The model also helps a center cope with two constraints: the limited number of dialysis units in a facility, which forces it to curtail patient time on a kidney dialysis machine or turn away new patients; and high costs, particularly the cost of a component known as a dialyzer.
During dialysis, the blood of a patient is withdrawn and passed through a dialyzer - a device with a semi-permeable membrane - allowing a significant reduction in the concentration of blood toxins. On average, say the authors, Medicare reimburses centers $126 per dialysis session. Because a dialyzer costs between $30 and $70, a center typically retains a patient's dialyzer until that person's next dialysis session. Dialyzers are typically reused as many as 20 times.
The authors note, however, that while a patient's treatment time on a dialysis machine remains fixed, reuse of the patient's dialyzer reduces its efficiency, thus gradually cutting the dosage every visit until the dialyzer is replaced.
Their model helps centers appropriately adjust patients' time on dialysis machines and the number of times that dialyzers are reused, thus producing optimal use of a center's scarce resources while improving life expectancy.
Accounting for Patient's Varying Needs
To determine the optimal dose for different patients, the authors divide those receiving dialysis into three classes of diabetics, and three of non-diabetics. The authors also factor overall for the relative efficiencies of low-, medium-, and high capacity dialysis centers.
The study looks at several alternate policies that employ an operations research technique known as optimiza
Contact: Barry List
Institute for Operations Research and the Management Sciences