Delirium in the intensive care unit: assessment and management

A significant portion of critical care patients experience delirium. This form of acute brain dysfunction is associated with increased hospital stay, increased mortality, and greater long-term cognitive deficits. Critical care nurses are on the frontline with these patients and can make a significant impact on patient outcomes, including reducing the negative outcomes and experience of delirium. It is, therefore, imperative that nurses be equipped with a solid knowledge base of understanding delirium, which includes what has been reported specifically unique to delirium in the intensive care unit. This article will provide an overview of delirium and describe an interdisciplinary model of care combining multiple evidence-based practice strategies that nurses can and should use to help systematically reduce modifiable delirium risk factors. In addition, this article will provide an overview of recent reports concerning pharmacologic management of delirium in the intensive care unit.     

Development of a scale measuring the difficulties faced by nurses who care for patients with delirium in intensive care units

BackgroundDelirium in patients in the intensive care unit is associated with adverse outcomes. Nurses experience many difficulties in caring for those with delirium, which can lead to nurse burnout, prevent effective care for patients, and negatively impact the patient. The identification of factors creating challenges for nurses is, therefore, important to enable intervention.ObjectivesThe aim of this study was to develop a new scale to assess the difficulties faced by nurses caring for patients with delirium in the intensive care unit and to examine its reliability and validity.MethodsWe based our draft scale items on literature reviews and interviews. Four experts evaluated the collected items. After a pilot study, 211 nurses working in intensive care units in Japan completed the questionnaire. Subsequent statistical analysis of results included factor validity, construct validity, known-group validity, internal consistency, and test–retest reliability.ResultsExploratory factor analysis extracted a scale of 33 items with eight factors and an additional scale of four items with one factor. The analysis of construct validity suggested a possible association with the Strain of Care for Delirium Index. In the known-group validity, a comparison with two groups based on experience in the intensive care unit found significant differences among the five factors. Internal consistency (Cronbach's α = 0.68–.87) and test–retest reliability (intraclass correlation coefficients = .46–.62) were confirmed.ConclusionWe developed a difficulty scale for nurses caring for patients with delirium in the intensive care unit and confirmed its reliability and validity. The difficulty factors were developed with the intention to identify educational interventions for nurses and the introduction of new organisational resources, such as manpower and providing emotional support and feedback to nurses.     

Risk factors and outcomes of sepsis-associated delirium in intensive care unit patients: A secondary data analysis

ObjectiveTo identify the risk factors of sepsis-associated delirium and determine their effect on intensive care unit adult patient outcomes.DesignA secondary analysis of data from system development studies.SettingKorean intensive care unit patients in a university hospital who were diagnosed with sepsis.MethodsThe risk factors for sepsis-associated delirium were classified into patient factors and sepsis clinical features and were analysed using hierarchical logistic regression analysis. Outcomes included in-hospital mortality, 30-day in-hospital mortality, duration of mechanical ventilation, length of stay in the intensive care unit, length of hospital stay, total medical expenses, discharge placement, re-hospitalisation and visits to the emergency department after discharge.ResultsThe risk factor for sepsis-associated delirium including patients aged 65 ≥years, dependent activity and high nursing needs (patient factors), low level of consciousness, tachypnoea, and thrombocytopaenia (clinical features of sepsis). Use of vasopressors/inotropes and albumin decreased the risk of sepsis-associated delirium. Mechanical ventilation duration was prolonged and discharge to skilled nursing facilities was increased by sepsis-associated delirium.ConclusionsThe risk factors for sepsis-associated delirium increased as the severity of condition for patients with sepsis increased. Early identification of risk factors associated with sepsis-associated delirium may improve patient outcomes.     

