Acute onset of decreased vision and hearing traced to hemodialysis treatment with aged dialyzers

Context A recent event in which 7 patients at 1 hospital developed decrease d vision and hearing, conjunctivitis, headache, and other severe neurologic symptoms 7 to 24 hours after hemodialysis drew attention to the issue of t he long-term integrity of dialysis machines and materials. Objective To determine the cause of the adverse reactions that occurred dur ing this event. Design, Patients, and Setting Retrospective cohort study of all 9 patients who received hemodialysis at hospital A on September 18, 1996, the day of t he outbreak. A case-patient was defined as any hospital A patient with acut e onset of decreased vision and hearing and conjunctivitis after dialysis o n that day. Non-case-patients were all others who underwent dialysis at hos pital A on that day but did not develop adverse reactions. in an attempt to reproduce the conditions of the event, cellulose acetate dialysis membrane s of various ages were retrieved from other sources and tested for physical and chemical degradation, and degradation products were identified, charac terized, and injected intravenously into rabbits. Main Outcome Measures Clinical signs and symptoms, time to resolution of sy mptoms, mortality, and dialyzer type and age, for case- vs non-case-patient s. Results Seven of the 9 patients met the case definition. In addition to dim inished vision and hearing, conjunctivitis, and headache, some case-patient s had blood leak alarm activation (n=6), confusion/lethargy (n=5), corneal opacification (n=4), cardiac arrest (n=2), or other neurologic signs and sy mptoms. One case-patient died during hospitalization after the event; 5 of 7 case-patients died within 13 months. Resolution of signs and symptoms var ied but persisted more than 3 years or until death in 3 of the 6 patients w ho survived hospitalization. All case-patients but no non-case-patients wer e exposed to 11.5-year-old cellulose acetate dialyzers (all of these dialyz ers were discarded by the hospital before our investigation). Laboratory in vestigation of field-retrieved 0- to 13.6-year-old dialyzers of similar typ e indicated significant chemical degradation in the older membranes. In viv o injection of extracts of membrane degradation products produced iritis an d hemorrhages in rabbits' eyes. Conclusions Severe patient injury was associated with exposure to aged cell ulose acetate membranes of dialyzers, allowing cellulose acetate degradatio n products to enter the blood. Clinicians should be aware that aged cellulo se acetate membranes may cause severe adverse reactions.