Sleep in the intensive care unit

How caregivers view patient comfort and what they do to improve it: a French survey

Background

Intensive care unit (ICU) patients are exposed to many sources of discomfort. Most of these are related to the patient’s condition, but ICU design or how care is organized also can contribute. The present survey was designed to describe the opinions of ICU caregivers on sources of patient discomfort and to determine how they were dealt with in practice. The architectural and organizational characteristics of ICUs also were analyzed in relation to patient comfort.

Methods

An online, closed-ended questionnaire was developed. ICU caregivers registered at the French society of intensive care were invited to complete this questionnaire.

Results

A total of 915 staff members (55% nurses) from 264 adult and 28 pediatric ICUs completed the questionnaire. Analysis of the answers reveals that: 68% of ICUs had only single-occupancy rooms, and 66% had natural light in each room; ICU patients had access to television in 59% of ICUs; a clock was present in each room in 68% of ICUs. Visiting times were <4 h in 49% of adult ICUs, whereas 64% of respondents considered a 24-h policy to be very useful or essential to patients’ well-being. A nurse-driven analgesia protocol was available in 42% of units. For caregivers, the main sources of patient discomfort were anxiety, feelings of restraint, noise, and sleep disturbances. Paramedics generally considered discomfort related to thirst, lack of privacy, and the lack of space and time references, whereas almost 50% of doctors ignored these sources of discomfort. Half of caregivers indicated they assessed sleep quality. A minority of caregivers declared regular use of noise-reduction strategies. Twenty percent of respondents admitted to having non-work-related conversations during patient care, and only 40% indicated that care often was or always was provided without closing doors. Family participation in care was planned in very few adult ICUs.

Conclusions

Results of this survey showed that ICUs are poorly equipped to ensure patient privacy and rest. Access by loved ones and their participation in care also is limited. The data also highlighted that some sources of discomfort are less often taken into account by caregivers, despite being considered to contribute significantly.

Speech intelligibility in hospitals

Effective communication between staff members is key to patient safety in hospitals. A variety of patient care activities including admittance, evaluation, and treatment rely on oral communication. Surprisingly, published information on speech intelligibility in hospitals is extremely limited. In this study, speech intelligibility measurements and occupant evaluations were conducted in 20 units of five different U.S. hospitals. A variety of unit types and locations were studied. Results show that overall, no unit had "good" intelligibility based on the speech intelligibility index (SII > 0.75) and several locations found to have "poor" intelligibility (SII < 0.45). Further, occupied spaces were found to have 10%-15% lower SII than unoccupied spaces on average. Additionally, staff perception of communication problems at nurse stations was significantly correlated with SII ratings. In a targeted second phase, a unit treated with sound absorption had higher SII ratings for a larger percentage of time as compared to an identical untreated unit. Taken as a whole, the study provides an extensive baseline evaluation of speech intelligibility across a variety of hospitals and unit types, offers some evidence of the positive impact of absorption on intelligibility, and identifies areas for future research.

Influence of the modern light environment on mood

Humans and other organisms have adapted to a consistent and predictable 24-h solar cycle, but over the past ~130 years the widespread adoption of electric light has transformed our environment. Instead of aligning behavioral and physiological processes to the natural solar cycle, individuals respond to artificial light cycles created by social and work schedules. Urban light pollution, night shift work, transmeridian travel, televisions and computers have dramatically altered the timing of light used to entrain biological rhythms. In humans and other mammals, light is detected by the retina and intrinsically photosensitive retinal ganglion cells project this information both to the circadian system and limbic brain regions. Therefore, it is possible that exposure to light at night, which has become pervasive, may disrupt both circadian timing and mood. Notably, the rate of major depression has increased in recent decades, in parallel with increasing exposure to light at night. Strong evidence already links circadian disruption to major depression and other mood disorders. Emerging evidence from the past few years suggests that exposure to light at night also negatively influences mood. In this review, we discuss evidence from recent human and rodent studies supporting the novel hypothesis that nighttime exposure to light disrupts circadian organization and contributes to depressed mood.

