What are the factors associated with delirium following electroconvulsive therapy a systematic review?

Delirium is a recognized side effect of electroconvulsive therapy (ECT), particularly in vulnerable older adults, with some studies reporting it in over 20% of elderly patients. This comprehensive article will explore what are the factors associated with delirium following electroconvulsive therapy a systematic review found to be significant.

Quick Summary

Factors associated with post-ECT delirium include pre-existing neurological conditions like dementia, cerebrovascular disease, and Parkinson's disease, catatonic features, advanced age, and specific procedural aspects such as bitemporal electrode placement and high stimulus intensity. The concomitant use of certain medications, like lithium and quetiapine, has also been linked to an increased risk of delirium in some patients.

Key Points

• Pre-existing Conditions: Patients with dementia, Parkinson's disease, or cerebrovascular disease have a higher risk of post-ECT delirium.

• Procedural Technique: Bitemporal electrode placement and higher stimulus intensity are associated with an increased incidence and duration of post-ECT confusion and delirium.

• Age and Frailty: Advanced age and physical frailty are independent risk factors for complications, including delirium, after ECT.

• Medication Interactions: Certain medications like lithium and quetiapine may increase the risk of delirium, especially in older adults receiving ECT.

• Preventive Approaches: Using ultrabrief pulse ECT or premedicating with dexmedetomidine has been shown to potentially reduce the risk of delirium.

• Management is Key: Careful patient monitoring, reorientation strategies, and management of sensory and environmental factors are important for managing post-ECT delirium.

Understanding Post-ECT Delirium

Electroconvulsive therapy (ECT) is an effective treatment for severe psychiatric disorders, especially treatment-resistant depression and catatonia. While its efficacy is well-established, ECT is associated with side effects, including temporary confusion and, in some cases, a more pronounced state of delirium. Post-ECT delirium is characterized by an acute disturbance in attention and cognition, often presenting with disorientation and fluctuating consciousness. The duration of this delirium is typically brief, but it can be prolonged, particularly in elderly patients or those with pre-existing vulnerabilities. For caregivers and healthcare providers, understanding the risk factors is crucial for prevention and management.

Patient-Related Risk Factors for Post-ECT Delirium

Several patient characteristics have been identified as increasing the likelihood of developing delirium after ECT. These factors relate to a patient's overall health and neurological status, and they often become more prevalent with age.

Advanced Age

Older adults are disproportionately affected by post-ECT delirium. Complication rates after ECT are notably higher in older patients compared to younger adults. Age-related neurological changes, such as a natural decline in cholinergic neurons, may weaken brain function and increase susceptibility to delirium.

Pre-existing Neurological and Cognitive Conditions

Systematic reviews have consistently identified pre-existing cognitive deficits and neurological issues as major risk factors. Specific conditions include:

• Dementia: Patients with pre-existing dementia have a significantly higher incidence of post-ECT delirium.
• Cerebrovascular Disease: Conditions affecting blood flow to the brain, such as prior strokes, are linked to an increased risk.
• Parkinson's Disease: The presence of Parkinson's disease can raise the risk of developing delirium following ECT.
• Catatonic Features: For patients with catatonia, a condition sometimes treated with ECT, the presence of catatonic features itself is an independent risk factor for post-ECT delirium.

Physical Comorbidities and Frailty

Beyond neurological conditions, a patient's overall physical health can influence delirium risk. Frailty, cardiovascular disease, and other comorbidities common in older populations increase vulnerability. For instance, a temporary increase in heart rate and blood pressure during ECT may pose a higher risk to patients with pre-existing heart problems. Infections and metabolic disturbances can also act as triggers.

ECT Procedure and Treatment-Related Factors

Apart from patient characteristics, elements of the ECT procedure itself can contribute to the risk of delirium. These factors involve the technical aspects of how the treatment is delivered.

Electrode Placement

ECT involves placing electrodes on the scalp to deliver electrical pulses. Systematic reviews have noted that bitemporal stimulation, where electrodes are placed on both sides of the head, increases the incidence of post-ECT delirium compared to unilateral placement. This is because bitemporal stimulation affects a broader area of the brain, potentially leading to more pronounced cognitive side effects.

