Maria Bergstrom, MD, PhD1, Per-Ola Park, MD, Professor1, Peter Falk, PhD2, Eva Haglind, Professor2, Lena Holmdahl, MD, PhD2. 1Dept of Surgery, South Alvsborg Hospital & Gothenburg University, 2Dept of Surgery, Gothenburg University
Laparoscopic surgery has been shown to induce less adhesion formation than open procedures. Pneumoperitoneum during laparoscopy is mainly achieved using CO2. This endogenous gas is safe, but alters acid-base balance. Helium (He) has been tried out as an alternative gas as it is considered to be inert and has also been shown to be safe. Local peritoneal fibrinolytic capacity is crucial in postoperative peritoneal regeneration or adhesion formation. With high fibrinolytic capacity the peritoneum regenerates after surgery but with low capacity adhesions form. The peritoneal t-PA content and local T-PA activity are crucial in this balance. The impact of laparoscopic gases on the fibrinolytic enzymes is unclear. The gas itself, or the flow of gas might change the local biology.
Thirty patients, scheduled for elective laparoscopic cholecystectomy, were randomized to surgery using either CO2 or He. Peritoneal pH was monitored throughout the procedure. Peritoneal tissue was sampled before start of gas insufflation, after establishment of pneumoperitoneum, and every 20 minutes during the procedure. Samples were snap frozen in liquid nitrogen and later homogenized and analysed for tissue concentrations of t-PA and the t-PA activity using ELISA technique.
Peritoneal pH decreased during gas insufflation with CO2 reaching 96% of initial values at 4 minutes. Insufflation with He did not affect pH. During laparoscopic surgery peritoneal pH decreased further in the CO2 group, reaching 91% at 40 min, the He group was stable at 99%.
Peritoneal fibrinolytic components did not change during gasinsufflation. During surgery both cohorts had a significant peroperative decrease in peritoneal t-PA (CO2: p=0.03, He: p=0.006), also correlating with time (p=0.006, p=0.05). However, the active fraction of t-PA measured as the t-PA-activity was maintained during surgery using CO 2, but decreased using He (p=0004), correlating with time (p=0.001).
CO2 had an immediate acidifying effect on the peritoneum. The peritoneal t-PA content was affected using both gases, but the t-PA activity was preserved using CO2, indicating better postoperative net fibrinolytic capacity in the peritoneum. It seems probable that the peritoneal acidification enhances t-PA-activity leading to less adhesion formation after laparoscopic procedures.