The experience of sleep deprivation in intensive care patients: findings from a larger hermeneutic phenomenological study

Sleep deprivation in critically ill patients has been well documented for more than 30 years. Despite the large body of literature, sleep deprivation remains a significant concern in critically ill patients in intensive care unit (ICU). This paper discusses sleep deprivation in critically ill patients as one of the main findings from a study that explored the lived experiences of critically ill patients in ICU with daily sedation interruption (DSI). Twelve participants aged between 20 and 76 years with an ICU stay ranging from three to 36 days were recruited from a 16 bed ICU in a large regional referral hospital in New South Wales (NSW), Australia. Participants were intubated, mechanically ventilated and subjected to daily sedation interruption during their critical illness in ICU. In-depth face to face interviews with the participants were conducted at two weeks after discharge from ICU. A second interview was conducted with eight participants six to eleven months later. Interviews were audio taped and transcribed. Data were analysed thematically. "Longing for sleep" and "being tormented by nightmares" capture the experiences and concerns of some of the participants. The findings suggest a need for models of care that seek to support restful sleep and prevent or alleviate sleep deprivation and nightmares. These models of care need to promote both quality and quantity of sleep in and beyond ICU and identify patients suffering from sleep deprivation to make appropriate referrals for treatment and support.

Sleep, anxiety and fatigue in family members of patients admitted to the intensive care unit: a questionnaire study

Introduction

Family members of critically ill patients often experience increased incidence of physical and mental health issues. One of the first ways family members suffer is by losing sleep. The purpose of this study is to understand sleep quality, levels of fatigue and anxiety, and factors contributing to poor sleep in adult family members of critically ill patients.

Methods

A questionnaire was designed to evaluate sleep, fatigue and anxiety during the intensive care unit (ICU) admission. We incorporated three validated instruments: General Sleep Disturbance Scale (GSDS), Beck Anxiety Index (BAI) and Lee Fatigue Scale (NRS-F). Adult family members of patients in ICU for more than 24 hours were approached for questionnaire completion. Patient demographics were recorded.

Results

The study population consisted of 94 respondents, (49.1 ± 12.9 years, 52.7% male); 43.6% were children and 21.3% were spouses of ICU patients. Sleep quality was rated as poor/very poor by 43.5% of respondents, and good/very good by 15.2%. The most common factors contributing to poor sleep were anxiety (43.6%), tension (28.7%) and fear (24.5%). Respondents' most common suggestions to improve sleep were more information regarding the patient's health (24.5%) and relaxation techniques (21.3%). Mean GSDS score was 38.2 ± 19.3, with 58.1% of respondents experiencing moderate to severe sleep disturbance. Mean BAI was 12.3 ± 10.2, with 20.7% of respondents experiencing moderate to severe anxiety. Mean NRS-F was 3.8 ± 2.5, with 57.6% of respondents experiencing moderate to high fatigue. Family members who spent one or more nights in the hospital had significantly higher GSDS, BAI and NRS-F scores. The patient's Acute Physiology and Chronic Health Evaluation (APACHE) II score at survey completion correlated significantly with family members' GSDS, BAI and NRS-F.

Conclusion

The majority of family members of ICU patients experience moderate to severe sleep disturbance and fatigue, and mild anxiety.

Sleep in the unresponsive wakefulness syndrome and minimally conscious state

The goal of our study was to investigate different aspects of sleep, namely the sleep-wake cycle and sleep stages, in the vegetative state/unresponsive wakefulness syndrome (VS/UWS), and minimally conscious state (MCS). A 24-h polysomnography was performed in 20 patients who were in a UWS (n=10) or in a MCS (n=10) because of brain injury. The data were first tested for the presence of a sleep-wake cycle, and the observed sleep patterns were compared with standard scoring criteria. Sleep spindles, slow wave sleep, and rapid eye movement sleep were quantified and their clinical value was investigated. According to our results, an electrophysiological sleep-wake cycle was identified in five MCS and three VS/UWS patients. Sleep stages did not always match the standard scoring criteria, which therefore needed to be adapted. Sleep spindles were present more in patients who clinically improved within 6 months. Slow wave sleep was present in eight MCS and three VS/UWS patients but never in the ischemic etiology. Rapid eye movement sleep, and therefore dreaming that is a form of consciousness, was present in all MCS and three VS/UWS patients. In conclusion, the presence of alternating periods of eyes-open/eyes-closed cycles does not necessarily imply preserved electrophysiological sleep architecture in the UWS and MCS, contrary to previous definition. The investigation of sleep is a little studied yet simple and informative way to evaluate the integrity of residual brain function in patients with disorders of consciousness with possible clinical diagnostic and prognostic implications.

