The effects of operative stress in abdominal surgery on portal and arterial visceral circulation

Reactive hyperemia of the splanchnic circulation after isolated intra-abdominal organ injury has not been demonstrated in humans. Characterizing this response is essential for understanding postoperative hemodynamics and for validating non-invasive monitoring approaches. The aim of this study was to characterize the splanchnic hemodynamic response to isolated intra-abdominal organ injury and to assess the reliability of Doppler ultrasound for quantifying portal and visceral blood flow in this specific clinical setting. In this prospective observational study, 60 patients were enrolled into three groups: right hemicolectomy (n = 20), radical gastrectomy (n = 20), and ventral hernia repair without organ resection (n = 20). Elective surgery served as a standardized model of isolated intra-abdominal organ injury, with hernia repair as the control condition. Doppler ultrasound was performed preoperatively and daily for five postoperative days to assess flow and diameter of the portal vein (PV), superior mesenteric artery, celiac trunk, and abdominal aorta. Portal venous flow was indexed to body surface area and expressed as the portal flow index (VPI/BSA). Data were analyzed using repeated-measures ANOVA and McNemar’s tests. Portal venous flow was successfully obtained in all patients (age 67.4 ± 11.34 years; height 169.25 ± 7.69 cm; males n = 37, females n = 23). Arterial vessel visibility declined significantly over time (p < 0.01). A significant effect of time on ΔVPI/BSA was observed (F(5,53) = 15.99, p < 0.001, ηp² = 0.601), with a significant interaction between surgical group and time (F(10,108) = 5.04, p < 0.001). Right hemicolectomy and gastrectomy were associated with a transient increase in portal flow of up to 21% from baseline values, peaking on postoperative day 1, while minimal changes were observed in controls. PV diameter did not differ significantly between groups, although temporal patterns varied. Standardized isolated intra-abdominal organ injury therefore induces a reproducible, reactive hyperemia–like response in the portal circulation, and Doppler ultrasound represents a reliable, non-invasive modality for monitoring portal venous flow in this context. Arterial assessment is limited postoperatively. These findings provide physiological evidence of reactive splanchnic hyperemia in humans and support the clinical utility of portal flow monitoring after abdominal surgery.