title: Strategy to control catheter encrustation with citrated drinks: a randomized crossover study.
abstract: OBJECTIVE
  Nucleation pH is the pH at which Ca and Mg come out of urine to form crystals. If the safety margin between voiding pH and nucleation pH could be increased, it would increase the possibility of an alternative to controlling the activity of urease producing bacteria as a strategy to control catheter encrustation.
  
  
  METHODS
  We performed a 6-week randomized crossover study in 24 patients with catheter blockage who were randomly allocated to a specific sequence of 3 consecutive available treatments, including increased fluid intake, lemon juice and potassium citrate. Each patient received all available regimens. At the end of each week 24-hour urine samples were analyzed for voiding and nucleation pH, citrate, Ca and Mg.
  
  
  RESULTS
  Mean +/- SD nucleation pH increased from 7.45 +/- 0.60 at baseline to 7.93 +/- 0.50, 7.68 +/- 0.64 and 7.96 +/- 0.37 in the lemon juice, increased fluid intake and potassium citrate groups, respectively (p <0.0001). Mean urinary citrate increased significantly (p <0.0001), in particular due to lemon juice and potassium citrate effects. The association between treatment and Ca was weak (p = 0.12) while that of Mg was negative due to lemon (p <0.001). Average increase in the safety margin (nucleation pH minus voiding pH) beyond baseline was 0.84 (95% CI 0.63-1.04), 0.57 (95% CI 0.37-0.78) and 0.41 (95% CI 0.20-0.61) for lemon juice, increased fluid intake and potassium citrate, respectively. A strong treatment effect on the safety margin was apparent even when controlling for study design (p <0.001).
  
  
  CONCLUSIONS
  Increased fluid intake with lemon juice may be a simple, inexpensive, effective strategy to control catheter encrustation.
authors.affiliation: BioMed Centre, Bristol Urological Institute, Southmead Hospital Bristol, Bristol, United Kingdom. docazhar@gmail.com
authors.forename: Azhar
authors.initials: A
authors.lastname: Khan
authors.forename: Fadi
authors.initials: F
authors.lastname: Housami
authors.forename: Roberto
authors.initials: R
authors.lastname: Melotti
authors.forename: Anthony
authors.initials: A
authors.lastname: Timoney
authors.forename: David
authors.initials: D
authors.lastname: Stickler
mesh_terms: D000328:Adult; D000368:Aged; D001628:Beverages; D002957:Citrus; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D019357:Potassium Citrate / Q000627:therapeutic use*; D011512:Proteus Infections / Q000150:complications* / Q000652:urine*; D011513:Proteus mirabilis; D014546:Urinary Catheterization / Q000009:adverse effects
chemical_list: D019357:Potassium Citrate