Placental gas exchange during amniotic carbon dioxide insufflation in sheep. - Amberg BJ; DeKoninck PLJ; Kashyap AJ; Skinner SM; Rodgers KA; McGillick EV; Deprest JA; Hooper SB; Crossley KJ; Hodges RJ (Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology, 2021)