Journal of Gerontological Nursing

Assessment 

DETECTION OF DELIRIUM USING THE CONFUSION ASSESSMENT METHOD

Johanne Laplante, RN, BSc, MSc(a); Martin G Cole, MD, FRCP(C)

Abstract

Nurses are encouraged to initiate interventions and perform mental assessments routinely to prevent deterioration of mental state in older adults who are hospitalized.

Abstract

Nurses are encouraged to initiate interventions and perform mental assessments routinely to prevent deterioration of mental state in older adults who are hospitalized.

Lipowski (1989) defines delirium as a transient global disorder of cognition that manifests itself suddenly and lasts for days or a few weeks. It is characterized by clouding of consciousness, altered thinking process, inattention, memory impairment, disorientation (e.g., time, place, person), perceptual disturbance, psychomotor agitation or retardation, altered sleep-wake cycle and fluctuating course.

Delirium is a significant problem for hospitalized elderly individuals. The occurrence of delirium among elderly patients admitted for medical problems ranges from 10% to 30% (Levkoff, CIeary, Liptzin, & Evans, 1991) and is associated with increased length of hospital stay, rates of institutional care, rates of nursing home placement upon discharge from hospital and mortality (Cole & Primeau, 1993; Levkoff, Besdine, Oc Wetle, 1986; Lipowski, 1983). Many of these factors contribute to increased hospital costs to provide care for elderly individuals who are acutely confused.

The elderly patient who is delirious requires increased intensity of nursing care and attention. Such a patient might be agitated and try to get out of bed, leave the unit, pull out a catheter, or pull off a dressing, for instance. Such patients might have impaired thought processes and be unable to communicate their needs, be inattentive and unable to retain any information, be disoriented or have visual or auditory hallucinations.

During an acute onset of confusion, individuals are unable to care independently for themselves and require more nursing supervision. The patient with acute onset of confusion may exhibit unsafe behaviors (Williams, Ward, & Campbell, 1988). Finally, such a patient is at greater risk for health complications and deterioration. O'Keefe and Lavan (1997) reported that individuals who experience delirium have a high risk of urinary incontinence, falls, and pressure sores. Milisen, Foreman, Godderis, Abraham, and Broos (1998) added that the persistence of the symptoms could impair the potential of the individual for rehabilitation.

Because of its fluctuating course and subtle presentations, delirium often is not recognized and managed appropriately (Francis, Martin, & Kapoor, 1990; Inouye, 1994; Lipowski, 1989). From a nursing point of view, this can be explained in part by a lack of consistency when assessing a patient's mental health status, either because nurses do irregular assessments or do not identify features of delirium. Eden and Foreman (1996) reported that two main problems in underrecogrution of delirium were nurses' lack of knowledge about ways to detect delirium and lack of communication among nursing staff in reporting symptoms of onset of delirium.

Despite the fact that nurses are present at the patient's bedside 24 hours a day, 7 days a week, assessment of cognitive function is not always performed in a systematic and standardized way. Documentation of changes in a patient's behavior in the hospital can be a marker for the onset of delirium (Morency, Levkoff, & Dick, 1994). It is important for nurses, as the frontline caregivers, to assess the patient's mental status routinely, using a structured approach to better recognize the features of delirium. Therefore, the goal of this article is to increase nurses' knowledge and awareness of signs of delirium using the Confusion Assessment Method (CAM) routinely and systematically.

Inouye et al. (1990) reported that a major barrier to the lack of recognition of delirium was the absence of a clinical tool. Consequently, they developed an instrument to diagnose delirium, the Confusion Assessment Method (CAM).

Two other instruments to diagnose delirium also exist - the Delirium Symptom Interview and the Delirium Rating Scale (DRS). The Delirium Symptom Interview, developed by Albert et al. (1992), requires 20 to 30 minutes to complete. It is a 33-question questionnaire that can be tiring for patient and time consuming for nurses. This instrument is not very useful for nurses because it cannot be performed routinely. The DRS, developed by Trzepacz, Baker, and Greenhouse (1988), is a ??-item scale. It is simple to use, but it does not assess all the key features of delirium and requires a lot of information from different sources that can be interpreted only by a skilled clinician.

