GLYCINE AS A POTENTIAL WINDOW FOR MINIMAL ACCESS FETAL SURGERY

Carbon dioxide insufflation of the uterine cavity in sheep enables ele ctrocautery to the surface and superficial tissues of the fetal lamb, using minimally invasive surgery. Absorption of the CO2, however, caus es a potentially lethal acidosis. To enable the use of electrocautery dissection of the fetal sheep, without using gas, we have partially re placed the amniotic fluid with 0.5% glycine. To determine whether glyc ine would have any short-or long-term deleterious effects on the devel oping fetus, we replaced amniotic fluid with 0.5% glycine in 10 normal fetuses at 101 days of gestation (normal gestation 145-149 days), wit hout later replacing it with the removed amniotic fluid. Histological changes were then sought in the skin, gastrointestinal tract, and pulm onary tree, at 2 ('early', n = 5) or 6 weeks ('late', n = 5) after the introduction of the glycine. There were no histological differences b etween these and normal sheep at either time point. The use of glycine as a replacement for amniotic fluid subsequently enabled us to carry out electrocautery dissection of the sheep fetus and electrocoagulatio n of any bleeding vessel. Its use was not associated with any apparent untoward effects. Therefore, it has the potential to be used in minim ally invasive surgery on the fetal trachea or on an enlarged fetal bla dder.