13, 14, 15, 18, 30
On VA ECMO flow is the primary lever for blood pressure — reach for flow first, vasopressor second, because pressors raise both the ventricle's afterload and the pump's. Flow sits between two walls: too little and delivery fails, too much and the ventricle stops ejecting and floods the lungs. NOTE THE OVERLAP: the recommended pulse-contour TARGET (10-15 mmHg) overlaps the pulse-pressure WARNING threshold (below 15 mmHg with low ETCO2) for near-absent native output — so the conventional target sits close to the LV-distension danger zone. Treat 10-15 mmHg as a floor prompting echocardiography, and target aortic valve opening rather than the number.
None — textbook chapters
Haemodynamic monitoring and target setting
No randomised evidence supports any target here; the trials in Chapter 11 tested whether to use VA ECMO at all, not how to set it. The Ch 28 targets are described as 'widely accepted' rather than cited. The ETCO2/pulse-pressure rule rests on a single reference not retrieved, with no sensitivity, specificity or validation cohort — 'good accuracy' is the source's phrase. The 80%-of-venous-return convention and the 20-25 mmHg left-heart pressure at which pulmonary oedema occurs are stated in ISCCM without supporting evidence.
TARGETS: MAP above 65 mmHg (Ch 28) or 60-70 mmHg controlled BY FLOW (Ch 5); SBP above 90; cardiac index above 2.2 L/min/m2; PCWP below 15; pulse contour 10-15 mmHg (Ch 5) or ~10 mmHg at 80% of venous return (ISCCM Ch 26); DO2:VO2 at or above 3:1; venous saturation above 70% when weaning. FLOW-SETTING SEQUENCE (Ch 5): plan from metabolic rate 3-4 mL/kg/min for both O2 and CO2 (80 kg septic adult needs 5 L/min and an oxygenator rated above 5 L/min for 300 mL O2/min); go to highest flow first to find maximum drainage capacity; then reduce until pulse contour is 10-15 mmHg; reduce vasoactives to low or absent and use FLOW to control pressure; if no LV function establish left atrial drainage; reassess oxygen kinetics at 6-12 h and transfuse to Hb 12-14 g/dL if DO2:VO2 under 3. NATIVE OUTPUT: PA catheter measures only the native pulmonary circulation and thermodilution is unreliable near the drainage cannula; ETCO2 below 14 mmHg WITH pulse pressure below 15 mmHg predicts native CO below 1 L/min 'with good accuracy'. Echocardiography is the reference standard. Flow above 4 L/min increases impaired ejection, LV overload and pulmonary congestion.
Adults on VA ECMO