Nursing Medium1. ECMO: the basic idea
ECMO means extracorporeal membrane oxygenation. Blood leaves the body through a drainage cannula, passes through a pump and membrane oxygenator, and returns through a return cannula. The oxygenator adds oxygen and removes carbon dioxide. ECMO provides temporary support while the team treats the underlying illness or assesses a suitable bridge to another treatment. It does not cure the illness.
Blood pathway — simplified schematic
- Venous drainage
- Pump + membrane oxygenator
- Return to vein (VV) or artery (VA)
| Mode | What it supports | Typical situation |
|---|---|---|
| VV: veno-venous | Gas exchange. The patient’s heart must still provide systemic circulation. | Severe, potentially reversible respiratory failure. |
| VA: veno-arterial | Circulation and gas exchange. Blood returns to the arterial system. | Severe cardiac pump failure with inadequate organ perfusion. |
Memory aid: VV = ventilation support; VA = ventilation + arterial circulation support. This is a learning aid, not a complete description of every circuit configuration.
[1] [2]2. Indications and patient selection
| VV ECMO | VA ECMO |
|---|---|
| Severe ARDS or other acute respiratory failure despite optimised conventional treatment, including prone positioning when appropriate. | Refractory cardiogenic shock despite appropriate treatment, for example selected myocarditis or post-cardiotomy failure. |
| Refractory hypoxaemia or hypercapnic respiratory acidosis where meaningful recovery or a viable bridge is possible. | Selected massive pulmonary embolism or carefully selected extracorporeal CPR cases in a specialist programme. |
ECMO referral is a multidisciplinary decision. Diagnosis alone is insufficient: reversibility, duration of injury, organ function and a realistic plan for leaving ECMO all matter.
[1] [2]3. Contraindications and important cautions
| Situation | Why it matters |
|---|---|
| No expected recovery and no viable bridge/decannulation plan | ECMO cannot provide a meaningful exit strategy. This is the central absolute contraindication described for VV ECMO. |
| Intracranial haemorrhage, major irreversible neurological injury, uncontrolled bleeding or inability to anticoagulate | Major risk. These require specialist assessment; bleeding or an anticoagulation concern is not an automatic absolute exclusion in every ECMO situation. |
| Advanced comorbidity, prolonged injurious ventilation, increasing age or severe immunosuppression | Relative selection concerns. There is no single universal age cut-off that nurses should apply. |
| VA-specific concerns: severe aortic regurgitation, aortic dissection or unsuitable peripheral vessels | May make a particular VA approach unsafe or require a different strategy. |
4. Nursing considerations BEFORE cannulation
- Confirm identity, planned mode, indication, consent/emergency authorisation and the team’s documented plan. Explain the procedure to the patient/family at an appropriate level.
- Record baseline consciousness, pupils, limb perfusion, vital signs, oxygenation, urine output and skin condition. Document existing deficits so later changes are recognisable.
- Check ordered laboratory results, blood availability when indicated, vascular access and prescribed infusions. Communicate bleeding, allergy and anticoagulant history.
- Prepare the sterile area and the team’s initiation checklist. Verify that trained staff have checked the circuit, gas supply, power and emergency equipment.
- Plan safe positioning and secure all lines. Use a coordinated handover before cannulation and connection.
5. Nursing considerations DURING ECMO
| Assess | Nursing focus |
|---|---|
| Patient and organ perfusion | Trend blood pressure, rhythm, oxygenation, lactate, urine output and fluid balance. Reassess pupils and neurological status whenever sedation allows. |
| Cannulae and circuit | Check fixation, external position, dressings, tubing, connections and ordered circuit observations. Escalate new bleeding, visible air, clot concerns, abnormal pressures or flow alarms immediately. |
| Bleeding and infection | Inspect cannula sites, other wounds, urine and stool; trend haemoglobin and coagulation. Use aseptic handling and assess for infection. |
| Peripheral femoral VA ECMO | Assess both legs, especially the cannulated limb: colour, warmth, capillary refill, movement/sensation and Doppler findings as ordered. Check the distal perfusion system if present. |
| Upper-body oxygenation on peripheral femoral VA | A right-arm saturation/right radial blood gas may reveal differential hypoxaemia even when lower-body oxygenation looks satisfactory. |
| Comfort and recovery | Provide pain assessment, mouth/eye care, nutrition, pressure-area care and coordinated repositioning. Mobilisation requires an individual plan and an ECMO-trained team. |
6. Nursing considerations AFTER weaning and decannulation
- Weaning and decannulation are specialist decisions based on recovery and a supervised assessment of reduced support—not a single normal saturation value.
- After removal, monitor the access site for bleeding or expanding haematoma and reassess distal perfusion. Report new limb pain, pallor, weakness or loss of Doppler signal urgently.
- Continue respiratory, haemodynamic, neurological and urine-output monitoring. Observe for deterioration after support is removed.
- Reconcile anticoagulation and other medicines with the new orders. Document cannula removal, blood loss, site care and handover findings.
- Support gradual rehabilitation, nutrition, sleep and psychological recovery. Explain follow-up for persistent weakness, cognitive changes or other complications.
