Delirium—acute fluctuating disturbance of consciousness accompanied by alteration of cognition.
Postoperative delirium in elderly undergoing elective surgery: 11%.
Postoperative delirium more common in vascular surgery and long-lasting oral surgery.
One in 10 Americans consumes excess alcohol and is at risk for withdrawal. The risk for delirium is doubled in this population.
Preoperative: age >70, preexisting cognitive impairment, alcohol abuse, narcotics and drug use, previous history of delirium.
Peroperative: significant blood loss, pain, hypoxia; anesthetic agents—ketamine, opioids, benzodiazepines, metoclopramide, anticholinergics, droperidol; possible influence of intraoperative embolization (e.g., joint replacement).
Postoperative: major surgery, perioperative hypoxia.
Acute cerebral dysfunction in relation to neurotransmitter disturbance, particularly anticholinergic, melatonin, norepinephrine, and lymphokines.
Confusion Assessment Method (CAM) in ICU and Intensive Care Delirium Screening Checklist (ICDSC) can be used to detect delirium in patients. However, mechanical ventilation and/or sedation make utilization of these screening tools challenging. In addition, medications for sedation might induce or treat symptoms of delirium.
Confusion Assessment Method
|Feature 1: acute onset or fluctuating change in baseline mental status in the past 24 h as evidenced by sedation scale, Glasgow coma scale, or other delirium assessment?||Yes or no|
|Feature 2: inattention test||Yes or no|
|Feature 3: altered level of consciousness—if RASS is other than alert and calm||Yes or no|
|Feature 4: disorganized thinking||Yes or no|
|Feature 1 plus 2 and either 3 or 4 = CAM–ICU positive|
The Intensive Care Delirium Screening Checklist
|1 point for each positive finding; score ≥4 indicates delirium|
- Altered level of consciousness
- Hallucination, delusion, or psychosis
- Psychomotor agitation or retardation
- Inappropriate speech or mood
- Sleep/wake cycle disturbance
- Symptom fluctuation
Nonpharmacologic treatment might benefit patients preoperatively and postoperatively.
- Daily orientation—increase exposure to daylight, clocks in rooms
- Reduce sleep deprivation
- Decrease unnecessary sedatives or antipsychotics
- Avoid use of restraints
- Encourage early mobilization; physical therapy and occupational therapy
- Early family contact
- After ensuring adequate ventilation and perfusion, treat any underlying acid base disturbances or electrolyte abnormalities. Physostigmine (0.5–2 mg IV) may reverse postoperative delirium due to anticholinergics
- For patients with history of substance abuse, detoxification is beneficial prior to surgery
- For prevention of the effects of stress on the hypothalamic–pituitary–adrenal axis (HPA axis), morphine 15 μg/kg/h is initiated prior to induction of anesthesia
- For patients with known alcohol use disorder, treatment is symptom-based during perioperative state:
- Benzodiazepines for agitation and seizures
- Clonidine or dexmedetomidine for autonomic symptoms
- Neuroleptics (haloperidol or risperidone) for hallucinations
- Long-acting benzodiazepine before the surgery or short-acting benzodiazepine on the morning of surgery
- After induction of anesthesia, clonidine 0.5 μg/kg/h, haloperidol up to 3.5 mg per day, ketamine 0.5 mg/kg
- Prevention of Wernicke encephalopathy:
- Thiamine 200 mg per day ...