To date, the CAM (see Appendix) remains the only diagnostic instrument that is easy to use and can be completed in 5 to 10 minutes by individuals without formal psychiatric training (lnouye et al., 1990). The CAM was designed to capture the cardinal features of delirium based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R). This instrument has been shown to have high interrater reliability (k = .81 to 1.0) and to be sensitive (94% to 100%) and specific (90% to 95%) compared to the diagnosis of a psychiatrist. Health care professionals can use the CAM to identify rapidly the features of delirium in both clinical and research settings. Moreover, a study from 1998 showed that a trained nurse using the CAM could identify delirium at least as well as psychiatrists (Zou et al., 1998).

The CAM diagnostic algorithm (see the Sidebar above) for delirium was developed based on the following four diagnostic features of the DSM-III-R:

* Acute onset of confusion and fluctuation course (Feature 1).

* Inattention (Feature 2).

* Disorganized thinking (Feature 3).

* Altered level of consciousness (Feature 4).

A diagnosis of delirium requires the presence of Features 1 and 2 and either 3 or 4 (lnouye et al., 1990). The other features of delirium are not included in the algorithm because lnouye et al. (1990) reported that they add nothing to the sensitivity and specificity of the instrument.

To help nurses understand and use this instrument, each feature of the instrument will be described and supported by clinical observations. Finally, assessments of two patients will be presented to illustrate how the CAM instrument and the diagnostic algorithm were applied.

DESCRIPTION OF THE CLINICAL FEATURES OF THE CAM

Acute Onset and Fluctuation Course

Acute onset and fluctuating course refers to an acute change in the patient's cognitive function in the last month compared to the usual baseline of the patient (lnouye et a]., 1990) or fluctuation in cognitive function (i.e., confused one day but not the next). This information is usually obtained from those who know the patient very well. Such individuals are either living with the patient (e.g., spouse), working with the patient (e.g., local center community services health care professionals, private health care professionals, owners of residence, health care professionals in long-term facilities, primary care physicians) or seeing the patient regularly (e.g., friends, children). It is usually easy for these individuals to recognize a change in a patient's cognition.

Acute change is sudden and often causes a crisis for the parient and family. The patient is totally different, not behaving as usual. Patients who are usually alen and oriented in the three spheres, able to follow and carry on an intelligent conversation, and able to manage basic and instrumental activities of daily living, become very confused. They might become lethargic; disoriented to place, and person (e.g., unable to recognize spouse, children); ramble; and become inappropriate in their answers. Patients often cannot keep track of what was said to them a few minutes ago and may have an illogical flow of ideas. This acute change in a patient's mental state is obvious and easily reported by the family or significant others because the patient often can no longer function alone.

Inattention

Inattention is observed when the patient is easily distractible or having difficulty keeping track of what is being said (Inouye et al., 1990). During conversations, patients are interrupted easily; the level of concentration is diminished; it becomes difficult to focus on one task; information needs to be repeated often for tasks to be registered and completed; and patients forget easily and may lose their train of thought. Inattention is usually easily detectable based on mental reversal (e.g., simple subtraction or reciting months of year backwards) (Inouye et al., 1990), ability to follow and carry a conversation (e.g., perseverâtes with an answer to a previous question), or accomplish a task.

Disorganized Thinking

Disorganized thinking is observed when the content of the patient's conversation is inappropriate to the questions asked, incoherent, rambling, or irrelevant. There is an illogical flow of ideas or unpredictable switching from subject to subject (Inouye et al., 1990). Once again, this is usually easily detectable through open-ended questions.

Altered Level of Consciousness

Altered level of consciousness refers to the level of the patient's alertness at the time of the evaluation. The delirious patient can be alert, hyperalert (i.e., overly sensitive to environmental stimuli), lethargic (i.e., sleepy but easily aroused), stuporous (i.e., difficult to arouse), or comatose (i.e., unarousable) (Inouye et al., 1990). If the situation is ambiguous, it is important to question family and significant others.

