What is the reason for discouraging clamp use to stop cannulation site bleeding?
The issue of clamp usage is very controversial and, as with virtually all practices in vascular access management, there is no real evidence or data from randomized, controlled trials of practices–thus no evidence supporting any given practice. Most of what is recommended is a result of observational or intuitive inferences and conclusions. For example, we tell patients not to wear a watch on the wrist with a radio-cephalic AVF–and to avoid blood pressures being taken on the same arm, etc. This is because we know that pressure, if excessive and prolonged, can cause thrombosis. With clamps, the rationale is the same. If the pressure applied is enough to prevent flow, or allows some flow but for too prolonged a period, thrombosis may be initiated. The thrombosis will not be evident until the patient is at home or returns for the next dialysis. This is because it takes time for a thrombus to propagate to full thrombosis–prior to which there will still be a bruit and thrill. However, on
