CTP Organ Preservation Techniques 5 — Questions and Answers
Question 1: What is the role of prostaglandin E1 (PGE1) in lung preservation during procurement?
- Pulmonary vasodilation to ensure uniform distribution of flush solution (Correct answer)
- Prevention of reperfusion injury through antioxidant mechanisms
- Reduction of surfactant production in alveolar cells
- Induction of hypothermia in the pulmonary vasculature
Correct answer: Pulmonary vasodilation to ensure uniform distribution of flush solution
PGE1 is administered before lung flush to dilate the pulmonary vasculature, ensuring uniform distribution of cold preservation solution throughout the lungs.
Question 2: In normothermic regional perfusion (NRP) for DCD donors, what is the primary goal of excluding the cerebral circulation?
- To prevent restoration of brain perfusion in a legally dead donor (Correct answer)
- To reduce systemic pressure during perfusion
- To allow higher flow rates to abdominal organs
- To prevent air embolism to the heart during ECMO initiation
Correct answer: To prevent restoration of brain perfusion in a legally dead donor
Cerebral vessels are ligated or clamped during NRP to ensure no blood flow is restored to the brain, preserving the legal and ethical basis of death determination.
Question 3: Which preservation solution is most commonly used for small bowel transplantation due to its ability to limit mucosal injury?
- University of Wisconsin (UW) solution (Correct answer)
- Celsior solution
- HTK Custodiol
- Euro-Collins solution
Correct answer: University of Wisconsin (UW) solution
UW solution is the standard for small bowel preservation, providing optimal protection for the ischemia-sensitive intestinal mucosa.
Question 4: Which parameter measured during hypothermic machine perfusion (HMP) of a kidney indicates vascular damage that predicts poor graft outcome?
- Persistently elevated resistive index (RI > 0.4) (Correct answer)
- Low perfusate lactate dehydrogenase (LDH)
- Stable flow rates above 100 mL/min
- Decreasing vascular resistance over time
Correct answer: Persistently elevated resistive index (RI > 0.4)
A persistently high RI during HMP indicates irreversible vascular damage and is associated with increased risk of delayed graft function or non-function.
Question 5: What is the primary metabolic substrate provided to organs during normothermic machine perfusion (NMP) to support aerobic metabolism?
- Red blood cells as oxygen carriers combined with glucose (Correct answer)
- Crystalloid solution with dissolved oxygen alone
- Albumin with amino acid supplementation
- Synthetic hemoglobin without glucose
Correct answer: Red blood cells as oxygen carriers combined with glucose
NMP perfusate contains packed red blood cells to carry oxygen and glucose as the primary energy substrate to sustain aerobic cellular metabolism.
Question 6: During cold static storage, at what temperature range is organ preservation most effective?
- 0–4°C (Correct answer)
- 8–12°C
- 15–20°C
- 20–25°C
Correct answer: 0–4°C
Storage at 0–4°C reduces cellular metabolic rate by approximately 12-fold compared to body temperature, significantly slowing ischemic injury.
Question 7: Which condition is most likely to occur if a kidney is stored in preservation solution at temperatures below 0°C?
- Ice crystal formation causing irreversible cellular membrane damage (Correct answer)
- Accelerated ATP depletion
- Enhanced free radical scavenging activity
- Improved vascular integrity due to reduced metabolism
Correct answer: Ice crystal formation causing irreversible cellular membrane damage
Freezing causes intracellular and extracellular ice crystal formation that physically disrupts cell membranes, leading to irreversible injury.
CTP Organ Preservation Techniques 5
What is the role of prostaglandin E1 (PGE1) in lung preservation during procurement?