High intra-abdominal pressure increases plasma catecholamine concentrations during pneumoperitoneum for laparoscopic procedures

Background: Laparoscopic procedures are associated with several complications, such as hemodynamic, respiratory, and endocrine complications. In our previous clinical study, plasma epinephrine and norepinephrine concentrations remained unchanged after the insertion of a Veress needle, but increased significantly immediately after insufflation with carbon dioxide into the peritoneum. The mechanisms for this increase are unknown. Objective: To investigate whether gas insufflation during pneumoperitoneum affects plasma catecholamine concentrations during laparoscopic procedures. Design: Experimental study in pigs. Main Outcome Measures: The plasma concentrations of epinephrine and norepinephrine were measured in the pigs before and after pneumoperitoneum. The mean arterial pressure, heart rate, cardiac output, and arterial blood gas levels were measured, and the systemic vascular resistance was calculated. Intervention: Air, nitrous oxide, or carbon dioxide were insufflated in turn into the peritoneal cavity of supine pigs. Thereafter, carbon dioxide was insufflated into the peritoneal cavity while the pig was in the left lateral decubitus position, and then in the right lateral decubitus position. Measures were performed before pneumoperitoneum and at the intra-abdominal pressures of 10 mm Hg and 20 mm Hg. One hour of resting time was allowed between each procedure. Results: As compared with baseline values, the plasma concentrations of epinephrine and norepinephrine remained unchanged at 10 mm Hg but increased significantly at 20 mm Hg regardless of the gas used for the pneumoperitoneum (P<.05). The type of gas and differences in the position of the animals had no effect on the plasma epinephrine and norepinephrine concentrations. Conclusions: Excessive intra-abdominal pressure, but not the type of gas or body position, increases plasma catecholamine concentrations during the insufflation of gas into the abdominal cavity. Therefore, excessive insufflation of the pneumoperitoneum should be avoided.