Delirium is a neuropsychiatric syndrome characterized by cognitive and attentional deficits, circadian rhythm, emotional and psychomotor dysregulation.

It is frequently encountered in patients admitted to an Intensive Care Unit (ICU) with a prevalence of 20-80% and associated with higher morbidity and mortality, prolonged hospitalization and cognitive impairment after hospitalization.

Alcoholism is an important risk factor that favors the development of delirium and a common comorbidity in patients admitted to the ICU.

Patients with alcohol use disorders can develop a withdrawal syndrome after cessation of alcohol consumption. The most severe form of alcohol withdrawal is the alcohol withdrawal delirium, which is characterized by a profound state of confusion. Early recognition and treatment significantly diminish severe complications of alcohol withdrawal delirium, including mortality.

The common pharmacological prevention and therapy of alcohol withdrawal syndrome is the administration of benzodiazepines, which have the potential to prevent or mitigate alcohol withdrawal delirium.

In the ICU setting the diagnosis of alcoholism based on self-report can be unreliable and complicated by acute illness.

The Anttila-Index is a parameter calculated from the carbohydrate-deficient transferrin and the gamma-glutamyltransferase. It has a high sensitivity and specificity for excessive alcohol consumption. Therefore, the Anttila-Index of patients admitted to the ICU could help identify patients at risk for developing delirium due to alcoholism or due to alcoholism in combination with other risk factors.

Schreiber et al. recently (October 2023) found significantly higher Anttila-Index in patients with delirium on a medical ICU. The investigators postulate that this also applies to the patients admitted to the mixed (medical and surgical) ICU at the University Hospital Basel (USB), since surgery is an additional crucial risk factor for delirium development.

Hypothesis: ICU delirium can be reduced by careful preventive administration of lorazepam in patients admitted to the ICU with an Anttila-Index at or above the cutoff value of four.

Inclusion Criteria:

• Emergency/unplanned admission to the ICU
• Age ≥ 18 years
• ICU stay ≤ 24 hours until first study intervention
• Hospital admission ≤ 24 hours before ICU admission
• Anttila-Index ≥ 4

Exclusion Criteria:

• Pre-existing delirium
• Admission diagnosis that requires the administration of benzodiazepines (e.g. epileptic seizure)
• Pre-existing therapy with benzodiazepines
• Women: Pregnancy or breastfeeding
• Sequelae of acute intoxication (drugs or alcohol) at time of inclusion
• Hypersensitivity, allergy, or other absolute contraindication to lorazepam
• Participation in another study with investigational drug within the 30 days preceding and during the present study