Hemodialysis provides ongoing life support for hundreds of thousands of people worldwide.4 min read
What Is Dialysis?
Hemodialysis provides ongoing life support for hundreds of thousands of people worldwide. However by nature of the fact that blood is being exposed to "foreign material" in the course of each procedure it is of no surprise that side effects occur from this exposure. These complications range from clinically insignificant to potentially life threatening.
Initially most artificial kidneys were made of cellulose based materials. These remain the most commonly used source of dialysis membranes. The most common of this type of membrane are cellulose acetate and Cuprophane. More recently synthetic membranes have been developed which are more "biocompatible". These include Polysulfone (PS), Polymethylmetherylate (PMMA) and Polyacrilonitrile (PAN). These newer high flux membranes are all synthetic and their use is increasing.
There are certain predictable acute sequelae of blood exposure to these artificial membranes. The white blood cell counts and platelet counts drop within the first hour of dialysis but return to normal towards the end of the procedure. These changes tend to be clinically insignificant.
However complement activation also predictably occurs. This may include an inflammatory response and may be the cause of the so-called "first use" reaction. This is typically described as chest pain, back pain and shortness of breath that occurs 20 to 40 minutes after hemodialysis is started and may be initiated by complement activation. As such this reaction tends to be less common with more biocompatible membranes which have an attenuated ability to activate complement.
The second and potentially more dangerous type of reaction is one of anaphylaxis. This is an allergic reaction mediated by an antigen antibody complex. Clinically these tend to occur within five minutes of the initiation of dialysis and the symptoms may include a burning sensation at the access site, shortness of breath, chest tightness, wheezing, localized edema, flushing, itching, nausea, vomiting, abdominal cramps and hypotension. Like anaphylactic reaction it can lead to respiratory insufficiency, shock and death.
These reactions may be due to the artificial membrane itself, ethylene oxide (commonly used for dialyzer sterilization), agents used for reuse (these are substances used to clean and sterilize the artificial kidney in order to allow it to be used more than one time, and include bleach, formaldehyde and renalin) and medications used in the dialysis procedure (particularly heparin, an anticoagulant almost universally used for anticoagulation of the blood prior to starting dialysis).