🔀

Chapter 3 — ECMO Configurations

Part I — Foundations · Chapter 3

🗓️

Evidence search date: 6 September 2026. Configuration selection is governed almost entirely by physiology and observational data. There are no randomised comparisons of ECMO configurations. Certainty is graded accordingly throughout.

Clinical Question

Where blood is drained from, and where it is returned to, determines what ECMO can and cannot do for a given patient. Which sites produce which physiology — and what does each configuration cost?

Why This Matters

Configuration is the one ECMO decision that is expensive to reverse. Settings change in seconds; a configuration change means new cannulae, new vessels, new bleeding risk and often a trip out of the ICU — on a fully anticoagulated patient.

It is also the decision most often made under time pressure, by whoever is available, and then lived with for weeks. Chapter 1 framed the choice as a single physiological question. This chapter supplies the anatomy, the flow physics and the trade-offs that make the answer concrete.

Notation: Drainage First, Return Second

Configurations are named by the path the blood takes. Letters before the return site describe drainage; letters after describe return.

Notation	Reads as	What it does
VV	Veno-venous	Drain venous, return venous. Gas exchange only; no circulatory support.
VA	Veno-arterial	Drain venous, return arterial. Gas exchange and systemic flow.
VAV	Veno-arterio-venous	One drainage limb; return split between artery and vein. For circulatory failure plus differential hypoxaemia.
VVA	Veno-veno-arterial	Two drainage limbs; arterial return. For inadequate drainage when high flow is needed.
V-Pa	Veno-pulmonary arterial	Drain venous, return into the pulmonary artery. Bypasses the right ventricle.
ECCO₂R	Extracorporeal CO₂ removal	Low-flow veno-venous (or arterio-venous) circuit for CO₂ clearance alone.

An important convention: the letters describe cannulation, not indication. A patient can be on VA ECMO for a purely respiratory problem, and a patient with cardiac failure can be entirely appropriately supported on VV. Do not infer the reason for support from the configuration.

VV Configurations

All VV configurations do the same thing physiologically — oxygenate and decarboxylate a fraction of the venous return — and differ only in how efficiently they do it, which is another way of saying they differ in recirculation.

Configuration	Drainage	Return	Strengths	Weaknesses
Femoro-jugular (the common default)	Femoral vein, tip in IVC near the cavo-atrial junction	Internal jugular, tip in SVC or upper RA	Drainage and return well separated, so recirculation is generally low; two operators can work simultaneously; large drainage cannula possible	Two puncture sites; jugular cannula limits neck movement and complicates tracheostomy
Jugulo-femoral	Internal jugular, tip in SVC/RA	Femoral vein, tip in IVC	Frees the groin for other access; useful when IVC drainage is poor	Higher recirculation risk in some geometries; drainage from a single cava
Femoro-femoral	One femoral vein, tip in IVC	Contralateral femoral vein, tip in RA	Neck untouched; feasible when jugular access is impossible	Tips are close together — recirculation is the main hazard; both groins occupied
Bicaval dual-lumen (e.g. Avalon Elite, Crescent)	Side holes in SVC and IVC through one cannula	Side port directed at the tricuspid valve from within the RA	Single site; frees both groins; permits mobilisation, physiotherapy and awake ECMO; low recirculation when correctly positioned	Requires precise placement under imaging; malposition is both common and consequential; higher insertion risk including RV perforation
Unicaval dual-lumen	Side holes in SVC	Open tip in the RA directed at the tricuspid valve, or in the pulmonary artery	Simpler geometry; the pulmonary artery variant also unloads the RV	Drains one cava only, limiting achievable flow

🧬

Physiology — recirculation is a geometry problem, not a machine problem

Recirculation is oxygenated return blood being drawn straight back into the drainage cannula without ever reaching the tissues. It inflates the pre-oxygenator saturation, flatters the circuit, and reduces effective extracorporeal blood flow — the term that actually appears in the mixing equation in Chapter 2.

