardia occurred in 4/22 (18.2%) cases of open closure and 21/46 (45.7%) cases of fetoscopic closure (P = 0.03). FHR decreased gradually in both cohorts after administration of general anesthesia and decreased further during surgery. FHR was significantly lower during hour 2 of surgery in the fetoscopic-repair cohort compared with the open-repair cohort. The change in FHR from baseline in the final stage of fetal surgery was significantly more pronounced in the fetoscopic-repair cohort compared with the open-repair cohort (mean, -32.4 (95% CI, -35.7 to -29.1) bpm vs -23.5 (95% CI, -28.1 to -18.8) bpm; P = 0.002). Abnormal UA-EDF (defined as absent or reversed EDF) occurred in 3/22 (13.6%) cases in the open-repair cohort and 23/46 (50.0%) cases in the fetoscopic-repair cohort (P = 0.004). There were no differences in UA-EDF or UA-PI between closure techniques at the individual stages of assessment.

CONCLUSIONS

We observed a decrease in FHR and abnormalities in UA Doppler parameters during both open and fetoscopic spina bifida closure. Fetal bradycardia was more prominent during fetoscopic closure following hhCO2 insufflation, but FHR recovered after cessation of hhCO2. Changes in FHR and UA Doppler parameters during in-utero spina bifida closure were transient, no cases required emergency delivery and no fetoscopic closure was converted to open closure. These observations should inform algorithms for the perioperative management of fetal bradycardia associated with in-utero spina bifida closure. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal bradycardia in open versus fetoscopic prenatal repair of spina bifida

OBJECTIVE

To compare the occurrence of fetal bradycardia in open versus fetoscopic fetal spina bifida surgery.

METHODS

This is a single-institution retrospective cohort study of patients undergoing open (n = 25) or fetoscopic (n = 26) spina bifida repair between 2017 and 2022. From October 2017 to June 2020, spina bifida repairs were performed via an open classical hysterotomy, and from November 2020 to June 2022 fetoscopic repairs were performed following transition to this technique. Fetal heart rate (FHR) in beats per minute (bpm) was recorded via echocardiography every 15 min during the procedure. Cohort characteristics, fetal bradycardia and maternal physiologic parameters were compared between the groups.

RESULTS

Fetuses undergoing an open repair more frequently developed bradycardia defined as <110 bpm (32% vs. 3.8%, p = 0.008), and a trend was observed for FHR decreases more than 25 bpm from baseline (20% vs. 3.8%, p = 0.073). Profound bradycardia less than 80 bpm was rare, occurring in only three operations (two in open, one in fetoscopic repair) with two fetuses (one in each group) requiring emergency cesarean delivery.

CONCLUSION

When compared to open fetal surgery, fetal bradycardia occurred less frequently in fetoscopic surgery despite a significantly greater anesthetic exposure and the use of the intraamniotic carbon dioxide insufflation.

Continuous Fetal Cardiac Monitoring during Fetoscopic Myelomeningocele Repair and Relationship to Spectral Doppler Changes

INTRODUCTION

No evidence-based protocols exist for fetal cardiac monitoring during fetoscopic myelomeningocele (fMMC) repair and intraprocedural spectral Doppler data are limited. We determined the feasibility of continuous fetal echocardiography during fMMC repair and correlated Doppler changes with qualitative fetal cardiac function during each phase of fMMC repair.

METHODS

Patients undergoing fMMC repair had continuous fetal echocardiography interpreted in real-time by pediatric cardiology. Fetal data included fetal heart rate (FHR), qualitative cardiac function, mitral and tricuspid valve inflow waveforms, and umbilical artery (UA), umbilical vein (UV), ductus arteriosus (DA), and ductus venosus (DV) Dopplers.

RESULTS

UA abnormalities were noted in 14/25 patients, UV abnormalities were observed in 2 patients, and DV and DA abnormalities were each noted in 4 patients. Qualitative cardiac function was normal for all patients with the exception of one with isolated left ventricular dysfunction during myofascial flap creation, concurrent with an abnormal UA flow pattern. All abnormalities resolved by the first postoperative day.

CONCLUSIONS

Continuous fetal echocardiography was feasible during all fMMC repairs. Spectral Doppler changes in the UA were common during fMMC procedures but qualitative cardiac dysfunction was rare. Abnormalities in the UV, DV, and DA Dopplers, FHR, and cardiac function were less common findings.

Anesthesia for fetal operative procedures: A systematic review

Objective

The anesthetic management of fetal operative procedures (FOP) is a highly debated topic. Literature on fetal pain perception and response to external stimuli is rapidly expanding. Nonetheless, there is no consensus on the fetal consciousness nor on the instruments to measure pain levels. As a result, no guidelines or clinical recommendations on anesthesia modality during FOP are available. This systematic literature review aimed to collect the available knowledge on the most common fetal interventions, and summarize the reported outcomes for each anesthetic approach. Additional aim was to provide an overall evaluation of the most commonly used anesthetic agents.

Methods

Two systematic literature searches were performed in Embase, Medline, Web of Science Core Collection and Cochrane Central Register of Controlled Trials up to December 2021. To best cover the available evidence, one literature search was mostly focused on fetal surgical procedures; while anesthesia during FOP was the main target for the second search. The following fetal procedures were included: fetal transfusion, laser ablation of placental anastomosis, twin-reversed arterial perfusion treatment, fetoscopic endoluminal tracheal occlusion, thoraco-amniotic shunt, vesico-amniotic shunt, myelomeningocele repair, resection of sacrococcygeal teratoma, ligation of amniotic bands, balloon valvuloplasty/septoplasty, ex-utero intrapartum treatment, and ovarian cyst resection/aspiration. Yielded articles were screened against the same inclusion criteria. Studies reporting anesthesia details and procedures’ outcomes were considered. Descriptive statistical analysis was performed and findings were reported in a narrative manner.

Results

The literature searches yielded 1,679 articles, with 429 being selected for full-text evaluation. A total of 168 articles were included. Overall, no significant differences were found among procedures performed under maternal anesthesia or maternal-fetal anesthesia. Procedures requiring invasive fetal manipulation resulted to be more effective when performed under maternal anesthesia only. Based on the available data, a wide range of anesthetic agents are currently deployed and no consistency has been found neither between centers nor procedures.

Conclusions

This systematic review shows great variance in the anesthetic management during FOP. Further studies, systematically reporting intraoperative fetal monitoring and fetal hormonal responses to external stimuli, are necessary to identify the best anesthetic approach. Additional investigations on pain pathways and fetal pain perception are advisable.