EFFECTS OF INTRAABDOMINALLY INSUFFLATED CARBON-DIOXIDE AND ELEVATED INTRAABDOMINAL PRESSURE ON SPLANCHNIC CIRCULATION - AN EXPERIMENTAL-STUDY IN PIGS

Background Intraabdominally insufflated carbon dioxide (CO2) during la paroscopy may have a specific effect on splanchnic circulation that ma y be unrelated to the effects of increased intraabdominal pressure alo ne. Therefore, the influences of insufflation with CO2 versus air on s planchnic circulation were compared. Methods: Pigs were chronically in strumented for continuous recording of mesenteric artery, portal venou s, inferior vena cava, and pulmonary arterial blood flow and portal ve nous pressure. After induction of anesthesia, CO2 or air was insufflat ed in 14 and 10 pigs, respectively. with the pigs in the supine positi on, intraabdominal pressure was increased in steps of 4 mmHg up to 24 mmHg by graded gas insufflation, Results: During air insufflation, mes enteric artery vascular resistance was unchanged, whereas mesenteric a rterial blood flow decreased with increasing intraabdominal pressure. Shortly after CO2 insufflation to an intraabdominal pressure of 4 mmHg , mean arterial pressure, mesenteric arterial blood flow, and mesenter ic arterial vascular resistance were increased by 21%, 12% and 9%, res pectively. Subsequently, with the onset of CO2 resorption in the third minute, mean arterial pressure declined to baseline values and mesent eric arterial vascular resistance declined to 85% of baseline values, whereas mesenteric arterial blood flow continued to increase to a maxi mum of 24% higher than baseline values. At steady-state conditions dur ing CO2 insufflation, mesenteric arterial blood flow was increased up to an intraabdominal pressure less than or equal to 16 mmHg but decrea sed at higher intraabdominal pressures. Conclusions: in contrast to ai r insufflation, intraabdominal insufflation of CO2 resulted in a moder ate splanchnic hyperemia at an intraabdominal pressure less than or eq ual to 12 mmHg. At higher intraabdominal pressure values, pressure-ind uced changes became more important than the type of gas used.