The association between nurse-administered midazolam following cardiac surgery and incident delirium: An observational study

BackgroundPost-operative delirium after cardiac surgery is an adverse event that affects patients’ recovery and complicates the delivery of nursing care. Numerous risk factors for delirium are uncontrollable; however, nurses’ pro re nata drug administration of sedatives may be a controllable risk factor.ObjectivesThis study examined the relationship between nurses’ pro re nata administration of midazolam hydrochloride to cardiac surgery patients and the development of post-operative delirium.DesignObservational study.SettingCardiac surgery intensive care and nursing units of a tertiary care center in Vancouver, Canada. Participants: 122 male and female patients requiring non-emergent surgery for coronary artery disease or valvular heart disease who did not have pre-existing cognitive impairment, severe hearing or visual impairment, substance misuse, alcohol intake exceeding 7 drinks per week, or renal impairment requiring hemodialysis.MethodsPatients were assessed for delirium, on three occasions, with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) during the first 72 h after surgery and through reviews of physicians’ notes. Risk factor and midazolam dosage data were collected from medical records.Results77.9% of the patients in this sample received midazolam hydrochloride post-operatively. The prevalence of delirium ranged from 37.7% to 44.3%. Almost all of the dosages of midazolam (85–87%) were given before the first indication of delirium; that is, most of the patients had received their entire dosage before the first signs of delirium were detected. Bivariate analysis with logistic regression models revealed that for every additional milligram of midazolam administered, the patients were 7–8% more likely to develop delirium. Multivariate logistic regression models demonstrated that the magnitude of the association between midazolam dosage and delirium was not confounded by established risk factors including age and peripheral vascular disease.ConclusionNurses play an important role in the prediction, assessment and prevention of post-operative delirium. Sedatives should be administered with caution because they increase a patient's risk of developing delirium. Nurses’ decisions regarding sedation administration must be informed by empirical knowledge, accurate assessment data and clear rationale with consideration of how these actions may contribute to the development of delirium.     

Nursing experience with reducing delirium in a hospitalized elderly patient

This article describes an experience of providing nursing care to an eighty year-old patient with urinary tract infection (UTI). The author cared for this patient in the role of clinical geriatric nurse specialist from May 11 to 23 in 2005. Through comprehensive assessment, careful review of medical records, contact with family and nursing home healthcare workers, it was determined that the patient's cognition and physical function declines were due to delirium resulting from the last time the patient had been hospitalized in the intensive care unit (ICU). In order to prevent incidents of delirium, three nursing goals were set: controlling infection, avoidance of delirium recurrence, and recovery of prior levels of physical function and self-care ability. Nursing interventions used included UTI control, tube and catheter removal as early as possible, control of environmental factors, and muscle strength and exercise training. After two weeks of care, the patient could take food orally and the nasogastric (NG) tube had been successfully removed. Physical function and self-care ability improved from "dependent" to "partial assistance". Although UTI was controlled, removal of the foley tube failed due to prostate hypertrophy. No delirious event occurred during hospitalization and cognitive functions improved. From this experience, early assessment and intervention should be conducted for high-risk elderly patients in order to prevent delirious events and declines in cognitive and physical functions. The author hopes this case report will prove a useful reference to nurses charged with caring for elderly patients at risk for delirium.     

Self-efficacy of caring for patients in the intensive care unit with delirium: Development and validation of a scale for intensive care unit nurses

BackgroundImproving the self-efficacy of intensive care unit nurses for delirium care could help them adapt to the changing situation of delirium patients. Validated measures of nurses' self-efficacy of delirium care are lackingObjectivesThe objective of this study was to develop a Delirium Care Self-Efficacy Scale for assessing nurses' confidence about caring for patients in the intensive care unit and to examine the scale's psychometric properties.MethodsDraft scale items were generated from a review of relevant literature and face-to-face interviews with intensive care unit nurses; content validity was conducted with a panel of five experts in delirium. A group of nurses were recruited by convenience sampling from intensive care units (N = 299) for item analysis of the questionnaire, assessment of validity, and reliability of the scale. Nurse participants were recruited from nine adult critical care units affiliated with a hospital in Taiwan. Data were collected from August 2020 to July 2021.ResultsContent validity index was 0.98 for the initial 26 items, indicating good validity. The critical ratio for item discrimination was 14.47–19.29, and item-to-total correlations ranged from 0.67 to 0.81. Principal component analysis reduced items to 13 and extracted two factors, confidence in delirium assessment and confidence in delirium management, which explained 66.82% of the total variance. Cronbach's alpha for internal consistency was 0.94 with good test–retest reliability (r = 0.92). High scale scores among participants were significantly associated with age (≥40 years), work experience in an intensive care unit (≥10 years), delirium education, and willingness to use delirium assessment tools.ConclusionsThe newly developed Delirium Care Self-Efficacy Scale demonstrated acceptable reliability and validity as a measure of confidence for intensive care nurses caring for and managing patients with delirium in the intensive care unit.     

