Most reports in the literature suggest that predisposing vulnerabilities for elder patients pose the largest risk for developing delirium (see Schuurmans, Duursma, & Shortridge-Baggett 2001 for review). Increasing age, pre-existing cognitive impairment, severe illness and dehydration, or comorbidities have all been suggested as important risk factors (Schuurmans et al. 2001). Inouye and Carpentier (1996) studied factors occuring after hospital admission that might predict the onset of acute confusion.
They identified five precipitating factors: use of physical restraints, malnutrition, more than three medications recently prescribed, use of bladder catheter, and any iatrogenic event (treatments or diagnostic procedures). They found that if scores of one point were attributed to each of these factors, then the potential for developing delirium could be calculated. Patients were at low risk if they scored 0 points (only 3% developed delirium). Intermediate-risk patients scored 1 to 2 points and had a risk of developing delirium of 20%. High-risk elders who scored 3 or more points were found to have a 59% chance of becoming acutely confused over the next 24 hours. Their research may prove important for identifying elders at risk; they concluded:
A simple predictive model based on the presence of five precipitating factors can be used to identify elderly medical patients at high risk for delirium. Precipitating and baseline vulnerability factors are highly interrelated and contribute to delirium in independent substantive, and cumulative ways (Inouye & Charpentier 1996:852). Incidence and tools for assessment Incidence rates reported for elderly hospitalised patients with delirium vary considerably.
This wide variance is thought to be related to the different research methodologies and diagnostic criteria used (Mentes et al. 1999). There were a variety of patients included or excluded in each of the studies (cut-off age for inclusion varied and patients exhibiting delirium when admitted to hospital where sometimes included, sometimes not). The setting for the research also varied with medical or surgical wards, emergency departments and either smaller or larger hospitals serving as the setting for research (Mentes et al. 1999). Schuurmans et al. (2001) reviewed the literature to find that reported rates vary between 5% and 51.5%, with a number of researchers reporting elderly delirium incident rates to be roughly 25%. These figures attest to the pervasive nature of elderly delirium in hospitals.
Other factors contributing to variable rates of incidence include the variety of assessment tools used and the skill of those doing assessments. The Clinical Assessment of Confusion A (CAC-A) scale, the Confusion Rating Scale (CRS), and the NEECHAM Confusion scale are diagnostic tools developed to detect delirium. Of these the NEECHAM Confusion scale is considered to be most reliable (Schuurmans et al. 2001).
However, this scale can not differentiate between chronic confusion, as seen with various dementing diseases, and acute confusional states (Schuurmans et al. 2001). The Confusion Assessment Method (CAM) was designed to differentiate between the two confusional states, but has shown varying degrees of reliability (Schuurmans et al. 2001). For the most part, this assessment tool has a tendency for the inclusion of false-positive results (Laurila, Pitkala, Strandberg, & Tilvis 2002). It has been suggested that CAM (see Appendix 1) is a quick and easy to use tool for screening, but that patients scoring positive for acute confusion should be further assessed using the Diagnostic and Statistical Manual of Mental Disorders (DSM), edition IV released by the APA in 1994 and presented below (cited in APA 1999):
If nurses fail to recognise delirium in the elderly as a sign of potentially life-threatening complications, then underlying, treatable medical causes will not be pursued. According to McCarthy (2003a), a staggering 33% to 95% of patients with acute confusion go unrecognised, or at least undocumented. Foreman (1996) reported that as many as 7 out of 10 patients who have delirium go unnoticed through hospital systems. While a lack of education on the part of nurses, inefficient diagnostic tools, or failure to assess patients on a routine basis may contribute to the low reporting or recognition of delirium, McCarthy (2003b:203) proposes that “the ability of nurses to recognize acute confusion and to distinguish it from dementia can be attributed to their personal philosophies about aging.”
McCarthy’s research (2003a,b) indicates that nurses ‘unwittingly’ have one out of three philosophical attitudes about ageing. They may have the decline perspective (DP), which sees cognitive impairment as a natural and inevitable part of the ageing process. Nurses who operate from this perspective see no need to probe, assess or question as confusion is expected in older patients. Nurses operating from the vulnerable perspective (VP) view cognitive decline as a frequent, but not necessarily ubiquitous occurrence among the elderly. Nurses with this perspective are ambiguous in their approach to assessment and investigation.
Without validation from others that the patient is acting different from usual, these nurses tend to assume that the patient has symptoms that can be attributed to normal ageing and that interventions other than standard nursing procedures are unnecessary. The third philosophical perspective which guides nurses is described as the healthful perspective (HP). According to McCarthy (2003a), nurses with this perspective view ageing as a normal process. Cognitive dysfunction was thought by these nurses to be pathological or unusual. From the HP perspective, delirious elders were immediately a cause for assessment and investigation. This attitude is evident from an excerpt of an interviewed nurse presented by McCarthy (2003a:97):
…It’s rare that I see somebody who is really confused just because they’re old. It’s usually from a disease process. I think of confusion as something that is pretty dramatic, pretty significant…It’s a matter of-if their wounds were bleeding, would you wait and see? Would you say, ”Well, maybe it’ll slow down a little bit?” I don’t think so. If cognitive dysfunction is judged ‘normal’, little action will be taken to discover treatable causes of delirium and elders will suffer the consequences. McCarthy (2003a, b) suggests that student or staff awareness programs might help overcome stereotypical models that fail to recognise healthy ageing as an option.
Diagnosing delirium is not a straight-forward process, even for nurses with a ‘healthy perspective’. Patients may be either hypoalert or hyperalert, or they may fluctuate between the two states (Inouye 2000). Symptoms may come and go with periods of normal cognition in between (Inouye 2000). If nurses have little time because staff levels are inadequate, the hypoactive patient, who has reduced psycho-motor activity and is less responsive to stimuli, may not be properly assessed. In addition, dementia may be present in elders that have delirium, making identification of symptoms particularly difficult without additional information from family or others who know the patient (Mentes et al. 1999). (See Appendix 2 for comparisons between dementia and delirium.)
Successful delirium management strategies Formalised programs adopted by hospitals have proved effective in preventing the occurrence of delirium in elderly patients and in limiting negative outcomes (Inouye, Bogardus, Charpentier, Leo-Summers, Acampora ; Holford 1999, Inouye 2000, Flaherty, Tariq, Raghavan, Baksh, Moinuddin, ;. Morley 2003). The success of these programs stems from a strong interdisciplinary approach to early assessment of patient risk, adoption of risk minimisation strategies, and a commitment to ongoing assessment. These successful programs also focus on education and staff support programs to engender a healthy perspective to ageing.