Inclusion Criteria:  18 years of age or older On support with veno-venous- or veno-arterial-ECMO  Exclusion Criteria:  Females who are pregnant or breast-feeding History of any moderate or severe hypersensitivity or allergic reaction to any β-lactam antibiotic (a history of mild rash to a cephalosporin followed by uneventful re-exposure is not a contraindication) Receiving Cefiderocol to treat documented or suspected infection within 72 hours of screening, or expected to receive Cefiderocol during the study intervention phase Severe renal dysfunction defined as a CrCL < 15 mL/min (as calculated by the Cockcroft Gault equation using actual body weight) or requirement for continuous renal replacement therapy or hemodialysis A hemoglobin less than 8 gm/dl at baseline Acute liver injury, defined as aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 5 times the upper limit of normal, or AST or ALT > 3 times the upper limit of normal with an associated total bilirubin > 2 times upper limit of normal Any rapidly progressing disease or immediately life-threatening illness (defined as imminent death within 48 hours in the opinion of the investigator) Any condition or circumstance that, in the opinion of the investigator, would compromise the safety of the patient or the quality of study data.