BACKGROUND: We performed this study to determine the changes of hemodynamic parameters following major surgical events such like incision for trochar insertion, institution and deflation of pneumoperitoneum during a laparoscopic cholecystectomy. METHODS: Ten-female patients ASA physical status 1 during a laparoscopic cholecystectomy were enrolled into this study. Anesthesia was performed with propofol, alfentanil and vecuronium. Pneumoperitoneum was instituted by CO2 gas with intraperitonial pressure under 12 mmHg. Hemodynamic parameters before skin incision (BI), after skin incision (AI), 2, 5, 10, 15 and 20 min after the institution of pneumoperitoneum (P + 2, P + 5, P + 10, P + 15 and P + 20), 2 and 5 min after deflation (D + 2 and D + 5) were measured by the use of a thoracic electrical bioimpedance technique (TEB). RESULTS: Trochar insertion did not significantly change the hemodynamic parameters. Heart rate, total fluid content and left cardiac work index were not significantly changed through this study. Mean BP (MBP), pre-ejection period (PEP) and systemic vascular resistance index (SVRI) were significantly increased, and acceleration time index (ACI), cardiac index (CI), stroke index (SI) and velocity index (VI) were significantly more decreased after institution of pneumoperitonium than those of BI and AI. However, all parameters in P + 20, D + 2 and D + 5 were not significantly different from those of BI and AI. CONCLUSIONS: MBP, PEP, SVRI, ACI, CI, SI and VI measured by TEB were significantly changed by the institution of pneumoperitonium during a laparscopic cholecystectomy, but they all recovered to the values before the institution of pneumoperitonium within 20 min.