Patient-ventilator synchrony and sleep quality with proportional assist and pressure support ventilation

OBJECTIVE

To examine patient-ventilator asynchrony and sleep quality in non-sedated critically ill patients ventilated with proportional assist ventilation with load adjustable gain factors (PAV+) and pressure support (PSV).

METHODS

This was a randomized crossover physiological study conducted in an adult ICU at a tertiary hospital. Patients who exhibited patient-ventilator asynchrony on PSV were selected. Polysomnography was performed in these patients over 24 h, during which respiratory variables were continuously recorded. During the study period, each patient was randomized to receive alternating 4-h periods of PSV and PAV+ equally distributed during the day and night. Sleep architecture was analyzed manually using predetermined criteria. Patient-ventilator asynchrony was evaluated breath by breath using the flow-time and airway pressure-time waveforms.

RESULTS

Fourteen patients were studied. The majority (85.7 %) had either acute exacerbation of COPD as admission diagnosis or COPD as comorbidity. During sleep, compared to PSV, PAV+ significantly reduced the patient-ventilator asynchrony events per hour of sleep [5 (1-17) vs. 40 (4-443), p = 0.02, median (25-75th interquartile range)]. Compared to PSV, PAV+ was associated with slightly but significantly greater sleep fragmentation [18.8 (13.1-33.1) versus 18.1 (7.0-22.8) events/h, p = 0.01] and less REM sleep [0.0 % (0.0-8.4) vs. 5.8 % (0.0-21.9), p = 0.02).

CONCLUSIONS

PAV+ failed to improve sleep in mechanically ventilated patients despite the fact that this mode was associated with better synchrony between the patient and ventilator. These results do not support the hypothesis that patient-ventilator synchrony plays a central role in determining sleep quality in this group of patients.

The 90% effective dose of a sufentanil bolus for the management of painful positioning in intubated patients in the ICU

CONTEXT

Pain and discomfort arising from the routine care of intubated patients in the ICU is managed by continuous infusion of narcotic and sedative drugs. There is benefit in keeping infusion rates low because lightening sedation improves clinical outcome, but this risks breakthrough pain. Management of this discomfort by bolus administration could permit lower background infusion rates, but the lowest effective bolus dose of sufentanil to achieve this is unknown.

OBJECTIVE

The aim of this study was to determine the effective analgesic dose in 90% of intubated patients (ED90) in the ICU given bolus sufentanil. Pain was assessed using a Behavioural Pain Scale (BPS) requiring a score of 3-4 during moving to the lateral decubitus position.

DESIGN

Prospective, dose response study.

SETTING

A 16-bed multidisciplinary ICU in a French university hospital. Study period was from January to June 2010.

PATIENTS

Intubated and ventilated patients were eligible for the study once they had reached a BPS of 3 or 4 and Ramsay score of 3-5 within 48 h of admission to the ICU.

INTERVENTION

The analgesic efficacy of a sufentanil bolus was measured during successive lateral decubitus positioning over a 72-h study period, using the BPS scale. The dose was increased with each subsequent turn to lateral decubitus until a BPS score of 3-4 was obtained (dose escalation, starting at zero).

MAIN OUTCOME MEASURES

BPS, Ramsay score, heart rate and mean arterial pressure were collected before and during each procedure.

RESULTS

A total of 25 patients were enrolled over 6 months. The ED90 bolus for sufentanil was 0.15 μg kg, but 40% of the patients subsequently demonstrated increased BPS with this dose.

CONCLUSION

The effective dose in 90% was 0.15 μg kg during the first 5 days of sedation. There were no adverse effects. A pre-emptive sufentanil bolus can be used to treat anticipated pain in the ICU. Regular and frequent assessments of acute pain and sedation are essential for adjusting the dose, on a case-by-case basis. This strategy may help clinicians to keep background infusions of sedatives and narcotics as low as possible and may improve clinical outcome.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01356732.

Effects of propofol on sleep quality in mechanically ventilated critically ill patients: a physiological study

PURPOSE

To access the effect of propofol administration on sleep quality in critically ill patients ventilated on assisted modes.

