17, 12, 59
The best available source on HOW to perfuse the limb and on the venous half of the problem, which the arterial-focused meta-analyses ignore entirely. Supplies the ELSO NIRS targets, the bilateral-difference criterion, the 100 mL/min flow target, and the finding that the distal perfusion cannula becomes less effective the later it is placed.
Not applicable
DOI 10.1177/02676591241236650
Not applicable - synthesis of distal limb perfusion techniques, venous congestion management and monitoring
Narrative review. Most technique data are single-centre series or case reports. The duplex ultrasound criteria for venous stasis are described by the authors as pilot findings in a small cohort. The NIRS timing study has standard deviations larger than the means.
TECHNIQUES. Antegrade distal perfusion cannula: short 6-8 Fr armoured cannula, male-to-male connector, target flow about 100 mL/min; meta-analytic absolute risk reduction 15.7% (9.7 versus 25.4%); current guidance recommends distal limb perfusion at the time of VA ECMO initiation in all patients. End-to-side graft: originally 10 mm PTFE; bidirectional flow through one cannula but limited control of the flow ratio, unsuitable for emergencies, wound oozing from high anastomotic pressures. Femoro-femoral bypass: external 6 mm by 40 cm PTFE (infection-prone) or endovascular 5 Fr catheter across the aortic bifurcation, used when antegrade femoral and retrograde tibial access both fail. Retrograde limb perfusion: 5 cm incision posterior to the medial malleolus, 6-8 Fr into the posterior tibial artery, achieving 156 plus or minus 82 mL/min; 8.3% (n=3) developed limb ischaemia when placed more than 6 hours after ECMO initiation. Bidirectional cannula: extra hole at the elbow, single puncture, but less control of distal flow and no reported experience during mobilisation. VENOUS CONGESTION: venous obstruction by the drainage cannula causing stasis and reduced arterial perfusion may be equally dangerous; facilitated venous drainage uses a 16 Fr secondary cannula draining the distal femoral vein, achieving 4-6 L/min patient flow with 1-2 L/min distal arterial flow, and excess distal flow increases congestion risk; a propensity-matched comparison of bilateral versus unilateral cannulation showed less compartment syndrome and lower mortality but no overall reduction in limb ischaemia. MONITORING: clamping the femoral artery dropped rSO2 from 61% to 38% (p=0.001), rising to 71% after distal perfusion cannula placement; cutoffs of NIRS below 40% or a fall over 25% from baseline identified 35% of VA ECMO patients, with 100% restoration after placement or replacement and no limb-related complications; NIRS detected ischaemia earlier than clinical assessment plus intermittent Doppler, mean time to perfusion 19.6 plus or minus 21.4 versus 42.0 plus or minus 69.0 hours, and no NIRS-guided patient developed compartment syndrome versus 13.9% of controls; ELSO targets NIRS above 50%, preferably 60%, with less than 20% difference between legs; only 50% of patients with loss of the Doppler pulse had clinical signs of limb ischaemia, so Doppler alone is insufficient.
Adults on peripheral VA ECMO with femoral artery cannulation. Perfusion 2024;39(1_suppl):23S-38S. Retrieved in full.