CTP Organ Preservation Techniques 2 — Questions and Answers
Question 1: Which component of University of Wisconsin (UW) solution is responsible for preventing cell swelling during cold ischemia?
- Hydroxyethyl starch (Correct answer)
- Lactobionate
- Raffinose
- Adenosine
Correct answer: Hydroxyethyl starch
Hydroxyethyl starch is the impermeant colloid in UW solution that prevents cell swelling by maintaining oncotic pressure.
Question 2: During normothermic machine perfusion (NMP) of the liver, which parameter best indicates adequate cellular metabolism?
- Perfusate lactate clearance (Correct answer)
- Portal vein flow rate
- Hepatic artery resistance
- Bile color
Correct answer: Perfusate lactate clearance
Lactate clearance during NMP reflects hepatocyte metabolic activity and is a key viability marker.
Question 3: What is the primary rationale for using pulsatile flow rather than continuous flow in hypothermic machine perfusion (HMP) of kidneys?
- It better mimics physiological conditions and reduces vascular resistance (Correct answer)
- It requires less oxygen delivery to the organ
- It allows higher perfusion temperatures
- It eliminates the need for preservation solution
Correct answer: It better mimics physiological conditions and reduces vascular resistance
Pulsatile flow in HMP mimics the cardiac cycle, reduces vascular resistance, and improves nutrient delivery to renal tissue.
Question 4: Which enzyme system is most critically impaired when ATP is depleted during warm ischemia?
- Na⁺/K⁺-ATPase pump (Correct answer)
- Cytochrome c oxidase
- Succinate dehydrogenase
- Xanthine dehydrogenase
Correct answer: Na⁺/K⁺-ATPase pump
The Na⁺/K⁺-ATPase pump requires ATP to maintain ion gradients; its failure leads to cell swelling and irreversible injury.
Question 5: In pancreas preservation, what is the maximum recommended cold ischemia time to optimize islet cell viability?
- 12 hours (Correct answer)
- 6 hours
- 24 hours
- 18 hours
Correct answer: 12 hours
Cold ischemia time for pancreas preservation should ideally not exceed 12 hours to maintain islet cell function.
Question 6: Which preservation solution additive acts as a free radical scavenger to reduce reperfusion injury?
- Glutathione (Correct answer)
- Lactobionate
- Mannitol
- Potassium
Correct answer: Glutathione
Glutathione is an antioxidant included in UW solution that scavenges free radicals generated during reperfusion.
Question 7: During ex vivo lung perfusion (EVLP), which fluid is typically used as the perfusate base?
- Steen Solution (Correct answer)
- Celsior solution
- Custodiol HTK
- Normal saline with albumin
Correct answer: Steen Solution
Steen Solution is the standard EVLP perfusate, providing oncotic pressure and electrolyte balance to support lung function assessment.
CTP Organ Preservation Techniques 2
Which component of University of Wisconsin (UW) solution is responsible for preventing cell swelling during cold ischemia?