Effect of low-frequency ultrasound on peritoneal transport in rabbits

It has recently been suggested that sonophoresis, or the application of ultrasound (US) in the kilohertz range, could enhance peritoneal mass transport. To examine this hypothesis, six nephrectomized rabbits were exposed to ultrasound while under isoflurane anesthesia. An additional five also had bilateral nephrectomies and were used as a control group. Each group underwent four exchanges of 90 minutes duration with 1.5% dextrose while anesthetized. Dialysate samples were taken at 0, 30, 60, and 90 minutes and assayed for urea, creatinine, glucose, and protein. Blood samples were taken pre- and postexchange. In the US group, 20 kHz ultrasound was applied during exchanges 2 and 3 at 47.5 W and 95 W, respectively, using a Virsonic 475 cell disrupter acoustically coupled to the abdomen through a water column and gel-coated PVC membrane. Results were analyzed by calculating the mass transfer area coefficient (MTAC) and 90-minute D/P values for each exchange. No significant differences were observed in the absolute means of either parameter between the control and US groups. However, when exchanges 2 to 4 were normalized with respect to exchange 1, the resulting urea D/P means were less for the US exchanges compared to the control (p < 0.05). This suggests a possible decrease in transport through US application.