In critically ill patients, sedation is often an integral part of management. While the patient is sedated, the nurse must incorporate a rehabilitation framework to maintain intact function, prevent complications and disabilities, and restore lost function to the maximum extent possible. It may be appropriate to gain assistance from therapists to achieve this and assist in the rehabilitation process.

Titration of sedation to achieve patient comfort and compliance with interventions (e.g. mechanical ventilation) is essential. Daily sedation breaks are useful in order to assess whether the level of sedation is appropriate, with an aim of using the minimal amount to achieve patient comfort. Some studies have suggested that using this strategy results in a reduction of ventilator days and length of stay (Jackson et al. [51]). However, a Cochrane review by Burry et al. ([18]) did not find conclusive support for this concept. Daily sedation holds remain common practice throughout intensive care practice (Richards‐Belle et al. [106]).

There is evidence that unconscious patients are aware of what is happening to them and can hear conversations around them (Boyle [16]). It is therefore important to tell patients what is going to happen (e.g. that they are going to be moved) and explain the procedure just as it would be explained to a conscious patient.

The human body is designed for physical activity and movement. Therefore, any lack of movement, regardless of reason, can result in multisystem deconditioning as well as anatomical and physiological changes. Guidance from a physiotherapist for passive exercises early in the period of unconsciousness may help in the prevention of further complications, for example joint stiffness and loss of joint movement. There is, however, no evidence to justify the inclusion of regular passive movements within the standard management of a patient's care. Intervention should be specific to the patient's presentation.

Despite sedation and critical illness, patients may be able to participate in some active movements and it has been shown that it is safe and appropriate for them to do so (Hodgson et al. [47]). Therefore, it is also important to assist the patient to complete early mobilization and functional movements, such as sitting over the edge of the bed, sitting in a chair and mobilizing. Guidance and intervention from physiotherapists and occupational therapists is essential to assist in the patient's rehabilitation and restore normal movement, and thus to minimize the effects and complications of prolonged immobility and bedrest (Denehy et al. [29]).

There are two major effects of muscle immobility:

Due to the immobility of the unconscious patient, there is an increased threat of them developing respiratory complications such as atelectasis, pneumonia, aspiration and airway obstruction. Respiratory assessment should be carried out prior to moving the patient and changing their position in order to provide a baseline that can be referred to following the procedure. The assessment should include checking the patency of the airway; monitoring the rate, pattern and work of breathing; testing peripheral oxygen saturations using a pulse oximeter; and measuring blood gases to assess adequacy of gaseous exchange (Hodgson et al. [47]).

Patients may require mechanical ventilation for the following reasons:

Mechanical ventilation may be required for days, weeks or even months (Damuth et al. [25]). It is worth remembering that mechanically ventilated patients often cannot express any sort of preference for certain body positions. If the patient is intubated with an endotracheal tube, they are at increased risk of developing nosocomial infections (Kalil et al. [55], Wang et al. [129]), so it is important that lung volumes and respiratory mechanics are continuously monitored in these patients. Consequently, early mobilization is of great benefit for this patient group. Referral to the physiotherapy team is vital to instigate early intervention and rehabilitation to minimize respiratory complications (Parry and Puthucheary [98]).

Immobility can cause changes in cardiovascular function, for example increased cardiac workload, decreased cardiac output, decreased blood pressure and decreased circulating volume (Koo and Fan [59]). Immobility causes a reduction in patients’ maximum oxygen uptake (VO₂ max) which is the body's ability to extract and utilize oxygen for work. This affects the body's reserve capacity and therefore the ability to perform exercise and everyday functional movements (Koo and Fan [59]). In addition, the positioning of the unconscious patient will cause central fluid shift, from the legs to the thorax and head, so the head of the unconscious patient with raised intracranial pressure may need to be elevated to at least 30° (Jeon et al. [52]).

The risk of deep vein thrombosis and pulmonary embolism is increased in the unconscious patient. This is due to several factors, including blood pooling in the legs, hypercoagulability and prolonged pressure from immobility in bed (Adam et al. [4]).