Stimulus Intensity and Pulse Width

• Stimulus Intensity: High stimulus intensity has been associated with more prolonged reorientation time and an increased risk of delirium. The ideal dosage is individualized to induce a seizure effectively while minimizing side effects.
• Pulse Width: The type of electrical pulse used also matters. Ultrabrief pulse ECT, which uses shorter electrical pulses, has been shown to reduce reorientation time and may have preventive effects on delirium compared to standard brief pulse ECT.

Seizure Length

Some evidence suggests that longer seizure lengths during the ECT procedure are positively associated with an increased risk of post-ECT delirium. Monitoring seizure duration is a standard part of the ECT protocol.

Medications and Anesthetics

The combination of certain medications with ECT can influence the risk of delirium. A recent study in elderly patients identified lithium and quetiapine as significant predictors of postictal delirium. Some anesthetic agents have also been linked to adverse cognitive effects, though specific findings can vary across studies. Proper management of all medications is a critical part of ECT care.

Non-Pharmacological Interventions

As seen in the general context of delirium management, non-pharmacological interventions are vital for prevention and care. Strategies include:

• Cognitive Orientation: Providing patients with calendars, clocks, and familiar objects can help reorient them after treatment.
• Sleep Promotion: Ensuring a calm, quiet environment and promoting good sleep hygiene can aid recovery.
• Mobility: Encouraging early and regular physical activity can help reduce delirium risk.
• Sensory Aids: For patients with visual or hearing impairments, ensuring they have their glasses or hearing aids readily available can reduce confusion.

Comparison of ECT Electrode Placements

To highlight the difference in delirium risk, a comparison of bilateral versus unilateral ECT is useful, based on evidence from relevant studies.

Feature	Bilateral ECT	Unilateral ECT
Electrode Placement	Electrodes on both sides of the head.	One electrode on one side (typically right temple), other on top of head.
Delirium Risk	Higher risk of post-ECT delirium and confusion.	Lower risk of cognitive side effects, including delirium.
Efficacy	Often considered highly effective, particularly for severe cases.	Effective for many patients, with potentially lower efficacy in some severe cases.
Cognitive Side Effects	Greater risk of memory impairment and cognitive side effects.	Less pronounced cognitive and memory side effects.

Conclusion: Navigating Delirium Risk After ECT

Delirium following ECT is a multifactorial issue influenced by both a patient's clinical profile and specific treatment parameters. Systematic reviews and studies have highlighted key risk factors, particularly pre-existing neurological conditions, advanced age, and procedural details like bitemporal electrode placement and higher stimulus intensity. However, findings also suggest preventative strategies, such as using ultrabrief pulse ECT and managing concomitant medications, can help mitigate this risk. A thorough pre-treatment assessment and individualized treatment planning are essential for maximizing the benefits of ECT while minimizing the risks of adverse cognitive effects.

For more in-depth information, you can consult the original systematic review abstract: Factors Associated With Delirium Following Electroconvulsive Therapy: A Systematic Review

Frequently Asked Questions

Can ECT cause confusion in older adults?

Yes, older adults are more susceptible to confusion and delirium following ECT compared to younger patients. This increased vulnerability is influenced by age-related brain changes and a higher prevalence of comorbidities.

Are all types of ECT equally likely to cause delirium?

No, the type of ECT and its parameters influence the risk. Studies show that bitemporal electrode placement carries a higher risk of cognitive side effects, including delirium, than unilateral ECT.

What patient-specific factors increase the risk of delirium after ECT?

Significant patient risk factors include advanced age, the presence of conditions like dementia, Parkinson's disease, or cerebrovascular disease, and features of catatonia.

How is post-ECT delirium managed?

Management focuses on supportive care, including reorienting the patient with clocks and familiar objects, providing a quiet and calm environment, and ensuring proper nutrition and hydration. In some cases of prolonged delirium, medications like acetylcholinesterase inhibitors have been used.

Is delirium following ECT permanent?

Post-ECT delirium is typically transient, resolving within hours to a few days. While prolonged cases can occur, especially in vulnerable patients, it is not usually a permanent state.

What role do medications play in post-ECT delirium?

Certain medications can increase delirium risk when used with ECT. For instance, studies have found associations with lithium and quetiapine in older patients. Premedications like dexmedetomidine, however, may have a preventive effect.

Can ECT-induced delirium be prevented?

While not all cases are preventable, certain measures can mitigate the risk. These include careful patient selection, using unilateral or ultrabrief pulse ECT where appropriate, and managing medications and environmental factors.