METHODS

This was a randomized crossover physiological study conducted in an adult ICU at a tertiary hospital. Two nights' polysomnography was performed in mechanically ventilated critically ill patients with and without propofol infusion, while respiratory variables were continuously recorded. Arterial blood gasses were measured in the beginning and at the end of the study. The rate of propofol infusion was adjusted to maintain a sedation level of 3 on the Ramsay scale. Sleep architecture was analyzed manually using predetermined criteria. Patient-ventilator asynchrony was evaluated breath by breath using the flow-time and airway pressure-time waveforms.

RESULTS

Twelve patients were studied. Respiratory variables, patient-ventilator asynchrony, and arterial blood gasses did not differ between experimental conditions. With or without propofol all patients demonstrated abnormal sleep architecture, expressed by lack of sequential progression through sleep stages and their abnormal distribution. Sleep efficiency, sleep fragmentation, and sleep stage distribution (1, 2, and slow wave) did not differ with or without propofol. Compared to without propofol, both the number of patients exhibiting REM sleep (p = 0.02) and the percentage of REM sleep (p = 0.04) decreased significantly with propofol.

CONCLUSIONS

In critically ill patients ventilated on assisted modes, propofol administration to achieve the recommended level of sedation suppresses the REM sleep stage and further worsens the poor sleep quality of these patients.

Factors affecting sleep quality of patients in intensive care unit

INTRODUCTION

Sleep disturbance is a frequently overlooked complication of intensive care unit (ICU) stay.

AIM

To evaluate sleep quality among patients admitted to ICU and investigate environmental and non-environmental factors that affect sleep quality in ICU.

METHODS

Over a 22-month period, we consecutively recruited patients who spent ≥ 2 nights post-endotracheal extubation in ICU and who were orientated to time, place, and person on the day of discharge. Self-reported sleep quality, according to a modified Freedman questionnaire, which provided data on self-reported ICU sleep quality in ICU and environmental factors affecting sleep quality in the ICU, were collected. We also investigated non-environmental factors, such as severity of illness, ICU interventions, and medications that can affect sleep quality.

RESULTS

Fifty males and 50 females were recruited with a mean (± SD) age of 65.1 ± 15.2 years. APACHE II score at admission to ICU was 18.1 ± 7.5 with duration of stay 6.7 ± 6.5days. Self-reported sleep quality score at home (1 = worst; 10 = best) was 7.0 ± 2.2; this decreased to 4.0 ± 1.7 during their stay in ICU (p < 0.001). In multivariate analysis with APACHE III as severity of illness (R(2) = 0.25), factors [exp(b)(95% CI), p value] which significantly affected sleep in ICU were sex [0.37(0.19-0.72), p < 0.01], age and sex interaction [1.02(1.01-1.03), p < 0.01], bedside phone [0.92(0.87-0.97), p < 0.01], prior quality of sleep at home [1.30(1.05-1.62), p = 0.02], and use of steroids [0.82(0.69-0.98), p = 0.03] during the stay in ICU.

CONCLUSION

Reduced sleep quality is a common problem in ICU with a multifactorial etiology.

Sleep disruptions and nocturnal nursing interactions in the intensive care unit

BACKGROUND

Sleep deprivation, common in intensive care unit (ICU) patients, may be associated with increased morbidity and/or mortality. We previously demonstrated that significant numbers of nocturnal nursing interactions (NNIs) occur during the routine care of surgical ICU patients. For this study, we assessed the quantity and type of NNIs in different ICU types: medical, surgical, cardiothoracic, pediatric, and neonatal. We hypothesized that the number and type of NNIs vary among different ICU types.

MATERIAL AND METHODS

We performed a prospective observational cohort study at our academic medical center examining potential sleep disruption in ICU patients secondary to NNIs from the hours 2200-0600 nightly. From May through November 2011, bedside nursing staff in five different ICUs collected data on NNIs, including the frequency and nature of each event (patient care activity, nursing intervention, nursing assessment, or patient-initiated contact) as well as the length of time of each event and whether the bedside care provider thought that the event could have been safely omitted without negatively affecting patient care. Additional data collected included patient demographics, the need for mechanical ventilation, and sedative/narcotic use.