Other Features of Delirium

Other features of delirium Include:

* Disorientation refers to the patients' inability to orient themselves in time (e.g., day, date, month, season, year, time of the day), place (e.g., somewhere else than where they are), or person (e.g., unable to recognize spouses, children, proxy) (Inouye et al, 1990).

* Memory impairment refers to the patient's difficulties in remembering recent events, such as reasons for admission, events in the hospital, or difficulties remembering instructions (Inouye et al., 1990).

* Perceptual disturbances refers to hallucinations (i.e., visual, auditory) and illusions (i.e., misinterpretations of a stimuli, thinking something was moving when it was not) (Inouye et al, 1990).

* Psychomotor agitation or retardation refers to an increased or decreased level of motor activity, such as restlessness, picking at bedclothes, tapping fingers, or making sudden changes of position (Inouye et al., 1 990) or an unusually decreased level of motor activity such as sluggishness, staring into space, staying in one position for a long time, or moving very slowly (Inouye et al., 1990).

* Altered sleep-wake cycle refers to the patient being awake much of the night and sleeping during the day (Inouye et al., 1990).

PATIENTS' MENTAL HEALTH ASSESSMENT

The two following assessments illustrate different features of delirium. The application of the CAM instrument and the diagnostic algorithm will be explained to demonstrate to nurses how they can perform a patient's cognitive assessment routinely and systematically while caring for their patients to better detect signs of early confusion (see the Sidebar above for instructions to facilitate the use of the CAM). A manual of instructions developed to provide guidelines for scoring is available from the authors of the CAM (Inouye et al., 1990).

Hyperalert Form of Delirium

Mrs. V. was brought to the hospital in an ambulance for a 7-day history of general deterioration. Physicians and nurses documented the following information in her chart. On the morning of her visit to the emergency room, the patient's son had visited and found her in a terrible state. She had been eating and drinking very little in the previous week, she was crying and rambling, she was incoherent and inappropriate when spoken to, and she kept switching the topics of conversation. She had also been incontinent of urine and feces.

Once admitted on the ward, the patient's nurse contacted the Clinical Nurse Specialist (CNS) to clarify Mrs. V.'s mental health status because she was requiring a lot of attention and was difficult to manage. The CNS assessed the patient's mental health status using the nine criteria operationalized in the CAM (Appendix). In the following paragraphs, the criterion being assessed is listed in parentheses.

Throughout the interview with the patient, the CNS observed that Mrs. V.'s level of consciousness fluctuated from alert to hyperalert (altered level of consciousness-fluctuation); she was disoriented in three spheres on and off (disorientation-fluctuation), and she was agitated and restless (agitation). The CNS also observed that she was unable to keep track of what she was told and was easily distractible (inattention). She could not even count backwards from 10. Furthermore, her conversation was rambling and irrelevant (disorganized thinking). Finally, after reviewing her chart, the CNS found that for 2 days, she was awake all night long and sleeping during the day (altered sleep-wake cycle).

The CNS discussed the patient with her nurse and physician. They both reported the same clinical observations. The CNS contacted Mrs. Vs son who added she had become dependent in all her basic and instrumental activities of daily living (decreased functional status) in the last 2 weeks. The son stated, "She had been managing very well at home. She was autonomous and doing her activities of daily living independently. She required only some assistance with her groceries, banking, and cleaning. Now, she can't function alone anymore. She does not make sense when she talks. I have observed an important change in her behavior in the last week" (acute onset).

The CNS went back to reassess Mrs. V. She had no recollection of her previous visit and had no idea of the reason for being hospitalized (memory impairment). The CNS noticed that she was still very agitated (agitation). She was seeing mosquitoes on the wall (visual hallucination). She stated, "These mosquitoes on the wall want to bite me."

After gathering all this information, the CNS filled out the CAM instrument. Mrs. V.'s mental health status assessment met all the criteria of the CAM questionnaire (Appendix). The CAM diagnostic algorithm (Sidebar on page 18) revealed that the patient was presenting the four required features of delirium (e.g., acute onset of confusion and fluctuation course, inattention, disorganized thinking, altered level of consciousness).

