Perioperative splanchnic perfusion variation around colorectal surgery using both indocyanine green spectrophotometry and fluorescence angiography

Background Indocyanine green (ICG) fluorescence enables validated clinical assessment of both global splanchnic perfusion, via specialised peripheral pulse spectrophotometry, and local intestinal perfusion, via near-infrared fluorescence angiography (ICGFA). This exploratory study investigated perioperative variations and correlations in measurements by these technologies, including their possible relevance with outcomes, in patients undergoing colorectal surgery. Methods In consenting patients, plasma disappearance rate (PDR) and percentage of residual ICG at 15 min (ICGR15) were measured preoperatively, intraoperatively and on postoperative day four using ICG-pulse spectrophotometry (LiMON, Getinge). ICGFA (Pinpoint, Stryker) was visually judged by an experienced surgeon concurrently with LiMON assessment intraoperatively and with quantitative analysis of fluorescence intensity–time curves in a subgroup of recorded procedures. Results Twenty-eight patients were included, of whom 22 (79%) underwent segmental colorectal resection with primary anastomosis in 19 (68%). While no significant within-subject variation in LiMON-derived perfusion indices evidenced across measurement time points, there was substantial inter-subject variation (notably with age > 65 years and distal resections), especially intraoperatively. Patients having distal resections tended towards greater postoperative rebound. Although patients who developed complications exhibited relatively reduced ICGR15 intraoperatively ( p = 0.041), there was no significant association with severe complications. Exploratory regression analyses found a modest association between spectrophotometric PDR values and fluorescence-derived parameters, including maximum intensity and time to peak intensity. Conclusion Intraoperative splanchnic perfusion varies substantially, particularly during distal colorectal resections. Although qualitative ICGFA may not reflect global hypoperfusion, quantitative fluorescence analysis shows concordance with spectrophotometric findings, supporting its potential as a complementary intraoperative perfusion-monitoring tool in colorectal surgery.