CCHT Water Treatment and Quality 2

Question 1

What is the primary purpose of the softener in the dialysis water treatment system?

Accepted Answer

To remove calcium and magnesium ions to prevent scaling and protect the reverse osmosis membrane

Answer

The water softener exchanges calcium and magnesium ions (which cause 'hardness') for sodium ions using a cation exchange resin. This prevents scaling and mineral deposit buildup in pipes, the reverse osmosis membrane, and dialysis machines.

Question 2

What is the maximum allowable bacterial count in dialysis water per AAMI standards?

Accepted Answer

200 CFU/mL (action level 50 CFU/mL)

Answer

AAMI standards require dialysis water to have less than 200 CFU/mL of bacteria, with an action level of 50 CFU/mL. Exceeding the action level requires investigation and corrective action before results reach the maximum allowable limit.

Question 3

Chloramine is particularly dangerous in dialysis water because it can cause which serious complication?

Accepted Answer

Hemolytic anemia from oxidative damage to red blood cell membranes

Answer

Chloramine (a combination of chlorine and ammonia used as a disinfectant in municipal water supplies) cannot be removed by reverse osmosis and can cross the dialyzer membrane to enter the patient's blood, causing oxidative damage to red blood cell membranes and hemolytic anemia.

Question 4

What does the conductivity test of dialysate measure, and why is it important?

Accepted Answer

The total dissolved solute concentration of the dialysate, confirming correct electrolyte mixing

Answer

Dialysate conductivity measures the total ionic concentration of the dialysate, which serves as a proxy for correct electrolyte composition (sodium, potassium, calcium, magnesium, bicarbonate). It confirms that concentrate and water are being mixed at the correct proportions.

Question 5

How often should activated carbon filters in the dialysis water treatment system be tested for chlorine/chloramine removal efficacy?

Accepted Answer

Before the first patient treatment of each day and after each shift

Answer

AAMI standards require testing the effluent of the activated carbon filters for total chlorine and chloramines before the first patient treatment of the day and after each shift change, because carbon capacity can be exhausted at any time, and breakthrough is not visually detectable.

CCHT - Certified Clinical Hemodialysis Technician Practice Test

CCHT - Certified Clinical Hemodialysis Technician Practice Test

CCHT Water Treatment and Quality 2