Evidence for the autoregulation of vesical circulation by intravesical potassium chloride and distension in the normal human bladder

Objectives To determine the influence of distension and intravesical KCl on vesical blood flow in the normal human bladder, Subjects and methods Nine normal volunteers underwent comparative cystometr y (NaCl vs 0.2 mol/L KCl; filling rate 50 mL/min), Peak systolic blood flow velocity (PSBFV) and end-diastolic blood flow velocity (EDBFV) were measur ed in several intramural arteries at a filling volume of 50 mL and at maxim um cystometric capacity (Cmax). For these measurements a colour Doppler uni t fitted with an endorectal probe was used. The resistance index (RI) was d efined as (PSBFV - EDBFV)/PSBFV. Results In the presence of NaCl, the mean PSBFV increased significantly fro m 9 cm/s at 50 mL to 17 cm/s at Cmax (512 mL). Compared with NaCl, KCl indu ced a significantly higher mean PSBFV at 50 mL (15 cm/s). With increasing d istension the rise in PSBFV with KCl filling (Cmax 478 mt) was nearly paral lel to that obtained on NaCl filling (mean 22 cm/s); the RI did not change, Conclusions Bladder distension and intravesical I(CI significantly increase d the PSBFV, The unchanged RI indicated a concomitant increase in perfusion rates, Hence, the composition of urine thigh potassium concentrations and hyperosmolarity) and its storage govern the autoregulation (independent of cardiac output) of vesical circulation, probably by reflexive pathways, The se findings provide further evidence for prevesical arteriovenous shunts.