Post-operative delirium remains a mystery, its causes and mechanisms poorly understood. Fortunately, you can manage this condition of confusion following surgery by identifying risk factors, optimizing the patient's general medical condition, maintaining adequate pain control, promoting normal sleep and providing good social support in the immediate post-operative period.

What is post-op delirium?
While its exact causes remain a mystery, post-op delirium is assumed to be a reflection of the reversible global neuronal dysfunction, which could be a result of oxygen deprivation, inflammation or physiologic stress. Many events happening during and after surgery could initiate these processes and eventually lead to delirium. Aging, a pre-existing brain disease such as stroke, dementia or depression and poor medical condition may make the brain more sensitive to the harmful effects of stimuli causing neuron dysfunction and facilitate the development of post-op delirium in patients with these pre-existing conditions.

"Delirium" is defined as an acute deterioration of brain function, which includes changes in the level of consciousness and the inability to receive, process and retain information. One of the central symptoms of delirium is disturbed attention with a failure to concentrate. Other symptoms include hallucinations (more often visual), language disturbances, disorientation, and an abnormal sleep pattern with daily sleepiness and nighttime agitation. Emotional instability, which can be expressed through anger, anxiety, fear or apathy, is also a common feature. Affected patients can be hyper-alert and hyperactive, or hypo-alert and hypoactive.

Symptoms of delirium develop within hours or days and can fluctuate over a 24-hour period. Diagnosis of post-op delirium is based on careful observation and examination of the patient's brain function. Information regarding the patient's pre-operative mental condition and cognitive function is essential in differentiating post-op delirium from other neurological or psychiatric disorders.

Preventive measures
Delirium prevention starts with the identification of high-risk patients. Risk factors include:

• Type of procedure. Incidence is highest after vascular (29% to 39%), cardiac (10% to 47%), orthopedic (24% to 50%) and general surgery (10%).
• Pre-existing patient conditions. These include older age, dementia, a history of stroke, depression, increased alcohol consumption, drug abuse and poor general health.
• Intraoperative issues. Long, complex surgical procedures, bleeding and blood transfusion have all been linked to post-operative delirium.
• Certain perioperative medications. All pain medications containing opiates and most sleeping pills can trigger delirium even after a single dose. Other medications that may contribute to delirium include antibiotics, antihypertensive drugs, diuretics and medications for nausea. Note that there is no relationship between the type of anesthesia used (general or regional) and post-operative delirium.

To prevent post-op delirium, stabilize the patient's medical condition before surgery, ensure the patient has maximal social support and avoid the administration of medications known to provoke this condition. In the post-op period, good communication between the patient, his caregivers and the surgical team is essential for delirium prophylaxis and treatment. Have repeated talks with the patient about his care and current events, as frequent reorientation is critical upon emergence from anesthesia. You can facilitate effective communication by applying hearing aids and glasses to the patient as soon as possible, communicating in a language that the patient can understand, and having him interact with the same team of nurses and physicians. When speaking with the patient's caregivers, encourage family visits and stress the importance of a normal sleep and day-night cycle when the patient returns home: Lights on during the day and off at night.

Pain control is a critical and complex issue in delirium prevention and treatment. Post-op pain can initiate delirium, but delirium is also a common side effect of many pain medications. You can overcome this dilemma by titrating doses of pain killers containing opiates, combining non-opioid medications with local anesthesia and using peripheral nerve blocks or epidural analgesia in high-risk patients.

When treatment is needed
You should have a system to inform patients who are at high risk of post-op delirium, plus their family members and other healthcare providers, that delirium could appear after the surgery. They should be familiar with the symptoms and the course of delirium so they can identify and treat it early if symptoms present after the patient is home. High-risk patients shouldn't be left alone for at least the first night after surgery. Inform patients and their family members that if symptoms of delirium occur, they should contact the patient's physician immediately. The patient may need to be admitted to the hospital for evaluation and stabilization.

Only begin pharmacological treatment of post-op delirium if the patient becomes agitated, combative and presents harm to himself or personnel. In this situation, IV administration of haloperidol, an antipsychotic drug, is indicated. Haloperidol has a light sedative effect and treats hallucinations and agitation; the most common side effects include cardiac arrhythmias and worsening of Parkinson's disease. Atypical antipsychotic medications are an alternative treatment to haloperidol, but most of these drugs are unavailable for IV administration and their role in the treatment of delirium is unclear.