Dialyzer reactions refer to all of the abnormal sequelae resulting from the interaction between blood constituents and the hemodialysis membrane. There are two types of reactions: type A and type B . In the past, these reactions were grouped under the term "first use syndrome" because they primarily occurred with new dialyzers. Before discussing the characteristics of these disorders, it is helpful to review the different types of dialyzers, since they can affect the frequency and type of reaction seen. The longer term clinical consequences of exposure to dialysis membranes are discussed separately. (See "Clinical consequences of hemodialysis membrane biocompatibility".)
TYPES OF HEMODIALYSIS MEMBRANES
There are four types of membranes currently used to manufacture dialyzers :
- Cellulose, also called cuprophan (or cuprophane), is a polysaccharide-based membrane obtained from pressed cotton. It is composed of chains of glucosan rings with abundant free hydroxyl groups.
- Substituted cellulose membranes are obtained by chemical bonding of a material to the free hydroxyl groups at the surface of the cellulose polymer. The most common type is cellulose acetate, in which acetate replaces 80 percent of the hydroxyl groups.
- Cellulosynthetic membranes are modified by the addition of a synthetic material (such as diethylaminoethyl in the production of Hemophane) to liquefied cellulose during its formation.
- Synthetic noncellulose membranes which have a higher permeability and are more biocompatible (and more expensive) than the cellulose membranes. There are a variety of synthetic membranes available, including polyacrylonitrile (PAN), acrylonitrile-sodium methallyl sulfonate (AN-69), polysulfone, polycarbonate, polyamide, and polymethylmethacrylate (PMMA) membranes.
TYPE A REACTIONS
Type A reactions are estimated to occur in approximately four of every 100,000 dialysis treatments. They usually begin in the first few minutes of dialysis, immediately after the return of blood from the dialysis circuit to the patient; in occasional cases, however, the onset is delayed for up to 30 minutes into the treatment .
The associated symptoms range from mild to severe . Mild cases may be associated with a variety of symptoms such as itching, burning sensation at the access site, urticaria, flushing, cough, sneezing, wheezing, abdominal cramps, diarrhea, headache, back and chest pain, nausea, vomiting, fever, and chills. More severe reactions lead to dyspnea, a sense of impending doom, and hypotension, potentially resulting in cardiac arrest and death. Patients with an allergic diathesis and eosinophilia appear to be predisposed to this type of reaction.