The training needs of Korean intensive care unit nurses regarding delirium

ObjectivesThe aim of this study was to investigate high-priority training needs by analysing the perceived importance and self-reported performance of nurses’ delirium care competency.DesignA cross-sectional survey with a convenience sample of 255 Korean intensive care units nurses.SettingIntensive care units in the Republic of Korea.Main outcome measuresIntensive care unit nurses’ delirium care competency.ResultsExploratory factor analysis of the Nurse Delirium Care Competency Scale showed a six-factor structure, which accounted for 67.51% of the variance in nurses’ delirium care competency: management algorithm, prevention, communication, nursing management, assessment, and collaboration. The self-reported performance scores of all six factors were significantly lower than their perceived importance scores. The delirium assessment factor was identified as a high training priority on the importance-performance matrix for new graduate nurses.ConclusionTraining programmes should be developed considering the six delirium care competency factors identified in this study. Further, nurse educators must adopt active educational modalities such as case-based small group learning and simulation-based learning to improve nurse competency in recognising and managing delirium.     

Use of a validated delirium assessment tool improves the ability of physicians to identify delirium in medical intensive care unit patients

OBJECTIVE: Although medical intensive care unit nurses at our institution routinely use the Intensive Care Delirium Screening Checklist (ICDSC) to identify delirium, physicians rely on traditional diagnostic methods. We sought to measure the effect of physicians' use of the ICDSC on their ability to detect delirium. DESIGN: Before-after study. SETTING: Medical intensive care unit of an academic medical center. PATIENTS AND PARTICIPANTS: A total of 25 physicians with >or=1 month of clinical experience in the medical intensive care unit conducted 300 delirium assessments in 100 medical intensive care unit patients. MEASUREMENTS AND MAIN RESULTS: Physicians sequentially evaluated two patients for delirium using whatever diagnostic method preferred. Following standardized education regarding ICDSC use, each physician evaluated two different patients for delirium using the ICDSC. Each physician assessment was preceded by consecutive, but independent, evaluations for delirium by the patient's nurse and then a validated judge using the ICDSC. Before (PRE) physician ICDSC use, the validated judge identified delirium in five patients; the physicians and nurses identified delirium in zero and four of these patients, respectively. The physicians incorrectly identified delirium in four additional patients. After (POST) physician ICDSC use, the validated judge identified delirium in 11 patients; the physicians and nurses identified delirium in eight and ten of these patients, respectively. The physicians incorrectly identified delirium in one patient. After physician ICDSC use, agreement improved between both the physicians and validated judge (PRE kappa = -0.14 [95% confidence interval {CI} = -0.27 to -0.02] to POST kappa = 0.67 [95% CI = 0.38 to 0.96]) and physicians and nurses (PRE kappa = -0.15 [95% CI = -0.29 to -0.02] to POST kappa = 0.58 [95% CI = 0.25 to 0.91]). Nurses vs. validated judge agreement was strong in both periods (PRE kappa = 0.65 [95% CI = 0.29 to 1.00] and POST kappa = 0.92 [95% CI = 0.76 to 1.00]). CONCLUSIONS: Use of the ICDSC, along with education supporting its use, improves the ability of physicians to detect delirium in the medical intensive care unit.     

Competence assessment of nursing graduates of Jordanian universities

This cross‐sectional survey assessed the level of competence of nursing graduates of Jordanian universities (2001–2004 cohorts) in relation to the type of university, sex, hospital type, and working area. A convenience sample (n = 258) of full‐time nurses (6 months–4 years' experience) was selected from public, private, and teaching hospitals. A specifically designed tool with a rating scale of 1–5 was used to evaluate the nurses' competence in five nursing competencies (management, professionalism, problem‐solving, nursing process, and knowledge of basic skills). The findings showed a satisfactory competency level with no significant differences related to the type of university or sex. General ward nurses scored significantly better than those in intensive care units in relation to management, professionalism, and nursing process, while the teaching hospital nurses showed significantly better performance in professionalism and management skills than did the nurses in the other two sectors. We recommend that nurse recruitment policies should consider individual competencies rather than innate characteristics in their selection of employees.     

