Arterial to end-tidal carbon dioxide pressure difference during laparoscopic surgery in pregnancy

Background: There is controversy about whether capnography is adequate to m onitor pulmonary ventilation to reduce the risk of significant respiratory acidosis in pregnant patients undergoing laparoscopic surgery. In this pros pective stud): changes in arterial to end-tidal carbon dioxide pressure dif ference (Pa-CO2-PETCO2), induced by carbon dioxide pneumoperitoneum, were d etermined in pregnant patients undergoing laparoscopic cholecystectomy, Methods: Eight pregnant women underwent general anesthesia at 17-30 weeks o f gestation. Carbon dioxide pnueumoperitoneum was initiated after obtaining arterial blood for gas analysis. Pulmonary ventilation was adjusted to mai ntain PETCO2 around 32 mmHg during the procedure. Arterial blood gas analys is was performed during insufflation, after the termination of insufflation , after extubation, and in the postoperative period. Results: The mean +/- SD for Pa-CO2-PETCO2 was 2.4 +/- 1.5 before carbon di oxide pneumoperitoneum, 2.6 +/- 1.2 during, and 1.9 +/- 1.4 mmHg after term ination of pneumoperitoneum. Pa-CO2 and PH during pneumoperitoneum were 35 +/- 1.7 mmHg and 7.41 +/- 0.02, respectively. There were no significant dif ferences in either mean Pa-CO2-PETCO2 or Pa-CO2 and pH during various phase s of laparoscopy. Conclusions: Capnography is adequate to guide ventilation during laparoscop ic surgery in pregnant patients. Respiratory acidosis did not occur when PE TCO2 was maintained at 32 mmHg during carbon dioxide pneumoperitoneum.