effects of CO2 pneumoperitoneum on end tidal CO[2] [ETCO[2]], arterial blood pressure and heart rate during laparoscopic cholecystectomy under general anaesthesia

ABSTRACT

To analyze the effects of CO2 pneumoperitoneum at 13 to 15 mmHg infra-abdominal pressure on end tidal CO2 [ETCO2], arterial blood pressure and heart rate during laparoscopic cholecystectomy under general anaesthesia with controlled mechanical ventilation. Prospective Descriptive Study. The study was conducted at the department of anaesthesia Fauji Foundation Hospital Rawalpindi from August 2005 to September 2006. Fifty consecutive ASA grade-1 patients, 47 females, 3 males and aged 35-65 years undergoing laparoscopic cholecystectomy were included in the study. All patients received a standardized balanced anaesthetic in which 0.7 - 1% isoflurane was used during maintenance. Ventilation was controlled and minute volume was kept at 100 ml/kg/min. Pneumoperitoneum was created with CO2 at a flow rate of 10 liter/min and 13 to 15 mmHg infra abdominal pressure was maintained during the operation. End tidal CO2 [ETCO2], heart rate and non invasive systolic, diastolic and mean arterial blood pressure was recorded immediately before infra abdominal C02 insufflation and then after 5 minutes interval during the period of CO2 pneumoperitoneum. Study period started immediately before infra-abdominal CO2 insufflation till about 60 minutes of surgical procedure. The end tidal CO2 [ETCO2] levels progressively increased to reach a plateau 36mmHg 20 minutes after the beginning of infra abdominal CO2 insufflation. The end tidal CO2 [ETCO2] levels increased to 21% of base line [from 30 to 36 mmHg] during CO2 pneumoperitoneum for laparoscopic cholecystectomy under controlled mechanical ventilation at minute volume 100 ml/kg/min. The systolic, diastolic and mean arterial blood pressure increased to 12% to 17% of the baseline during CO2 pneumoperitoneum at 13-15 mmHg infra abdominal pressure. There was no significant change in heart rate. CO2 pneumoperitoneum produces rise in end tidal CO2 [ETCO2] levels and hemodynamic alterations proportional to the increased infra abdominal pressure during laparoscopic surgery under general anaesthesia with controlled mechanical ventilation