Pneumoperitoneum induced pH changes in follicular and Douglas fluids during laparoscopic oocyte retrieval in humans

The effects of different insufflation media gases for pneumoperitoneum on the acidity of follicular fluid and blood acid--base balance were studied in two groups of patients during laparoscopic oocyte retrieval. Insufflation with 100% CO2 was compared with insufflation with 5% CO2 in air. End-tidal CO2 and the acid-base status of arterial blood, follicular and Douglas fluids were evaluated. When using 5% CO2 in air as insufflation gas, pH values and pCO2 levels observed in the aspirated follicular (pH: 7.35 +/- 0.06, pCO2: 38.8 +/- 4.5 mmHg) and Douglas fluid (pH: 7.40 +/- 0.07, pCO2: 38.5 +/- 6.2 mmHg) remained normal. With 100% CO2 insufflation, the follicular fluid pH (7.22 +/- 0.07) and pCO2 (53.1 +/- 10.9 mmHg) and the Douglas fluid pH (6.99 +/- 0.12) and pCO2 (90.3 +/- 18.4 mmHg) were grossly disturbed and outside the physiological range. No differences occurred in pO2 or HCO3 levels. These data suggest that pneumoperitoneum with 5% CO2 in air provides more optimal environmental conditions for oocytes used for in-vitro fertilization. However, further investigations on large patient groups are required to demonstrate whether such environmental conditions influence the success rate of in-vitro fertilization in humans.