In the studies by Heemann et al.[41] and Sen et al.[42] an improvement in HE was considered when encephalopathy grade was reduced by one or more grades vs. basal values; for Hassenein et al., in their randomized controlled trial, improvement was considered when a decrease of two grades was observed.[43] In the latter, 70 patients with acute on chronic liver failure and encephalopathy grade III and IV were included. Likewise, Kramer et al.[44] estimated an HE improvement when an improvement in peak N70 latency in electroencephalograms was observed. Sen et al.44 observed a significant reduction in Child-Pugh Score (p<0,01) at 7 days following a MARS treatment, without any significant change in the controls.