In the above case, the patient's behavior changed drastically. However, the following type of case is more difficult to detect and can he easily missed or misinterpreted by health care professionals.

Hypoalert Form of Delirium

Mr. B. came to the emergency room with an important weight loss of 80 pounds over a period of 6 months. The chart also revealed that he had no appetite and felt very fatigued lately. The CNS visited Mr. B. the day following his admission. The patient was only disoriented to the day and date (disorientation) and he could not remember his own phone number (memory impairment). After 10 minutes of conversation, the CNS did not observe any inattention or disorganized thinking. He was able to carry on a simple conversation and follow simple commands. He was mentally alert. He was still investing a lot of money in the stock market everyday. However, considering Mr. B's health status, the CNS decided to spend more time with him to assess his capacities to return home alone.

Because Mr. B. was responding very well in a structured interview, the CNS opted to use a non-structured interview. Therefore, the CNS asked open-ended questions and let him carry on the conversation. Mr. B's cognitive impairments emerged. He was inattentive, as he could not keep track of the purpose of the conversation (inattention). His thoughts were also very disorganized. He kept switching from one topic to the other (disorganized thinking). At some point he told the CNS that it was very dark for 3 o'clock, when in fact it was only 10 o'clock (disorientation). Finally, Mr. B. could not remember the purpose of the CNS's visit after only 20 minutes of conversation (memory impairment).

When the CNS read through his chart, no documentation of signs of confusion was written. The physician and the nurse caring for him reported that because of his alertness, his kindness, and his apparent capacity to function, they did not further investigate his mental status.

The CNS reassessed Mr. B. later on in the afternoon and the day after. His mental status kept fluctuating (e.g. he had difficulty keeping track of the content of the conversation [inattention] and he was incoherent in some occasions [disorganized thinking]). No hallucination or psychomotor agitation was observed. Throughout the conversation with Mr. B's girlfriend, the CNS was informed that he was not active lately. The patient's girlfriend stated, "He often stares into space and he moves very slowly (psychomotor retardation). He is usually more active." To clarify her assessment, the CNS asked Mr. B's girlfriend more precise questions. She reported that Mr. B. had been confused in the last 2 weeks. She stated, "On two occasions, he told me stories that did not make any sense. It never happened before (acute onset)."

After finishing her evaluation with the patient, health care professionals, and patient's girlfriend, the CNS completed the CAM instrument using the nine operationalized criteria (Appendix). Mr. B. met the following criteria: acute onset, inattention, disorganized thinking, disorientation, memory impairment, psychomotor retardation, and fluctuation. Using the CAM diagnostic algorithm (Sidebar on page 1 8), the nurse found that Mr. B. met the minimum required criteria (three of four) of delirium (i.e., acute onset and fluctuation course, inattention, disorganized thinking).

Such patients are often not identified, as they are withdrawn and still able to answer simple questions. Therefore, it is extremely important for health care professionals to investigate the patient's mental health status routinely and systematically, regardless of the appearance of the patient. It is also important to realize that assessing the patient's mental state once only might not capture all the features of delirium. A patient who is delirious may have lucid intervals (Sullivan & Foge!, 1986). The interviewer should assess the patient's mental state several times during the same day or on consecutive days, and use ail sources of information available such as an interview with the patient, the medical chart, or a proxy or the health care professionals caring for the patient. Zou et al. (1998) reponed there is a greater chance of detecting delirium when several sources of information are used, a structured instrument (CAM) is used, and the patient is assessed at multiple points in time.

NURSING IMPLICATIONS AND RECOMMENDATIONS

It is recommended that nurses assess elderly individuals' mental health status everyday so any change in a patient's behavior is identified promptly. The 24-hour work schedule of nurses facilitates a more comprehensive assessment of a patient's cognition than any other health care professional can perform. Nurses assume the best position to detect any subtle changes in a patient's health status.

