Comparison of Changes in Arterial Blood Gases during Endoscopic Thyroidectomy, Laparoscopic Cholecystectomy and Gynecologic Laparoscopic Surgery

Abstract

Background: Because laparoscopic surgery has many advantages compared with conventional methods, it has recently been applied to not only intraabdominal or intrathoracic surgery but also thyroidectomy. It is possible that arterial blood gases and hemodynamic variables can be changed by patient position and insufflation of pressurized CO2 into extraperitoneal or intraperitoneal space, so we examined the changes in arterial blood gases, end tidal CO2 (PETCO2) and hemodynamic variables during an endoscopic thyroidectomy with extraperitoneal CO2 insufflation, laparoscopic cholecystectomy and gynecologic laparoscopic surgery with intraperitoneal CO2 insufflation under N2O, enflurane inhalational general anesthesia. Methods: Forty ASA class I or II patients were included in this study, endoscopic thyroidectomy group (n = 10), laparoscopic cholecystectomy group (n = 18), gynecologic laparoscopic surgery group (n = 12). All patients were underwent controlled mechanical ventilation (tidal volume: 10 ml/kg, respiratory rate: 12/min) and the ventilator mode was fixed in this volume and rate until the end of the operation. The position of patients during the endoscopic thyroidectomy and laparoscopic cholecystectomy were under 5 degree reverse Trendelenburg position, whereas the gynecologic laparoscopic surgery was under a 10 degree head-down lithotomy position. Variables were measured before CO2 insufflation (10 minute after induction), 10, 20 and 30 minutes after CO2 insufflation and 40 minutes after CO2 deflation. Results: PaCO2 and PETCO2 were significantly increased during CO2 insufflation compared with preinsufflation values in all groups, but the magnitude of increases of PaCO2 and PETCO2 was not significantly different among the three groups. The mean magnitude of increases of PaCO2 at 10 minutes after CO2 insufflation were as follows: gynecologic laparoscopic surgery (6.21 2.0 mmHg), endoscopic thyroidectomy (5.07 2.3 mmHg), and laparoscopic cholecystectomy (5.01 G 2.2 mmHg).