"use of one's own blood "during the course of a surgical operation" implies salvage/capture of blood lost in the course of a surgery that is then routed in an eventually continuous loop back into the circulatory system. The tubes, capture bag/container, and other paraphernalia enabling this can be viewed as a [temporary] extension of the body's circulatory system so that the blood never leaves the living organism."
This is outdated information. Per the October 15, 2001 Watchtower, "use of one's own blood " isn't limited to blood lost during surgery that is put back into the veins via a machine in a continuous loop. JW's are now allowed to have blood completely removed from their body, taken to a lab, stored, treated in some manner and then later transfused back into their veins. The only requirement is that the blood be removed and reused within a single hospital stay. The November 2006 Kingdom Ministry lists several of these approved procedures.