It rises with: proximity of the two cannula tips, high pump flow relative to venous return, hypovolaemia, and anything that reduces forward RV output. It is a property of where the tips sit, not of the pump.

📊

Evidence — dual-lumen cannulae: the design is not the problem, the depth is

In a computational fluid dynamics study, Parker and colleagues modelled two commercial bicaval dual-lumen cannulae (Avalon Elite and MC3 Crescent, both scaled to 27 Fr) in a patient-averaged right atrium and cavae at 2–6 L/min. Both designs achieved recirculation fractions below 7% at correct position — essentially zero at 2 and 4 L/min, rising to 3.0–6.2% at 6 L/min — with near-identical pressure-drop curves.

Rotation mattered little: even at ±60°, recirculation stayed at 2.4–3.1%. Insertion depth mattered enormously. Too shallow a position produced recirculation of 31.2–44.6% at every flow rate tested. (Parker LP, et al. Sci Rep 2023)

Certainty: physiological rationale (in silico). A computational model, not a patient cohort — but the direction and magnitude of the depth effect are large and mechanistically unambiguous.

💡

Clinical Pearl

When a dual-lumen cannula is underperforming, the first hypothesis should be position, not device. A cannula sitting a few centimetres too shallow can convert a 5% recirculation fraction into a 40% one, and no amount of pump speed will fix it. Confirm depth with echocardiography before considering an exchange.

VA Configurations

VA ECMO returns oxygenated blood to the arterial tree. Where it enters determines who gets the oxygenated blood, how much afterload the left ventricle sees, and which limb is at risk.

Configuration	Return site	Flow direction	Key consequences
Peripheral femoro-femoral	Common femoral artery, tip in the common iliac artery or distal aorta	Retrograde up the aorta	Fast, percutaneous, bedside-feasible — the ECPR default. Creates a mixing zone in the aorta; risks differential hypoxaemia and limb ischaemia; maximally increases LV afterload.
Axillary / subclavian	Right axillary or subclavian artery, usually via an end-to-side graft	Antegrade into the aortic arch	Perfuses the arch and cerebral vessels with oxygenated blood, largely avoiding differential hypoxaemia. Permits mobilisation. Risks arm hyperperfusion and oedema, and requires surgical anastomosis.
Central	Ascending aorta directly, with right atrial drainage	Antegrade, physiological	Best drainage and best flow; no differential hypoxaemia; direct venting possible. Requires sternotomy, and carries the highest bleeding and mediastinitis burden. Usual route post-cardiotomy.
Carotid	Common carotid artery	Antegrade cerebral	Standard in neonates; rarely used in adults because of stroke risk.

🧬

Physiology — the watershed

In peripheral femoro-femoral VA ECMO, retrograde circuit flow meets antegrade flow ejected by the native left ventricle somewhere in the aorta. The position of that mixing zone is not fixed: it moves distally as native cardiac output recovers, and proximally as circuit flow rises.

This single fact generates three of the most important VA ECMO problems, each with its own chapter:

Blood proximal to the mixing zone comes from the native lung. If that lung is failing, the coronaries and the brain receive poorly oxygenated blood while the femoral saturation looks perfect — differential hypoxaemia, Chapter 16.
Retrograde flow raises the pressure the left ventricle must eject against, worsening distension in a ventricle that may be unable to open the aortic valve at all — LV distension, Chapter 15.
A large cannula in a small common femoral artery obstructs antegrade flow to the leg — limb ischaemia, below and in Chapter 17.

Sample the right radial artery. It is the arterial site most likely to be supplied by the native heart, and therefore the one that will reveal differential hypoxaemia first.

📊

Evidence — limb ischaemia and the distal perfusion cannula

In a 2024 review of distal limb perfusion in adult peripheral femoral VA ECMO, Simons and colleagues report limb ischaemia in 10–30% of patients, with historical rates as high as 70% before preventive techniques. A meta-analysis they summarise found that distal perfusion cannula (DPC) use reduced limb ischaemia from 25.4% to 9.7% — an absolute risk reduction of 15.7%, risk ratio 0.41 (p < 0.01); in one series, 3.4% of patients with a DPC required intervention for critical limb ischaemia versus 21.4% without.