7. Medicines and supportive therapies
There is no single mandatory drug list for every ECMO patient. Indication, organ function, bleeding risk and local protocols determine the prescription. Exact doses and targets are intentionally not standardised here.
| Medicine / group | Purpose | Nursing considerations |
|---|---|---|
| Unfractionated heparin | Common systemic anticoagulant to reduce circuit/patient thrombosis. | Check the infusion and prescribed aPTT/anti-Xa/ACT monitoring strategy. Watch for bleeding and platelet fall. |
| Bivalirudin or argatroban, selected cases | Alternative anticoagulation, for example when heparin-induced thrombocytopenia is suspected/confirmed. | Specialist prescription; monitoring and dose adjustment depend on the agent and organ function. |
| Analgesics and sedatives, e.g. a prescribed opioid and propofol or another suitable sedative | Comfort, procedural care and patient–ventilator synchrony when needed. | Assess pain, sedation depth and haemodynamics. ECMO can alter drug handling; agent selection and titration need specialist review. Support neurological assessment when appropriate. |
| Vasopressors/inotropes, e.g. norepinephrine or dobutamine when indicated | Support vascular tone or cardiac function. | Use the prescribed perfusion goals; monitor rhythm and peripheral perfusion. |
| Antimicrobials when indicated | Treat suspected/confirmed infection or a defined procedural indication. | ECMO alone does not mean every patient needs continuous antibiotics. Collect ordered cultures and review dosing with the team. |
| Blood components—not medicines | Treat clinically significant bleeding or selected deficiencies. | Administer only as ordered; monitor transfusion safety and response. |
8. Investigations before, during and after
| Test / assessment | Before / baseline | During and after: why repeat? |
|---|---|---|
| ABG, oxygenation and lactate | Severity of gas-exchange failure and perfusion disturbance. | Assess response, acid–base status and perfusion; right radial sampling when indicated for peripheral VA. |
| CBC and platelets; coagulation including fibrinogen | Identify anaemia, thrombocytopenia and bleeding risk. | Trend bleeding/thrombosis risk and guide ordered anticoagulation or component therapy. |
| Urea/creatinine, electrolytes including ionised calcium; liver tests | Document organ function and correctable abnormalities. | Detect organ injury and electrolyte changes; guide renal support and medicines. |
| Blood group / crossmatch when indicated | Prepare for procedural bleeding/transfusion needs. | Repeat compatibility work and haemoglobin assessment when clinically necessary. |
| Echocardiography and appropriate cannula imaging | Assess cardiac function and plan/confirm cannula placement. | Evaluate recovery, cannula concerns, VA ventricular distension and weaning readiness. |
| Plasma-free haemoglobin, LDH and clinical haemolysis assessment | Baseline if included in the service protocol. | Investigate haemolysis; dark urine or rising markers require prompt review. |
| Cultures / other imaging as indicated | Investigate the underlying illness or suspected infection. | Target new clinical concerns; these are not automatic daily tests for everyone. |
Sampling frequency and targets follow the ECMO service protocol and the patient’s condition. After decannulation, repeat relevant tests to assess recovery, bleeding and organ function; do not order an indiscriminate fixed panel.
[6] [8]10. Scenario practice — 12 MCQs
These are original learning questions, not recalled examination questions. Choose one best answer, then open the explanation. Medicines and emergency actions follow supervised local protocols.
Q1. A patient has severe reversible ARDS despite optimised ventilation and prone positioning. Cardiac function is adequate. Which mode primarily fits the support needed?
- VA solely because oxygen is low
- VV ECMO
- Dialysis without respiratory support
- No assessment because all ARDS requires ECMO
Show answer & rationale
Correct answer: B. VV ECMO
Rationale: VV supports oxygen and carbon dioxide exchange while the patient’s heart maintains circulation. The specialist team still decides eligibility. [1]
Q2. A patient with fulminant myocarditis remains in cardiogenic shock despite appropriate treatment. Which ECMO mode can provide circulatory support?
- VV only
- Neither mode can support circulation
- VA ECMO
- Peritoneal ECMO
Show answer & rationale
Correct answer: C. VA ECMO
Rationale: VA returns blood to an artery and can support systemic perfusion as well as gas exchange. VV alone does not replace cardiac pump function. [2]
Q3. Before ECMO, a relative asks whether older age automatically rules out treatment. What is the best response?
- Every patient above 60 is excluded
- Age alone guarantees benefit
- Only age matters
- Age is considered with recovery potential, comorbidity and the overall treatment plan
Show answer & rationale
Correct answer: D. Age is considered with recovery potential, comorbidity and the overall treatment plan
Rationale: Increasing age is a risk consideration, not a universal stand-alone cut-off. Selection requires the whole clinical picture. [1]
Q4. During a turn, the external cannula marking changes and fresh bleeding appears. What should the nurse do first?
