1
ECMO Specialist Exam 101 Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
[SECTION 1: ECMO Circuit Components & Physiology — Questions 1-20]
Q1: Which component of the modern ECMO circuit is responsible for removing carbon dioxide
from the blood based on the principle of diffusion?
A. Centrifugal pump
B. Heat exchanger
C. Membrane oxygenator [CORRECT]
D. Arterial cannula
Correct Answer: C
Rationale: The membrane oxygenator contains microporous hollow fibers where gas exchange
occurs; CO2 diffuses from the blood into the sweep gas due to the partial pressure gradient. The
pump (Option A) creates flow but does not perform gas exchange, and the heat exchanger
(Option B) only manages temperature.
Q2: In a centrifugal pump, what is the primary mechanism used to generate blood flow?
A. Positive displacement rollers compressing tubing
B. Kinetic energy transferred from a rotating impeller to the blood [CORRECT]
C. Gravity-fed siphon effect
D. Pneumatic compression of a bladder
Correct Answer: B
Rationale: Centrifugal pumps utilize an impeller spinning at high speeds to create kinetic energy,
which converts to pressure head to propel blood forward. Option A describes a roller pump,
which is rarely used in modern long-term ECMO due to hemolysis risks.
,2
Q3: What is the clinical significance of the "Delta P" (Transmembrane Pressure) across the
oxygenator?
A. It measures the patient's systemic blood pressure
B. It indicates the pressure gradient between the pre-oxygenator and post-oxygenator sites,
reflecting resistance to flow through the device [CORRECT]
C. It calculates the amount of oxygen delivered to the patient
D. It represents the negative pressure generated by the pump
Correct Answer: B
Rationale: Delta P is the difference between inlet and outlet pressures of the oxygenator; a rising
Delta P indicates increasing resistance, often due to thrombosis or fouling of the fibers. Option A
is measured via an arterial line, and Option C is determined by blood flow and saturation.
Q4: When setting the sweep gas flow on a VV ECMO circuit, which parameter is primarily
affected?
A. Oxygenation (PaO2)
B. Carbon dioxide removal (PaCO2) [CORRECT]
C. Hemoglobin concentration
D. Systemic vascular resistance
Correct Answer: B
Rationale: Sweep gas flow creates the gradient for CO2 removal; increasing sweep gas lowers
PaCO2. While oxygen delivery is affected by the FiO2 of the sweep gas, the volume of sweep
primarily manages ventilation (CO2 clearance).
Q5: Which cannulation configuration is typically used for a patient suffering from severe
hypoxemic respiratory failure without hemodynamic compromise?
A. Veno-Arterial (VA) ECMO
B. Veno-Venous (VV) ECMO [CORRECT]
C. Arterio-Venous (AV) ECMO
D. Veno-Arterial-Venous (VAV) ECMO
Correct Answer: B
,3
Rationale: VV ECMO provides respiratory support by oxygenating blood and returning it to the
venous system, leaving the heart to handle hemodynamics. Option A (VA) is indicated for
cardiac failure or combined cardiopulmonary failure.
Q6: What is the primary function of the bridge or shunt located between the arterial and venous
limbs of the ECMO circuit?
A. To allow for medication administration
B. To facilitate continuous hemofiltration
C. To maintain circuit patency and allow for recirculation if the pump is off [CORRECT]
D. To measure post-oxygenator pressure
Correct Answer: C
Rationale: The bridge allows blood to recirculate passively when the ECMO pump is turned off
(e.g., during weaning trials or emergencies), preventing stasis and thrombosis. It is not used for
medication (Option A) or hemofiltration (Option B) directly.
Q7: In the context of ECMO physiology, pre-oxygenator pressure is most closely monitored to
detect which complication?
A. Arterial hypertension
B. Excessive negative pressure (chattering) or drainage issues [CORRECT]
C. Oxygenator failure
D. Post-pump hemolysis
Correct Answer: B
Rationale: Pre-oxygenator pressure reflects the pressure in the drainage cannula; excessively
negative values indicate "chattering" or poor drainage due to hypovolemia, malposition, or
kinking. Option C would be indicated by a rising Delta P.
Q8: Which substance is commonly used to prime the ECMO circuit before connection to the
patient to prevent air from entering the bloodstream?
A. Sterile water
B. Lactated Ringer's solution or Plasma-Lyte [CORRECT]
, 4
C. Normal Saline only
D. Colloids (Albumin) exclusively
Correct Answer: B
Rationale: Crystalloid solutions like Plasma-Lyte or Lactated Ringer's are standard priming
fluids; Normal Saline can cause hyperchloremic acidosis, and colloids are expensive and usually
reserved for specific protocols.
Q9: The phenomenon where oxygenated blood from the return cannula is immediately drawn
back into the drainage cannula is known as:
A. Recirculation [CORRECT]
B. Shunting
C. Steal phenomenon
D. Harlequin syndrome
Correct Answer: A
Rationale: Recirculation occurs in VV ECMO when the drainage and return cannulae are too
close or flows are too high, reducing the efficiency of oxygen delivery. Option D refers to
differential hypoxia in VA ECMO.
Q10: According to ELSO guidelines, what is the maximum recommended pressure limit for the
post-oxygenator pressure to avoid damage to the circuit components?
A. 200 mmHg
B. 300 mmHg [CORRECT]
C. 400 mmHg
D. 500 mmHg
Correct Answer: B
Rationale: Most oxygenators and circuits are rated to withstand pressures up to 300-350 mmHg;
exceeding this risks rupture or connection failure. Option A is too conservative for some high-
flow scenarios, and C/D exceed safety limits.
