Thick silk fibroin vascular graft: A promising tissue-engineered scaffold material for abdominal vein grafts in middle-sized mammals.

Abdominal vein replacement with synthetic tissue-engineered vascular grafts constructed from silk-based scaffold material has not been reported in middle-sized mammals. Fourteen canines that underwent caudal vena cava replacement with a silk fibroin (SF) vascular graft (15 mm long and 8 mm diameter) prepared with natural silk biocompatible thread were allocated to two groups, thin and thick SF groups, based on the graft wall thickness. The short-term patency rate and histologic reactions were compared. The patency rate at 2 weeks after replacement in the thin and thick SF groups was 50% and 88%, respectively (p = 0.04). CD31-positive endothelial cells covered the luminal surface of both groups at 4 weeks. The elastic modulus of the thick SF graft was significantly better than that of the thin SF graft (0.0210 and 0.0007 N/m2, p < 0.01). Roundness of thick SF groups (o = 0.8 mm) was better than thin SF (o = 2.0 mm). There was significant difference between the groups (p = 0.01). SF vascular grafts are a promising tissue-engineered scaffold material for abdominal venous system replacement in middle-sized mammals, with thick-walled grafts being superior to thin-walled grafts.

Effect of Smoke Evacuator on Reduction of Volatile Organic Compounds and Particles in Surgical Smoke: A Randomized Controlled Trial.

BACKGROUND: Surgical smoke is an occupational health problem and is increasingly recognized as a potential source of virus transmission. Dedicated smoke evacuators are used to protect against surgical smoke exposure. We tested the hypothesis that using smoke evacuators would reduce volatile organic compounds and the number of particles in surgical smoke during the laparotomy procedure. STUDY DESIGN: A randomized, double-blind clinical trial was conducted in patients undergoing laparotomy from June 11, 2021, to March 30, 2022, to compare the effectiveness of smoke evacuators with a control (registration, UMIN000044250). The primary outcome was a change in the acetaldehyde level. Secondary outcomes were changes in the formaldehyde level and particle count assessed by the particle size of 0.3, 0.5, 1.0, and 5.0 nm. RESULTS: A total of 42 patients were randomized and assessed (smoke evacuator group, n = 22 vs control group, n = 20). The acetaldehyde level was significantly lower in the smoke evacuator group than in the control group: mean (95% CI), 10.6 (3.7 to 17.5) vs 47.2 (19.9 to 74.5) µg/m 3 , p < 0.001. Similarly, the formaldehyde level was 72.2% lower in the smoke evacuator group than in the control group. Particle counts by each particle size category were 80% to 95% lower in the smoke evacuator group than in the control group (all, p < 0.001). CONCLUSIONS: Dedicated smoke evacuators reduced the level of acetaldehyde and formaldehyde, and the number of particles in surgical smoke, minimizing the potential exposure to volatile organic compounds and particle matters during surgery.