On March 11th, 2020 the World Health Organization declared the new coronavirus disease
(COVID-19) as a global pandemic. In México, approximately 35% of COVID-19 positive patients
require hospital admission and 4.4% do it in the intensive care unit. Acute kidney injury
(AKI) in mild to moderate COVID-19 disease seems to be infrequent; in contrast, critically
ill patients or those with a severe disease develop AKI in up to 30% of the cases and nearly
half of them will need renal replacement therapy in the form of continuous renal replacement
therapy (CRRT). AKI in this context seems to be a marker of multiorgan dysfunction and it
produces increased mortality in this population.
Multiple mechanisms of AKI in COVID-19 disease have been proposed: direct injury into
podocytes and proximal convoluted tubule cells, organ-organ interactions (lung-kidney axis),
and cytokine storm. Of them, the severe cytokine-induced injury seems to be the strongest
mechanism participating in AKI in this group of severely ill patients with CRRT need thus
representing a valuable therapeutic option.
Lately, extracorporeal blood purification therapies have been proposed as a therapeutic tool
for cytokine removal in patients with sepsis (prototype of cytokine storm model). Therefore,
new membranes with hemoadsorption capacity have been developed and are now commercially
available. The first group of membranes used for patients with sepsis and inflammatory
systemic response syndrome was high cut-off semipermeable membranes (HCO) followed by
non-selective adsorbent membranes, semi selective semipermeable membranes (AN69), and last
highly selective semipermeable (especially those with endotoxin and cytokine adsorption, such
as AN69-Oxiris). Although these membranes were designed to improve inflammation, they can
also be used as a regular filter in CRTT in patients with AKI. These products can be
purchased in our country and internationally but there is scant evidence supporting its
efficacy to improve clinical outcomes in patients with overt sepsis.
Highly selective semipermeable membranes (AN69-Oxiris) possess a great capacity for endotoxin
adsorption and cytokine removal (interleukin 6 [IL-6], tumor necrosis factor-alfa [TNF-α], C
reactive protein [CRP] , and interleukin 1b), representing a valuable therapeutic option in
septic shock; these findings have been tested mainly in experimental models. There are
human-based studies with non-representative statistical samples in which these membranes
appear to improve severity scores without any impact in mortality. This membrane has been
used in some regions around the world during the COVID-19 pandemic; recently, Ma et al
published two severe COVID-19 patients who were treated with AN69-Oxiris resulting in
decreased levels of inflammatory markers (ie, CRP and IL-6) and better lymphocyte counts.
However, there is uncertainty in the clinical benefit of those changes.
Given the lack of specific drugs or vaccine targeted for COVID-19 and, taking into account
the pathophysiologic basis that supports the use of extracorporeal blood purification
therapies to reduce the cytokine storm in COVID-19 infected patients with AKI requiring CRRT,
the use of these membranes could be of clinical utility in the disease. Here our group
presents a randomized,open-label, controlled trial to evaluate efficacy and safety of a
highly selective semipermeable membrane (AN69-Oxiris) in comparison with a semi selective
semipermeable membrane ( standard AN69) in COVID-19 associated acute kidney injury.
Hypothesis Research question: In critically ill patients with COVID-19 disease and AKI
requiring CRRT, is the AN69-Oxiris membrane of greater benefit to sustain MAP a lower
vasopressor dose in comparison with a conventional AN69 standard membrane, after 72 hours of
treatment?
Alternative hypothesis: The use of the AN69-Oxiris membrane will decrease vasopressor
requirement in at least 0.1 micrograms/kilogram/minute to sustain a stable MAP in contrast
with the usage of AN69 standard membrane, in critically ill patients with COVID-19 and AKI
requiring CRRT after 72 h of treatment.
Goals Primary goal: To demonstrate the clinical efficacy of AN69-Oxiris in decreasing
vasopressor requirement in at least 0.1 micrograms/kilogram/minute to sustain a stable MAP in
contrast with the usage of AN69 standard membrane, in critically ill patients with COVID-19
and AKI requiring CRRT after 72 h of treatment.
Exploratory goals:
To evaluate the safety in using the AN69-Oxiris membrane in contrast with the use of a
conventional membrane in critically ill patients with COVID-19 associated AKI and CRRT
requirements.
To examine the efficacy of the AN69-Oxiris membrane in reducing inflammatory
interleukins compared with reduction using conventional membranes in this specific group
of patients.
To exhibit the potential benefit of AN69-Oxiris in decreasing ICU length of stay versus
the effect of using conventional membranes in COVID-19 associated AKI.
To investigate the effect of AN69-Oxiris in reducing 28-day mortality in contrast
compared with the effect of a conventional membrane in this population.