ECMO Specialist Exam 101 Actual Exam
2026/2027 – Complete Exam-Style Questions
with Detailed Rationales | 100% Verified |
Pass Guaranteed – A+ Graded
[SECTION 1: ECMO Circuit Components & Physiology — Questions 1-20]
Q1: Which component of the modern ECMO circuit is responsible for removing carbon dioxide
from the blood based on the principle of diffusion?
A. Centrifugal pump
B. Heat exchanger
C. Membrane oxygenator [CORRECT]
D. Arterial cannula
Correct Answer: C
Rationale: The membrane oxygenator contains microporous hollow fibers where gas exchange
occurs; CO2 diffuses from the blood into the sweep gas due to the partial pressure gradient. The
pump (Option A) creates flow but does not perform gas exchange, and the heat exchanger
(Option B) only manages temperature.
Q2: In a centrifugal pump, what is the primary mechanism used to generate blood flow?
A. Positive displacement rollers compressing tubing
B. Kinetic energy transferred from a rotating impeller to the blood [CORRECT]
C. Gravity-fed siphon effect
D. Pneumatic compression of a bladder
Correct Answer: B
Rationale: Centrifugal pumps utilize an impeller spinning at high speeds to create kinetic energy,
which converts to pressure head to propel blood forward. Option A describes a roller pump,
which is rarely used in modern long-term ECMO due to hemolysis risks.
,2
Q3: What is the clinical significance of the "Delta P" (Transmembrane Pressure) across the
oxygenator?
A. It measures the patient's systemic blood pressure
B. It indicates the pressure gradient between the pre-oxygenator and post-oxygenator sites,
reflecting resistance to flow through the device [CORRECT]
C. It calculates the amount of oxygen delivered to the patient
D. It represents the negative pressure generated by the pump
Correct Answer: B
Rationale: Delta P is the difference between inlet and outlet pressures of the oxygenator; a rising
Delta P indicates increasing resistance, often due to thrombosis or fouling of the fibers. Option A
is measured via an arterial line, and Option C is determined by blood flow and saturation.
Q4: When setting the sweep gas flow on a VV ECMO circuit, which parameter is primarily
affected?
A. Oxygenation (PaO2)
B. Carbon dioxide removal (PaCO2) [CORRECT]
C. Hemoglobin concentration
D. Systemic vascular resistance
Correct Answer: B
Rationale: Sweep gas flow creates the gradient for CO2 removal; increasing sweep gas lowers
PaCO2. While oxygen delivery is affected by the FiO2 of the sweep gas, the volume of sweep
primarily manages ventilation (CO2 clearance).
Q5: Which cannulation configuration is typically used for a patient suffering from severe
hypoxemic respiratory failure without hemodynamic compromise?
A. Veno-Arterial (VA) ECMO
B. Veno-Venous (VV) ECMO [CORRECT]
C. Arterio-Venous (AV) ECMO
D. Veno-Arterial-Venous (VAV) ECMO
Correct Answer: B
,3
Rationale: VV ECMO provides respiratory support by oxygenating blood and returning it to the
venous system, leaving the heart to handle hemodynamics. Option A (VA) is indicated for
cardiac failure or combined cardiopulmonary failure.
Q6: What is the primary function of the bridge or shunt located between the arterial and venous
limbs of the ECMO circuit?
A. To allow for medication administration
B. To facilitate continuous hemofiltration
C. To maintain circuit patency and allow for recirculation if the pump is off [CORRECT]
D. To measure post-oxygenator pressure
Correct Answer: C
Rationale: The bridge allows blood to recirculate passively when the ECMO pump is turned off
(e.g., during weaning trials or emergencies), preventing stasis and thrombosis. It is not used for
medication (Option A) or hemofiltration (Option B) directly.
Q7: In the context of ECMO physiology, pre-oxygenator pressure is most closely monitored to
detect which complication?
A. Arterial hypertension
B. Excessive negative pressure (chattering) or drainage issues [CORRECT]
C. Oxygenator failure
D. Post-pump hemolysis
Correct Answer: B
Rationale: Pre-oxygenator pressure reflects the pressure in the drainage cannula; excessively
negative values indicate "chattering" or poor drainage due to hypovolemia, malposition, or
kinking. Option C would be indicated by a rising Delta P.
Q8: Which substance is commonly used to prime the ECMO circuit before connection to the
patient to prevent air from entering the bloodstream?
A. Sterile water
B. Lactated Ringer's solution or Plasma-Lyte [CORRECT]
, 4
C. Normal Saline only
D. Colloids (Albumin) exclusively
Correct Answer: B
Rationale: Crystalloid solutions like Plasma-Lyte or Lactated Ringer's are standard priming
fluids; Normal Saline can cause hyperchloremic acidosis, and colloids are expensive and usually
reserved for specific protocols.
Q9: The phenomenon where oxygenated blood from the return cannula is immediately drawn
back into the drainage cannula is known as:
A. Recirculation [CORRECT]
B. Shunting
C. Steal phenomenon
D. Harlequin syndrome
Correct Answer: A
Rationale: Recirculation occurs in VV ECMO when the drainage and return cannulae are too
close or flows are too high, reducing the efficiency of oxygen delivery. Option D refers to
differential hypoxia in VA ECMO.
Q10: According to ELSO guidelines, what is the maximum recommended pressure limit for the
post-oxygenator pressure to avoid damage to the circuit components?
A. 200 mmHg
B. 300 mmHg [CORRECT]
C. 400 mmHg
D. 500 mmHg
Correct Answer: B
Rationale: Most oxygenators and circuits are rated to withstand pressures up to 300-350 mmHg;
exceeding this risks rupture or connection failure. Option A is too conservative for some high-
flow scenarios, and C/D exceed safety limits.
