Anastomotic perfusion assessment with indocyanine green in robot-assisted low-anterior resection, a multicenter study of interobserver variation.

BACKGROUND: Securing sufficient blood perfusion to the anastomotic area after low-anterior resection is a crucial factor in preventing anastomotic leakage (AL). Intra-operative indocyanine green fluorescent imaging (ICG-FI) has been suggested as a tool to assess perfusion. However, knowledge of inter-observer variation among surgeons in the interpretation of ICG-FI is sparse. Our primary objective was to evaluate inter-observer variation among surgeons in the interpretation of bowel blood-perfusion assessed visually by ICG-FI. Our secondary objective was to compare the results both from the visual assessment of ICG and from computer-based quantitative analyses of ICG-FI between patients with and without the development of AL. METHOD: A multicenter study, including patients undergoing robot-assisted low anterior resection with stapled anastomosis. ICG-FI was evaluated visually by the surgeon intra-operatively. Postoperatively, recorded videos were anonymized and exchanged between centers for inter-observer evaluation. Time to visibility (TTV), time to maximum visibility (TMV), and time to wash-out (TWO) were visually assessed. In addition, the ICG-FI video-recordings were analyzed using validated pixel analysis software to quantify blood perfusion. RESULTS: Fifty-five patients were included, and five developed clinical AL. Bland-Altman plots (BA plots) demonstrated wide inter-observer variation for visually assessed fluorescence on all parameters (TTV, TMV, and TWO). Comparing leak-group with no-leak group, we found no significant differences for TTV: Hazard Ratio; HR = 0.82 (CI 0.32; 2.08), TMV: HR = 0.62 (CI 0.24; 1.59), or TWO: HR = 1.11 (CI 0.40; 3.11). In the quantitative pixel analysis, a lower slope of the fluorescence time-curve was found in patients with a subsequent leak: median 0.08 (0.07;0.10) compared with non-leak patients: median 0.13 (0.10;0.17) (p = 0.04). CONCLUSION: The surgeon's visual assessment of the ICG-FI demonstrated wide inter-observer variation, there were no differences between patients with and without AL. However, quantitative pixel analysis showed a significant difference between groups. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04766060.

Leukocyte, plasma, and organ-associated cytokine profiles in an animal model of acute inflammation.

Systemic administered lipopolysaccharide (LPS) induces a cytokine response in peripheral blood without correlations with cytokine content at the organ level. We hypothesised (1) that cytokine mRNA expression in peripheral blood mononuclear cells (PBMCs) preceded the plasma cytokine increase during endotoxaemia and (2) that statins as anti-inflammatory agents modified the LPS-induced cytokine responses. 30 pigs were randomised into 3 groups: placebo (I) or atorvastatin 80 mg (II) for 21 days, followed by LPS-infusion on day 22, or controls (III). LPS was infused at increasing concentrations (2.5 to 15 microg/kg/h) for 30 min, followed by sustained infusion (2.5 microg/kg/h) for 330 min. We measured plasma IL-6, IL-10, and TNF-alpha, and their mRNA expression in PBMCs during the LPS-infusion, and the cytokine content in kidney and heart biopsies at 360 min. LPS reduced TNF-alpha mRNA in PBMCs at 60 min, whereas IL-6 mRNA increased at 240 min. There were no correlations with plasma cytokines, which peaked at 60 min (IL-10 and TNF-alpha) and 240 min (IL-6). Cytokine content did not increase in organs, and no effects of statins could be demonstrated. In conclusion, LPS-infusion reduced leukocyte TNF-alpha mRNA and increased IL-6 mRNA, whereas plasma TNF-alpha, IL-6, and IL-10 increased markedly.

Circulating free fatty acids do not contribute to the acute systemic inflammatory response. an experimental study in porcine endotoxaemia.

Intensive insulin therapy, aiming for strict normoglycaemia, is associated with increased survival in critically ill patients. Insulin therapy concomitantly reduces plasma-free fatty acids. Recent studies indicate that free fatty acids mediate inflammation. In addition to plasma glucose and free fatty acid-lowering effects, insulin also has anti-inflammatory properties. This study was designed to study the pro-inflammatory effects of two free fatty acid concentrations during acute endotoxaemia and controlled comparable levels of plasma glucose and insulin. Twenty pigs were anaesthetized and mechanically ventilated. Pigs were randomized to two different, constant Intralipid infusion rates, throughout observation. All pigs were administered continuous intravenous infusion of endotoxin and subjected to controlled levels of p-glucose (4.5 mmol/l) and insulin by use of a hyperinsulinaemic euglycaemic clamp. Changes in circulating tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-6, leucocytes, insulin, glucose, free fatty acids, triglycerides, albumin, blood gases, temperature, and, haemodynamic function were monitored. Immediately following killing, biopsies were taken from heart and kidney. Biopsies were analysed for protein content of TNF-alpha, IL-6, IL-8 and IL-10. Sustained elevated and significantly different plasma levels of free fatty acids were demonstrated between groups (mean free fatty acid concentrations, 1.62 mM versus 0.58 mM, p < 0.0002). Endotoxaemia induced a steep increase in plasma TNF-alpha, IL-6 and leucocytes, however, without differences between the low- and high-free fatty acid groups. Cytokine content in heart and kidney tissue was not modified by free fatty acids. Compared with the response obtained at lower free fatty acid levels, high free fatty acid levels did not exacerbate the inflammatory response to acute endotoxaemia. Our results do not support the role of free fatty acids as a significant pro-inflammatory mediator.