11.   The heart muscle suddenly goes into fibrillation, beating so fast and shallowly that no blood can circulate.

12.   They sit in reclining chairs for three to four hours as their blood circulates through machines that filter out the impurities their kidneys no longer can remove.

13.   Without elevation, blood circulates downward but has trouble returning to the heart, causing blood to settle throughout most of the lower half of his atrophied leg.

14.   The thickened blood must circulate through already-constricted vessels, creating a potentially dangerous situation, Siegel said.