Study objective: To test the hypothesis that intraabdominal pressures (IAP) associated with abdominal insufflation for laparoscopic procedures can alter pulmonary and hemodynamic values in the pregnant baboon and hemodynamic values in the fetus.
Design: A descriptive physiologic study.
Setting: Animal research facility at Scott and White Memorial Hospital, Temple, TX.
Participants: Four pregnant baboons at 120 +/- 7 days' gestation.
Interventions: The baboons underwent general anesthesia, Swan-Ganz and arterial catheter placement, and abdominal insufflation at 10 and 20 mm Hg IAP for 20-minute intervals at each pressure. The following end points were measured: maternal heart rate (MHR), mean arterial pressure (MAP), cardiac output (CO), pulmonary capillary wedge pressure (PCWP), pulmonary artery pressures (PAP), central venous pressure (CVP), systemic vascular resistance (SVR), ventilator rate (VR), oxygen saturation, and end-tidal carbon dioxide (CO2). Fetal heart rate and fetal growth values were measured, and umbilical artery Doppler flow studies were performed.
Measurements and main results: The PCWP (p <0.026), CVP (p <0.0012), and PAP (p <0.046) were significantly increased at 20 mm Hg IAP; CO decreased as IP increased. The MAP, MHR, and SVR did not change significantly with increased IAP. The only significant change in pulmonary values was the increase in peak airway pressure (p <0.001). The VR was increased from an average of 18 to 41 breaths/minute in an attempt to maintain adequate oxygen saturation and to normalize end-tidal CO2 when IAP was increased to 20 mm Hg. Respiratory acidosis (pH <7. 35, partial pressure of carbon dioxide >50 torr) was demonstrated in three of four animals within 20 minutes at an IAP of 20 mm Hg. Results of Doppler flow studies on the effects of the fetuses were unaltered immediately after this procedure compared with baseline measurements. Normal interval growth was demonstrated 2 weeks after the procedure.
Conclusion: The baboon mothers and fetuses had no adverse effects at an IAP of 10 mm Hg, but may have significant cardiovascular and respiratory alterations associated with IAP of 20 mm Hg.