| | Fig. 8.9. Text
a Left: Omnifix syringe; right: (shaded) Injekt syringe. Preparation I: sterile filtration of air. The Sterifix 0.2-µm sterile filter is first screwed onto the threepart, 10-ml Omnifix syringe for sterile filtration of ambient air (step 1A), and an exact amount of 8 ml ambient air is drawn up in accordance with the graduation of the syringe barrel (step 1B). A hygienically proper procedure is mandatory. Preparation II: drawing up of Aethoxysklerol. Afterward, the Sterifix 0.2-µm sterile filter is removed and 1 ampoule of Aethoxysklerol 3% is drawn up completely (2 ml), as usual, into the same syringe using a sterile disposable cannula (step 1C). The inadvertent drawing up of additional sterile air is to be avoided. Preparation III: assembling the dual syringe system. The Combidyn adapter is first firmly connected to the filled Omnifix syringe (step 2A) then to the Injekt syringe (step 2B) by rotation in order to assemble the dual syringe system. (Personal communication from J-C.G.R.Wollmann M.D.).b Left: Omnifix syringe; right: (shaded) Injekt syringe. Foam generation I: mixing phase. The foam generation is performed in two phases: In the first mixing phase,Aethoxysklerol 3% and sterile air are mixed to obtain a dispersion. This is achieved by moving the plunger of the filled Omnifix syringe five times forward and backward with a short, firm, thumb pressure of one hand (step 3). The thumb of the other hand holds the plunger of the (shaded) Injekt syringe so that pumping must be done against a resistance, and the Omnifix plunger returns to its starting position by passive pressure. The (shaded) Injekt syringe is held a bit lower. Foam generation II: homogenization phase. The homogenization phase follows immediately: The plunger of the Omnifix syringe is pressed quickly while the plunger of the (shaded) Injekt syringe is not fixed but can move freely so that no resistance is generated at that time. This forward and backward movement is followed by an opposite backward movement by exerting pressure on the plunger of the (shaded) Injekt syringe in the same manner. A total of seven quick forward and backward movements are performed (step 4). The plunger of the Omnifix syringe is drawn back to the 10- ml mark to make sure that no excess pressure remains in the double- syringe system (DSS) (step 5). The adapter and the (shaded) Injekt syringe are eventually removed and discarded. The mixing phase and the homogenization phase will take a total of 4–5 s for experienced users. A sterile, very fine, homogenous foam is obtained, which remains stable for a couple of minutes. The procedure ensures a high degree of reproducibility if performed correctly. A common injection cannula is then attached or screwed on to the Omnifix syringe, which now contains 10 ml Aethoxysklerol foam for immediate further use. (Personal communication from J-C.G.R.Wollmann M.D.) | |
