Management of ICU Delirium

1. Introduction

In the critical care setting, haemodynamic failure is recognised by monitoring the patient’s blood pressure and pulse and treatment may involve fluid resuscitation or the use of inotropic agents (Webb & Singer, 2005). In respiratory failure, the patient’s respiration rate and oxygen saturations are closely monitored and ventilatory support is sought (Cutler, 2010). Just like the heart and lungs, the brain can acutely fail in critical illness. An acute disturbance in brain function is recognised as delirium (Page & Ely, 2011). Historically, delirium was accepted by the medical and nursing community as an inevitable consequence of the ICU experience (Shehabi et al., 2008). More recently, delirium is beginning to gain acceptance as a serious condition in the adult intensive care unit (ICU) and early identification and timely treatment is essential so as to reduce the detrimental effects on patient outcomes (Arend & Christensen, 2009 & Boot, 2011).

Nurses are well-positioned to not only detect discrete fluctuations in levels of consciousness but to also minimise modifiable risk factors and to prompt doctors to review the critically unwell adult (Page & Ely, 2011). However, there is a growing recognition that delirium in the ICU is misunderstood and underreported by health professionals and hence continues to cause cognitive dysfunction in affected patients (Wells, 2010). This introduction discusses delirium in adult patients hospitalised in the ICU; specifically nurses’ knowledge, attitudes, beliefs and current practices regarding ICU delirium, and presents the literature review problem, question and the aim and objectives.

The literature has used numerous terms interchangeably to describe cognitive impairment in the ICU. There are references to ICU psychosis (Justice, 2000), ICU syndrome (Granberg-Axell, 2001), acute confusional syndrome (Tess, 1991), and acute brain failure (Lipowski, 1980; cited in Page & Ely, 2011, p. 6). The multiplicity of terms in the literature may explain why the condition has not received the degree of prioritisation it deserves (McGuire et al., 2000). The above expressions are gradually being superseded by a more widely accepted expression termed ‘ICU delirium’ (Boot, 2011).

Criteria set by the ‘Diagnostic and Statistical Manual of Mental Disorders’ (DSM-IV; American Psychiatric Association, 2000) describes delirium as a disturbance of consciousness (i.e. limited awareness of surroundings) and cognitive fluctuations (e.g. a memory deficit); the onset is over a short period of time and the syndrome is a consequence of a physiological condition. There are three subtypes of delirium; namely: hypoactive, hyperactive and mixed delirium. Page & Ely (2011) provide data on the prevalence of delirium: One in five adult patients hospitalised in the ICU develop delirium. A higher incidence occurs in ventilated patients (four out of five patients).

A considerable body of research is dedicated to the investigation of the adverse effects of delirium on patient outcomes. A prospective cohort study by Girard (2010) concludes that the duration of delirium in ventilated patients in the ICU is an independent predictor of cognitive impairment up to 1 year following discharge. This conclusion has far-reaching implications for the growing population of patients who are concerned about the preservation of cognitive function following hospitalisation during a period of critical illness. Similarly, Ouimet et al., (2007) used a prospective study design to conclude that delirium increased the risk of mortality in a population of 820 patients admitted to the ICU for a period of more than 24 hours. In addition to this, delirium was associated with an extended period of hospitalisation. The implementation of preventative measures, early recognition tools and the timely delivery of treatment may prove useful in the preservation of cognitive function in affected patients (Boot, 2011).

Although there are several assessment tools available for ICU patients, the National Institute for Health and Clinical Excellence (NICE, 2010) recommends the use of the Confusion Assessment Method for the ICU (CAM-ICU; Ely et al., 2001). The tool has high validity for detecting the delirious non-intubated patient (Ely, et al., 2001); however the symptoms of hypoactive delirium such as lethargy and drowsiness are not always recognised by the CAM-ICU (McNicoll et al., 2005).

The topic of this review was selected based on observations made in clinical practice; for example, it was witnessed that very few delirium assessments were being performed in the ICU and subsequent conversations with critical care nurses reinforced the perception that approaches to delirium monitoring in the ICU are inconsistent. In an attempt to address this clinical problem, the topic of ICU delirium was selected as the main focus of inquiry for the present research. So as to construct a relevant and well framed review question it was necessary to explore the literature pertaining to this clinical problem.

In a telephone-based questionnaire study conducted in the Netherlands (Van Eijk et al., 2008) it was concluded that 7% of the ICUs surveyed in this nationwide study routinely practiced delirium monitoring using a validated tool such as the CAM-ICU; despite the presence of international guidelines that advocate delirium assessment practices. Ely et al., (2001) states that very few institutions routinely practice delirium monitoring despite well-documented adverse effects associated with the syndrome. The implications of this are that timely diagnosis and the implementation of management strategies are prevented (Ista et al., 2014).

Boot (2009) proposes that nurses in the ICU may not have the appropriate level of knowledge to guide nursing practice. On the contrary, Wells (2012) states that a lack of knowledge may not fully explain why nurses do not engage in delirium monitoring and that the reason lies with the barriers to delirium as identified by Devlin et al., (2008) such as difficulties in assessing intubated patients. An alternative explanation is that nursing practices are based on the deep-rooted belief that delirium is an expected consequence of critical illness (Boot 2009). Undoubtedly, a lack of scientific attention given to the topic of ICU delirium may have contributed to a lack of general awareness (Page and Ely, 2011). In recent years, there has been a growing recognition in the literature and clinical practice that a change in attitude is required, which may need to be supported by educational efforts. Prior to introducing a change in attitude; it is first necessary to understand why so many nurses are failing to incorporate screening into their routine practice (Wells, 2010).

In an attempt to gain an improved understanding of the perceived barriers, beliefs, current practices and knowledge levels of critical care nurses, Devlin et al., (2008) identified nurses’ responses regarding delirium monitoring in the ICU using a questionnaire design. One of the main findings from this study was that nurses who did not routinely practice delirium monitoring were unaware that the syndrome was underreported and that delirium is characterised by fluctuating symptoms such as levels of consciousness. The study’s findings bring to attention a severe deficit in nurses’ knowledge relating to questions about delirium in the ICU. Mention should be made here of an important limitation of the study, that is, the results are only representative of 331 nurses in the Massachusetts area of North America. By employing a systematic search strategy to identify similar research, a synopsis of the level of support required to alleviate the clinical problem will be created (Aveyard, 2010). There appears to be no published evidence of an attempt to produce a systematic review that has explored critical care nurses’ responses in relation to delirium and delirium monitoring in the ICU. In light of this, the present review will explore this gap in research evidence at the level of a literature review in which a selected body of literature will be critically appraised.

1.1 The Review Question

‘What knowledge, practices and attitudes do critical care nurses have about delirium and its assessment in the ICU?’

1.2 Aim and Objectives

The aim of this review is to critically appraise primary research studies to reveal the knowledge, practices and attitudes of critical care nurses regarding delirium in the ICU and its assessment, whilst identifying implications and recommendations for clinical practice.

The following objectives describe the individual steps that will be undertaken as part of this review:

To employ a systematic search strategy to retrieve primary research articles that are relevant to the research question as specified above, through the use of inclusion and exclusion criteria.
To use appropriate databases and hand searching techniques to identify additional articles that are relevant to the research question and that meet the inclusion and exclusion criteria.
To critically appraise the selected research articles using a validated appraisal tool so as to establish their research quality and reliability.
To extract the findings from the selected articles so as to effectively answer the research question.
To draw conclusions from the findings whilst discussing the limitations of the review and implications and recommendations for clinical practice.

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