Current guidance is prophylactic placement at the time of cannulation in all patients, not reactive placement once ischaemia appears. Typical DPC is a short 6–8 Fr armoured cannula at a target flow of about 100 mL/min, sited antegrade in the femoral or superficial femoral artery, or retrograde via the posterior tibial artery. Monitoring: near-infrared spectroscopy with values above 50% and preferably 60%, and a bilateral difference under 20%; duplex ultrasound as an adjunct; clinical examination, which is of limited value in a sedated patient. (Simons J, et al. Perfusion 2024)

Certainty: moderate for the effect of DPC (pooled observational data, no randomised comparison); consensus for prophylactic placement.

🚨

Danger

A warm, pink, pulsatile leg at the time of cannulation does not predict the leg six hours later. Vasopressor dose rises, the cannula settles, thrombus forms around it. Limb ischaemia on VA ECMO is frequently discovered late in a sedated patient, and amputation is a real outcome. Decide about distal perfusion at cannulation, and monitor the limb on every round — Chapter 17.

V-Pa: Supporting the Right Ventricle

Returning blood into the pulmonary artery rather than the right atrium changes the configuration from lung support to right ventricular support: blood is drained from the venous system, oxygenated, and delivered beyond the RV, which is thereby bypassed.

What it solves. Isolated right ventricular failure with an adequately functioning left ventricle — the physiology described in Chapter 2, in which RV afterload is the limiting problem.
How it is done. A long venous cannula from the internal jugular, subclavian or femoral vein into the pulmonary artery, placed under fluoroscopic or transoesophageal echocardiographic guidance; single-lumen, or a dual-lumen RA-to-PA cannula that achieves the same result from one site.
What it buys. A percutaneous right ventricular assist device that simultaneously oxygenates. Because it decompresses the RV rather than loading the LV, it avoids the afterload problem that dominates peripheral VA ECMO.
What it costs. Technically demanding placement; risk of pulmonary artery injury; position is critical and migration is consequential.

💡

Clinical Pearl

When a patient with severe ARDS fails to improve haemodynamically on VV ECMO despite corrected gas exchange, Chapter 2 predicts that the RV failure was primary rather than secondary. That is precisely the patient in whom a V-Pa configuration, rather than escalation to VA, deserves consideration.

Hybrid Configurations

Hybrid configurations exist because patients change. A VV patient develops shock; a VA patient's lungs fail; drainage proves inadequate. Each hybrid solves a specific mismatch, and each adds cannulae, bleeding risk and complexity.

Configuration	Problem it solves	Typical cannulation	Evidence status
VAV	Differential hypoxaemia on VA ECMO, or circulatory failure developing on VV support	Single venous drainage; return split between a femoral (or axillary) artery and a jugular vein	Case series only. Reported mortality in the region of 50–61%, with substantial bleeding, limb ischaemia and neurological complications — in a population selected for having failed a simpler configuration
VVA	Combined lung and cardiac failure where a single drainage cannula cannot supply the required flow	Two venous drainage cannulae; femoral arterial return	Anecdotal
VVVA / VVAV	Inadequate drainage at high target flow; complex combined support	Three drainage limbs, or dual drainage with both arterial and venous return	Anecdotal; single case reports
V-Pa	Isolated RV failure with preserved LV	Venous drainage; pulmonary artery return	Small series; no major complications reported, but numbers are small
VA + LV vent	LV distension on VA ECMO	Left atrial or transapical vent, or a percutaneous axial pump; vent joined by Y-connector to the drainage limb	Observational, with propensity-matched data suggesting benefit for axial-pump unloading — examined properly in Chapter 15 and Chapter 80

(Configuration taxonomy and reported outcomes: Brasseur A, et al. J Thorac Dis 2018.)

