Recovery of Physical Function After Critical Illness In Older Adults

The proposed study is a prospective, observational study assessing the recovery of muscle and physical function in patients surviving critical illness (n =150) at hospital discharge (baseline) and repeated serially. Patients will be enrolled after life-saving modalities have been weaned near hospital discharge. Patients will participate in testing at baseline, 3-, 6-, 12-, and 24-months after hospital discharge. In a subset of patients (n = 18), muscle biopsies will be performed at baseline and then repeated once at either 12- or 24-months after hospital discharge.

The overarching goal of the proposed study is to determine the trajectories of physical recovery and cellular markers involved with the underlying failure to recover muscle after critical illness, while exploring which characteristics are associated with sustained physical disability. This proposal will examine muscle pathophysiology carefully aligned with physical function outcomes in order to longitudinally assess the recovery, or failed recovery, of muscle function in participants after critical illness: Aim 1: Determine the long-term trajectory of muscle strength, physical function and ADL recovery in ICU survivors. Patients (n = 150) will participate in a battery of tests to determine muscle and physical function aligned with self-reported measures of ADLs and quality of life at hospital discharge, 3-, 6-, 12-, and 24-months post. Aim 2: Assess cellular changes in skeletal muscle in ICU survivors contributing to long-term physical dysfunction. In a subgroup of patients enrolled in Aim 1, muscle biopsies will be collected at baseline and long-term follow-up to determine oxidative stress, mitochondrial function, and cellular senescence.