ALTERNATIVE METHODS OF EXPOSURE MINIMIZE CARDIOPULMONARY RISK IN EXPERIMENTAL-ANIMALS DURING MINIMALLY INVASIVE SURGERY

Background: Alternative methods of exposure are needed for minimally i nvasive surgery to avoid hypercarbia and acidosis associated with carb on dioxide (CO2) abdominal insufflation, The goals of this study were to determine the pulmonary and hemodynamic effects of both helium (HE) abdominal insufflation and placement of a mechanical abdominal wall-l ifting device (lifter) during laparoscopy. Methods: Sixteen adult dome stic pigs under general endotracheal anesthesia underwent baseline mea surements of pulmonary capillary wedge pressure (PCWP), cardiac output (CO), and arterial blood gas. Six pigs underwent standard CO2 abdomin al insufflation, five pigs underwent abdominal insufflation with HE, a nd a lifter was used for exposure in five other animals. Sequential re adings of PCWP, CO, and arterial blood gas were recorded at 20-min int ervals for 60 min in all 16 animals. Results: No significant changes f rom baseline values were noted in arterial pCO(2) or pH in animals who underwent placement of the lifter at any time point. After undergoing HE insufflation, animals experienced modest but significant acidosis and little change in pCO(2). There was a significant rise in arterial pCO(2) and decrease in pH from baseline values at all time points in a nimals undergoing CO2 insufflation. Conclusions: This study shows that neither HE abdominal insufflation or the lifter have significant dele terious pulmonary or hemodynamic effects on experimental animals durin g laparoscopy. Gasless laparoscopy or HE insufflation may provide a sa fer alternative method of exposure for minimally invasive surgery in p atients with pre-existing pulmonary or cardiac dysfunction. By minimiz ing risk in these patients, costly invasive monitoring may be avoided.