Signs and Symptoms of Opioid-associated Iatrogenic Withdrawal in Critically Ill Adults

Inclusion Criteria: * Patients requiring mechanical ventilation and receiving continuous or regular intermittent opioids for at least 72 hours. * Weaning of at least 10% from previous stable opioid dose. A weaning episode is defined as a ≥ 10% decrease in the total stable opioid dose received over 4 hours for opioid infusions and over 12 hours for intermittent opioid administration. Exclusion Criteria: * Patient for whom consent cannot be obtained * Patient and/or family unable to communicate in French or English * Patient who is deaf without appropriate hearing aid * Imminent and predictable death (\< 72 hours) according to medical team * Severe brain injury, defined as Glasgow Coma Scale (GCS) score of 8 or less at ICU admission * Moderate brain injury, defined as GCS between 9 and 12, with elevated intracranial pressure (ICP \> 20 mmHg) which requires ICP monitoring and osmotherapy * Acute neurological condition (e.g. status epilepticus, encephalopathy, stroke). If the acute neurological condition resolves within 72 hours, the patient may be included in the study. * Substance abuse prior to ICU admission. * Chronic alcohol use defined as alcohol consumption of more than 2 drinks/day and/or more than 14 drinks/week for men and 9 drinks/week for women. * Chronic use of illicit drugs and amphetamines (except amphetamines taken for therapeutic purposes) defined as a consumption of at least 3 times per week. * Chronic use of opioids (e.g. transdermal fentanyl, methado…