Partial amniotic carbon dioxide insufflation during minimally invasive fetoscopic interventions seems safe for the fetal brain in sheep.
BACKGROUND
Partial amniotic carbon dioxide insufflation (PACI) during fetoscopic interventions greatly improves visualization of intraamniotic contents. The purpose of this study was to assess any histologically discernable effects from this approach on the fetal brain after long-term survival in sheep.


METHODS
Six pregnant ewes between 63 and 92 days of gestation underwent PACI after fetoscopic intraamniotic access. Insufflation pressures ranged between 7 and 15 mm Hg (mean 11.7; median 12.5). Insufflation times ranged between 45 and 80 minutes (mean 55.8 minutes; median 52.5) and depended on the duration of various percutaneous fetoscopic maneuvers (e.g., posturing, fetal transesophageal electrocardiography, and chronic fetal vascular access) that were tested during these studies. After fetal spontaneous delivery between 147 and 150 days of gestation, 5 of the lambs were observed for abnormal neurological symptoms. The last ewe and her sheep were terminated at 133 days of gestation for humane reasons. All six brains were examined for hemorrhage, embolism, infarctions, inflammatory changes, and abnormal cortical maturation. An unoperated sibling was available as a control.


RESULTS
The 5 sheep that were spontaneously delivered exhibited no abnormal neurological findings. In all 6 sheep, PACI did not result in any histologically discernable damage to their brain in these long-term studies. Maternal and fetal complications were not observed during or after the approach.


CONCLUSIONS
The application of PACI during minimally invasive fetoscopic interventions seems safe for the fetal brain. Due to the still limited clinical experience with PACI, continued assessment of its maternal and fetal risks as well as management are required.
Kohl
Thomas
T
German Center for Fetal Surgery and Minimally Invasive Therapy, University of Giessen , Giessen, Germany.
Ziemann
Miriam
M
Weinbach
Julia
J
Tchatcheva
Kristina
K
Gembruch
Ulrich
U
Hasselblatt
Martin
M
D000650:Amnion; D000818:Animals; D001921:Brain / Q000502:physiology*; D002245:Carbon Dioxide / Q000008:administration & dosage*; D005332:Fetoscopy; D005333:Fetus; D005740:Gases; D007327:Insufflation; D019060:Minimally Invasive Surgical Procedures; D012756:Sheep
D005740:Gases; D002245:Carbon Dioxide