🚨

Danger — the cost of adding a limb

Every added cannula is another vessel injured, another site to bleed and become infected, and another path for thrombus and air. Splitting return flow between an artery and a vein requires active flow balancing — usually a partial-occlusion clamp with dedicated flow monitoring on each limb — and getting that balance wrong produces either persistent differential hypoxaemia or inadequate circulatory support, while the increased shear raises haemolysis.

Conversion between modes is undertaken on a fully anticoagulated patient and carries a materially higher bleeding risk than the original cannulation. Hybrid configurations are a considered decision, not an escalation reflex.

⚠️

Pitfall

The reported mortality figures for hybrid configurations are not evidence that hybrids cause harm. These patients reached a hybrid configuration precisely because a simpler one had failed. Confounding by indication is total, and no comparative study exists. Read those numbers as a description of a sick population, not as an effect estimate.

ECCO₂R

Chapter 2 established the asymmetry: CO₂ clearance is easy, oxygenation is hard. Extracorporeal CO₂ removal exploits it directly. A low-flow veno-venous circuit — flows well below those needed for oxygenation, sometimes through a dialysis-calibre catheter — can clear a clinically meaningful fraction of CO₂ production, because CO₂ removal is governed by sweep gas and by a content curve that does not saturate.

What it offers. Reduction of ventilator intensity — lower tidal volume, lower driving pressure, lower respiratory rate — in patients whose problem is ventilation rather than oxygenation, or control of hypercapnic acidosis in obstructive disease.
What it does not offer. Meaningful oxygenation. A patient with severe hypoxaemia needs blood flow, and ECCO₂R does not provide it.
Where the evidence sits. The physiological rationale is strong and the clinical benefit is not established. ECCO₂R is treated in the ventilation chapters (Chapter 53) rather than here, because the question it raises is about lung protection, not about configuration.

What Actually Limits Flow

Configuration determines what ECMO can do; cannula physics determines whether it will.

Q = \frac{\Delta P \cdot \pi \cdot r^4}{8 \cdot L \cdot \mu}

Variables and units. $Q$ — flow, L/min. $\Delta P$ — pressure drop across the cannula, mmHg. $r$ — internal radius, mm. $L$ — cannula length, cm. $\mu$ — dynamic viscosity of blood.

Assumptions. The Hagen–Poiseuille relation assumes steady laminar flow of an incompressible Newtonian fluid through a smooth rigid tube. Blood is non-Newtonian, ECMO flow through side-holed multistage cannulae is partly turbulent, and vessels are neither rigid nor smooth. The equation therefore predicts direction and rough magnitude, not exact flow — which is why manufacturers publish measured pressure–flow curves.

Reading the equation

Radius dominates, to the fourth power. Everything else is a linear term.
Length is linear. Doubling cannula length halves flow at the same pressure drop.
Sizing convention: 3 Fr = 1 mm. A 25 Fr cannula has an outer diameter of about 8.3 mm.
Outer diameter is what is printed; inner diameter is what matters. Wall thickness varies between manufacturers, so two 25 Fr cannulae are not interchangeable. Since ISO 18193:2021, manufacturers must state the inner diameter on the packaging and must test resistance using a blood-analogue fluid rather than water — older water-based figures systematically underestimated true resistance.

Worked example — why 21 Fr and 25 Fr are not a small difference

Step	Calculation	Result
21 Fr outer diameter	21 ÷ 3	7.0 mm (radius 3.50 mm)
25 Fr outer diameter	25 ÷ 3	8.33 mm (radius 4.17 mm)
Radius ratio	4.17 ÷ 3.50	1.19
Flow ratio at equal pressure drop	1.19⁴	≈ 2.0

Clinical interpretation. Stepping from 21 Fr to 25 Fr roughly doubles achievable drainage at the same suction pressure. Four French sizes is the difference between a circuit that supports 3 L/min and one that supports 6 L/min. This is why undersizing the drainage cannula is the commonest self-inflicted cause of a flow-limited circuit, and why it cannot be corrected by pump speed.

Caveat. The calculation above uses outer diameter as a proxy for inner diameter, and treats a multistage side-holed cannula as a smooth tube. Both are simplifications. The manufacturer's pressure–flow curve is the correct basis for selection; the arithmetic is here to show why the effect is large, not to size a cannula.

