ECMO Nursing Care
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Direct answer
Blood drains from a large vein, threads through a spinning pump and a membrane oxygenator, and returns warmed and oxygenated — either to a vein, for pure lung support (VV ECMO), or to an artery, for heart and lung support (VA ECMO). Typical flows run about 60-80 mL/kg/min for respiratory support and roughly 3-4 litres per minute in adults on VA support, and weaning proceeds by stepping flow down toward about 2 litres per minute before a trial off. Nursing care is the systematic hourly interrogation of three coupled systems: the patient (perfusion, sedation, cannula sites, distal limbs), the circuit (pre- and post-membrane pressures, clots, sweep gas), and the blood (anticoagulation per unit protocol, haemolysis markers, platelets). Complications are mostly mechanical or haematologic — cannula bleeding, limb ischaemia, circuit clotting, haemolysis, infection — and every ECMO bedside nurse rehearses the emergency drills: power failure, circuit rupture, pump-head malfunction.
What you must remember
- VA versus VV at the bedside: VA supports the failing heart, so a pulsatile arterial trace may flatten when flows are high; VV supports only lungs, and saturations in the high 80s to low 90s are often tolerated — knowing the mode changes what the alarms mean.
- Flow benchmarks: around 60-80 mL/kg/min for VV respiratory support, roughly 3-4 L/min in adults on VA; weaning tapers to roughly 2 L/min before a trial off.
- Anticoagulation: continuous heparin titrated to unit protocol — commonly ACT- or anti-Xa-guided — with haemoglobin, platelets and coagulation profile watched daily, since bleeding and clotting compete for the same patient.
- Circuit surveillance: rising pre- and post-membrane pressures warn of oxygenator clotting; visible clots in tubing and falling post-membrane oxygen delivery trigger perfusion review.
- Haemolysis alerts: dark cola-coloured urine and rising plasma-free haemoglobin signal pump-induced red cell destruction — a change-the-circuit problem, not a kidney problem first.
- Limb watch: femoral arterial cannulation threatens leg ischaemia, so distal perfusion cannulation is used where possible and pulses, colour, temperature and capillary refill compared hourly between limbs.
- Emergency competence: every nurse can clamp, hand-crank and isolate a ruptured segment from memory — drills, not manuals, manage the first thirty seconds.
The hourly round, systematised
Walk the bedside in one fixed order and nothing is missed. Patient first: pupils, sedation, ventilator settings, urine colour and output — the urine the colour of cola is the five-second haemolysis test that outruns any laboratory. Perfusion: mean arterial pressure, saturations interpreted per mode, lactate trend. Cannula sites: ooze or haematoma at neck and groin, sutures intact, dressings dated; both legs compared for warmth, colour and pulses, because comparison is the earliest detector of a failing distal perfusion cannula.
Circuit second: pump speed and displayed flow, pre- and post-membrane pressures against the last hour, sweep gas and FiO2, heat exchanger temperature, and a slow visual sweep of the tubing for fibrin strands — the nurse's eye here is a monitoring device no console replaces. Blood third: today's anticoagulation result, haemoglobin and plasma-free haemoglobin trend, platelets.
Where newcomers slip
The commonest conceptual slip is reading the pulse oximeter as if the patient were on conventional support. On VV ECMO, recirculation keeps displayed saturations modestly low and expected; on VA ECMO with sick lungs, the upper body may be perfused by the patient's own poorly oxygenated output while the lower body runs on ECMO blood — differential hypoxaemia — so the probe site carries clinical meaning, pre-ductal preferred. The second slip is treating the console as infallible: a kinked cannula or hypovolaemic patient shows falling flow with rising pump speed, a combination that should summon someone. In viva terms, expect the complications question answered as a triad — bleeding, thrombosis, infection — plus limb ischaemia and haemolysis, and be ready to name the drill actions for power failure, because "call the doctor" alone is the answer of someone who has never stood at that bed.
Frequently asked questions
What is the difference between VV and VA ECMO at the bedside?
VV replaces lung function only, returning blood to a vein, so the heart still pulses and moderate desaturation is common; VA also supports circulation, returning blood to an artery, so perfusion depends largely on circuit flow.
What flow rates are typical in ECMO?
Respiratory VV support commonly runs about 60-80 mL/kg/min, adult VA roughly 3-4 L/min, and weaning tapers to around 2 L/min before a trial off and decannulation.
How is anticoagulation managed on ECMO?
Continuous heparin titrated to unit protocols using ACT or anti-Xa monitoring, balanced against bleeding risk — targets vary between centres.
What signs suggest circuit clotting or haemolysis?
Rising pre- or post-membrane pressures, visible clot in tubing or oxygenator, falling oxygen transfer, and haemolysis markers — dark urine and rising plasma-free haemoglobin.
Why is limb perfusion checked hourly in femoral ECMO?
Arterial cannulation can obstruct distal flow and cause critical leg ischaemia; distal perfusion cannulation plus hourly pulse, colour and temperature comparison detects it early.