Documentation of any changes in the elderly individual's behaviors becomes an excellent source of information about the onset of delirium or fluctuation of the patient's mental state. In fact, Milisen et al. (1998) reported that nurses have the most frequent and ongoing contact with the patient and can easily detect periods of fluctuation. Early recognition of delirium by nurses will have an important outcome on different aspects of the individual's life (Fick & Foreman, 2000). Mentes (1995) reported that nurses who intervene rapidly to eliminate the causative factors of delirium will decrease further morbidity and loss of function in their elderly patients.

Nurses' assessments and interventions will not only improve the quality of life of these elderly patients, they will also have an important impact in the present health care system. Inouye, Schlesinger, and Lydon (1999) estimated that decreasing the length of hospital stay by just 1 day, for individuals older than age 65 with delirium, would save more than $4 billion annually. Such outcomes should persuade nurses of the importance of their assessments and interventions.

It is also recommended that nurses use a structured approach when assessing a patient's mental status. Nurses' assessments should be performed similarly and reflect changes in a patient's mental status only. Inouye et al. (1990) reported that the use of the CAM instrument may facilitate recognition of delirium and lead to early intervention by health care professionals.

The CAM is a standardized and validated tool that can be used by individuals without specific training in psychiatry to quickly identify delirium. Finally, the CAM questionnaire (Appendix) can serve to systematize and record clinical observations. In using a structured approach to detect delirium routinely, nurses can better assess this complex health problem. They can be proactive in requesting appropriate treatments and in managing autonomously, the elderly individual's surroundings (Mentes, 1995).

Another important aspect to recommend is ongoing education of nursing staff to empower them when caring for this population and improve elderly individuals' quality of life. Mentes and Buckwalter (1998) proposed that on a Dementia Special Care Unit (SCU) well-trained staff can provide care that will have a positive outcome for residents with dementia, as well as preventing burnout and turnover.

Delirium can manifest itself in myriad ways that can be confusing to nurses and can be entirely missed. When the features of delirium are obvious and present alone (e.g. not superimposed on dementia), detecting delirium may be easy - the patient is disoriented, agitated, disorganized, and hallucinating. However, misinterpretation of these symptoms as a part of a dementing illness happens frequently. They both involve cognitive deficits and may be superimposed (Trzepacz, Baker, & Greenhouse, 1988).

Inouye and Charpentier (1996) and Pompei et al. (1994) have observed that hospitalized elderly individuals suffering from dementia or even a mild form of cognitive impairment are more at risk to develop delirium and less likely to be recognized and treated by practitioners (Pick & Foreman, 2000). Furthermore, when an elderly patient presents atypical behaviors, such as being extremely quiet or withdrawn, or exhibits the above symptoms to a lesser intensity, detecting delirium can become difficult. Because these patients do not become agitated, nurses may not see this new behavior as an acute change in the patient's mental health status. These patients are identified as being depressed most of the time.

CONCLUSION

Although delirium is recognized as an important health problem among hospitalized elderly patients, its detection by health care professionals can be challenging at times. Confusion has been considered a part of the aging process for a long time and is still a stigma for this growing segment of the population. As health care professionals, we must reevaluate our visions and beliefs about the way care is provided to the elderly population. Therefore, as the population ages, increased attention will be required to deliver care to this clientele.

Nurses are encouraged to perform mental assessments routinely and systematically to prevent further deterioration of mental state and complications. Fick and Foreman (2000) reported that early recognition of signs of confusion can improve the outcomes of individuals suffering from delirium. Use of the CAM by nurses may facilitate assessment of the mental status of older patients and enhance the ability to recognize the features of delirium. This process can be facilitated by evaluating elderly individuals within the context of their family and community (Gottlieb 8c Rowat, 1987), and strongly influence the nurse's capacity to detect and manage delirium in elderly patients. Finally, the literature is unanimous, delirium remains a phenomenon difficult to detect by health care professionals. To ensure a healthier way of living for this population, ongoing education is essential to increase nurse's knowledge and awareness of signs of delirium.

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10.3928/0098-9134-20010901-05

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