Inclusion Criteria:

• Adult patients ≥ 18 years old.
• Admission in intensive care unit in Mayo Clinic, Rochester, MN.
• Ability to provide informed consent or has a surrogate who can provide informed consent.
• Have at least one of this conditions:
  • Septic shock requiring volume resuscitation;
  • Acute decompensated heart failure requiring volume removal (with diuretics or ultrafiltration);
  • Before and after cardiopulmonary bypass surgery high-risk for AKI assessed by Cleveland Clinic Foundation score of > 6.

Exclusion Criteria:

• Known pregnancy.
• Prisoners.
• Vulnerable adults.
• Those who were volume resuscitated before admission to ICU.
• Chronic kidney disease stage IV and V.
• End-stage kidney disease requiring dialysis.
• Kidney transplant.
• Moderate-to-severe COPD.
• ILD.
• Significant consolidation in upper lobs of the lung.