Question 1: Define dialysis and explain how it assists in maintaining homeostasis in patients with kidney failure.

Answer: Dialysis is a medical procedure that removes waste products, excess salts, and water from the blood when the kidneys are unable to do so. It helps maintain proper fluid and electrolyte balance, thus supporting homeostasis.

Question 2: Describe the main components involved in a dialysis machine and their functions.

Answer: A dialysis machine typically includes a blood pump, a dialyser (artificial kidney), and a sterile fluid called dialysate. The blood is circulated through the dialyser where waste products and excess salts are removed before returning to the patient.

Question 1: Calculate the total volume of blood filtered during a 4-hour dialysis session if the blood flow rate is 300 mL per minute.

Answer: Total volume = flow rate × time = 300 mL/min × 240 min = 72,000 mL or 72 litres.

Question 2: If a dialysis machine removes 1.5 mmol of sodium per litre of blood processed, how much sodium is removed after processing 50 litres of blood?

Answer: Sodium removed = removal rate × volume = 1.5 mmol/L × 50 L = 75 mmol.

Question 3: Using the formula clearance (C) = (V × 0.693) / t, where V is the volume of plasma cleared and t is time in minutes, calculate the clearance if 150 mL of plasma is cleared in 60 minutes.

Answer: C = (150 mL × 0.693) / 60 min ≈ 1.73 mL/min.

Question 1: Identify three variables that must be controlled during dialysis to ensure patient safety.

Answer: Blood flow rate, dialysate composition, and duration of the session.

Question 2: Describe two safety precautions that should be observed when setting up a dialysis machine.

Answer: Ensuring sterile equipment to prevent infection, and correctly matching blood and dialysate circuits to prevent contamination.

Question 1: A patient undergoing dialysis shows a decrease in blood sodium levels from 140 mmol/L to 135 mmol/L after a 4-hour session. Explain what this indicates about the dialysate composition and the process.

Answer: It indicates that the dialysate had a lower sodium concentration than the blood, leading to diffusion of sodium out of the blood into the dialysate, helping to correct hypernatremia.

Question 1: Explain the principles of diffusion and osmosis in the context of dialysis, including how they help in removing waste products and excess water from the blood. (6 marks)

Answer: In dialysis, diffusion allows waste products like urea and excess salts to move from the blood, where their concentration is higher, into the dialysate, where their concentration is lower. Osmosis helps remove excess water by water moving from the blood into the dialysate, which has a lower water potential. Together, these processes maintain the body's fluid and chemical balance, mimicking the natural functions of the kidneys.

Question 1: Discuss how advancements in dialysis technology have improved patient quality of life and treatment outcomes.

Answer: Advancements such as portable dialysis machines, improved dialysate formulations, and better sterilisation techniques have increased convenience, reduced complications, and allowed patients to have more flexible lifestyles, ultimately improving their quality of life and treatment success.