There are several methods that can be applied to various applications in order to stabilize probes. The following suggestions can be applied acutely or chronically.
Make sure that the size of the probe is appropriate for the vessel diameter. The vessel should fill 75 -95% of the probe lumen. If it is an acute application, a closer fit will be more stable because it will use less gel.
The position of the cable (back or side) is often determined by the anatomical placement of the probe and the adjacent tissues. Back (perpendicular to the vessel) is more convenient if the approach is deep. Side (parallel to the vessel) is useful if there is access to lay the probe and cable flat along side the vessel. A suture may be applied around the cable to keep the probe in place. There are also suture holes in opposite sides of the reflector and slide cover.
Silicone wrap goes around the probe and vessel like an envelope and extends the length of the probe along the vessel to provide more stability. The wrap gives additional places where sutures may be placed for stability. The wrap also helps to keep gel in place. It is typically used on side exit probes, but may be applied on back exit probes too.
This is a flange around the perimeter of the probe. It is typically used in LAD coronary artery applications to keep a probe around a deep vessel from pulling the vessel out of its natural position. Suture holes are provided to sew the probe down on the tissue for stability. It is also applied in uterine artery applications and has been successful in stabilizing a flow probe on the thoracic duct.
If gel melts during a long experiment and is the cause of the instability of the signal, you should try a closer fittiing probe. The modifications above help to keep the gel in place, but it is also possible to use an angio catheter to deposit more gel in place when it does melt away - or consider using Nalco 1181 Superabsorbant Powder to make the gel more viscous.
NOTE: This is only available for terminal experiements.