Mixed Deck — All ECMO Topics Flashcards

The term 'ECMO-CPR' (ECPR) refers to:

Answer: Initiating VA-ECMO during active cardiac arrest to restore perfusion

ECPR is the deployment of VA-ECMO during refractory cardiac arrest to restore systemic perfusion and allow time for resuscitation, intervention, or recovery.

Hemolysis in an ECMO circuit is best monitored by measuring:

Answer: Plasma-free hemoglobin and lactate dehydrogenase (LDH) levels

Plasma-free hemoglobin and LDH are direct markers of red cell destruction, indicating mechanical trauma from pump cavitation, high negative pressures, or circuit thrombosis.

What is the significance of a 'chattering' or 'sucking' cannula during VV ECMO?

Answer: It signals that drainage is impaired, usually from hypovolemia or cannula malposition

Cannula chattering occurs when the circuit intermittently collapses venous inflow, indicating inadequate preload or a positional drainage issue requiring immediate attention.

What happens to PaCO2 when sweep gas flow is doubled while ECMO blood flow remains constant?

Answer: PaCO2 decreases, potentially causing hypocapnia

Doubling sweep gas flow dramatically increases CO2 removal, often causing significant hypocapnia, so sweep adjustments require careful monitoring of blood gas values.

The ELSO (Extracorporeal Life Support Organization) registry reports the highest survival rates among which ECMO patient group?

Answer: Neonatal respiratory ECMO

Neonatal respiratory ECMO has the best outcomes, with survival to discharge approximately 73% according to ELSO registry data.

Following a circuit change for oxygenator failure, the ECMO specialist notes the new circuit's post-membrane pO2 is 500 mmHg on FiO2 1.0. This confirms:

Answer: The new oxygenator is functioning appropriately

A post-membrane pO2 of approximately 500 mmHg on 100% FiO2 is the expected result of a fully functional oxygenator, confirming successful circuit exchange.

A patient on VV ECMO requires Continuous Renal Replacement Therapy (CRRT). The CRRT circuit is initiated, drawing blood from a pre-pump access port and returning it post-oxygenator. Shortly after initiation, the ECMO circuit's pre-membrane (access) pressure becomes significantly more negative, and the venous line begins to chatter. What is the most probable cause?

Answer: The CRRT machine's ultrafiltration rate is too high, causing patient hypovolemia.

Aggressive fluid removal (ultrafiltration) by the CRRT machine can rapidly deplete the patient's circulating volume. This resulting hypovolemia leads to insufficient venous return to fill the ECMO circuit, causing the drainage cannula to suck against the vessel walls. This is manifested as an increasingly negative pre-membrane pressure and visible 'chatter' in the line.

You respond to a call at a dialysis center for an unresponsive 75-year-old female. They collapsed just before starting their dialysis run for the day. When you arrive, you are unable to palpate a pulse. While you are preparing to start chest compression, your partner places the patient on the monitor. When you perform a rhythm check, you notice ventricular fibrillation. After giving epinephrine and defibrillations, you start transporting to the nearest hospital. Is this patient a good candidate for ECPR (refractory arrest, “ECMO Alert”)?

Answer: No, because she has end-stage renal disease and is on dialysis.

Explanation: No, this patient has end-stage-renal-disease and is on dialysis so this would exclude her from ECPR (refractory arrest, “ECMO Alert”).

During gradual flow reduction in VV-ECMO weaning, which laboratory value should be monitored most closely to detect inadequate native lung CO2 clearance?

Answer: Arterial PaCO2

Rising arterial PaCO2 during sweep reduction signals that native lungs cannot clear CO2 sufficiently to sustain the wean.

A neonate on femoral VA-ECMO develops progressive ipsilateral lower extremity ischemia. The most appropriate intervention is:

Answer: Insert a distal perfusion catheter into the superficial femoral artery

A distal perfusion catheter (DPC) inserted antegrade into the superficial femoral artery restores distal limb perfusion while maintaining ECMO support.

A patient on VA-ECMO for cardiogenic shock undergoes a 30-minute clamp trial. During the trial, the arterial pressure waveform becomes pulsatile with a pulse pressure of 40 mmHg. This finding indicates:

Answer: Adequate left ventricular recovery to consider decannulation

A robust pulsatile waveform during VA-ECMO clamping reflects meaningful left ventricular stroke volume, suggesting cardiac recovery.

Which patient position is generally preferred during VV ECMO to optimize oxygenation in refractory ARDS?

Answer: Prone positioning

Prone positioning improves V/Q matching and recruits dorsal lung regions, complementing VV ECMO support in refractory ARDS.

The primary goal of ECMO support in pediatric myocarditis is:

Answer: Bridging to myocardial recovery or cardiac transplantation

Myocarditis can cause fulminant cardiac failure, and ECMO provides hemodynamic support while awaiting spontaneous recovery or listing for transplantation.

What is the physiological rationale for targeting a lower 'lung-protective' ventilator strategy (ultra-protective ventilation) during VV-ECMO?

Answer: ECMO assumes gas exchange, allowing the lungs to rest and potentially recover from VILI

With ECMO handling gas exchange, tidal volumes and pressures can be minimized to prevent ventilator-induced lung injury (VILI) and promote lung recovery.

A patient on ECMO receiving unfractionated heparin has an aPTT of 220 seconds. The appropriate intervention is:

Answer: Hold heparin infusion and recheck aPTT in 2 hours

A supratherapeutic aPTT of 220 seconds greatly increases bleeding risk; holding the heparin infusion temporarily allows levels to fall while avoiding full reversal that risks circuit thrombosis.

What is the minimum gestational age generally accepted as a criterion for neonatal ECMO candidacy?

Answer: 34 weeks

Most centers require ≥34 weeks gestational age because premature neonates face prohibitively high rates of intracranial hemorrhage on ECMO anticoagulation.

What is the effect of hypothermia on oxygen-hemoglobin dissociation during ECMO?

Answer: Shifts curve leftward, increasing hemoglobin O2 affinity

Hypothermia shifts the oxyhemoglobin dissociation curve to the left, increasing hemoglobin's affinity for oxygen and impairing tissue O2 delivery.

Which cannula configuration is used in veno-arterial-venous (VAV) ECMO?

Answer: One venous drainage, one arterial return, and one additional venous return cannula

VAV-ECMO uses one venous drainage cannula with both an arterial and a venous return cannula, providing both cardiac and respiratory support while improving upper body oxygenation.

What does a persistently elevated lactate during ECMO most commonly indicate?

Answer: Insufficient systemic oxygen delivery or utilization

Elevated lactate (>2 mmol/L) persisting on ECMO reflects ongoing tissue hypoxia or impaired lactate clearance, signaling inadequate support.

A patient fails multiple VA-ECMO weaning trials over 14 days. The ECMO team should next consider:

Answer: Evaluation for durable ventricular assist device implantation or heart transplantation

Repeated weaning failure after 2 weeks indicates the heart is unlikely to recover; escalation to a durable VAD or transplant evaluation is the appropriate next step.