7 healthy pigs, anesthetized with ketamine/azaperon/thiopentone and ve
ntilated with O-2/N2O by volume control, underwent anterior resection
of the descending colon by laparoscopic view. During operation a pneum
operitoneum by inflating CO2 to an abdominal pressure of 14 mm Hg was
installed. Immediately (+2 min) after the onset of insufflation, both
systemic and pulmonary arterial pressure increased. However, pulmonary
artery pressure started to decrease after 10 min, whereas systemic ar
terial pressure remained elevated until the end of the experimental pr
otocol. Left ventricular (LV) pressure and LV dp/dt increased in paral
lel with the systemic arterial pressure. Peak inspiratory pressure and
central venous pressure increased in parallel with the abdominal pres
sure. Blood gas analysis of arterial and pulmonary blood demonstrated
increased pCO(2) associated with mild acidosis. Arterial pO(2) did not
change significantly indicating that the decreased pulmonal distensib
ility did not endanger the oxygenation. Pulmonary pO(2) and pulmonary
O-2 saturation increased early (+10 min) after start of insufflation a
nd were stable during the 2 h of observation indicating either increas
ed cardiac output or decreased O-2 extraction. We conclude that the sh
arp initial rise of both arterial pressures could be the effect of a m
echanical action, whereas sustained hemodynamic alterations would invo
lve complex regulatory mechanisms like an increase of sympathetic acti
vity, baroreceptor control, or a response to acidosis. The acute and,
in the systemic circulation, stable increase of ventricular afterload
should be considered in patients with underlying cardiac diseases such
as ischemic heart disease or valvular dysfunction or in patients taki
ng drugs which interfere with normal compensatory processes.