Objective: To determine whether an indwelling catheter on free drainage provides a constantly low intravesical pressure in patients with a neuropathic bladder.
Patients and methods: Thirty patients with complete spinal-cord injury (SCI) whose bladders were managed exclusively with an indwelling catheter were assessed urodynamically using natural-fill urodynamics (ambulatory monitoring) while their catheters were left on free drainage. Their upper urinary tracts were assessed using plain X-rays and ultrasonography.
Results: Detrusor contractions causing intravesical pressure rises of >40 cmH2O for up to 4.5 min were observed in 11 patients. Renal scarring was observed in nine patients; of these, six were in the group with contractions of > 40 cmH2O, whereas only five of 21 patients with normal kidneys had such pressure rises.
Conclusion: An indwelling catheter on free drainage is no guarantee of a constantly low intravesical pressure. This study provides evidence to suggest that there is an association between phasic bladder contractions which occur despite catheter drainage and upper urinary tract damage in permanently catheterized patients with SCI.