Expansion
Muscle wasting, bone loss, orthostatic intolerance and thrombosis
Expansion
Musculoskeletal
- Muscle mass and strength fall by 1 to 1.5 per cent a day, fastest in antigravity muscles; critical illness myopathy accelerates this greatly
- Bone loss of 1 to 2 per cent a month with hypercalciuria
- Joint contractures within days to weeks
Cardiovascular
- Plasma volume falls by 10 to 15 per cent within days
- Orthostatic intolerance, from reduced volume and blunted baroreflex
- Increased resting heart rate, reduced stroke volume and VO2 max
- Venous thromboembolism from stasis
Respiratory
- Reduced functional residual capacity, basal atelectasis, impaired cough and secretion clearance, so pneumonia risk rises
Other
- Pressure sores, insulin resistance, constipation, urinary stasis and stones, delirium and depression
Recovery takes far longer than the loss, roughly three times the duration of immobility in older patients, which is the argument for early mobilisation even in critically ill and ventilated patients, where it has been shown to reduce delirium and improve functional outcome.