Patients who have been admitted to Intensive Care Units (ICU) and are intubated and mechanically ventilated for longer than 48 hours have impaired physical, psychological and social health and well-being six to twelve months after discharge. The advocacy of intensive physiotherapy and mobilization early in the course of critical illness has been established. It is of great importance to study the long-term outcomes (physical function and quality of life) in intubated and ventilated patients who start exercising and ambulating mobilizing) as soon as possible during ICU stay because the most effective mode, intensity or frequency of exercise needs to be identified.

The aim is to study the short- and long-term outcomes of enhanced early physiotherapy and upright position in critically ill patients on prolonged invasive ventilation and to develop principles to guide physiotherapists in their clinical decision making in the ICU.

Mobilization is an intervention prescribed by physiotherapists, for critically ill patients in the ICU, to prevent as well as remediate a range of multisystem problems and complications. Mobilization which refers to low levels of exercise and progressive position changes from being supine to being upright and moving, is both a gravitational and an exercise stimulus. Given the hemodynamic status of patients in the ICU can change suddenly, physiotherapists gauge the patient's status moment by moment, and change the parameters of an intervention accordingly, i.e., the type and level of an intervention, its duration and rest periods. The aim of this research is to study the short- and long-term outcomes of enhanced early physiotherapy, with mobilization and upright position, in critically ill patients on prolonged invasive ventilation. This is a prospective, randomized, single blind trial where the intervention permits variation in the physiotherapist's clinical decision making to simulate the general practice. This study started in November 2011, data collection and intervention will continue until November 2014 with 12 months follow up until november 2015.

Inclusion Criteria:

• Patient participants will be at least 18 years of age and admitted to the ICU of Landspitali Fossvogur or Landspitali Hringbraut of the The National University Hospital of Iceland.
• Intubated and on mechanical ventilation for > 48 hours
• Icelandic speaking.
• Upright position and ambulation is not contraindicated or impossible.

Exclusion Criteria:

-Those patients deemed by the medical teams of each unit not to be sufficiently stable. These would include diagnoses such as: Intracranial insults including:Severe head injury, Subarachnoidal hemorrhage, Elevated intracranial pressure, Intraventricular drain, Neurological deterioration, Status epileptics

• Unstable fractures of the vertebral column
• Spinal cord injuries
• Unstable pelvic fractures and/or balanced skeletal traction
• Severe burns
• Mental status precluding being able to follow instructions and cooperate with treatment appropriately