CHBT Hemodialysis Principles and Practices 2

Question 1

Which solute transport mechanism in hemodialysis relies on a concentration gradient between blood and dialysate?

Accepted Answer

Diffusion

Answer

Diffusion is the primary mechanism of solute removal in hemodialysis. Solutes move from an area of higher concentration (blood) to lower concentration (dialysate) across the semipermeable membrane.

Question 2

What is ultrafiltration in the context of hemodialysis?

Accepted Answer

The removal of excess fluid from the blood by applying transmembrane pressure

Answer

Ultrafiltration removes excess fluid (water) from a patient's blood using transmembrane pressure (TMP) across the dialyzer membrane. It is controlled by the dialysis machine to achieve the patient's target dry weight.

Question 3

The dialysate flow rate in a standard hemodialysis session is typically set at:

Accepted Answer

500 mL/min

Answer

Standard dialysate flow rate is 500 mL/min, which is approximately twice the blood flow rate (usually 250–350 mL/min). This ratio maintains a favorable concentration gradient for efficient diffusion.

Question 4

Which type of dialyzer membrane is most commonly used in modern hemodialysis?

Accepted Answer

Synthetic high-flux membrane (e.g., polysulfone)

Answer

High-flux synthetic membranes such as polysulfone are the current standard. They allow removal of larger middle molecules and have better biocompatibility compared to older cellulose-based membranes.

Question 5

What is the significance of the blood pump speed in hemodialysis?

Accepted Answer

It determines the blood flow rate through the dialyzer, directly affecting solute clearance

Answer

The blood pump speed (set in mL/min) determines how fast blood passes through the dialyzer. Higher blood flow rates (Qb) increase solute clearance, particularly for small molecules like urea.

CHBT - Certified Hemodialysis Bio-Medical Technician Practice Test

CHBT - Certified Hemodialysis Bio-Medical Technician Practice Test

CHBT Hemodialysis Principles and Practices 2