Impact of anastomotic technique and norepinephrine on microcirculation in colorectal surgery: findings from a porcine model using laser speckle contrast imaging.

Background: Proper intestinal anastomosis healing in colorectal surgery relies on optimal microcirculation, with surgeons choosing between the hand-sewn and stapled techniques. However, the impact of these methods on the microcirculation remains unclear. This study used laser speckle contrast imaging (LSCI) to objectively assess the impact of hand-sewn and stapled techniques on microcirculation in a porcine model during open surgery and examined microcirculatory changes during hypotension and norepinephrine (NE) correction.

Methods: Ten healthy female pigs underwent midline laparotomy, with one hand-sewn and one stapled anastomosis in both the small intestine and colon. LSCI measurements were obtained before creation (baseline), immediately after anastomosis (T₀), after 1 h of rest (T₆₀), during induced hypotension, and after NE infusion. Measurements were performed directly on the anastomosis, adjacent tissue, and an untouched area of the intestine.

Results: At T₀, microcirculation significantly decreased across all anastomosis types, with hand-sewn anastomoses experiencing a greater decline than stapled anastomoses. An improvement was noted at T₆₀ for all anastomoses. Hypotension worsened microcirculation in all anastomosis types, and NE infusion did not improve microcirculation despite increased and stabilized mean arterial pressure (MAP).

Conclusions: Stapled anastomoses initially exhibited superior microcirculation compared with hand-sewn anastomoses, but the disparity disappeared after 1 h. Hypotension significantly impairs simple anastomotic microcirculation. Moreover, while NE is effective in stabilizing the general blood pressure, it contributed to further diminishment in intestinal microcirculation, especially around anastomoses. Thus, the use of NE postoperatively may be considered a risk factor for anastomotic leakage.