Haemodynamic changes in patients undergoing laparoscopic cholecystectomy: measurement by transthoracic electrical bioimpedance.

Using transthoracic electrical bioimpedance with the BoMed NCCOM3-R7, we measured cardiovascular changes in 16 ASA I and II Chinese patients undergoing laparoscopic cholecystectomy. The peritoneal cavity was insufflated with carbon dioxide to a pressure up to 15 mm Hg. Tidal volume, minute volume and end-tidal carbon dioxide partial pressure were kept constant. Insufflation resulted in a mean (SD) 13 (14)% decrease in stroke index (SI) (P < 0.01), but the effect on cardiac index (CI) was more variable (mean 7 (17)% decrease, range 36% decrease to 22% increase (P = 0.07)). Mean arterial pressure increased by 55 (29)% (P < 0.001) and systemic vascular resistance index increased by 63 (33)% (P < 0.001), with the maximum effect occurring 10-15 min after the commencement of insufflation. Multiple regression analysis showed a greater decrease in SI in patients with a small body mass index and large intraperitoneal pressure (P = 0.01), while a greater decrease in CI was found in patients with a small body mass index and younger age (P = 0.001). Three patients had a further reduction in CI during surgery, with one patient having a 48% decrease compared with pre-induction values. Deflation of the peritoneum resulted in an increase in both CI (25 (26)%) and (22 (29)%) (P < 0.01) to values which were not different from pre-induction data. Arterial blood-gas analysis showed decreases in pH and base excess after 1 h of insufflation (P < 0.01).