Here's a tip I borrowed indirectly from our colleagues in the U/S guided biopsy field. The cap of a pen (obviously without a pocket clip), when pressed firmly but gently into the skin for a count of about 5 seconds will leave a distinct mark which will last for several minutes. I map the vein as if I had a marker pen then wipe off the gel and connect the dots with a marker pen. You can devise your own system for marking the location and direction of branches. I usually double check branch location after the main conduit is marked. I indicate the size of the vein at the groin, knee, ankle and foot. If you are having trouble visualizing veins try sitting the patient up on the edge of the elevated bed with their foot resting on your seat between your legs. It sounds kinky but it works and it beats getting all bent out of shape crawling around on the floor. In this position you can comfortably scan the LSV and the calf portion of the GSV. Mapping the LSV in this position takes practice and you may wind up back on the floor. Always remember that with the patient sitting or standing, the hydrostatic pressure on the veins approaches that of an artery so they don't compress all too well, don't be fooled into concluding that they are noncompressible. If in doubt, retest with patient supine. I hope this has been useful. We do a fair wack of vein mapping and it seems to work. We get lots of feedback from the surgeons on our accuracy and we are rated for QA: a score of 3 means bang on; 2 means close but no cigar and 1 means next time put your glasses on. Fortunately we have had mostly 3's. Steve Knight RVT Fletcher-Allen Health Care In affiliation with the University of Vermont