Bench-to-bedside review: delirium in ICU patients - importance of sleep deprivation

Intensive care unit delirium: a review of the literature

PURPOSE

The recent literature regarding intensive care unit (ICU) delirium and updated clinical practice guidelines are reviewed.

SUMMARY

Recent studies show that ICU delirium in critically ill patients is an independent predictor of higher mortality, longer ICU and hospital stay, and is associated with multiple clinical complications. Delirium has been reported to occur in greater than 80% of hospitalized critically ill patients, yet it remains an underdiagnosed condition. Several subtypes of delirium have been identified including hypoactive, hyperactive, and mixed presentation. Although the exact mechanism is unknown, several factors are thought to interact to cause delirium. Multiple risk factors related to medications, acute illness, the environment, and patient characteristics may contribute to the development of delirium. Practical bedside screening tools have been validated and are recommended to identify ICU patients with delirium. Nonpharmacologic interventions such as early mobilization have resulted in better functional outcomes, decreased incidence and duration of delirium, and more ventilator-free days. Data supporting pharmacologic treatments are limited.

CONCLUSION

Clinicians should become familiar with tools to identify delirium in order to initiate treatment and remove mitigating factors early in hospitalization to prevent delirium. Pharmacists are in a unique position to reduce delirium through minimization of medication-related risk factors and development of protocols.

Human Factors in Critical Care Medical Environments

The purpose of this chapter on human factors in critical care medical environments is to provide a systematic review of the human factors and ergonomics contributions that led to significant improvements in patient safety over the last five decades. The review will focus on issues that contributed to patient injury and fatalities and how human factors and ergonomics can improve performance of providers in critical care. Given the complexity of critical care delivery, a review needs to cover a wide range of subjects. In this review, I take a sociotechnical systems perspective on critical care and discuss the people, their technical and nontechnical skills, the importance of teamwork, technology, and ergonomics in this complex environment. After a description of the importance of a safety climate, the chapter will conclude with a summary on how human factors and ergonomics can improve quality in critical care delivery.

Levels and sources of sound in the intensive care unit - an observational study of three room types

BACKGROUND

Many intensive care unit (ICU) patients describe noise as stressful and precluding sleep. No previous study in the adult setting has investigated whether room size impacts sound levels or the frequency of disruptive sounds.

METHODS

A-frequency S-time weighted equivalent continuous sound (LAS eq), A-frequency S-time weighted maximum sound level (LAS max) and decibel C peak sound pressure (LC peak) were measured during five 24-h periods in each of the following settings: three-bed room with nursing station (NS) alcove, single-bed room with NS alcove (1-BR with NSA) and single-bed room with bedside NS. Cumulative restorative time (CRT) (> 5 min with LAS max < 55 dB and LC peak < 75 dB) was calculated to describe calm periods. Two 8-h bedside observations were performed in each setting in order to note the frequency and sources of disruptive sounds.

RESULTS

Mean sound pressure levels (LAS eq) ranged between 52 and 58 dBA, being lowest during night shifts. There were no statistically significant differences between the room types in mean sound levels or in CRT. However, disruptive sounds were 40% less frequent in the 1-BR with NSA than in the other settings. Sixty-four percent of disruptive sounds were caused by monitor alarms and conversations not related to patient care.

CONCLUSIONS

Single-bed rooms do not guarantee lower sound levels per se but may imply less frequent disruptive sounds. Sixty-four percent of disruptive sounds were avoidable. Our findings warrant sound reducing strategies for ICU patients.

Comparison of sleep quality with mechanical versus spontaneous ventilation during weaning of critically III tracheostomized patients

BACKGROUND

In mechanically ventilated patients under mechanical ventilation in the ICU, ventilatory mode or settings may influence sleep quality. The aim of this study was to evaluate the direct impact of mechanical ventilation per se on sleep quantity and quality in patients who were able to tolerate separation from mechanical ventilation over prolonged periods.

DESIGN AND SETTING

Randomized crossover clinical trial in a medical ICU.

PATIENTS

Sixteen conscious patients, free of sedation and tracheostomized because of prolonged weaning from mechanical ventilation, were included in the study when able to tolerate at least 5 hours of spontaneous ventilation.

INTERVENTIONS

Patients were randomized to receive either spontaneous ventilation or mechanical ventilation at low levels of pressure support for two crossover periods of 5-hour duration each, from 22:00 to 08:00. Polysomnography was performed throughout the study.

