Recognition of delirium in ICU patients: a diagnostic study of the NEECHAM confusion scale in ICU patients

Delirium is a serious, high frequency complication in intensive care unit (ICU) patients (incidence: 40–82%) [1‐5], being defined as a transient organic mental syndrome characterised by a disturbance in awareness, cognition and attention [6]. These disturbances are frequently manifested in expressions of disorientation, memory impairment, disturbance in mental processes, motor unrest, sleep problems, anxiety and agitation. Abrupt onset and fluctuation of the symptoms are characteristic, and onset frequently occurs from within a few hours to a few days of hospital admission. Symptoms of delirium can present differently: in a hyperactive/hyper-alert form, a hypoactive/hypo-alert form, or a combination of these two [7]. The patient can be restless, agitated and aggressive. In the delirious state, the patient will often remove his or her lines, catheters and/or tube. Nurses are most familiar with the hyperactive/hyper-alert form and often overlook the hypoactive/hypo-alert type of patients [1], who are calm and sleepy, react slowly and seldom move. Sometimes they mumble to themselves or make inappropriate gestures. Research shows that >60% of all cases delirious patients, [8] go unrecognised by doctors and nurses. Systematic screening of cognitive functions is rare in general hospital practice [1] and a delirium is often not considered a potential medical emergency. Moreover, in elderly patients delirium symptoms are often mistaken for symptoms of dementia or another mental illness [9, 10]. Therefore these patients are treated either inadequately or not at all [2, 11, 12]. The consequences for the patient can be serious, entailing greater risk of morbidity and mortality, longer hospital stays, greater need for nursing care, and greater risk of complications, bodily injuries in general, and more frequent admission to nursing homes following discharge from hospital [1, 5, 13]. The high prevalence and the severity of the consequences emphasises the fact that delirium should be a major concern for ICU staff [8].

Nursing staff monitor the patient 24 h a day; with little effort they can enable early recognition of a delirium, and enhance the prognosis and benefits of any treatment [1, 14, 15]. To achieve this, there is a need to increase awareness, and to develop and implement valid, user-friendly assessment tools [4].

A nursing observation scale was tested for use in ICU patients. This scale, the NEECHAM confusion scale, proved valid and reliable in several studies in the general hospital population [16‐18, 21, 22]. A small pilot study in 19 ICU patients [19] gave positive results.

The aim of our study was to extend testing of the NEECHAM confusion scale for use in ICU patients by determining its reliability, validity and user-friendliness in monitoring this group of patients.

An overall score of ≤ 19 points on the NEECHAM, indicating moderate to severe acute confusion and/or delirium, was found in 49 (19.4%) ratings. An overall score of between 20 and 24, indicating mild or early acute confusion and/or delirium, was found in 40 (15.8%) ratings.

All other ratings (n = 164, 64.8%) with scores of 25 or higher, indicated normal cognitive functioning. In 72 (43.9%) of these, a NEECHAM score of 25 or 26 was found. This score indicates non-acute confusion and/or delirium, however, and the presence of high risk.

The psychometric characteristics of the NEECHAM confusion scale of this ICU study are generally consistent with validity research previously reported for the general hospital population. The interrater's reliability between two raters (kappa 0.60) is, as in Neelon's research [16] (0.65), fairly good. The internal consistency of the scale is good, as it is in all the other studies [16‐19] (Cronbach's alpha ≥ 0.81), and the physiological functions did not correlate with the total item coefficient of correlation. On the basis of both the results from the internal consistency and from the principal component analysis (PCA), one might suggest that the vital functions and oxygen saturation be removed from the NEECHAM confusion scale. Like the studies of Neelon [16] and Milisen [18], two components were found after a PCA. Neelon [16], however, divided the instrument into three subscales, which appears to imply that there are three components.

The chi-square value of 67.5 (p = 0.001) between the DSM-IV-TR criteria and the NEECHAM scale show good concurrent validity. The sensitivity is just as high (> 90%) as in other studies; however, we found the specificity of 82.8% to be higher in this study than in that of Neelon (78%) [21].

The user-friendliness of the NEECHAM scale has not been previously examined in this way. The ICU nurses rated the user-friendliness generally as good. However, the scale in its present form is not suitable for use with intubated ICU patient. Adjustment of two items for non-verbal communication should be further studied.

Possible limitations of the present study could be the reliability of the gold standard (diagnosis by a psychiatric intern), and the collection of the data by nurses during regular care. Both of these elements, however, are representative of clinical reality and therefore enhance the implementation of the results.

We conclude that the NEECHAM confusion scale has good psychometric characteristics and is easy to use with ICU patients who are not being intubated. In view of the high diagnostic value of the scale, the instrument is promising for screening delirium in ICU. Further study of the scale is needed to adapt it for use with intubated patients. The results of the PCA in this study suggest that the items with regard to the physiological condition could be removed. This would give a reduction of the scale from nine to six items which would enhance its user-friendliness, but more work is needed to confirm this conclusion.

Delirium in ICU patients is a serious and frequent adverse event. Current ICU clinical practice does not routinely screen for behavioural changes, as a result of which many delirious patients are not recognised in time. The NEECHAM confusion scale offers an opportunity to screen behaviour with little stress on either the seriously ill ICU patients or the busy ICU nurses. The instrument is simple, repeatable, and quick to apply on the basis of observation during regular care. The ready availability of an assessment tool is the first step in enhancing the quality of care for this group of patients. Improvement in detection methods and increasing knowledge, however, is not sufficient. To ensure use of these methods not only requires the requisite knowledge, but also acknowledgement of the emergency that a delirium can present [9].