title: Use of alkaline rinsing solution to prevent hypersensitivity reactions during hemodialysis: data from a multicentre retrospective analysis.
abstract: BACKGROUND
  Hypersensitivity reactions (HSRs) can be enhanced by contact phase system activation leading to bradykinin (BK) generation. In patients treated with angiotensin converting enzyme inhibitors (ACE-I), an impaired kinin degradation can magnify the phenomenon. We have previously demonstrated that the electronegative charge of the dialysis membrane (e.g. AN69) and other cofactors including diluted blood buffer power promote BK generation, and that kallikrein synthesis on diluted plasma may be inhibited by keeping the pH value above 7.4. Our in vitro and ex vivo studies have demonstrated that the use of an alkaline solution to rinse both filter fluid compartments before their clinical use can inhibit the activation of mediators that are likely to be involved in HSRs.
  
  
  METHODS
  The present study was aimed at gathering data from a multicenter retrospective analysis of HSRs in 15 Italian centers, with special attention to the precautions chosen to avoid recurrence, and at evaluating whether a rinsing procedure maintaining the pH of the diluted blood above 7.4 may prevent further HSRs.
  
  
  RESULTS
  HSRs were reported in 54 patients on dialysis treatment between January 1995 and June 1997. 39/54 HSRs occurred when AN69 was used. In 44.4% of cases, HSRs were associated with ACE-I treatments. The HSR prevention modalities varied considerably among the centers. Two thirds of the nephrologists did not change their dialysis prescription but tried to modify the acidic environment of the patient's diluted blood at the first contact with the dialysis device using an alkaline rinsing procedure (BioPrime with alkaline solution). In other cases ACE-I withdrawal or a change of dialysis membrane was adopted. Thirty-six patients who received alkaline rinsing of the filters were monitored for a total of 686 months (median 17.6 months/patient) to control HSR recurrences. None of the patients enrolled in this study developed new episodes of HSRs.
  
  
  CONCLUSIONS
  Even if considered with the caution called for by this kind of study, which was retrospective and uncontrolled, our data suggest a protective effect of the alkaline rinsing procedure with buffered solutions in the development of HSRs.
authors.affiliation: Nephrology and Dialysis Department, Regina Margherita Hospital, Torino, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Amore
authors.forename: G
authors.initials: G
authors.lastname: Guarnieri
authors.forename: M
authors.initials: M
authors.lastname: Atti
authors.forename: F P
authors.initials: FP
authors.lastname: Schena
authors.forename: R
authors.initials: R
authors.lastname: Coppo
mesh_terms: D000707:Anaphylaxis / Q000209:etiology / Q000517:prevention & control; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D001769:Blood; D001920:Bradykinin / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006969:Hypersensitivity, Immediate / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D008567:Membranes, Artificial; D008875:Middle Aged; D012008:Recurrence; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D012996:Solutions
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D008567:Membranes, Artificial; D012996:Solutions; D001920:Bradykinin