Extracorporeal Blood Purification and Organ Support in the Critically Ill Patient during COVID-19 Pandemic: Expert Review and Recommendation

Abstract

Critically ill COVID-19 patients are generally admitted to the ICU for respiratory insufficiency which can evolve into a multiple-organ dysfunction syndrome requiring extracorporeal organ support. Ongoing advances in technology and science and progress in information technology support the development of integrated multi-organ support platforms for personalized treatment according to the changing needs of the patient. Based on pathophysiological derangements observed in COVID-19 patients, a rationale emerges for sequential extracorporeal therapies designed to remove inflammatory mediators and support different organ systems. In the absence of vaccines or direct therapy for COVID-19, extracorporeal therapies could represent an option to prevent organ failure and improve survival. The enormous demand in care for COVID-19 patients requires an immediate response from the scientific community. Thus, a detailed review of the available technology is provided by experts followed by a series of recommendation based on current experience and opinions, while waiting for generation of robust evidence from trials.

Keywords: Continuous renal replacement therapies; Cytokine removal; Extracorporeal organ support; Hemoadsorption; Hemoperfusion.

Fig. 1

A complete overview of 40 years of evolution in technology for extracorporeal therapies in the critically ill patient (modified from Ref. [3]). CAVHD, continuous arteriovenous hemodialysis; CAVHDF, continuous arterio-venous hemofilration; CVVH, continuous veno-venous hemofiltration; CVVHD, continuous veno-venous hemodialysis; CVVHDF, continuous veno-venous he­modiafiltration; CRRT, continuous renal replacement therapy; MOST, multi-organ support therapy; CPFA, coupled plasma filtration adsorption; ECCO₂R, extracorporeal CO₂ removal; HCO, high cut-off.

Fig. 2

Schematic representation of different ECOS systems. ECOS, extracorporeal organ support; CVVH, continuous veno-venous hemofiltration; CVVHD, continuous veno-venous hemodialysis; CVVHDF, continuous veno-venous hemodiafiltration; CRRT, continuous renal replacement therapy; SLED, slow extended dialysis; SCUF, slow continuous ultrafiltration; CPFA, coupled plasma filtration adsorption; ECCO₂R, extracorporeal CO₂ removal; VA-ECMO, veno-arterial extracorporeal membrane oxygenation; VV-ECMO, veno-venous extracorporeal membrane oxygenation; AHD, adsorption hemodialysis; HP, hemoperfusion; PF, plasmafiltration; PE, plasma exchange.

Fig. 3

Pathways of kidney damage and proposed treatments in COVID-19 infections. Didactically 3 broad aspects are involved in COVID-19-associated AKI. Bidirectional involvement of each element occurs, represented by Set Theory and the presence of intersections. Treatment strategies also influence different elements simultaneously. a Neutro-macroporous resin adsorbing beads magnified picture. b Bead on transmission electron microscopy. c Cytokine release syndrome and other triggers for cytokine generation. d MCO has more uniformity in pore size distribution and pore density; these characteristics enable the membrane to effectively remove middle molecules in the range of most cytokines with tolerable albumin loss. e ECMO circuit. f Filter used in CRRT for fluid balance control, removal of nephrotoxins, correction of hyperkalemia, and metabolic acidosis. AKI, acute kidney injury; AV ECMO, arteriovenous ECMO; β2MG, β2 microglobulin; CRRT, continuous renal replacement therapy; CVVH, continuous veno-venous hemofiltration; ECCO₂R, extracorporeal carbon dioxide removal; ECMO, extracorporeal membrane oxygenation; HCO, high cut-off; MCO, medium cut-off membrane; IAH, intra-abdominal hypertension; IL, interleukin; kDa, kilodalton; LVAD, left ventricular assist device; TNF, tumor necrosis factor; VV ECMO, veno-venous ECMO.