%0 Journal Article %T The Effects of Insufflation Conditions on Rat Mesothelium %A Andrew K. Davey %A Jessica Hayward %A Jean K. Marshall %A Anthony E. Woods %J International Journal of Inflammation %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/816283 %X Aim. The aim of this investigation was to examine the alterations in the peritoneum after cold dry CO2, heated dry CO2, and humidified heated CO2 at pressures equivalent to intraperitoneal pressures used in human laparoscopy. Methods. Eighteen rats were divided into 4 treatment groups¡ªgroup 1: untreated control; group 2: insufflation with cold dry CO2; group 3: insufflation with heated, dry CO2; group 4: insufflation with heated and humidified CO2. 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 CO2 are the least likely to induce mesothelial damage. 1. Introduction Carbon dioxide (CO2) gas is the most common insufflation agent used to create pneumoperitoneum during laparoscopic surgery [1]. In the absence of conditioning, standard CO2 used in laparoscopic surgery is cold and dry at 20 to 21¡ãC, <1% relative humidity, at the point of entry into the peritoneal cavity [2, 3]. The condition of standard CO2 is in marked contrast to the physiologic intra-abdominal condition. Experimental and clinical investigations have demonstrated that the cool, dry nature of standard CO2 insufflation causes desiccation resulting in visible structural, morphological, and biochemical alterations to the mesothelial cells of the peritoneum [4¨C8]. This includes bulging of the mesothelial cells, widening of intercellular junctions, exposure of the basement membrane [5], and increased peritoneal cytokine response [9]. Previous animal investigations have demonstrated that the use of humidified heated CO2 can attenuate peritoneal damage caused by desiccation [4, 6]. Compared to standard CO2 insufflation, the use of humidified heated CO2 results in no exposure of the basement membrane [4], no visible intercellular clefts [4], improvements in perioperative temperature, and decreased adhesion formation [6]. However, insufflation during these animal investigations was performed in %U http://www.hindawi.com/journals/iji/2013/816283/