Practical targets and trade-offs

Component	Typical adult figures	Why it matters
Drainage cannula	Longer (up to ~55 cm), wider (roughly 21–29 Fr), multistage side holes	Drainage is almost always the flow-limiting side. Side holes provide alternative paths and prevent the cannula sucking onto the vessel wall
Return cannula (venous)	Shorter, narrower	Return works with the pump, not against a collapsing vein
Arterial return cannula	15–19 Fr, 15–30 cm; 15–17 Fr commonly delivers 4–5 L/min	Constrained by femoral artery calibre, not by desired flow. Oversizing causes the limb ischaemia described above
Working pressure drop	Aim below ~50 mmHg for drainage, below ~100 mmHg for return	Rising drop at constant flow signals obstruction, malposition or thrombus
Tubing calibre	3/8 inch: ~2 mmHg/m per L/min, ~71 mL/m prime. 1/4 inch: ~11 mmHg/m per L/min, ~32 mL/m prime	Low resistance is bought with priming volume — roughly five-fold less resistance for roughly twice the prime
Circuit prime volume	~500–700 mL in adults (100–250 mL neonatal)	Determines the dilutional hit at initiation and therefore the haemoglobin fall

(Cannula and circuit specifications: ELSO Red Book, 6th ed.; ECPR and Resuscitative ECMO; ISCCM Manual of RRT and ECMO in ICU; ECMO: A Practical Guide to Management.)

⚠️

Pitfall — filling the vessel

The cannula should be smaller than the vessel it occupies. A cannula that fills the lumen obstructs flow around itself, producing venous hypertension, stasis, thrombosis and — on the arterial side — the ischaemic limb. Size the vessel with ultrasound before choosing the cannula, not after.

Matching the Problem to the Configuration

Clinical problem	Configuration	Physiological reason	Chapter
Severe hypoxaemic respiratory failure, adequate cardiac output	VV — femoro-jugular or bicaval dual-lumen	Gas exchange is the deficit; circulation is intact	4–10
Hypercapnic failure needing ventilator de-escalation, oxygenation acceptable	Low-flow VV / ECCO₂R	CO₂ clearance is achievable at low blood flow	53
Cardiogenic shock, lungs adequate	VA — peripheral or central	Flow is the deficit	11–18
Cardiac arrest, ongoing CPR	VA (ECPR), femoro-femoral	Speed dominates every other consideration	19–22
Cardiogenic shock plus failing lungs, upper body desaturating	VAV, or VA with axillary return	The coronaries and brain must receive oxygenated blood	16, 78
Isolated RV failure, LV preserved	V-Pa (or RA-to-PA dual lumen)	Bypasses the RV without loading the LV	78
Adequate configuration but flow will not reach target	Add a drainage limb (VVA), or upsize	Drainage is the limiting side	34
Awake, ambulating, or bridge-to-transplant candidate	Bicaval dual-lumen VV, or axillary VA	Single site and an untouched groin permit mobilisation	59, 83, 84

When to Change Configuration

The commonest error in this algorithm is entering it at all. Most deteriorations on ECMO are settings, physiology or measurement problems, and Chapter 2's four Fick terms resolve them. Configuration change is the answer only when the configuration itself is the constraint.

Clinical Pearls

Name the configuration in the handover, every time. "VV femoro-jugular, 25 Fr drainage at the cavo-atrial junction, 21 Fr return in the SVC" tells the next clinician where every sample comes from and which numbers can be believed. "On ECMO" tells them nothing.
Drainage is nearly always the limiting side. If flow is inadequate, look at the drainage cannula, the volume state and the tip position before touching the pump.
Sample the right radial artery on VA ECMO. It is the site most likely to be supplied by the native heart.
On VV ECMO, a rising pre-oxygenator saturation with a falling arterial saturation is recirculation until proven otherwise — the circuit is working hard and delivering nothing.
A cannula that fits perfectly is too big. Blood must be able to pass around it.

