ICU Combined Assessment of Cardio-Respiratory Exercise

Rate of participant enrollment in the study will be recorded. Feasibility of enrollment will be one participant per month.

The number of completed sessions within 12 months for each eligible patient will be recorded. Feasibility target will be ≥ 80% completion of the protocol at 6 month time point for all participants.

Peak Oxygen uptake (VO2, mL/kg/min) will be measured during incremental exercise on a cycle ergometer during cardiopulmonary exercise testing (CPET).

time constant (seconds) of oxygen uptake will be assessed at the transition to constant work rate exercise at the beginning of CPET; time constant (seconds) of oxygen uptake will also be assessed at the transition to rest at the end of CPET after reaching VO2 peak.

NIRS will be applied to the vastus lateralis during exercise testing. Deoxygenation profile, as measured by increase in deoxy-hemoglobin will be recorded throughout exercise. Higher values indicate impaired oxygen delivery to tissue.

NIRS will be applied to the vastus lateralis during exercise testing. Deoxygenation profile, as measured by decrease in tissue saturation index will be recorded throughout exercise. Lower values indicate impaired oxygen delivery to tissue.

will assess functional capacity, and will be administered by research staff. Response will be sought directly from the patient. FIM is scored with motor (13-91) and cognitive (5-35). Lower scores indicate lower functional independence

The frailty index identifies 42 deficits, each coded as 0 (absent), 1 (present), or 0.5 (where intermediate values were possible). It was calculated as the cumulative proportion of deficits present (minimum score 0; maximum score 1.0), and then graded as mild (0 and 0.2), moderate (0.2 and 0.4) or severe frailty (>0.4). See references for studies where Index is derived.

Medical Research Council (MRC) sum score tests power in muscle groups for upper and lower extremities and score is tallied as the sum of all tested muscles. Value ranges from complete paralysis (0/60) to full strength (60/60). Score less than 48/60 denotes clinically significant weakness.

Work rate at anaerobic threshold (AT), represented at percentage of VO2 peak will be quantified with CPET. This corresponds to the time where oxygen (O2) utilization and carbon dioxide (CO2) production curves begin to diverge.

Standard spirometry techniques are used to quantify the maximum volume of expired breath (Litres), and represented as a %predicted compared to reference values. All tests are performed in accordance with standard ATS guidelines.

Standard spirometry techniques are used to quantify the volume of expired breath (Litres) in 1 second, and represented as a %predicted compared to reference values. All tests are performed in accordance with standard ATS guidelines.