RESULTS

Two hundred ICU patients were enrolled over 51 separate nocturnal time periods (3.9 patients/nocturnal time period). Of those 200 patients, 53 (26.5%) were mechanically ventilated; 12.5% underwent sedative infusion; and 23.0% underwent narcotic infusion. There were a total of 1831 NNIs; most (67%) were due to nursing assessment or patient care activity. The surgical ICU had the most frequent NNIs (11.8 ± 9.0), although they were the shortest (6.66 ± 6.06 min), as well as the highest proportion of NNIs that could have been safely omitted (20.9%). Nursing staff estimated that, of all NNIs in all ICU types, 13.9% could have been safely omitted.

CONCLUSIONS

NNIs occur frequently and vary across different ICU types. Many NNIs are due to nursing assessment and patient care activities, much of which could be safely omitted or clustered. A protocol for nocturnal sleep promotion is warranted in order to standardize ICU NNIs and minimize nighttime sleep disruptions.

Sleep disturbances and sedation practices in the intensive care unit--a postal survey in the Netherlands

BACKGROUND

Sleep disturbances are common in critically ill patients treated in the intensive care unit (ICU) with possible serious consequences.

OBJECTIVE

The aim of this study was to get insight into sleeping and sedation practices in the adult ICUs in the Netherlands and survey which factors are important with respect to sleep in critically ill patients in the ICU.

METHOD

A multi-centre, exploratory survey sent via mail to nurse managers of all adult ICUs in the Netherlands.

RESULTS

Interventions without medication to improve the sleep of the critically ill patients were mostly defined as keeping patients awake during the day (94.2%), reducing noise of the ICU staff (89.7%) and reducing nursing interventions at night (86.8%). None of the ICUs used a sleep questionnaire. Nursing autonomy regarding sleep and sedation practices for patients (rated on a 10-point numerical scale) was judged as moderate (median 5, interquartile range (IQR) 3-7). How often nursing observations influence sleeping practices in the ICU was judged as good (median 8, IQR 7-8). How the average ICU patient was sleeping was judged as moderately well (median 6, IQR 5-7). Most intensive care units (83.8%) did not have a sleeping protocol, but 67.6% of these intensive care units suggested they should implement a sleeping protocol.

CONCLUSIONS

The average critically ill patient has sleep disturbances, that is, is sleeping moderately well according to nurses' views and opinions, mostly due to a disturbed sleep-awake cycle, delirium and nursing interventions. Intensive care nurses perceive only a moderate feeling of autonomy and influence regarding the management of sleeping practices.

Effort-adapted modes of assisted breathing

PURPOSE OF REVIEW

New developments in mechanical ventilation have focused on increasing the patient's control of the ventilator by implementing information on lung mechanics and respiratory drive. Effort-adapted modes of assisted breathing are presented and their potential advantages are discussed.

RECENT FINDINGS

Adaptive support ventilation, proportional assist ventilation with load adjustable gain factors and neurally adjusted ventilatory assist are ventilatory modes that follow the concept of adapting the assist to a defined target, instantaneous changes in respiratory drive or lung mechanics. Improved patient ventilator interaction, sufficient unloading of the respiratory muscles and increased comfort have been recently associated with these ventilator modalities. There are, however, scarce data with regard to outcome improvement, such as length of mechanical ventilation, ICU stay or mortality (commonly accepted targets to demonstrate clinical superiority).

SUMMARY

Within recent years, a major step forward in the evolution of assisted (effort-adapted) modes of mechanical ventilation was accomplished. There is growing evidence that supports the physiological concept of closed-loop effort-adapted assisted modes of mechanical ventilation. However, at present, the translation into a clear outcome benefit remains to be proven. In order to fill the knowledge gap that impedes the broader application, larger randomized controlled trials are urgently needed. However, with clearly proven drawbacks of conventional assisted modes such as pressure support ventilation, it is probably about time to leave these modes introduced decades ago behind.

Patients and Their Families Weigh in on Evidence-Based Hospital Design

Background

In 2 landmark publications, the Institute of Medicine reported on significant deficiencies in our current health care system. In response, an area of research examining the role of the physical environment in influencing outcomes for patients and staff gained momentum. The concept of evidence-based design has evolved, and the development of structural guidelines for new hospital construction was instituted by the American Institute of Architects in 2006.

Objective

To determine perceptions of patients and their families of evidence-based design features in a new heart center.

