Laparoscopy without pneumoperitoneum - Effects of abdominal wall retraction versus carbon dioxide insufflation on hemodynamics and gas exchange in pigs

Laparoscopic surgery with CO₂ insufflation is associated with adverse effects on hemodynamics and gas exchange. The abdominal wall retractor (AWR) is an alternative for pneumoperitoneum. Hemodynamics and gas exchange during the use of an AWR were compared to those of CO₂ pneumoperitoneum. In eight pigs subjected to 1 h of CO₂ pneumoperitoneum or abdominal wall retraction, hemodynamics, gas exchange, and oxygen transport were studied in a randomized cross-over study design. The only change observed during abdominal wall retraction was mild respiratory alkalosis. In contrast, during CO₂ pneumoperitoneum mean arterial blood pressure increased 13%, central filling pressures doubled, and a small increase in cardiac output was observed. Peak airway pressures increased 50%, end-tidal CO₂ increased 20%, and respiratory acidosis was induced (arterial pH from 7.46±0.07 to 7.31±0.06 and pCO₂ from 33±3 mmHg to 53±4 mmHg). Arterial PO₂ decreased but mixed venous oxygen saturation and oxygen consumption were unaffected. In contrast with CO₂ pneumoperitoneum, laparoscopy using abdominal wall retraction was not associated with adverse effects on hemodynamics or gas exchange.