The blocking urinary catheter: the role of variation in urine flow

OBJECTIVES: To relate blockage of the urinary catheter to urine chemistry. PATIENTS AND METHODS: Of 44 patients (age range 19-72 years) with an indwelling urinary catheter, 21 were troubled by frequent blockage and 23 experienced no blockage. Variation in urinary pH and calcium concentration were determined during a 24 h period and related to the occurrence of blockage using discriminant analysis. RESULTS: The maximum pH and calcium concentrations observed, or the maximum discriminant factors calculated, correctly discriminated 91% of patients (95% CI, 78-97%). CONCLUSION: Attention to volume and variability of fluid intake by the patient should have a major impact on the incidence of blockage of the indwelling urinary catheter.