Methods

Hospitalized patients and their families, most of whom were in intensive care and step-down units, were surveyed and data from the Hospital Consumer Assessment of Healthcare Providers and Systems were reviewed to determine perceptions of evidence-based design features incorporated into a new heart center and to assess patients’ satisfaction with the environment.

Results

Responses were reviewed and categorized descriptively. Five general environment topics of focus emerged: privacy, space, noise, light, and overall atmosphere. Characteristics perceived as being dissatisfying and satisfying are discussed.

Conclusions

Critical care nurses must be aware of the current need to recognize how much the physical environment influences care delivery and take steps to maximize patients’ safety, satisfaction, and quality of care.

Analgesia and sedation of mechanically ventilated patients - a national survey of clinical practice

BACKGROUND

The importance of balanced sedation and pain treatment in intensive care units (ICUs) is evident, but regimes and use of medication differ widely. Previous surveys have focused on the use of various medications and regimes. What has not been explored is the process by which nurses and physicians assess patients' needs and work together toward a defined level of sedation and pain for the ICU patient. The purpose of the study was to determine the use of protocols and medications for sedation and analgesia in Norwegian ICUs and the degree of cooperation between nurses and physicians in using them.

METHODS

A national survey was conducted in autumn 2007, using postal self-administered questionnaires.

RESULTS

Written pain treatment and sedation protocols were not routinely used in Norwegian ICUs; however, half of the departments titrated sedation according to a scoring system, most commonly the Motor Activity Assessment Score. The most commonly used sedatives were propofol and midazolam, while fentanyl and morphine were the most used analgesics. The majority of respondents were concerned about the side effects of sedation and analgesics, leading to circulatory instability and delayed awakening. Nurses and physicians agreed upon the main indications for sedation: patient tolerance for ventilation, tolerance for medical and nursing interventions, and patient symptoms.

CONCLUSIONS

Potential factors which may improve sedation and pain management of mechanically ventilated patients in Norwegian ICUs are more systematic assessments of pain and sedation, and the use of written protocols. Strategies which reduce side effects should be addressed.

Noise in an intensive care unit

Patients and staff in hospitals are exposed to a complex sound environment with rather high noise levels. In intensive care units, the main noise sources are hospital staff on duty and medical equipment, which generates both operating noise and acoustic alarms. Although noise in most cases is produced during activities for the purpose of saving life, noise can induce significant changes in the depth and quality of sleep and negatively affect health in general. Results of a survey of hospital staff are presented, as well as measurements in two German hospital wards: a standard two-bed room and a special intermediate care unit (IMC-Unit), each in a different intensive care unit (ICU). Sound pressure data were collected over a 48 hour period and converted into different levels (L(AFeq), L(AFmax) L(AFmin), L(AF 5%)), as well as a rating level L(Ar), which is used to take tonality and impulsiveness into account. An analysis of the survey and the measured data, together with a comparison of thresholds of national and international regulations and standards describe the acoustic situation and its likely noise effects on staff and patients.

Wireless technology in disease management and medicine

Healthcare information, and to some extent patient management, is progressing toward a wireless digital future. This change is driven partly by a desire to improve the current state of medicine using new technologies, partly by supply-and-demand economics, and partly by the utility of wireless devices. Wired technology can be cumbersome for patient monitoring and can restrict the behavior of the monitored patients, introducing bias or artifacts. However, wireless technologies, while mitigating some of these issues, have introduced new problems such as data dropout and "information overload" for the clinical team. This review provides an overview of current wireless technology used for patient monitoring and disease management. We identify some of the major related issues and describe some existing and possible solutions. In particular, we discuss the rapidly evolving fields of telemedicine and mHealth in the context of increasingly resource-constrained healthcare systems.

Soundscape evaluations in two critical healthcare settings with different designs

Intensive care units (ICUs) have important but challenging sound environments. Alarms and equipment generate high levels of noise and ICUs are typically designed with hard surfaces. A poor sound environment can add to stress and make auditory tasks more difficult for clinicians. However few studies have linked more detailed analyses of the sound environment to nurse wellbeing and performance. This study is aimed at understanding the relationships between objective acoustic measures and self-reported nurse outcomes. Two 20-bed ICUs with similar patient acuity and treatment models were tested: A recently built neurological ICU and a 1980s-era medical-surgical ICU. The medical-surgical ICU was perceived as louder, more annoying, and having a greater negative impact of noise on work performance, health outcomes, and anxiety as compared to the neurological ICU. Surprisingly, there were little differences between two ICU sound environments based on traditional overall noise measures. The objective differences between the occupied sound environments in the two units only emerged through a more comprehensive analysis of the "occurrence rate" of peak and maximum levels, frequency content, and the speech interference level. Furthermore, mid-level transient sound occurrence rates were significantly and positively correlated to perceived annoyance and loudness levels.

