The Effects of Insufflation Conditions on Rat Mesothelium

Aim . The aim of this investigation was to examine the alterations in the peritoneum after cold dry CO 2 , heated dry CO 2 , and humidified heated CO 2 at pressures equivalent to intraperitoneal pressures used in human laparoscopy. Methods . Eighteen rats were divided into 4 treatment groups—group 1: untreated control; group 2: insufflation with cold dry CO 2 ; group 3: insufflation with heated, dry CO 2 ; group 4: insufflation with heated and humidified CO 2 . The abdomen was insufflated to 5 mm/Hg (flow rate 50 mL/min) for 2 h. Twelve hours later, tissue samples were collected for analysis by light microscopy (LM) and scanning electron microscopy (SEM). Results . Group 1: no abnormalities were detected. Group 2: specimens revealed an inflammatory response with loss of mesothelium and mesothelial cell nuclei showing lytic change. Cells were rounded with some areas of cell flattening and separation. Group 3: some animals showed little or no alteration, while others had a mild inflammatory response. Mesothelial cells were rounded and showed crenation on the exposed surface. Group 4: specimens showed little change from the control group. Conclusions . The LM results indicate that insufflations with heated, humidified CO 2 are the least likely to induce mesothelial damage.