Nurses' and physicians' approaches to delirium management in the intensive care unit: A focus group investigation

BackgroundDelirium in the intensive care unit (ICU) is common, but reliable evidence-based recommendations are still limited.ObjectivesThe aim of our study was to explore nurses' and physicians' experiences and approaches to ICU delirium management.MethodOur study had a qualitative multicentre design using interdisciplinary focus groups and framework analysis. Participants were strategically selected to include nurses and physicians with experience in delirium management at five ICUs in four out of five regions in Denmark.ResultsWe conducted eight focus group interviews with 24 nurses and 15 physicians; median ICU experience was 9 years (range 1–35). The main issues identified were (1) the decision to treat or not to treat ICU delirium based on delirium phenotype, (2) the decision to act based on experience or evidence, and (3) the decision to intervene using nursing care or medications. ICU delirium was treated with pharmacological interventions in patients with signs of agitation, hallucinations, and sleep deprivation. The first choice of agent was haloperidol or olanzapine. Agitated and combative patients received benzodiazepines, propofol, or dexmedetomidine. Calm delirious patients were managed with non-pharmacological solutions. Physicians recommended pro re nata (PRN) orders to prevent over medication, whereas nurses opposed PRN orders with the fear that it would increase their responsibilities.ConclusionOur study described an algorithm of contemporary delirium management in Danish ICUs based on qualitative inquiry. When evidence-based solutions are unclear, nurses and physicians rely on personal experience, collective experience, and best available evidence to determine which patients to treat and what methods to use to treat ICU delirium. Delirium management still needs clear objectives and guidelines with evidence-based recommendations for first-line treatment and subsequent treatment options.     

Delirium and use of sedation agents in intensive care

Aim: The aim of the review was to consider the relationship between delirium and aspects of sedative and analgesic drug use in mechanically ventilated intensive care patients. The basis for routine delirium screening and the implications for nurses are discussed along with a brief outline of the treatment of delirium. Background and context: Delirium is common in intensive care patients and like other markers of organ failure is associated with worse outcomes. The risk of developing delirium is dependent on the patients’ individual vulnerability and on the burden of precipitating factors they are exposed to. Detection of delirium in intensive care patients is often difficult and requires the regular use of a validated screening tool. Intensive care patients are exposed to multiple delirium risk factors, and sedative and analgesic agents present an important subgroup, which we can attempt to control. Sedative and analgesic drug choice, their mode of administration, monitoring and titration have consequences for delirium development. Method: Literature review. Conclusions: Sedative and analgesic drugs have an important role in the prevention and treatment of delirium in intensive care patients. Routine delirium screening should be included as part of sedation monitoring practice. When detected, treatment is focused on the prompt correction of precipitating factors, non‐pharmacological interventions and appropriate drug therapy for symptom control.     

Nursing assessment as an effective tool for the identification of delirium risk in older in‐patients: A case–control study

Aims and objectives

To evaluate the usefulness of comprehensive nursing assessment as a strategy for determining the risk of delirium in older in‐patients from a model of care needs based on variables easily measured by nurses.

Background

There are many scales of assessment and prediction of risk of delirium, but they are little known and infrequently used by professionals. Recognition of delirium by doctors and nurses continues to be limited.

Design and methods

A case–control study. A specific form of data collection was designed to include the risk factors for delirium commonly identified in the literature and the care needs evaluated from the comprehensive nursing assessment based on the Virginia Henderson model of care needs. We studied 454 in‐patient units in a basic general hospital. Data were collected from a review of the records of patients’ electronic clinical history.

Results

The areas of care that were significant in patients with delirium were dyspnoea, problems with nutrition, elimination, mobility, rest and sleep, self‐care, physical safety, communication and relationships. The specific risk factors identified as independent predictors were as follows: age, urinary incontinence, urinary catheter, alcohol abuse, previous history of dementia, being able to get out of bed/not being at rest, habitual insomnia and history of social risk.

Conclusions

Comprehensive nursing assessment is a valid and consistent strategy with a multifactorial model of delirium, which enables the personalised risk assessment necessary to define a plan of care with specific interventions for each patient to be made.

Relevance to clinical practice

The identification of the risk of delirium is particularly important in the context of prevention. In a model of care based on needs, nursing assessment is a useful component in the risk assessment of delirium and one that is necessary for developing an individualised care regime.     

