Imaging photoplethysmography as an easy-to-use tool for monitoring changes in tissue blood perfusion during abdominal surgery

Evaluation of tissue perfusion at various stages of surgery is of great importance for the implementation of the concept of safe surgery, including operations on the abdominal organs. Currently, there is no accurate and reliable intraoperative method for assessing tissue perfusion that could help surgeons determine the risks of ischemia and improve outcomes. We propose novel method of intraoperative assessment of tissue perfusion using video camera synchronized with the electrocardiogram. The technique is referred to as imaging photoplethysmography (iPPG). It can be used continuously for monitoring blood supply to organs e.g., before and after anastomosis. In our study, we followed 14 different surgical cases (four stomach and ten colorectal cancers) requiring reconstruction of various organs with anastomosis. With iPPG, intraoperative blood perfusion was successfully visualized and quantified in all 14 patients under study. As most indicative, here we describe in detail two clinical demonstrations during gastrectomy for gastric cancer and right-sided hemicolectomy for cancer of the ascending colon. Feasibility of the iPPG system to assess blood perfusion in organs before and after anastomosis during open surgery was demonstrated for the first time.