MEASUREMENTS AND RESULTS

Total sleep time was higher during mechanical ventilation than during spontaneous ventilation (183 min vs 132 min, p = 0.04). No significant differences between mechanical ventilation and spontaneous ventilation were observed in slow wave sleep time (45 min vs 28 min), rapid eye movement sleep time (11 min vs 3 min), or the fragmentation index (25 vs 23 arousals and awakenings per hr). In four patients, however, our analysis of patient-ventilator interaction suggested that the ventilatory settings were suboptimal and could have been improved to potentially improve sleep.

CONCLUSIONS

In difficult-to-wean tracheostomized patients, sleep quality was similar with or without the ventilator. Sleep quantity was higher during mechanical ventilation. Reconnection to the ventilator during the night period may favor sleep efficiency in tracheostomized patients in prolonged weaning.

Neuropeptides in sepsis: from brain pathology to systemic inflammation

Septic encephalopathy is frequently diagnosed in critically ill patients and in up to 70% of patients with severe systemic infection [19]. The syndrome is defined by diffuse cerebral dysfunction or structural abnormalities attributed to the effects of systemic infection, rather than a direct central nervous system cause. The clinical characteristics can range from mild delirium to deep coma, but patients are often medically sedated making the diagnosis difficult. Any manifestation, however, is specific and markers of disease are lacking [43]. Sepsis survivors present long term cognitive impairment, including alterations of memory, attention and concentration [10,54]. Here, we propose that neuropeptides may play a key role in septic encephalopathy, leading to a vicious circle characterized by brain disease and systemic inflammation.

Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit

OBJECTIVE

To revise the "Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult" published in Critical Care Medicine in 2002.

METHODS

The American College of Critical Care Medicine assembled a 20-person, multidisciplinary, multi-institutional task force with expertise in guideline development, pain, agitation and sedation, delirium management, and associated outcomes in adult critically ill patients. The task force, divided into four subcommittees, collaborated over 6 yr in person, via teleconferences, and via electronic communication. Subcommittees were responsible for developing relevant clinical questions, using the Grading of Recommendations Assessment, Development and Evaluation method (http://www.gradeworkinggroup.org) to review, evaluate, and summarize the literature, and to develop clinical statements (descriptive) and recommendations (actionable). With the help of a professional librarian and Refworks database software, they developed a Web-based electronic database of over 19,000 references extracted from eight clinical search engines, related to pain and analgesia, agitation and sedation, delirium, and related clinical outcomes in adult ICU patients. The group also used psychometric analyses to evaluate and compare pain, agitation/sedation, and delirium assessment tools. All task force members were allowed to review the literature supporting each statement and recommendation and provided feedback to the subcommittees. Group consensus was achieved for all statements and recommendations using the nominal group technique and the modified Delphi method, with anonymous voting by all task force members using E-Survey (http://www.esurvey.com). All voting was completed in December 2010. Relevant studies published after this date and prior to publication of these guidelines were referenced in the text. The quality of evidence for each statement and recommendation was ranked as high (A), moderate (B), or low/very low (C). The strength of recommendations was ranked as strong (1) or weak (2), and either in favor of (+) or against (-) an intervention. A strong recommendation (either for or against) indicated that the intervention's desirable effects either clearly outweighed its undesirable effects (risks, burdens, and costs) or it did not. For all strong recommendations, the phrase "We recommend …" is used throughout. A weak recommendation, either for or against an intervention, indicated that the trade-off between desirable and undesirable effects was less clear. For all weak recommendations, the phrase "We suggest …" is used throughout. In the absence of sufficient evidence, or when group consensus could not be achieved, no recommendation (0) was made. Consensus based on expert opinion was not used as a substitute for a lack of evidence. A consistent method for addressing potential conflict of interest was followed if task force members were coauthors of related research. The development of this guideline was independent of any industry funding.

CONCLUSION

These guidelines provide a roadmap for developing integrated, evidence-based, and patient-centered protocols for preventing and treating pain, agitation, and delirium in critically ill patients.

Delirium: is sleep important?

