The use of tissue oxygen measurements compared to indocyanine green imaging for the assessment of intraoperative tissue viability of human bowel

Abstract

Background: Adequate tissue oxygenation and perfusion remain fundamental to safe bowel resection surgery. Near infrared (NIR) imaging using indocyanine green has proven itself superior to clinical evaluation alone in assessing bowel perfusion, but requires expensive equipment not readily available in many centers.

Methods: We studied the IntraOx device (Vioptix Inc, Newark, CA USA), a handheld, tissue oxygen saturation assessment tool, to assess whether tissue bed oxygen saturation (StO2) is comparable to NIR assessment of bowel viability. Patients undergoing elective colon resection for benign and malignant disease were included. After choosing a clinical margin (CM) and dividing the mesentery, StO2 was measured at 5-cm intervals along the colon. A tissue oxygen saturation margin (TOM) was assigned where StO2 dropped off by at least 10 percentage points. NIR perfusion was then assessed to determine NIR margin (NIRM). Intraoperative and postoperative data were collected.

Results: 32 consecutive patients undergoing colectomies were analyzed. IntraOx sensitivity was 90.6%, specificity was 94.3%. The mean StO2 difference across the NIRM was 23.1%. In all but one case, the TOM matched the NIRM. In 3 cases, the TOM and NIRM concurred, but were a mean of 3.3 cm proximal to the CM and altered the surgical plan. At 4-week follow-up, no significant complications were reported.

Conclusions: The IntraOx device consistently identified a margin of significant saturation "drop-off" which correlated with the findings on NIR perfusion and clinical assessment. These early data indicate that StO2 measurement may be equivalent to NIR assessment of bowel perfusion. In addition, the IntraOx device may be a more cost-effective solution for surgeons looking for adjunctive evaluation of bowel viability. More study is warranted in a larger group of patients to confirm these preliminary findings and to judge the impact of StO2 assessment on reducing anastomotic leaks.

Keywords: Anastomotic leak; Colon resection; ICG; NIR; Tissue oxygen saturation.