Real-time probe measurement of tissue oxygenation during gastrointestinal stapling: mucosal ischemia occurs and is not influenced by staple height

Abstract

Tension, ischemia, and technical error are factors leading to anastomotic complications such as leak, stricture, and ulceration with bleeding. Currently, surgeons evaluate tissue ischemia without any simple routine measurement technique. A new tissue surface probe, T-Stat 303, provides continuous measurement of tissue hemoglobin oxygen saturation (StO(2)) and may have clinical utility for intraoperative assessment of blood flow in areas of surgical anastomosis. This pilot study aimed to determine local StO(2) during gut stapling using various staple sizes for the purpose of assessing the tool's ability to measure changes and the reproducibility of those changes with stapling. Measurements were made in nine anesthetized adult swine during laparotomy. Various staple heights were used to transect small bowel and colon. Serosal and mucosal surface measurements were obtained at baseline and on each side of the transection using the T-Stat device adjacent to the staple line and 2 cm away from it. Both small bowel and colon mucosal StO(2) adjacent to the staple line showed significant ischemia compared with baseline (p < 0.001) and 2 cm away from the staple line (p < 0.001) using all staple heights. The serosa of both small bowel and colon adjacent to the staple line was not significantly different from baseline serosa (p > 0.11) except when the grey stapler was used (baseline, 58 +/- 6.6 vs. staple line, 51 +/- 15.1; p = 0.022). The baseline mucosa of the small bowel and colon did not differ from mucosa 2 cm away from the staple line (p > 0.08). The small bowel serosa 2 cm away from the staple line did not differ from baseline mucosa, whereas the colon serosa 2 cm away significantly increased after stapling compared with baseline mucosa (p < 0.012). No statistically significant StO(2) difference was found between the various staple load sizes. Mucosal ischemia occurs after gastrointestinal stapling and is not affected by various staple heights. The T-Stat probe provides a real-time method for assessment of gut ischemia by surgeons during surgical procedures.