Delirium Causes Risk Factors Delirium is a common but potentially preventable syndrome, particularly among hospitalized older adults. It is one of the major contributors to poor health outcomes and a leading cause of increased morbidity, mortality, and institutionalization in this population (Siddiqi, House, & Holmes, 2006). Nursing interventions, early recognition, and management strategies are crucial for preventing and mitigating the effects of delirium. This comprehensive overview will cover the etiology, pathophysiology, risk factors, assessment, and nursing management strategies for delirium.
What Is Delirium?
Delirium is an acute, fluctuating disturbance of consciousness, characterized by impaired attention and disorganized thinking. It typically develops rapidly, often within hours or days, and is usually a direct consequence of an underlying physiological or medical condition (American Psychiatric Association, 2000).
Delirium manifests in various ways, including reduced ability to focus, sustain, or shift attention, memory impairment, disorientation, illusions, hallucinations, or misinterpretations of stimuli. Delusional thinking may also be present. Unlike other chronic cognitive impairments, such as dementia, delirium develops over a short period and tends to fluctuate throughout the day. Patients with delirium may present with hyperactive, hypoactive, or mixed motoric subtypes (Meagher, 2009). While nurses often associate delirium with hyperactivity and agitated behaviors, the hypoactive subtype, characterized by a lack of overt psychomotor activity, is also common and may carry a higher risk of mortality, especially when it coexists with dementia (Yang et al., 2009).
Prevention of Delirium
Delirium can be prevented by identifying modifiable risk factors and employing standardized nursing protocols. Involvement of geriatric specialists can further enhance prevention efforts (Siddiqi, Stockdale, Britton, & Holmes, 2007). If delirium does develop, early recognition is paramount to treating the underlying pathology and minimizing its consequences. Nurses play a critical role in both the prevention and early recognition of this potentially devastating condition in older hospitalized adults (Milisen et al., 2005).
Background and Statement of Problem
Delirium is a disturbance of consciousness accompanied by reduced ability to focus, sustain, or shift attention, memory impairment, disorientation, and possible hallucinations or delusional thinking (APA, 2000). Delirium differs from other cognitive impairments due to its rapid onset and fluctuating course. This syndrome may present in hyperactive, hypoactive, or mixed forms. The hypoactive form is especially concerning because it may go unrecognized due to its subtle presentation (Meagher, 2009; Pandharipande, Cotton, et al., 2007). Patients with hypoactive delirium are often at a higher risk of adverse outcomes, including increased mortality, particularly when delirium is superimposed on existing dementia (Yang et al., 2009).
Etiology and Epidemiology of Delirium
Prevalence and Incidence
Delirium is highly prevalent among hospitalized older adults, affecting 10% to 31% of older patients on admission and 11% to 42% during hospitalization (Siddiqi et al., 2006). Among patients undergoing hip surgery, the incidence ranges from 4% to 53%, with the highest risk seen in those with pre-existing cognitive impairment (Bruce, Ritchie, Blizard, Lai, & Raven, 2007). In medical ICUs, both prevalent and incident delirium rates are reported at 31% (McNicoll et al., 2003). In surgical ICUs, the prevalence on admission is lower (2.6%), but 28.3% of patients develop delirium during their stay (Balas et al., 2007). Up to 83% of mechanically ventilated ICU patients experience delirium (Ely et al., 2001), and more than half of older patients in medical ICUs have persistent delirium upon transfer (Pisani, Murphy, Araujo, & Van Ness, 2010). The incidence of delirium superimposed on dementia ranges from 22% to 89% (Fick, Agostini, & Inouye, 2002), and delirium can persist for months after discharge (Cole, Ciampi, Belzile, & Zhong, 2009).
Pathophysiology of Delirium
The pathogenesis of delirium is not fully understood, but there is increasing evidence supporting several mechanisms. Cholinergic deficiency, dopamine excess, and cytokine activity are considered major contributors to delirium (Inouye, 2006). A genetic predisposition has also been identified, with a link between delirium and the apolipoprotein E epsilon 4 allele (van Munster et al., 2009).