Pitfalls

Inferring the indication from the configuration, or assuming VA implies cardiac disease.
Treating a flow-limited circuit as a pump problem.
Deciding about distal perfusion after cannulation rather than during it.
Escalating to a hybrid configuration before excluding the simpler explanations in Chapters 2 and 9.
Reading hybrid-configuration mortality figures as an effect of the hybrid rather than of the population.
Assuming two cannulae of the same French size are interchangeable.

Controversies

⚖️

Controversy — bicaval dual-lumen or two-site VV?

Clinical question: Should a single dual-lumen cannula be the default for VV ECMO?

Evidence supporting dual-lumen: One site rather than two; both groins free; recirculation below 7% when correctly positioned in computational modelling; enables sitting, physiotherapy, mobilisation and awake ECMO, which matter enormously in transplant candidates and prolonged runs.

Evidence supporting two-site: Placement is technically demanding and requires imaging; malposition is common and converts a low-recirculation configuration into a 30–45% one; insertion carries a risk of right ventricular or pulmonary artery perforation; a large femoral drainage cannula reliably achieves higher flows in a large or hyperdynamic patient.

Current consensus: Neither is uniformly superior. Choice turns on operator experience, imaging availability, expected duration, the flow target, and whether mobilisation is a goal.

Practical approach: Match the configuration to the plan for the patient. A short rescue run in a hyperdynamic septic patient is not the same problem as a six-week bridge to lung transplant.

Knowledge gap: No randomised comparison exists, and the recirculation data are computational rather than clinical.

⚖️

Controversy — femoral or axillary arterial return for VA ECMO?

Clinical question: Should antegrade axillary return be preferred over femoral return in non-emergent VA cannulation?

Evidence supporting axillary: Antegrade arch perfusion largely prevents differential hypoxaemia, delivers oxygenated blood to the coronaries and brain, avoids femoral limb ischaemia, and permits mobilisation in a bridge-to-transplant or bridge-to-device patient.

Evidence supporting femoral: Percutaneous, fast and bedside-feasible — decisive in ECPR and in crashing shock. Axillary cannulation usually requires a surgical graft, and carries arm hyperperfusion, oedema and, occasionally, compartment syndrome.

Current consensus: Femoral for emergencies; axillary considered for planned, prolonged or mobilisation-oriented support. Practice varies widely by centre and by available surgical support.

Practical approach: Let the time available and the expected duration decide, and reassess the choice if the run extends beyond a few days.

Knowledge gap: Comparative data are observational and heavily confounded by why each route was chosen.

Evidence Summary

Statement	Certainty	Basis
Configuration is defined by drainage and return sites, and determines whether gas exchange, flow, or both are supported	High — definitional	Mechanistic
Recirculation is determined by cannula tip geometry and position, not by pump performance	High — physiological rationale	Fluid dynamics; Parker 2023
Correctly positioned bicaval dual-lumen cannulae recirculate below 7%; too-shallow placement produces 31–45%	Physiological rationale (in silico)	Parker 2023 — computational fluid dynamics, not a patient cohort
Limb ischaemia complicates 10–30% of peripheral femoral VA ECMO	Moderate	Pooled observational data summarised in Simons 2024
Distal perfusion cannulae reduce limb ischaemia (25.4% to 9.7%; RR 0.41)	Moderate	Meta-analysis of observational studies; no randomised comparison
Prophylactic distal perfusion at cannulation in all peripheral femoral VA patients	Consensus	Current guidance as summarised in Simons 2024
Flow through a cannula varies with the fourth power of internal radius and inversely with length	High — physical law, with stated modelling limits	Hagen–Poiseuille; manufacturer pressure–flow curves are the practical reference
Hybrid configurations improve outcomes	Not established	Case series only, with total confounding by indication. Reported mortality describes the population, not the intervention
Any configuration is superior to any other for a given indication	Not established	No randomised comparison of ECMO configurations exists

