The effect of pH and lignocaine on detrusor instability

The effects of intravesical alkaline solution and lignocaine have been studied in 42 patients with detrusor instability, eight patients with low bladder compliance and eight with stable bladders. Filling the bladder with alkaline solution instead of saline resulted in a significant increase in bladder capacity in the unstable and low compliance bladders (35.9 and 27.5% respectively). The addition of lignocaine to the alkaline solution further increased bladder capacity in patients without bladder outflow obstruction. In all patients with flow rates of less than 10 ml/s, lignocaine reduced bladder capacity. There was a qualitative improvement in instability on using an alkaline filling medium. However, in three patients with outflow obstruction lignocaine caused the instability to worsen. Possible mechanisms for these findings are discussed.