Critical Illness Myopathy and Trajectory of Recovery in AKI Requiring CRRT

Acute kidney injury (AKI), the abrupt loss of kidney function, is a common complication that affects more than half of all intensive care unit (ICU) admissions, and it is associated with substantially higher rates of morbidity and mortality in both the short- and the long-term. This is especially true in patients with AKI requiring renal replacement therapy (AKI-RRT), also known as dialysis. An understudied mechanism by which AKI-RRT may contribute to poor clinical outcomes, both in the hospital and after discharge, is through its impact on muscle mass and muscle function. AKI of any severity is known to alter tissue utilization of amino acids, and preliminary data suggest that RRT in the ICU may exacerbate muscle dysfunction through the removal of large quantities of amino acids from the patient's plasma. This study will determine whether patients with AKI-RRT have greater lean muscle loss over 1 week than historical critically ill controls, whether patients with AKI-RRT have diminished recovery of muscle mass and function at 1-3 months following discharge compared to controls, and whether changes in plasma levels of amino acids during hospitalization correlate with loss of muscle function or lack of recovery.