The first laparoscopies in pregnancy were performed in the early 1990s. Since then, laparoscopy has been widely adopted as an alternative to laparotomy for the diagnosis and treatment of surgical conditions arising in pregnancy. Accordingly, surgeons should be aware of the distinct physiologic changes during gestation that may require technique modification. With these adjustments, gravidas can benefit from advantages of laparoscopy similar to those experienced by nonpregnant patients.
Laparoscopy was previously considered contraindicated during pregnancy because of concerns regarding its cardiopulmonary impairment and potential trauma to the fetus and gravid uterus. However, surgeons knowledgeable of these consequences can often minimize or avoid their effect.
Laparoscopy produces distinct cardiovascular and pulmonary changes, which may be particularly important for a gravida. These include: (1) absorption of carbon dioxide (CO2) across the peritoneum and into circulation, (2) increased intraabdominal pressure generated by the pneumoperitoneum, and (3) Trendelenburg positioning (Table 15-1). These changes may be exacerbated in pregnancy due to maternal physiologic changes and the gravid uterus.
TABLE 15-1.Physiologic Effects of CO2 Insufflation of the Peritoneal Cavity
First, laparoscopy requires abdominal wall elevation, and this is usually achieved by instilling gas into the abdominal cavity. In most cases, CO2 is selected to create this pneumoperitoneum and offers the advantages of low combustibility and rapid absorption. However, absorption of this gas across the peritoneum and into blood can lead to systemic CO2 accumulation and hypercarbia. In turn, hypercarbia produces sympathetic stimulation that raises systemic and pulmonary vascular resistance and increases blood pressure. Moreover, if hypercarbia is not cleared by compensatory ventilation, acidemia develops. From this, direct myocardial contractility depression and decreased cardiac output can follow (Ho, 1995; Reynolds, 2003; Sharma, 1996). Hypercarbia can also lead to tachycardia and arrhythmia. Fortunately, the effects of CO2 are typically compensated by controlled ventilation by anesthesia staff.
Second, insufflation of any gas elevates intraabdominal pressure. Pneumoperitoneum pressures above 10 mm Hg have consistently led to a 25- to 35-percent reduction in cardiac output regardless of patient positioning (Johannsen, 1989; Torrielli, 1990). This decline is attributable to pressure-mediated pooling of blood in the lower extremities, consequent decreased venous return, and a compensatory increase in systemic vascular resistance. Diminished venous return and cardiac output can lower uteroplacental perfusion, which may have fetal effects. In pregnancy, this can be partially compensated by using low insufflation pressures and a maternal left-lateral tilt (p. 248). Of other concerns, a distention pressure of 20 mm Hg reduces renal blood flow, glomerular filtration rate, mesenteric arterial flow, and intestinal mucosal blood flow (Diebel, 1992; Richards, 1983). These hemodynamic changes may hold more significance for those with impaired cardiac function, anemia, ...