Interaction Between Perfluorcarbon Liquid and Heavy Silicone Oil: Risk Factor for "Sticky Oil" Formation

Purpose: To investigate in vitro the interaction between perfluorcarbon liquids (PFCLs) and heavy silicone oils (HSOs). Methods: Interactions between different kinds of PFCL [perfluoro-n-octane (PFO) or perfluorodecaline (PFD)] and HSO (either alkane or ether) were studied in vitro by incubating fluids for 7 days at regulated temperatures. The samples were divided into two groups: Group A, PFCL (PFO or PFD) + 5 ml of HSO (silicone oil + alkane or ether) and Group B, HSO (silicone oil + alkane or ether) without PFCL. Each sample was kept at 36 degrees C for 7 days. HSOs were then removed with a 20 g, 7 mm-long cannula under 600 mm Hg of vacuum pressure at two different temperatures: 36 and 22 degrees C. The time needed to remove the oils and the presence of opacity was recorded. Each experiment was repeated three times. Results: In vitro, interactions between PFCL and HSO oil led to the formation of hyper-viscous solutions with significative increase in aspiration time in Group A. (P = 0.006, Kruskal-Wallis test) Temperature was also found to affect HSOs' saturation, as a decrease in temperature determined an increase in opacity and shear viscosity of the solution (P = 0.02, Kruskal-Wallis test). No differences between alkane and ether (P = 0.74) and n-octane and decaline (P = 0.56) was found. Conclusion: Interactions between PFCL-HSO and variation in temperature lead to the formation of hyper-viscous solutions that could be described as "sticky oil".