25, 15, 13, 54
Quantifies the trade-off that governs every haemodynamic decision on venoarterial support: more flow buys mean arterial pressure and total oxygen delivery and costs left ventricular volume; less vasoconstriction buys volume back and costs pressure; more inotropy buys ejection and costs myocardial oxygen consumption. You cannot increase flow and unload at the same time without paying in pressure. Whenever flow is changed, record pulse pressure, pulmonary artery diastolic pressure and vasopressor dose before and after, or the trade is invisible.
Varying systemic vascular resistance between 600 and 1,000 dynes per second per cm to the fifth
DOI 10.1111/aor.70163
Varying ECMO flow between 2 and 4 L/min
A simulation with fixed elastance relationships and no patient data; the magnitudes are model outputs and only the structure should be carried to the bedside. Indexed passage only. [VERIFICATION REQUIRED]
At 2 L/min with a resistance of 1,000, mean arterial pressure was 68.9 mmHg. Raising flow to 4 L/min at the same resistance shifted the pressure-volume loop rightward and raised left ventricular end-diastolic volume from 150 to 180 mL. Reducing resistance to 800 at that higher flow gave 160 mL, still above the 2 L/min value. End-diastolic volume fell below the 2 L/min value only at a resistance of 600, which dropped mean arterial pressure to 61.1 mmHg.
Simulated circulation with severe left ventricular failure, a normal right ventricle, and mean circulatory filling pressure of 7 or 12 mmHg