Delirium and poor sleep quality are common and often co-exist in hospitalised patients. A link between these disorders has been hypothesised but whether this link is a cause-and-effect relationship or simply an association resulting from shared mechanisms is yet to be determined. Potential shared mechanisms include: abnormalities of neurotransmitters, tissue ischaemia, inflammation and sedative exposure. Sedatives, while decreasing sleep latency, often cause a decrease in slow wave sleep and stage rapid eye movement (REM) sleep and therefore may not provide the same restorative properties as natural sleep. Mechanical ventilation, an important cause of sleep disruption in intensive care unit (ICU) patients, may lead to sleep disruption not only from the discomfort of the endotracheal tube but also as a result of ineffective respiratory efforts and by inducing central apnoea events if not properly adjusted for the patient's physiologic needs. When possible, efforts should be made to optimise the patient-ventilator interaction to minimise sleep disruptions.

An update on delirium in the postoperative setting: prevention, diagnosis and management

Delirium is a serious and pervasive problem in the postoperative setting. Research to date has identified a number of key risk factors implicated in the development of delirium after surgical intervention, including advanced age, pre-existing cognitive impairment, lower pre-morbid functional status and history of psychiatric illness. Efforts to prevent postoperative delirium in the form of multi-component programs and prophylactic administration of medications have yielded some positive results. Studies investigating the effectiveness of various antipsychotics in the treatment of postoperative delirium have demonstrated somewhat mixed outcomes. Recent research has identified more sophisticated management of pain and sedation protocols as a way to prevent or mitigate delirium, with promising results. This chapter reviews the most recent literature pertaining to the prevention, diagnosis and management of postoperative delirium.

The Use of Pentobarbital in Cases of Severe Delirium

Delirium is a common syndrome present at the end of life and causes significant distress for patients and families. Sleep disruption is a common precipitating factor for delirium and restoration of sleep may be instrumental in attenuating symptoms. In this cases series, we present three patients who were unresponsive to escalating doses of standard delirium medications, but whose delirium resolved once improved sleep was achieved using Pentobarbital. In a fourth patient, delirium was successfully treated where neuroleptics were contraindicated. Pentobarbital has been shown to reduce the time to sleep onset, decrease the number of body movements during sleep and spontaneous awakenings and increase the total sleep time. Pentobarbital may provide an additional treatment option for patients whose delirium is refractory to standard management approaches.

Neurologic Implications of Critical Illness and Organ Dysfunction

Critical illness has consequences for the nervous system. Patients experiencing critical illness are at risk for common global neurologic disturbances, such as delirium, long-term cognitive dysfunction, ICU-acquired weakness, sleep disturbances, recurrent seizures, and coma. In addition, complications related to specific organ dysfunction may be anticipated. Cardiovascular disease presents the possibility for CNS injury after cardiac arrest, sequelae of endocarditis, aberrancies of blood flow autoregulation, and malperfusion. Respiratory disease is known to cause short-term effects of hypoxia and long-term effects after ARDS. Sepsis encephalopathy and sickness behavior syndrome are early signs of infection in patients. In addition, commonly encountered organ dysfunction including uremia, hepatic failure, endocrine, and metabolic disturbances present with neurologic findings which may manifest in the critically ill patient as well.

Preventing delirium in the intensive care unit

Delirium in the intensive care unit (ICU) is exceedingly common, and risk factors for delirium among the critically ill are nearly ubiquitous. Addressing modifiable risk factors including sedation management, deliriogenic medications, immobility, and sleep disruption can help to prevent and reduce the duration of this deadly syndrome. The ABCDE approach to critical care is a bundled approach that clinicians can implement for many patients treated in their ICUs to prevent the adverse outcomes associated with delirium and critical illness.

Meanings of being critically ill in a sound-intensive ICU patient room - a phenomenological hermeneutical study

The aim of this study was to illuminate the meanings of being critically ill in a sound-intensive ICU patient room, as disclosed through patients’ narratives. Patient rooms in ICUs are filled with loud activity and studies have revealed sound levels comparable to those of a busy road above the patient’s head. There is a risk that the sound or noise is disturbing and at worst a major problem for the patient, but there is a lack of knowledge concerning the patients’ own experiences. Thirteen patients were asked to narrate their experiences of the sound environment in ICU patient rooms. The interviews were analyzed using a phenomenological- hermeneutical method inspired by the philosophy of Ricoeur. Six themes emerged from the analysis. Conclusion: The meanings of being a patient in a sound- intensive environment were interpreted as never knowing what to expect next regarding noise, but also of being situated in the middle of an uncontrollable barrage of noise, unable to take cover or disappear. This condition is not to be seen as static; for some patients there is movement and change over time. The meanings indicate that the unpredictable shifts between silence and disturbing sounds stress the critically ill patient and impede sleep and recovery. Our findings indicate the need to reduce disturbing and unexpected sounds and noise around critically ill patients in high-tech environments in order to facilitate wellbeing, sleep and recovery. Nurses have a vital role in developing such an environment.

