Effects of different inhaled oxygen concentration and end-expiratory positive pressure on Pa-etCO2 in patients undergoing gynecological laparoscopic surgery.

There is some disagreement about whether the PetCO2 is reliable in predicting the PaCO2 in laparoscopic procedures with CO2 inflation. The aim of the present study is to measure the Pa-etCO2 differences over time in healthy patients undergoing gynecological laparoscopic surgery with different ventilation methods.After intubation, patients were randomized into three groups. The patients in group A were ventilated with air/O2 (FiO2 = 50%) and supplied with PEEP (5cmH2O). The patients in group B were ventilated with 50% oxygen while the patients in group C were ventilated with 100% oxygen. All patients were conducted with volume-controlled ventilation. PetCO2 and PaCO2 were measured at baseline, one minute after intubation, every 30 min thereafter and 5 minutes after deflation of pneumoperitoneum.The differences in Pa-etCO2 between groups A, B and C were insignificant one minute after intubation. The Pa-etCO2 in group B and C significantly increased compared with that in group A at other time points after intubation.Oxygen concentration and positive end-expiratory pressure could affect Pa-etCO2 in laparoscopic surgery patients.