Residual urine following intermittent catheterisation in patients with spinal cord injuries

Residual urine following catheterisation was studied using ultrasonography (Ultramark II Scientific Medical System) in 12 patients with spinal cord injury, for an average of 4 months (range 3-7 months) after the time of injury. All of the patients were examined on three occasions. Urinary tract infections were also registered, and the functional type of the urinary bladder was identified by a cystometric examination. Ultrasonography showed residual urine volumes after 25 of a total of 36 catheterisations (70%). In seven of these catheterisations the residual urine volume exceeded 50 ml, and in two patients was more than 100 ml. None of the patients had a residual urinary volume of more than 50 ml after all three catheterisations, but in all but two patients, some residual urine volume was found after at least one of the catheterisations. Low and non-significant correlations were found between residual volume and frequency of urinary tract infections. It is possible that even small residual urine volumes after catheterisations may predispose to urinary tract infections in these patients.