Sodium tetradecyl sulphate foam stability prior to injection: factors affecting liquid reformation

Abstract

Regardless of the method and details of the foam produced, sclerotherapists should be aware of the dynamics and speed of foam degradation, and reconstitute foam at the first sign of liquid reformation, as this heralds the onset of rapid degradation of the foam. This is particularly relevant for rapidly deteriorating foam produced from CO(2), or without the use of a filter.

Sclerotherapy – How to Achieve a Spectacular Outcome

“…When treating reticular and small varicose veins, I prefer to do direct puncture with a 30G needle, either with direct visualization or ultrasound guidance when the vessel is not visible. While literature has suggested that small needles may disrupt fine microbubbles, this is unlikely to be of consequence when treating small caliber vessels [20].…”

“…However, three-way connector does allow for partial closure which narrows the caliber between the two syringe to create a longer-lasting foam [16]. The use of a 5 μm in-line filter for creating foam, while not necessary to prevent bacterial contamination [19], improves foam stability [20]. Tessari et al noted that smaller needles (27 and 30 gauge) may produce a less stable foam and advocates the use of 25 gauge for injection [16].…”

“…Tessari et al noted that smaller needles (27 and 30 gauge) may produce a less stable foam and advocates the use of 25 gauge for injection [16]. Subsequent study noted variability in foam stability between needle size (83 sec for 25 gauge; 70 sec for 27 gauge, 67 sec for 30 gauge), though this is unlikely to affect its clinical effectiveness [20]. Standard liquid-to-gas ratio is 1:4, as this produces a dense and stable foam [16].…”

“…The stability (half-life) of foam varies depending on the type of gas used (room air, sterile air, CO2 vs other mixture of gas). Room air which contains 72 % nitrogen, is readily available, creates a stable foam (1-2 min) [20], but does not dissolve quickly in blood due to its nitrogen content. CO2 is more soluble in blood but creates a less stable foam (25 sec) [20], that must be injected immediately [16].…”

“…Room air which contains 72 % nitrogen, is readily available, creates a stable foam (1-2 min) [20], but does not dissolve quickly in blood due to its nitrogen content. CO2 is more soluble in blood but creates a less stable foam (25 sec) [20], that must be injected immediately [16]. The use of a physiologic gas with the addition of O2 creates a foam that has a slightly longer half-life and readily diffusible in blood.…”