Manufacture of foam using the Tessari technique.
The foam must be prepared just before use and administered by a physician appropriately trained in the correct generation and administration of foam.
Strict aseptic technique must be maintained while manufacturing the foam.
To create the foam 1ml of liquid sclerosant is drawn into a sterile syringe and 3ml or 4ml of sterile air is drawn into another sterile syringe (Fig. 1). The air is drawn through a 0.2 μm filter to ensure it is sterile. The syringes are then connected using a sterile three way tap/valve (Fig. 2). The sclerosant/air mixture is then forced back and forth from one syringe to the other through the 3-way valve approximately 20 times to produce a smooth, consistent foam (Fig. 3&4). The syringe containing the foam, is then removed and the vein is injected immediately.
The sclerosant foam must be used within sixty seconds of production. After sixty seconds any remaining foam should be discarded. More foam should be prepared if required. The quality of the foam should be checked before administration. It should appear homogeneous with no large bubbles visible to the naked eye.