Risk Factors for Delirium
Delirium risk factors can be classified into predisposing and precipitating factors:
Predisposing Factors
The strongest predisposing risk factors include advanced age (70 years or older), severity of illness, and pre-existing cognitive impairment (Michaud et al., 2007). Additional risk factors include depression, sensory impairment, fluid and electrolyte disturbances, and polypharmacy, especially the use of psychotropic medications.
Precipitating Factors
Precipitating factors that can trigger delirium during hospitalization include central nervous system pathology (such as stroke), metabolic, electrolyte, and endocrine disturbances, infection, drug toxicity or withdrawal, pain, hypoperfusion/hypoxia, the number of medications (particularly psychotropic and anticholinergic drugs), and physical restraints. Environmental factors, such as ICU admission, frequent room changes, and the absence of a clock or eyeglasses, can also contribute to delirium development (Michaud et al., 2007). In older patients admitted for hip surgery, early cognitive impairment, underlying physical illness, and advanced age are strong predictors of delirium (de Jonghe et al., 2007; Kalisvaart et al., 2006).
Outcomes of Hospitalized Patients with Delirium
Delirium in hospitalized patients, particularly older adults, is associated with several adverse outcomes. Persistent delirium at 1, 3, and 6 months post-discharge is linked to increased mortality, nursing home placement, and decreased functional status and cognitive function compared to patients without delirium (Cole et al., 2008; Witlox et al., 2010). Delirium also causes significant distress to patients, their families, and healthcare staff (Bruera et al., 2009; Cohen, Pace, Kaur, & Bruera, 2009). As such, delirium represents a high-priority challenge for nursing care in hospitalized older adults.
Assessment of Delirium
Identifying Risk Factors
The first step in assessing delirium involves identifying risk factors. Eliminating or reducing these risk factors can prevent delirium in many cases (Milisen et al., 2005). Recognizing the clinical features of delirium is essential to identify, eliminate, or reduce precipitating factors such as pain, infection, or other acute illnesses. This can be achieved through routine assessment using a standardized delirium screening tool, although only 17% of hospitals currently implement such practices (Neuman et al., 2010).
Screening Tools
The Confusion Assessment Method (CAM) is widely used and has high sensitivity and specificity in various settings, including ICUs, emergency departments, acute care, and long-term care facilities (Wei, Fearing, Sternberg, & Inouye, 2008). The CAM-ICU version is recommended for critically ill patients (Jacobi et al., 2002; Schuurmans et al., 2003). The CAM instrument identifies key features of delirium, such as acute onset, inattention, disorganized thinking, altered levels of consciousness, disorientation, memory impairment, perceptual disturbances, psychomotor agitation or retardation, and altered sleep-wake cycles (Inouye et al., 1990). For a diagnosis of delirium, there must be the presence of Feature 1 (acute onset or fluctuating course), Feature 2 (inattention), and either Feature 3 (disorganized thinking) or Feature 4 (altered level of consciousness).
It is important to recognize that delirium can occur concurrently with dementia or depression. Between 22% and 89% of older adults with dementia also have delirium superimposed on dementia (Fick et al., 2002). Patients with dementia are at an increased risk for developing delirium and have worse outcomes when they do (Yang et al., 2009). Family members and caregivers can be invaluable in distinguishing cognitive changes in these circumstances when the patient is not well known.
Bedside nurses are in the best position to recognize delirium due to their continuous patient assessment and ability to identify risk factors and early cognitive changes. Early identification of risk factors and the earliest signs of delirium are critical to implementing strategies to minimize the occurrence of this condition in hospitalized older adults.
