An investigation of side-effects and efficacy of foam-based sclerotherapy with carbon dioxide or room air in the treatment of reticular leg veins: a pilot study

Objectives In sclerotherapy, carbon dioxide (CO2) or room air can be employed by phlebologists for foam creation. We compared room air (RA) and carbon dioxide in treating reticular leg veins with foam sclerotherapy. Methods Twenty patients were randomly treated with RA- or CO2-created sodium tetradecyl sulphate (STS) foam. Concentration and volume of STS, side-effects and efficacy were determined. Results There was no difference in the efficacy, local side-effects or distant side-effects between RA and CO2 foam in the treatment of reticular leg veins. The total volume of foam sclerosant required for treatment was greater with CO2 compared with RA ( P value = 0.01). Conclusion No differences were found in efficacy or side-effects between RA- and CO2-foam sclerotherapy for reticular leg veins. CO2 foam's shorter half-life was hypothesized to be responsible for larger total volumes of CO2 foam sclerosant.

Properties of Foam and Soil Improvements for Earth-Pressure Balance Shield Construction in Red Soils

Soil improvement by foam is a key technique to control formation damage in shield construction. The half-life of three kinds foam was obtained by test self-developed foam and other two types. Meanwhile, their characteristics of stability and dissipation were analyzed. The physical-mechanical characteristic of red clay which was improved by foam was tested. Test result show that as the foam concentration increasing, the cohesion and plastic fluidity of soil increases firstly and then decreases, but the internal fiction angle decrease always. The permeability of red clay was measured by penetration test. The impregnation depth of foam in red clay was analyzed. The results provide key parameters for shield construction to prevent engineering accidents, such as, flowing, sand gushing, mud boiling, collapse and so on.