Patients who survive critical illness usually experience long-lasting physical and psychological impairments, which are often debilitating. Rehabilitation interventions started in the ICU may reduce this morbidity. In-bed cycling, which uses a special bicycle that attaches to the hospital bed, allows critically ill patients who are mechanically ventilated (MV) to gently exercise their legs while in the ICU. The main goal of this study is to determine whether critically ill MV adults recover faster if they receive early in-bed cycling than if they do not. Another objective is to determine whether in-bed cycling is a cost-effective intervention. 360 patients admitted to the ICU and receiving MV will be enrolled in the study. Following informed consent, patients will be randomized to either (1) early in-bed cycling and routine physiotherapy or (2) routine physiotherapy alone. Patients' strength and physical function will be measured throughout the study. If early in-bed cycling during critical illness improves short-term physical and functional outcomes, it could accelerate recovery and reduce long-term disability in ICU survivors.

Background: Survivors of critical illness have a long road of physical, cognitive, and psychological recovery. Although medical advances have reduced the mortality of critical illness, survival often comes with substantial long-term morbidity and societal cost. At 1-year follow-up, ~35% of intensive care unit (ICU) survivors had sub-normal 6-minute walk distance, and ~50% had not returned to work. Rehabilitation interventions started in the ICU may reduce this morbidity. In-bed cycling is a novel technology that may help critically ill, mechanically ventilated (MV) patients receive exercise very early to prevent or attenuate muscle weakness. Patients on MV typically receive prolonged bedrest and are often perceived as 'too sick' for physiotherapy (PT) interventions. However expert consensus and our previous multicentre pilot work suggest these interventions are safe. The CYCLE RCT will evaluate whether early in-bed cycling compared to usual PT interventions improves patient-reported outcomes.

Objectives:

1. CYCLE RCT: To determine if early in-bed cycling and routine PT compared to routine PT alone in critically ill, mechanically ventilated adults improves the primary outcome of physical function at 3 days after ICU discharge and secondary outcomes of strength, physical function, frailty, psychological distress, quality of life, mortality, and healthcare utilization.
2. Economic Evaluation: To determine the cost-effectiveness of cycling and routine PT compared to routine PT alone among critically ill, mechanically ventilated adults.

Design: 360-patient concealed open-label RCT with blinded outcome assessment

Population: Critically ill adults receiving MV in a medical-surgical ICU

Methods: After informed consent, patients will be randomized to receive 30 minutes/day of cycling, 5 days per week and routine PT interventions or routine PT interventions alone. Assessors, blinded to treatment allocation, will measure the primary outcome of patients' physical function at 3 days post-ICU. Secondary outcomes will be measured at ICU awakening, ICU discharge, 3 days post-ICU, hospital discharge, and 90-days post-enrollment.

Relevance: By 2026, demand for ICU services is estimated to increase by 40% and more survivors will be at risk for post-ICU disability. If early cycling during critical illness improves short-term physical and functional outcomes, it could accelerate recovery and reduce long-term disability in ICU survivors.

Inclusion Criteria:

• Patient is ≥ 18 years of age
• Patient is invasively mechanically ventilated ≤ 4 days
• Expected additional 2 day ICU stay
• Ability to ambulate independently (with or without gait aid) before their critical illness
• ICU length of stay ≤ 7 days

Exclusion Criteria:

• Pre-hospital inability to follow simple commands in local language at baseline
• Acute conditions impairing ability to receive cycling
• Severe cognitive impairment pre-ICU
• Traumatic brain injury
• Acute proven or suspected central or peripheral neuromuscular weakness affecting the legs (e.g., stroke, Guillian-Barre syndrome, spinal injury)
• Temporary pacemaker (internal or external)
• Expected hospital mortality ≥ 90%
• Equipment unable to fit patient's body dimensions (elg., leg amputation, morbid obesity)
• Palliative goals of care
• Pregnancy (suspected or proven)
• Specific surgical exclusion as stipulated by surgery or ICU team
• Physician declines
• Cycling exemption not resolved during first 4 days of mechanical ventilation
• Patient already able to march on spot at time of screening