Table 1.

Criteria for determining blood perfusion

Grade	1	2	3	4	5
Clinical assessment (the intestinal tube was visualised with the naked eye)	The tissue was dull in colour.	The tissue was bloody and patchy.	The bowel was pink, but there was no arterial bleeding or anastomotic oozing.	The bowel was pink, the mesenteric blood vessels were pulsating and the anastomotic oozes blood, but clinical survival remained a concern.	The bowel was pink, the mesenteric blood vessels are pulsatile and the anastomotic oozes was bleeding.
Fluorescent rendering	No obvious fluorescence was observed.	The fluorescence was patchy.	Marked and uniform hypo fluorescence.	Contrast of high and low fluorescence intensity can be discernible by naked eye.	All regions showed strong fluorescence.