Prevention, detection and intervention with delirium in an acute care hospital: a feasibility study

Background. The prevalence of delirium in acute care hospitals ranges from 5–86%. Delirious patients are at greater risk of negative health outcomes and their care is often more costly. Aim. To determine the feasibility of a full‐scale trial to test the effectiveness of an intervention designed to improve delirium prevention, detection and intervention in an acute care hospital. Design. A delirium prevention protocol was designed by an interdisciplinary group of clinicians and implemented on intervention unit patients who passed a mental status screen, were at high risk for delirium according to the modified NEECHAM scale, and met other eligibility criteria. These patients were reviewed at daily interdisciplinary team meetings and team recommendations were placed in the patient’s chart. On the usual care unit, physicians were notified if their patients were at high risk, but the delirium protocol was not implemented. Methods. The delirium protocol was pilot tested with 35 high risk patients on an Acute Care for Elders (ACE) unit. Outcomes were compared to 35 high risk patients on a similar medical unit without the delirium protocol. Results. The main outcome examined whether there is a difference in average day 3 modified NEECHAM scores comparing the intervention and control groups. The mean modified NEECHAMs on day 3 were not statistically significantly different (intervention group 3.76 and control group 3.24) (P= 0.368). Baseline NEECHAM scores did not correlate well with development of delirium (P = 0.204). A history of confusion during a previous hospitalization was the strongest predictor of developing delirium during the current hospitalization. Conclusion. This pilot study was not powered to detect an effect of the intervention, however, feasibility for a fully powered trial was established. Relevance to clinical practice. Completion of the NEECHAM screen every shift was not considered burdensome for either nurses or patients and may help identify acute delirium.     

Satisfaction with nursing care and work during a year of clinical supervision and individualized care. Comparison between two wards for the care of severely demented patients

An intervention study was set up to explore the effects of the implementation of planned individualized care and regular systematic clinical supervision regarding nurses' degree of satisfaction with nursing care and work. All nurses on two similar wards caring for severely demented patients participated as experimental ward (EW) (n = 19) and control ward (CW) (n = 20). Data were collected before intervention and at 6 months and 12 months during intervention, by means of a questionnaire developed in Sweden which assesses aspects of satisfaction with nursing care and work. Analysis was performed by means of principal component analysis, Wilcoxon rank sum test and Friedman two-way ANOVA. The baseline data showed no significant differences in the responses from the nurses on the two wards; they were found to be more satisfied than dissatisfied with their job although recognition from management was poor. During the intervention, the experimental ward nurses' experience of praise, professional growth, autonomy and quality of care, as well as their feeling of co-operation with colleagues and comfort improved significantly, while no changes occurred on the control ward. The quality of the written documentation on patients' needs and care improved significantly, and the experimental ward nurses also rejected significantly more strongly that their knowledge about patients and work was unsatisfactory. Their improved satisfaction with nursing care and work was believed to be related to the support they received in cognitive and emotional coping, the possibility of reflective learning and the change in management style associated with intervention.     

Practice and clinical decision-making autonomy among Hellenic critical care nurses

BACKGROUND: Nursing autonomy has been associated with better patient-outcomes; therefore, it is a priority for critical care nursing management. Low authority has been a persistent complaint of Hellenic intensive care unit nurses; however, issues of nursing autonomy have not been previously addressed empirically in Hellas. PURPOSE: To investigate: (1) the perceived contribution to clinical decision-making, (2) the degree of autonomy in technical tasks, and (3) factors related to practice autonomy in critical care nurses in Hellas. Additionally, because of the lack of sufficient tools, this study also aimed to construct and to validate a new tool for assessing practice and clinical decision-making autonomy among Hellenic intensive care unit nurses. MATERIALS AND METHODS: A Hellenic intensive care nursing autonomy scale, focused on technical aspects of care, was developed through literature review, a panel of experts and a pilot study in a random sample of 120 respondents. Items were refined by factor analysis, which revealed three major conceptual categories of autonomy: (1) basic technical, (2) advanced technical, and (3) clinical decision. Hellenic intensive care nursing autonomy (Likert 4, range: 38-152), was distributed to all nurses employed in intensive care units in Hellas (n = 807; attrition: 27%). Comparisons, correlation and multivariate regression were employed. RESULTS: The Hellenic intensive care nursing autonomy scale exhibited appropriate reliability (Cronbach's alpha = 0.86) and validity properties. Autonomy scores were moderate (mean: 105.24 +/- 9.58). Highest autonomy was attributed to basic technical tasks, followed by advanced technical tasks and decision-making. Male gender and higher education were predictors of higher overall, advanced technical and decision-making autonomy (P = 0.01). Bachelor degree graduates scored higher in decisional autonomy (P = 0.03). Intensive care unit experience and type of intensive care unit were also important determinants of decisional autonomy (P = 0.02). CONCLUSIONS: The results revealed moderate autonomy in technical tasks and low decisional autonomy among Hellenic intensive care unit nurses. Factors related to the educational preparation of nurses, gender issues and institutional characteristics might hinder intensive care unit nurses' autonomy in Hellas.     

