The shock waves break the stones into tiny fragments so they can be excreted in the urine. Researchers were interested in determining if the severity of changes in kidney function after lithotripsy could be correlated to different doses of shock waves. There are no prior studies testing how the kidney responds to various levels of shock waves in animal models or human patients. By measuring changes in kidney blood flow and the animals' ability to make urine, researchers found that 8,000 shock waves applied to one kidney caused similar large and sustained reductions of blood flow and function in both kidneys. Further study is warranted to determine why both kidneys are affected.
Blood flow is critical to healthy kidney function.
The study showed that, following high dose shock wave treatment, blood flow to both kidneys was reduced for the four-hour length of the study. After 1 hours of severely reduced blood flow, kidney cells may begin to die. During the four-hour course of this study, there was at least a 50 percent reduction in blood flow and at least a 50 percent drop in urine formation in both kidneys. The animals were subjected to either 2,000 or 8,000 shock waves. The 2,000 shock wave level is a typical clinical dose, but higher amounts are administered if treatment indicates.