Carbon Dioxide Pneumoamnios Causes Acidosis in Fetal Lamb

Abstract

Recently developed techniques of video-endoscopic surgery may offer new hope for the future of fetal surgery. To allow this approach, the amniotic cavity has to be temporarily enlarged, either by carbon dioxide (CO₂) insufflation or by amnioinfusion. In 6 anesthetized ewes, CO₂ insufflation of the amniotic cavity produced severe fetal hypercapnia (from 57.6 ± 1.6 to 87.0 ± 7.0 torr) and acidosis (from 7.22 ± 0.03 to 7.11 ± 0.08) despite normal maternal CO₂ pressure and pH. CO₂ pneumoamnios does not therefore appear to be an ideal working medium. Fetal endoscopic surgery through amnioinfusion of physiologic fluid may be a safer alternative.

Effects on the Maternofetal Unit of the Rabbit Model after Substitution of the Amniotic Fluid with Perfluorocarbons

“…Another advantage of PFC is the lack of conductivity, allowing effective electrocauterization in the fl uid-fi lled amniotic cavity. Other fetoscopic media have been tried, but have specifi c disadvantages: Insuffl ation of the amniotic cavity with CO 2 causes respiratory acidosis [8] . Glycine is nonconductive [9] , but is equally affected by suspended blood and debris.…”

Impact of partial amniotic carbon dioxide insufflation (PACI) on middle cerebral artery blood flow in mid‐gestation human fetuses undergoing fetoscopic surgery for spina bifida aperta

“…A more complex, percutaneous insufflation approach that involves both amniotic and peritoneal cavities was pioneered by our group 2 . The concerns with PACI may have been prompted by the observation of the development of progressive fetal acidosis during early insufflation studies in sheep 3,4 . Before and during the clinical introduction of PACI, our group also studied its safety in this species 5 -7 .…”

The use of endoscopy in fetal medicine

“…We use warmed, isotonic Hartmann solution, which has been proven to be safe in experimental and clinical conditions [41,42]. Gas distension (CO 2 , N 2 O) may permit a clearer view, even in the presence of bleeding, yet interferes with the use of ultrasound and some fear fetal side effects [43][44][45][46]. The camera system and light sources are no different from other endoscopic operations, though the light cables are smaller in diameter.…”