Delirium is defined as a mental disorder of acute onset with a fluctuating course, characterized by disturbances in consciousness, attention, orientation, memory, thought, perception and behaviour [1
]. It is a common problem among elderly patients admitted to acute and long-term care (LTC) facilities, with its prevalence ranging from 9.6% to 89% [2
]. The wide variation in these estimates is likely related to methodological issues such as differences in the population under study, the type of clinical settings in question and the criteria used for diagnosis. For example, higher prevalence was found in cohorts composed of hospitalized elderly patients with pre-existing cognitive impairment [5
It is now recognised that delirium in older patients is associated with numerous negative outcomes. Consequences for elderly patients who develop delirium include decline in their functional and cognitive status as well as increased morbidity and mortality rates [7
]. Furthermore, older patients with delirium have been found to be at greater risk for pressure ulcers, falls and pneumonia [11
]. Deleterious effects of delirium are not limited to patient outcomes. It also represents a great source of distress for family members, an increased nursing time per patient and higher costs for hospitals [12
]. Moreover, since delirium can be an early indication of an underlying medical condition such as sepsis or a myocardial infarction, not recognising it may prove detrimental for the patient who may then become critically ill [13
Early recognition of delirium allows not only prompt management of the underlying medical cause but also permits the rapid implementation of targeted interventions against predisposing and precipitating individual risk factors, thereby resulting in a reduction of delirium severity, duration and consequences [3
Given its high prevalence rates, associated complications and potential underlying medical emergency, delirium and its detection should be of major concern for clinicians and especially for nurses, who spend more time at the patient's bedside.
Despite its clinical importance, delirium among older hospitalized patients often goes undetected. Several studies have studied the delirium detection rate of nursing staff in different clinical settings and recognition rates as low as 31% have been reported [3
Some studies have identified factors associated with delirium undetected by nurses in hospital settings and although their results cannot be generalized to older residents in LTC settings, a review of these is worthwhile. These factors can be divided into three groups: factors related to the characteristics of: 1) the delirium itself, 2) the elderly, and 3) the bedside nurse.
Two delirium-related factors have been linked to delirium that is undetected by nurses among elderly hospitalized patients: its forms and its fluctuating nature. Delirium can be classified into four different subtypes depending on its clinical manifestation: the hypoactive form (characterized by lethargy, slow motor reaction, reduced interaction with surroundings), the hyperactive form (characterized by restlessness, hyper-vigilance and aggressiveness), a combination of both (mixed) or the absence of both (normal motor pattern). Because patients with the hypoactive form of delirium are less likely to demonstrate behavioural disturbances interfering with nursing care than are patients with the hyperactive form, the hypoactive form often goes unrecognised by nurses [19
]. Since the hypoactive form is more prevalent among older patients [1
], such non-recognition constitutes an important issue. In addition to this, the fluctuation of symptoms during the course of the day that is characteristic of episodes of delirium, makes its detection even more challenging [1
]. In this sense, delirium may go undetected if the evaluation is not based on observations gathered over a sufficient period of time.
With regard to patient characteristics, three factors have been associated with the delirium undetected by nurses. Inouye et al. [20
] have shown that having impaired vision, being over 80 years of age and pre-existing cognitive impairment are all factors linked to increased risk of under-recognition. The importance of prior cognitive impairment for under-recognition of delirium was further confirmed in a study by Fick and Foreman [5
]. Although dementia and delirium are two distinct entities, the overlap of some of the symptoms may make delirium detection more difficult, especially if the individual assessing it lacks proper training.
Undetected delirium has also been found to be linked to nurse-related factors such as a lack of knowledge about delirium and how to detect it [3
]. For example, nurses were found to frequently use the term "confused" and "acute confusion" inappropriately [22
]. Furthermore, the lack of awareness among the nursing profession of the clinical importance of delirium was also found to be involved in this situation [14
In addition to the aforementioned factors, some authors have argued that under-recognition of delirium likely reflects a poor conceptualization of delirium and consequently scientists in general should also take some ownership of the problem [23
As already mentioned, most studies on the detection of delirium have been carried out in hospital settings. Expanding our knowledge about delirium and the way nurses go about detecting it in elderly residents in LTC facilities, is essential to being able to offer quality health care to this population. Moreover, given the high prevalence of dementia in LTCS, efforts should be made to target this very frail and unique population. To the best of the authors' knowledge, there has been no study to date examining the detection rate of delirium and its associated factors among seniors with pre-existing dementia residing in LTC facilities. As the general population ages, the prevalence of delirium among this specific population is likely to increase [14
], as is the risk of under-recognition of delirium and this underscores the need to fill this gap in our knowledge. The objectives of the present study are:
1) To determine the rates for nurse-detection of delirium among seniors with pre-existing dementia in LTC facilities.
2) To identify those delirium symptoms that are most challenging for nurses to detect.
3) To identify those factors associated with delirium that goes undetected by nurses among this specific population.