Maternal Insufflation during the Second Trimester Equivalent Produces Hypercapnia, Acidosis, and Prolonged Hypoxia in Fetal Sheep

Abstract

Previous studies with near-term sheep determined that carbon dioxide pneumoperitoneum produces respiratory acidosis but does not decrease fetal oxygenation. In contrast, the current findings indicate that in the preterm fetus, insufflation-induced hypercapnia and acidosis are accompanied by prolonged fetal hypoxia and cardiovascular depression. This result suggests that additional work should be conducted to confirm the presumed safety of conducting minimally invasive procedures during the second trimester.

Anesthetic Techniques for Fetal Surgery

“…Previous studies have shown that fetal acidosis from inhalational anesthetic agents or impaired uterine blood flow was reversible within 2-24 h. 16,20 With more than a 40-h washout interval, we found no differences between the first and the second experiments in baseline hemodynamic and physiologic parameters, including fetal hematocrit. However, two fetal cardiac arrests with HD-DES exposure occurred during the second experiment.…”

“…Maternal hypotension results in decreased uterine blood flow, which impairs fetal perfusion and leads to fetal hypercarbia and acidosis. 16 Second, high-dose inhalational anesthesia may result in fetal cardiac depression. The fetal anesthetic requirement is much lower than the maternal requirement.…”

“…Uemura et al found the same phenomenon in midgestational sheep anesthetized with 1.5 MAC of isoflurane. 16,22 Because EtCO 2 inaccurately estimates maternal PaCO 2 , arterial blood gas monitoring is recommended in addition to standard monitoring during invasive surgical procedure in pregnant women. 28 Higher maternal PaO 2 did not increase fetal PaO 2 in our study, a phenomenon consistently observed in other fetal sheep studies.…”

Bilateral ovarian laparoscopic cystectomy of dermoid cysts and pregnancy

“…Animal models, which have been used to evaluate the maternal and foetal effects of the increased intra-abdominal pressure associated with CO 2 pneumoperitoneum, have shown that there are no long-term adverse effects. Even more importantly, there is no evidence to indicate any long-term detrimental effects resulting from CO 2 pneumoperitoneum in humans [18][19][20][21][22]. Even though intra-abdominal pressure needs to be sufficient to allow for adequate working space, maintenance of a low pressure is mandatory, given the possible adverse effects of increased intra-abdominal pressure on the haemodynamic and respiratory physiology of the gravid patient.…”

“…Generally asymptomatic, they are usually discovered during routine clinical or ultrasound examinations and almost invariably disappear spontaneously as the pregnancy progresses. In fact, by [16][17][18][19][20] weeks, they are present in only 0.3% of pregnancies. Most other ovarian masses discovered during pregnancy are benign dermoid cysts which account for 20-40% of ovarian neoplasms [1][2][3].…”