Interventions and Care Strategies for Delirium
According to the latest Cochrane Review (Siddiqi et al., 2007), there is no strong evidence from randomized controlled trials (RCTs) to guide clinical practice for delirium prevention. Only one of six RCTs effectively prevented delirium with proactive geriatric consultation for older adults undergoing surgery for hip fracture (Marcantonio et al., 2001). Prophylactically administered low-dose haloperidol reduced the severity and duration of delirium but not its incidence (Kalisvaart et al., 2005).
Given the prevalence and severity of delirium, its complex etiology, and the challenges associated with conducting RCTs, clinical practice guidelines based on other strong intervention studies are recommended for both the prevention and treatment of delirium.
Standardized Protocols
When a patient is identified as being at risk for delirium, a standardized delirium protocol should be initiated immediately. Protocols tested in multicomponent interventions have effectively prevented delirium (Inouye et al., 1999; Marcantonio et al., 2001). These protocols varied somewhat, but two key principles emerged from the research:
- Minimize the risk for delirium by preventing or eliminating the etiologic agent(s).
- Provide a therapeutic environment and general supportive nursing care.
Older adults treated on a specialized geriatric unit with protocol-guided care by a staff trained in geriatric care education developed significantly less delirium (Lundstrom et al., 2007). In patients who developed delirium after hip surgery, a multicomponent intervention program reduced the duration of delirium, complications, total days of hospitalization (Lundstrom et al., 2007), and improved health-related quality of life without incurring additional costs (Pitkala et al., 2008). Although multicomponent delirium-reduction interventions have yet to be tested extensively in critical care settings, sedation interruption and early occupational and physical therapy in mechanically ventilated patients have resulted in shorter delirium duration (Schweickert et al., 2009).
Pharmacological Interventions
Non-pharmacological interventions are preferred and should be used first (Michaud et al., 2007). However, antipsychotics such as haloperidol have been found to be effective in managing agitated delirium in certain populations (Breitbart et al., 1996; Devlin et al., 2010). Light propofol sedation may reduce the severity and duration of delirium in hip surgery patients (Sieber et al., 2010).
Dexmedetomidine, a promising alternative for sedation, has been associated with lower rates of delirium and costs compared to propofol and midazolam in ICU settings (Maldonado et al., 2009). It is also more effective than lorazepam in achieving the target level of sedation and promoting more days alive without coma or delirium (Pandharipande, Pun, et al., 2007). When compared to midazolam in mechanically ventilated patients, dexmedetomidine resulted in less delirium (Riker et al., 2009).
Pain Management
Alternative pain management strategies may also help reduce delirium. For example, hip fracture patients at low risk for delirium who received a prophylactic fascia iliac block experienced significantly less delirium than those receiving traditional pain management regimens (Mouzopoulos et al., 2009).
Nursing Care Strategies
- Risk Factor Identification: Identify and address risk factors for delirium upon admission and throughout the patient’s hospital stay.
- Routine Screening: Implement routine screening for delirium using standardized tools such as the CAM or CAM-ICU.
- Patient and Family Education: Educate patients and families about the signs and symptoms of delirium, the importance of early detection, and the benefits of preventative strategies.
- Environmental Modifications: Create a calm, orienting environment with clear signage, clocks, and calendars. Reduce noise and ensure adequate lighting.
- Pain and Symptom Management: Optimize pain management strategies and promptly address symptoms such as hypoxia, dehydration, or constipation.
- Supportive Care: Provide consistent orientation to the patient, involve family in care, and ensure the use of sensory aids such as eyeglasses or hearing aids.
- Multidisciplinary Collaboration: Involve a multidisciplinary team, including geriatric specialists, to create a comprehensive care plan tailored to each patient’s needs.
Conclusion
Delirium is a significant and challenging condition among hospitalized older adults. Its prevention, early recognition, and management are essential components of nursing care. By understanding the risk factors, employing standardized assessment tools, and implementing both pharmacological and non-pharmacological interventions, healthcare professionals can minimize the impact of delirium on patients and improve overall outcomes. Nurses, in particular, play a crucial role in the prevention, detection, and management of delirium, making it a priority in the care of older hospitalized patients.