Bright light therapy as an adjunctive treatment with risperidone in patients with delirium: a randomized, open, parallel group study

OBJECTIVE

The purpose of this study was to determine the effect of adjuvant light therapy with antipsychotic treatment in patients with delirium.

METHODS

Thirty-six patients were referred to the consulting psychiatry division of our hospital for a disturbance in consciousness. The patients were randomized to risperidone (n=16) or risperidone with light therapy (n=20). They were evaluated on Day 0 (baseline) and on Days 1 to 5 with the Delirium Rating Scale (DRS) and the Memorial Delirium Assessment Scale (MDAS). Sleep parameters were measured using a sleep log.

RESULTS

Mean DRS and MDAS scores decreased significantly over time in both treatment groups. Risperidone with light therapy group showed a significantly greater decrease in the DRS score than the risperidone-only group (F=2.87, P=.025), but the MDAS score was not significantly different between the two groups. There was a significant improvement in total sleep time (F=2.07, P=.037) and sleep efficiency (F=2.79, P=.029) in the risperidone with light therapy group than in the risperidone-only group.

CONCLUSIONS

Our results indicate that risperidone with light therapy may be a helpful adjuvant treatment for patients with delirium. Adequately powered studies with a head-to-head comparison design are mandatory to confirm our findings.

Sleep disturbances in critically ill patients in ICU: how much do we know?

Sleep disturbances in the intensive care unit (ICU) seem to lead to development of delirium, prolonged ICU stay, and increased mortality. That is why sufficient sleep is important for good outcome and recovery in critically ill patients. A variety of small studies reveal pathological sleep patterns in critically ill patients including abnormal circadian rhythm, high arousal and awakening index, reduced Slow Wave Sleep, and Rapid Eye Movement sleep. The purpose of this study is to summarise different aspects of sleep-awake disturbances, causes and handling methods in critically ill patients by reviewing the underlying literature. There are no studies of level 1 evidence proving the positive impact of the tested interventions on the critically ill patients' sleep pattern. Thus, disturbed sleep in critically ill patients with all the severe consequences remains an unresolved problem and needs further investigation.

Incorporating the treatment of medical and psychiatric disorders in the critical care area

Critical care areas are fast moving, often chaotic, and therefore confusing, even frightening, to patients attempting to understand what has happened to them. The nurse acts to mitigate these reactions by understanding the range of possibilities that can occur with patients, including potential psychiatric issues, and serving as patient advocate to ensure that appropriate treatment is initiated. Certainly there may be other psychiatric problems not described in the preceding text. The main possibilities are covered in this article. Assessing and acting early are tools the critical care nurse uses to meet patient needs and prevent behavioral problems that can interfere with life-preserving care.

Postoperative complications: delirium

Delirium is a common feature of the postoperative period, leading to increased morbidity and mortality and significant costs. Multiple factors predispose a patient to delirium in its hypoactive, hyperactive, or mixed forms. Tools have been validated for its quick and accurate identification to ensure timely and effective multidisciplinary intervention and treatment. A significant percentage of patients may require placement in skilled nursing facilities or similar care environments because of the long-lasting effects. The physician must be vigilant in the search for and identification of all forms of delirium and must effectively treat the underlying medical condition and symptoms.

Sleep quality and its association with delirium among veterans enrolled in hospice

OBJECTIVES

: The objectives of this study were to describe sleep quality and evaluate the association of sleep quality with delirium onset among patients enrolled in hospice.

DESIGN

: The study utilized secondary data from a prospective, observational, longitudinal study.

SETTING

: Veterans enrolled in hospice were recruited from the Portland Veterans Affairs Medical Center, Portland, Oregon.

PARTICIPANTS

: The cohort consisted of 105 patients, of whom 73% had at least one sleep measurement.

MEASUREMENTS

: Sleep quality was measured with the Pittsburgh Sleep Quality Index. Delirium was measured with the Confusion Assessment Method. Other important variables were recorded from the medical record and/or longitudinal interviews with patients and their caregivers. Cox regression was used to estimate hazard ratios (HRs) to measure the association between sleep quality and delirium onset.

