title: Methemoglobinemia in critically ill patients during extended hemodialysis and simultaneous disinfection of the hospital water supply.
abstract: BACKGROUND
  To evaluate the cause of methemoglobinemia in patients undergoing extended daily hemodialysis/hemodiafiltration we analyzed the relationship between methemoglobinemia and the water disinfection schedule of the hospital.
  
  
  METHODS
  We reviewed all arterial blood gas analyses, obtained over a one-year period, in patients undergoing extended hemodialysis/hemodiafiltration, and compared the methemoglobin concentrations obtained on the days when the water supply was disinfected, using a hydrogen peroxide/silver ion preparation, with data measured on disinfection-free days.
  
  
  RESULTS
  The evaluation of 706 measurements revealed a maximum methemoglobin fraction of 1.0 (0.8; 1.2) % (median and 25th; 75th percentiles) during hemodialysis/hemodiafiltration on the disinfection-free days. The methemoglobin fraction increased to 5.9 (1.3; 8.4) % with a maximal value of 12.2% on the days of water disinfection (P < 0.001 compared to disinfection-free days). Spot checks on hydrogen peroxide concentrations in the water supply, the permeate, and the dialysate, using a semi-quantitative test, demonstrated levels between 10 and 25 mg/l during water disinfection.
  
  
  CONCLUSIONS
  Our results demonstrate that even a regular hospital water disinfection technique can be associated with significant methemoglobinemia during extended hemodialysis. Clinicians should be aware of this potential hazard.
authors.affiliation: Dialysis Centre Bad Krozingen, Heart Centre Bad Krozingen, Suedring 15, 79189 Bad Krozingen, Germany. Bek.Martin@web.de.
authors.forename: Martin Johannes
authors.initials: MJ
authors.lastname: Bek
authors.forename: Sven
authors.initials: S
authors.lastname: Laule
authors.forename: Christine
authors.initials: C
authors.lastname: Reichert-Jünger
authors.forename: Rainer
authors.initials: R
authors.lastname: Holtkamp
authors.forename: Michael
authors.initials: M
authors.lastname: Wiesner
authors.forename: Cornelius
authors.initials: C
authors.lastname: Keyl
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001784:Blood Gas Analysis; D016638:Critical Illness; D004203:Disinfection / Q000379:methods*; D005260:Female; D006761:Hospitals; D006801:Humans; D006861:Hydrogen Peroxide; D008297:Male; D008706:Methemoglobin / Q000032:analysis / Q000096:biosynthesis*; D008708:Methemoglobinemia / Q000175:diagnosis / Q000209:etiology*; D008875:Middle Aged; D006435:Renal Dialysis; D012189:Retrospective Studies; D018030:Silver Compounds; D013997:Time Factors; D014871:Water Microbiology / Q000592:standards; D014881:Water Supply / Q000592:standards*
chemical_list: D018030:Silver Compounds; D008706:Methemoglobin; D006861:Hydrogen Peroxide