- Stop the movement, assess the patient and urgently call the ECMO team
- Push the cannula back to the previous mark
- Remove the securing sutures
- Wait for routine rounds
Show answer & rationale
Correct answer: A. Stop the movement, assess the patient and urgently call the ECMO team
Rationale: A position change may indicate displacement. Prevent further movement and obtain immediate expert review; blind repositioning can cause serious harm. [7]
Q5. A patient on femoral VA ECMO develops a cold, pale cannulated leg with a reduced Doppler signal. What is the priority?
- Apply a tight bandage
- Document it for tomorrow
- Urgently escalate possible limb ischaemia
- Increase sedation without assessment
Show answer & rationale
Correct answer: C. Urgently escalate possible limb ischaemia
Rationale: This suggests impaired limb blood flow. Delayed assessment risks tissue injury; assess and report perfusion findings promptly. [4]
Q6. On peripheral femoral VA ECMO, lower-body oxygenation looks acceptable but right-hand saturation falls. What problem should be considered?
- Differential hypoxaemia affecting the upper body
- A normal finding that never needs review
- A reason to remove the arterial line immediately
- Proof that the saturation probe must be wrong
Show answer & rationale
Correct answer: A. Differential hypoxaemia affecting the upper body
Rationale: Poorly oxygenated blood from the native heart may supply the upper body while ECMO blood supplies the lower body. Right radial assessment helps detect this. [2]
Q7. A heparin-treated ECMO patient has a marked platelet fall and the team suspects HIT. Which plan is appropriate?
- Give extra heparin without review
- Discuss stopping heparin and an alternative anticoagulant with the specialist team
- Ignore platelets because ECMO always lowers them
- Stop all monitoring
Show answer & rationale
Correct answer: B. Discuss stopping heparin and an alternative anticoagulant with the specialist team
Rationale: Suspected HIT requires urgent assessment and a non-heparin anticoagulation strategy when indicated. Nurses do not independently select a replacement dose. [9]
Q8. Fresh cannula-site bleeding increases and haemoglobin falls. What is the best nursing response?
- Automatically increase anticoagulation
- Treat the laboratory value as irrelevant
- Give oral fluids only
- Assess haemodynamics and bleeding, notify the team and follow the urgent bleeding plan
Show answer & rationale
Correct answer: D. Assess haemodynamics and bleeding, notify the team and follow the urgent bleeding plan
Rationale: Clinical bleeding and laboratory trends must be reviewed together. Anticoagulation adjustment and blood components need a coordinated prescription. [5]
Q9. An ECMO patient develops dark urine and a rising plasma-free haemoglobin. What should be suspected?
- Expected recovery
- Isolated dietary pigment with no need to assess
- Haemolysis needing urgent circuit and patient review
- A reason to increase pump speed independently
Show answer & rationale
Correct answer: C. Haemolysis needing urgent circuit and patient review
Rationale: Red-cell breakdown can reflect circuit or drainage problems. Escalate promptly and investigate; dark urine alone does not establish the cause. [8]
Q10. An ECMO flow alarm sounds while the patient becomes hypotensive. Which action is safest?
- Silence it and leave
- Assess the patient, call the ECMO team and follow the trained emergency protocol
- Disconnect the oxygenator
- Clamp random tubing to find the problem
Show answer & rationale
Correct answer: B. Assess the patient, call the ECMO team and follow the trained emergency protocol
Rationale: The patient may be losing effective support. Immediate skilled help and the service emergency algorithm are safer than untrained circuit manipulation. [7]
Q11. A patient’s saturation is normal on full ECMO support. Does this alone show readiness for decannulation?
- Yes, remove the cannula now
- Yes, oxygenation is the only criterion
- No, recovery must be assessed during a supervised weaning process
- No patient can ever leave ECMO
Show answer & rationale
Correct answer: C. No, recovery must be assessed during a supervised weaning process
Rationale: A normal value during full support may reflect the machine’s work. The team must assess whether the patient can maintain function with reduced support. [2]
Q12. After decannulation, an access-site swelling enlarges and blood pressure falls. What is the priority?
- Urgently assess for bleeding and activate the local escalation response
- Encourage walking immediately
- Wait until the next dressing change
- Restart anticoagulation without an order
Show answer & rationale
Correct answer: A. Urgently assess for bleeding and activate the local escalation response
Rationale: An expanding haematoma with hypotension may indicate significant bleeding. Prompt assessment and emergency escalation take priority. [7]
Sources and scope
- ELSO: Adult venovenous ECMO guideline (2021)
- ELSO: Adult venoarterial ECMO guideline (2021)
- Alfred ECMO: Initiation
- Alfred ECMO: Routine nursing overview
- Alfred ECMO: Anticoagulation and bleeding
- Alfred ECMO: Routine blood sampling
- Alfred ECMO: Patient safety rules
- Alfred ECMO: Haemolysis
- ELSO: Anticoagulation guideline (published 2022)
- ELSO: Guidelines directory, including adult rehabilitation guidance
- Alfred ECMO: Sedation and analgesia
Sources checked 21 October 2026. Adult nursing revision; paediatric and neonatal prescriptions differ. Institutional ECMO protocols illustrate specialist practice and are not universal targets. Drug doses, monitoring intervals and treatment changes require the current patient-specific prescription and local protocol. These notes are educational; independent specialist review is not claimed.