CARBON-DIOXIDE PNEUMOPERITONEUM INDUCES FETAL ACIDOSIS IN A PREGNANT EWE MODEL

The objective of this study was to evaluate the physiologic consequenc es of a pneumoperitoneum (pneumo) to the midterm fetus in a pregnant s heep model. The performance of laparoscopic cholecystectomy (LC) durin g pregnancy is controversial. The primary concern regarding the safety of LC during pregnancy is the physiologic consequences of the CO2 pne umo to the fetus. Eight ewes with singlet pregnancies between 100 and 120 days of gestation were anesthetized and intubated. Carotid artery and internal jugular catheters were placed in the ewe and in the fetus . Two trocars were placed through the abdominal wall of the ewe and th e abdomen was inflated with CO2 or N2O at 15 mmHg pressure for 90-120 min. Hemodynamic and blood gas data were obtained every 15 min before, during, and after the pneumo. In two ewes attempts were made to keep maternal P-CO2 constant with hyperventilation. In two other animals th e pneumo was increased stepwise in five mmHg increments to 25 mmHg. On e fetus succumbed during the CO2 pneumo, but this animal appeared to b e ill during the establishment of invasive monitoring. Fetal respirato ry acidosis occurred, reproducibly, after establishment of CO2 pneumo but did not occur before insufflation or under N2O pneumo (P < 0.0001) , Hemodynamic changes were minimal with all agents but it appeared tha t there a was greater prevalence of fetal tachycardia and hypertension during CO2 pneumo than during N2O pneumo, Alterations in ventilator s ettings based on maternal capnography resulted in late and incomplete correction of respiratory acidosis. Despite clinical reports of succes sful LC during pregnancy, significant respiratory acidosis may be indu ced in the fetus with CO2 pneumo. Alternative gases (e,g,, N2O) or abd ominal suspension devices may be preferable to CO2 when performing lap aroscopy in pregnant patients.