Abstract
BackgroundFetal surgery is increasingly performed to correct congenital defects. Currently, fetal brain perfusion cannot be assessed intra-operatively. The purpose of this study was to determine if contrast-enhanced ultrasound (CEUS) could be used to monitor fetal cerebral perfusion during fetal surgery and if parameters correlate with fetal hemodynamics or acid/base status.MethodsCannulated fetal sheep were insufflated with carbon dioxide gas in an extra-uterine support device and in utero to mimic fetal surgery. Fetal heart rate, mean arterial pressure, and arterial blood gases were serially measured. CEUS examinations of the brain were performed and time-dependent metrics were quantified to evaluate perfusion. The relationships between measured parameters were determined with mixed linear effects models or two-way repeated measures analysis of variance.Results6 fetal sheep (113 ± 5 days) insufflated at multiple time-points (n = 20 experiments) in an extra-uterine support device demonstrated significant correlations between time-dependent perfusion parameters and fetal pH and carbon dioxide levels. In utero, 4 insufflated fetuses (105 ± 1 days) developed hypercarbic acidosis and had reductions in cerebral perfusion parameters compared to age-matched controls (n = 3). There was no significant relationship between cerebral perfusion parameters and fetal hemodynamics.ConclusionsCEUS-derived cerebral perfusion parameters can be measured during simulated fetal surgery and strongly correlate with fetal acid/base status.
Highlights
Fetal surgery is increasingly performed to correct congenital defects
Maternal hemodynamics, blood gases and lactate levels are continuously monitored via arterial access, but analogous parameters cannot be monitored in the fetus without invasive procedures such as arterial line placement and repeated serum blood gas analysis, which are prohibitively dangerous at mid-gestation [6]
Ex utero insufflation Fetuses were insufflated for a total of 20 experiments within the EXTrauterine Environment for Neonatal Development (EXTEND) system for 4 h with one exception, one study was terminated early due to animal movement resulting in transient hemodynamic instability
Summary
Fetal surgery is increasingly performed to correct congenital defects. Currently, fetal brain perfusion cannot be assessed intra-operatively. Over the past three decades, the field of fetal surgery has advanced rapidly with increasingly complex intrauterine procedures performed at more than fifty fetal centers in the United States [1, 2]. These surgeries are performed at mid-gestation via maternal laparotomy and hysterotomy, or more recently, via hysterotomy-sparing endoscopy with partial amniotic carbon dioxide insufflation (PACI) to aid visualization [3,4,5]. Until now, there has been no reliable, noninvasive method to measure fetal brain perfusion in utero during fetal surgery
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