Delirium in an intensive care unit: a study of risk factors

OBJECTIVES: (1) To establish risk factors for the development of delirium in an intensive care unit (ICU) and (2) to determine the effect of delirium on morbidity, mortality and length of stay. DESIGN: Prospective study. SETTING: Sixteen-bed medical/surgical ICU in a university hospital. PATIENTS: Two hundred and sixteen consecutive patients admitted to the ICU for more than 24 h during 5 months were included in the study. INTERVENTIONS: Medical history, selected laboratory values, drugs received and factors that may influence patient psychological and emotional well-being were noted. All patients were screened with a delirium scale. A psychiatrist confirmed the diagnosis of delirium. Major complications such as self-extubation and removal of catheters, as well as mortality and length of stay were recorded. RESULTS: Forty patients (19%) developed delirium; of these, one-third were not agitated. In the multivariate analysis hypertension, smoking history, abnormal bilirubin level, epidural use and morphine were statistically significantly associated with delirium. Traditional factors associated with the development of delirium on general ward patients were not significant in our study. Morbidity (self-extubation and removal of catheters), but not mortality, was clearly increased. CONCLUSION: Predictive risk factors for the development of delirium in studies outside the ICU may not be applicable to critically ill patients. Delirium is associated with increased morbidity. Awareness of patients at risk may lead to better recognition and earlier intervention.     

Individual delirium symptoms: do they matter?

OBJECTIVES: To evaluate the impact of individual manifestations of delirium on outcome, describe them in critically ill adults, and validate nurses' bedside item assessments from the Intensive Care Delirium Screening Checklist (ICDSC). DESIGN: Prospective study. SETTING: Single 16-bed medical/surgical university hospital intensive care unit. PATIENTS: Six hundred consecutive patients admitted to the intensive care unit for >24 hrs. INTERVENTIONS: All patients were evaluated with the eight-item ICDSC throughout their intensive care unit stay. In all patients scoring positive on any ICDSC item, individual checklist items were tallied throughout the intensive care unit stay and assessed for impact on mortality. In addition, when the ICDSC score indicated delirium (> or = 4 of 8), the subsequent overall frequency of each item was also independently documented to describe delirious patient symptoms. ICDSC items were tested for discrimination between delirious and nondelirious patients. Throughout the study, the validity of bedside delirium assessments was assessed in 30 nurses. MEASUREMENTS AND MAIN RESULTS: We were able to assess 537 patients. In nondelirious patients, psychomotor agitation by ICDSC assessment was associated with a higher risk of mortality after adjustment for Acute Physiology and Chronic Health Evaluation, age, and the presence of coma. One hundred eight-nine patients (35.1%) developed delirium (i.e., ICDSC score > or = 4). On presentation (and throughout the intensive care unit stay), the most frequent features of delirium were inattention, disorientation, and psychomotor agitation. Each ICDSC item was highly discriminating between delirious vs. nondelirious patients. Correlation between gold standard adjudicators and nurses for the overall bedside evaluations of delirium were excellent (Pearson's correlation R = 0.924, p < .0005). Individual symptom evaluation by nurses varied: Alteration in level of consciousness was poorest (R = 0.681, p < .0005), and both disorientation and hallucinations evaluated best (R = 1.000). CONCLUSIONS: In nondelirious patients, agitation was associated with a higher risk of mortality. Each of the eight ICDSC items is highly discriminating for the diagnosis of delirium, suggesting that any screening or diagnostic scales should incorporate them. Quality assurance and educational efforts should, therefore, emphasize independent assessment of the individual features of delirium.