When should indocyanine green be assessed in colorectal surgery, and at what distance from the tissue? Quantitative measurement using the SERGREEN program.

BACKGROUND: Suture dehiscence is one of the most feared postoperative complications. Correct intestinal vascularization is essential for its prevention. Indocyanine green (ICG) is one of the methods used to assess vascularization, but this assessment is usually subjective. Our group designed the SERGREEN program to obtain an objective measurement of the degree of vascularization. We do not know how long after ICG administration the fluorescence of the tissues should be evaluated, or how far away the measurement should be performed. The aim of this study is to establish the optimal moment and distance for analyzing the fluorescence saturation of ICG. METHODS: Prospective observational study in patients undergoing elective laparoscopic colorectal surgery. The optimal time for ICG analysis was tested in a sample of 20 patients (10 right colon and 10 left colon), and the optimal distance in a sample of ten patients. ICG was administered intravenously, and colon vascularization was quantified using SERGREEN; RGB (Red, Green, Blue) encoding was used. The intensity curve of the ICG was analyzed for ten minutes after its administration. Distances of 1, 3, and 5 cm were tested. RESULTS: The intensity of fluorescence increased until 1.5 min after ICG administration (reaching figures of 112.49 in the right colon and 93.95 in the left). It then remained fairly stable until 3.5 min (98.49 in the right and 83.35 in the left), at which point it began to decrease gradually. ICG saturation was inversely proportional to the distance between the camera and the tissue. The best distance was 5 cm, where the confidence interval was narrower [CI 86.66-87.53]. CONCLUSION: The optimal time for determining ICG in the colon is between 1.5 and 3.5 min, in both right and left colon. The optimal distance is 5 cm. This information will help to establish parameters of comparison in normal and pathological situations.

Experimental study of the quantification of indocyanine green fluorescence in ischemic and non-ischemic anastomoses, using the SERGREEN software program.

Tissue ischemia is a key risk factor in anastomotic leak (AL). Indocyanine green (ICG) is widely used in colorectal surgery to define the segments with the best vascularization. In an experimental model, we present a new system for quantifying ICG fluorescence intensity, the SERGREEN software. Controlled experimental study with eight pigs. In the initial control stage, ICG fluorescence intensity was analyzed at the level of two anastomoses, in the right and in the left colon. Control images of the two segments were taken after ICG administration. The images were processed with the SERGREEN program. Then, in the experimental ischemia stage, the inferior mesenteric artery was sectioned at the level of the anastomosis of the left colon. Fifteen minutes after the section, sequential images of the two anastomoses were taken every 30 min for the following 2 h. At the control stage, the mean scores were 134.2 (95% CI 116.3-152.2) for the right colon and 147 (95% CI 134.7-159.3) for the left colon (p = 0.174) (Scale RGB-Red, Green, Blue). The right colon remained stable throughout the experiment. In the left colon, intensity fell by 47.9 points with respect to the pre-ischemia value (p < 0.01). After the first post-ischemia determination, the values of the ischemic left colon remained stable throughout the experiment. The relative decrease in ICG fluorescence intensity of the ischemic left colon was 32.6%. The SERGREEN program quantifies ICG fluorescence intensity in normal and ischemic situations and detects differences between them. A reduction in ICG fluorescence intensity of 32.6% or more was correlated with complete tissue ischemia.

A single-center prospective observational study on the effect of trimodal prehabilitation in colorectal surgery. / Estudio observacional prospectivo unicéntrico sobre el efecto de la prehabilitación trimodal en cirugía colorrectal.

INTRODUCTION: A trimodal prehabilitation protocol was designed with the aim to evaluate whether it contributes to reducing postoperative morbidity, to evaluate the effect of prehabilitation on overall hospital stay, and to analyze the evolution of functional capacity before and after surgery. METHODS: A single-center observational study of patients with colorectal cancer who underwent surgery with curative intent after a trimodal prehabilitation protocol. We collected data for postoperative morbidity according to the Comprehensive Complication Index and hospital stay, which were compared with a historical matrix. Functional capacity data were also collected before and after the application of the prehabilitation protocol. RESULTS: Compared to the historical population, the overall Comprehensive Complication Index was reduced from 13.2 to 11.5, which was statistically significant. Analyzed by morbidity type, all decreased in percentage, although without achieving significance (surgical site infection from 11.7% to 8.4%, nosocomial infection 15.8 to 10% and medical morbidity 8.6% to 4.2%). The overall hospital stay went from 6 to 4 days, and the decrease in the percentage of patients who prepared at home was statistically significant in both cases. CONCLUSIONS: Trimodal prehabilitation can contribute to lowering the postoperative morbidity and overall hospital stay of patients undergoing colorectal cancer surgery.