25, 54, 28
The macrocirculation is restored within seconds of starting the pump and the microcirculation over about a day, after which it plateaus - and where that plateau sits separates survivors from non-survivors in every study that looked. Met macrocirculatory targets with no clinical improvement is therefore a microcirculatory description, not an argument for escalating flow. Do not make it a target: no threshold exists, and the one study testing it at a weaning decision point found no difference between stable and unstable groups.
Pre-ECMO measurements, and survivors against non-survivors
DOI 10.1111/micc.12891; PROSPERO CRD42021243930
Sidestream or incident darkfield imaging of the sublingual microcirculation - small vessel density, perfused vessel density, perfused small vessel density, proportion of perfused vessels, microvascular flow index, heterogeneity index
Eleven heterogeneous studies, no standardised acquisition, no agreed threshold, no intervention arm; association in survivors is not evidence that acting on the measurement helps. Indexed passage only. [VERIFICATION REQUIRED]
Three studies reported increased perfused small vessel density, proportion of perfused vessels and microvascular flow index at 24 hours after initiation compared with before it. Microcirculatory perfusion then stabilised - it did not continue to improve. Four studies out of four showed higher perfused small vessel density and a higher proportion of perfused vessels in survivors than in non-survivors.
1,215 records screened; 11 studies reporting sublingual microcirculatory perfusion in adults on venoarterial ECMO, cardiogenic shock the indication in eight