Multistate outbreak of hemolysis in hemodialysis patients traced to faultyblood tubing sets

Background. Hemolysis associated with hemodialysis is rare. The most freque nt causes of hemodialysis-associated hemolysis are chemical contamination, heat, or mechanical injury of erythrocytes from occluded or kinked hemodial ysis blood lines. When patients in three states developed hemolysis while u ndergoing hemodialysis between May 13 and 23, 1998, an investigation was in itiated. Methods. A case-patient was defined as any patient at healthcare facilities A (Nebraska), B (Maryland), or C (Massachusetts) during May 13 through 23, 1998 (epidemic period), who had hemolysis diagnosed greater than or equal to 48 hours after undergoing hemodialysis. To identify case-patients and to determine background rates, the medical records of patients from facilitie s A, B, and C who were undergoing hemodialysis during the epidemic and pre- epidemic (that is, May 5 through 19, 1998) periods were reviewed. Experimen ts simulating hemodialysis with the same lot numbers of hemodialysis blood tubing cartridge sets used on case- and control-patients were conducted. Results. The rates of hemolysis among patients at facilities A, B, and C we re significantly higher during the epidemic than the pre-epidemic period (1 3 out of 118 vs. 0 out of 118. Pt 0.001: 12 out of 298 vs. 0 out of 298, P = 0.001: and 5 out of 62 vs. 0/65, P = 0.03, respectively). All case-patien ts had hemolysis. Twenty (66%) had hypertension. Eighteen (60%) had abdomin al pain, and 10 (36%) were admitted to an intensive care unit. There were t wo deaths. The only commonality among the three outbreaks was the use of th e same lot of disposable hemodialysis blood tubing from one manufacturer. E xamination of the implicated hemodialysis blood tubing cartridge sets revea led narrowing of an aperture through which blood was pumped before entering the dialyzers. In vitro experiments with the hemodialysis blood tubing rev ealed that hemolysis was caused by increased pressure on erythrocytes as th ey passed through the partially occluded hemodialysis blood tubing. Conclusions. Our investigation traced the multiple hemolysis outbreaks to p artially occluded hemodialysis blood tubing produced by a single manufactur er. On May 25, 1998, the manufacturer issued a voluntary nationwide recall of the implicated lots of hemodialysis blood tubing cartridge sets.