Effect of carbon dioxide pneumoperitoneum on tissue blood flow in the peritoneum,rectus abdominis,and diaphragm muscles

Background: Changes in local blood flow may play a role in the pathogenesis of port-site metastasis. This study aimed to investigate the effect of pneumoperitoneum induced by carbon dioxide (CO₂) on the blood flow in the peritoneum and abdominal wall muscle layers, which are target structures for this phenomenon. Methods: The study was performed on domestic farm swine of both genders weighing 20 to 25 kg. Intraabdominal pressures (IAP) of 0, 5, and 10 mmHg were produced by either CO₂ (n = 9) or helium (He) (n = 6) insufflations. The colored microsphere technique was used to measure blood flow distributions in the parietal peritoneum, rectus abdominis, and diaphragm muscles. Results: Insufflation of CO₂ was associated with a threefold increase in blood flow of the parietal peritoneum at both 5 and 10 mmHg IAP (p < 0.001 for both pressure levels). In contrast, insufflation of He caused a significant decrease in blood flow in the parietal peritoneum at both 5 and 10 mmHg (p < 0.05). In the rectus abdominis and diaphragm muscles, blood flow remained unchanged after insufflation of CO₂ at both 5 and 10 mmHg IAP. However, after insufflation of He, there was a substantial decrease in blood flow both in the rectus abdominis and diaphragm muscles at both 5 mmHg (p < 0.01 and p < 0.05, respectively) and 10mmHg (p < 0.001 and p < 0.01, respectively). Conclusions: Despite high intraabdominal pressure, tissues surrounding the abdominal cavity, particularly the peritoneum, respond to insufflation of CO₂ with increased blood flow, which may favor the growth of tumor cells.