".. Anesthesia and the Trendelenburg position increased the CVP, PCWP and pulmonary arterial pressures and decreased cardiac output. Pneumoperitoneum increased these pressures further mostly in the beginning of the laparoscopy, and cardiac output decreased towards the end of the laparoscopy. The risk of systemic CO2-embolus was increased during laparoscopy."
Ref: Acta Anaesthesiol Scand. 1995 Oct;39(7):949-55.