Does hypercarbia develop faster during laparoscopic herniorrhaphy than during laparoscopic cholecystectomy? Assessment with continuous blood gas monitoring

The use of CO₂ to create and maintain a pneumoperitoneum during laparoscopic surgery may lead to hypercarbia and acidosis. CO₂ is also insufflated into the preperitoneal space to create and maintain a pneumopreperitoneum for laparoscopic herniorrhaphy. This study examined the influence of CO₂ pneumopreperitoneum on the development of hypercarbia and acidosis assessed with continuous intraarterial blood gas monitoring. Changes in blood gas values were measured with both continuous intraarterial and intermittent blood gas monitoring. Over a 4-mo period, blood gas values of 14 patients undergoing laparoscopic herniorrhaphy (pneumopreperitoneum) were compared with those of 13 patients undergoing laparoscopic cholecystectomy (pneumoperitoneum) in a tertiary referral center. Additionally, heart rate and blood pressure were measured during stable ventilation at constant insufflation pressure. Pneumopreperitoneum resulted in a significantly faster development of hypercarbia (P = 0.023) and acidosis (P = 0.027) than pneumoperitoneum. These results were not explained when corrected for changes in hemodynamic and ventilatory variables using analysis of covariance. We conclude that the more rapid development of hypercarbia and acidosis during pneumopreperitoneum can be explained by increased CO₂ absorption through an increasing gas exchange area during the procedure and through a larger wound bed.