Key Takeaways

Configurations are named drainage-first, return-second, and the letters describe cannulation — never the indication.
VV configurations differ from each other mainly in recirculation, which is a geometry problem: tip position, not pump speed.
For dual-lumen cannulae, insertion depth is the variable that matters. Too shallow converts 5% recirculation into 40%.
In peripheral VA ECMO, the aortic mixing zone generates differential hypoxaemia, LV distension and limb ischaemia — three separate chapters from one piece of anatomy.
Decide about distal limb perfusion at cannulation. Prophylactic placement roughly halves limb ischaemia in pooled observational data.
V-Pa supports the right ventricle without loading the left, and is the configuration to consider when RV failure is primary.
Hybrids solve real mismatches at a real cost, and their published mortality reflects the patients who needed them.
Drainage is the limiting side. Radius to the fourth power means 21 Fr to 25 Fr roughly doubles achievable flow.
There are no randomised comparisons of configurations. Every recommendation in this chapter is physiology or observation, and is labelled as such.

Key References

Simons J, Mees B, MacLaren G, et al. Evolution of distal limb perfusion management in adult peripheral venoarterial extracorporeal membrane oxygenation with femoral artery cannulation. Perfusion. 2024;39(1_suppl):23S–38S. DOI: 10.1177/02676591241236650
Parker LP, Svensson Marcial A, Brismar TB, Broman LM, Prahl Wittberg L. Hemodynamic and recirculation performance of dual lumen cannulas for venovenous extracorporeal membrane oxygenation. Scientific Reports. 2023;13:7472. DOI: 10.1038/s41598-023-34655-1
Brasseur A, Scolletta S, Lorusso R, Taccone FS. Hybrid extracorporeal membrane oxygenation. J Thorac Dis. 2018. DOI: 10.21037/jtd.2018.03.84
Tomarchio E, Momigliano F, Giosa L, et al. The intricate physiology of veno-venous extracorporeal membrane oxygenation: an overview for clinicians. Perfusion. 2024;39(1_suppl):49S–65S. DOI: 10.1177/02676591241238156
Brodie D, Peek G, MacLaren G, et al. (eds). Extracorporeal Life Support: The ELSO Red Book, 6th edition — Chapter 3, The Circuit (Hagen–Poiseuille relationship; cannula design; bicaval and unicaval dual-lumen designs; tubing resistance and priming volumes; ISO 18193:2021)
Shinar Z, Badulak J (eds). ECPR and Resuscitative ECMO — arterial and venous cannula selection; Poiseuille's law applied to cannulae
Taha AR, Caridi-Scheible M, Leiendecker E, et al. ECMO: A Practical Guide to Management — Chapter 7, ECMO Cannulation and Configuration (dual-lumen cannula anatomy; distal perfusion cannula technique)
Indian Society of Critical Care Medicine. ISCCM Manual of RRT and ECMO in ICU — cannula sizing and vessel-diameter considerations
Cross-references: Chapter 1 (the configuration question), Chapter 2 (effective ECBF and the mixing equation), Chapters 5 and 12 (cannulation technique), Chapter 9 (hypoxaemia on VV), Chapters 15–17 (LV distension, differential hypoxaemia, limb ischaemia), Chapter 34 (cannula problems), Chapter 78 (hybrid configurations in depth)

🔍

Citation verification status. The Simons 2024 and Parker 2023 citations, including DOIs, journal, volume and page details and all quoted figures, were verified against source records during the 6 September 2026 search cycle. The Brasseur 2018 citation and DOI were verified; the individual case-series mortality figures it reports were taken from that review rather than from the primary papers, and are presented as such.

Book-derived specifications are attributed to the named texts in the project library and are expert-synthesis sources, not primary evidence.

Correction applied during audit: one project source states the sizing convention as "1 Fr = 3 mm". This is an error — the correct convention is 3 Fr = 1 mm (1 Fr ≈ 0.33 mm), and the correct figure is used throughout this chapter.

⚠️

Educational use only. This chapter does not replace institutional ECMO protocols, local policy, specialist consultation, current guidelines or patient-specific clinical judgement.