title: The blocking urinary catheter: the role of variation in urine flow.
abstract: OBJECTIVE
  To relate blockage of the urinary catheter to urine chemistry.
  
  
  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%).
  
  
  CONCLUSIONS
  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.
authors.affiliation: National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Burr
authors.forename: I
authors.initials: I
authors.lastname: Nuseibeh
mesh_terms: D000328:Adult; D000368:Aged; D002118:Calcium / Q000652:urine; D002408:Catheters, Indwelling; D004868:Equipment Failure; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D014546:Urinary Catheterization; D014554:Urination; D014556:Urine / Q000737:chemistry
chemical_list: D002118:Calcium