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

Alexei A Kamshilin,Alexander V Lodygin,Victor A Kashchenko,Valery V Zaytsev

doi:10.1038/s41598-022-05080-7

Abstract

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.

Highlights

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
There are two optical methods exploiting coherent light that are considered promising for intraoperative assessment of blood flow parameters: laser Doppler perfusion imaging (LDPI) and laser speckle contrast imaging (LSCI)
The basic operative maneuver in these cases was mesenteric dissection, which required devascularization, i.e., ligation of supplying blood vessels to the level of the intended anastomosis. It leads to blood supply redistribution throughout the organ, often revealing tissue perfusion disorders

Summary

Introduction

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. There have been rather successful attempts to use the fluorescence technique in association with indocyanine green (ICG) fluorophore for intraoperative assessment of tissue perfusion both before and after anastomosis[2,3,4] Application of this technology in clinical practice could help surgeons to optimize the level of resection and validate anastomosis. The blood flow in laser Doppler methods is characterized by means of relative perfusion units, the physical significance of which has a contentious interpretation[6] Another optical technique, LSCI, referred to as dynamic light scattering, provides imaging of cerebral blood flow in two dimensions with high resolution[7,8]. The results of the LSCI technique are ambiguous in interpretation due to multiple light scattering in biological tissue[9]

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