[Correlation between Pet-CO2 and PaCO2 in morbidly obese patients during anesthesia for laparoscopic gastric bypass surgery].

ABSTRACT

OBJECTIVE: To investigate the correlation between arterial partial pressure of CO2 (PaCO2) and end expiratory tidal partial pressure of CO2 (Pet-CO2) in morbidly obese patients during anesthesia for laparoscopic gastric bypass surgery. METHODS: Forty morbidly obese patients with a body mass index (BMI) between 35 and 50 kg/m(2) underwent laparoscopic gastric bypass surgery under general anesthesia. PaCO2 and Pet-CO2 were measured after intubation and before induction of pneumoperitoneum (T0), at 30 min (T1), 60 min (T2), and 120 min (T3) during pneumoperitoneum, and at 30 min (T4) and 60 min (T5) after deflation. RESULTS: At each time point of measurement, Pet-CO2 was lower than PaCO2 in all the patients. PaCO2 and Pet-CO2 were positively correlated before, during, and after pneumoperitoneum (P<0.05). At a moderate pressure of CO2 pneumoperitoneum (16 mmHg), the level of correlation between PaCO2 and Pet-CO2 at T1, T2, and T3 differed from that before and after post-pneumoperitoneum. CONCLUSIONS: PaCO2 and Pet-CO2 are closely correlated during a moderate CO2 pneumoperitoneum in morbidly obese patients undergoing laparoscopic gastric bypass surgery.