Pain assessment using self-report scales (Visual Analogue Scale, Numerical Rating Scale), is recommended in the general population, however it is not always possible in patients with altered neurological status such as sedated patients or patients with delirium. Consequently, pain assessment is highly challenging in these ICU patients. This is a prospective observational study assessing 3 behavioral pain scales in the ICU.

The hypothesis of this proposal is that one of the three ICU pain scales has a more important reliability than the others. Such a scale could be recommended to be used to measure pain intensity in ICU patients not able to communicate.

The aims of this observational study are to measure and compare the psychometric properties of Behavioral Pain Scale (BPS), Critical Care Pain Observation Tool (CPOT) and Non Verbal Pain Scale (NVPS) at baseline and following repositioning procedure in the ICU

Inclusion Criteria:

• age > 18 years
• not comatose, defined by a Richmond Agitation Sedation Scale (RASS) ≥ -3, i.e. between -3 and +4
• not able to self-report accurately their pain intensity using a visually enlarged 0-10 numeric rating scale

Exclusion Criteria:

-neurological deficits (acute or chronic) that prevent observation of the muscle tonus or movement. For example:

• Quadriplegia
• Current use of Neuromuscular blocking agents
• Severe brain injuries

Intensive Care Unit patients