RESULTS

: Of the patients who could be assessed, 44% had poor average sleep quality and 58% reported at least one episode of poor sleep. Overall, sleep quality did not appear to worsen as patients neared death although an increasing number of patients were unable to report on sleep quality. Poor sleep quality was associated with an increased risk of developing delirium, with an HR of 2.37 (95% CI: 1.50-3.74), for every one point worsening in the sleep quality score on a 4-point scale.

CONCLUSIONS

: Poor sleep quality was common among Veteran patients enrolled in hospice. These findings may help guide decision making between clinicians, patients, and families regarding the likely impact of sleep disturbance and may help identify patients at higher risk of developing delirium.

Sleep deprivation in critical illness: its role in physical and psychological recovery

Critically ill patients frequently experience poor sleep, characterized by frequent disruptions, loss of circadian rhythms, and a paucity of time spent in restorative sleep stages. Factors that are associated with sleep disruption in the intensive care unit (ICU) include patient-ventilator dysynchrony, medications, patient care interactions, and environmental noise and light. As the field of critical care increasingly focuses on patients' physical and psychological outcomes following critical illness, understanding the potential contribution of ICU-related sleep disruption on patient recovery is an important area of investigation. This review article summarizes the literature regarding sleep architecture and measurement in the critically ill, causes of ICU sleep fragmentation, and potential implications of ICU-related sleep disruption on patients' recovery from critical illness. With this background information, strategies to optimize sleep in the ICU are also discussed.

Preventing intensive care unit delirium: a patient-centered approach to reducing sleep disruption

Delirium in the intensive care unit is a disorder with multifactorial causes and is associated with poor outcomes. Sleep-wake disturbance is a common experience for patients with delirium. Care processes that disrupt sleep can lead to sleep deprivation, contributing to delirium. Patient-centered care is a concept that considers what is best for each individual. How can clinicians use a patient-centered approach to alter processes to decrease patient disruptions and improve sleep and rest? Could timing of blood draws and soothing music work to promote sleep?

Pharmacological and nonpharmacological management of delirium in critically ill patients

Delirium is a common yet under-diagnosed syndrome of acute brain dysfunction, which is characterized by inattention, fluctuating mental status, altered level of consciousness, or disorganized thinking. Although our recognition of risk factors for delirium has progressed, our understanding of the underlying pathophysiologic mechanisms remains limited. Improvements in monitoring and assessment for delirium (particularly in the intensive care setting) have resulted in validated and reliable tools such as arousal scales and bedside delirium monitoring instruments. Once delirium is recognized and the modifiable risk factors are addressed, the next step in management (if delirium persists) is often pharmacological intervention. The sedatives, analgesics, and hypnotics most often used in the intensive care unit (ICU) to achieve patient comfort are all too frequently deliriogenic, resulting in a longer duration of ICU and hospital stay, and increased costs. Therefore, identification of safe and efficacious agents to reduce the incidence, duration, and severity of ICU delirium is a hot topic in critical care. Recognizing that there are no medications approved by the Food and Drug Administration (FDA) for the prevention or treatment of delirium, we chose anti-psychotics and alpha-2 agonists as the general pharmacological focus of this article because both were subjects of relatively recent data and ongoing clinical trials. Emerging pharmacological strategies for addressing delirium must be combined with nonpharmacological approaches (such as daily spontaneous awakening trials and spontaneous breathing trials) and early mobility (combined with the increasingly popular approach called: Awakening and Breathing Coordination, Delirium Monitoring, Early Mobility, and Exercise [ABCDE] of critical care) to develop evidence-based approaches that will ensure safer and faster recovery of the sickest patients in our healthcare system.

Control of breathing during mechanical ventilation: who is the boss?

Over the past decade, concepts of control of breathing have increasingly moved from being theoretical concepts to "real world" applied science. The purpose of this review is to examine the basics of control of breathing, discuss the bidirectional relationship between control of breathing and mechanical ventilation, and critically assess the application of this knowledge at the patient's bedside. The principles of control of breathing remain under-represented in the training curriculum of respiratory therapists and pulmonologists, whereas the day-to-day bedside application of the principles of control of breathing continues to suffer from a lack of outcomes-based research in the intensive care unit. In contrast, the bedside application of the principles of control of breathing to ambulatory subjects with sleep-disordered breathing has out-stripped that in critically ill patients. The evolution of newer technologies, faster real-time computing abilities, and miniaturization of ventilator technology can bring the concepts of control of breathing to the bedside and benefit the critically ill patient. However, market forces, lack of scientific data, lack of research funding, and regulatory obstacles need to be surmounted.