Effect of daily sedative interruption on sleep stages of mechanically ventilated patients receiving midazolam by infusion

Daily sedative interruption (DSI) may reduce excessive sedation and shorten the duration of mechanical ventilation. It is not clear, however, how DSI affects sleep characteristics. For patients receiving mechanical ventilation, we compared the effect on sleep quality of DSI and continuous sedation (CS). Twenty-two mechanically ventilated patients who were receiving midazolam by infusion were randomly assigned to two groups, DSI (n = 11) or CS (n = 11). In the DSI group, sedatives were interrupted until the patients awoke and expressed discomfort, after which midazolam or opioids were administered intermittently as needed during the daytime (0600 to 2100 hours); during the night (2100 to 0600) midazolam was administered intravenously to maintain Ramsay sedation scale 4 to 5. In the CS group, the sedatives were titrated to obtain Ramsay sedation scale 4 to 5 throughout the day. The polysomnography of each patient was recorded continuously over a 24 hour period. Sleep stages were analysed using Rechtschaffen and Kales criteria. In the DSI group, the amount of stage 3 and 4 non-rapid eye movement sleep (slow wave sleep) was longer (6 vs 0 minutes, P = 0.04) and rapid eye movement sleep was longer than in CS (54 vs 0 minutes, P = 0.02). In the CS group, total sleep time during night-time was longer (8.7 vs 7.3 hours, P = 0.047) and frequency of arousal was lower (2.2 vs 4.4 event/hour, P = 0.03) than those in the DSI group. All mechanically ventilated patients demonstrated abnormal sleep architecture, but, compared with CS, DSI increased the amount of slow wave sleep and rapid eye movement sleep.

Sleep disturbances and fatigue in critically ill patients

Sleep disturbances and fatigue are significant problems for critically ill patients. Existing sleep disorders, underlying medical/surgical conditions, environmental factors, stress, medications, and other treatments all contribute to a patient's inability to sleep. Sleep disturbance and debilitating fatigue that originate during acute illness may continue months after discharge from intensive care units (ICUs). If these issues are unrecognized, lack of treatment may contribute to chronic sleep problems, impaired quality of life, and incomplete rehabilitation. A multidisciplinary approach that incorporates assessment of sleep disturbances and fatigue, environmental controls, appropriate pharmacologic management, and educational and behavioral interventions is necessary to reduce the impact of sleep disturbances and fatigue in ICU patients. Nurses are well positioned to identify issues in their own units that prevent effective patient sleep. This article will discuss the literature related to the occurrence, etiology, and risk factors of sleep disturbance and fatigue and describe assessment and management options in critically ill adults.

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.

A long-term clinical evaluation of autoflow during assist-controlled ventilation: a randomized controlled trial

BACKGROUND

Many new mechanical ventilation modes are proposed without any clinical evaluation. "Dual-controlled" modes, such as AutoFlow™, are supposed to improve patient- ventilator interfacing and could lead to fewer alarms. We performed a long-term clinical evaluation of the efficacy and safety of AutoFlow during assist-controlled ventilation, focusing on ventilator alarms.

METHODS

Forty-two adult patients, receiving mechanical ventilation for more than 2 days with a Dräger Evita 4 ventilator were randomized to conventional (n = 21) or AutoFlow (n = 21) assist-controlled ventilation. Sedation was given using a nurse-driven protocol. Ventilator-generated alarms were exhaustively recorded from the ventilator logbook with a computer. Daily blood gases and ventilation outcome were recorded.

RESULTS

A total of 403 days of mechanical ventilation were studied and 45,022 alarms were recorded over a period of 8074 hours. The course of respiratory rate, minute ventilation, Fio(2), positive end-expiratory pressure, Pao(2)/Fio(2), Paco(2), and pH and doses and duration of sedation did not differ between the 2 groups. Outcome (duration of mechanical ventilation, ventilator-associated pneumonia, course of Sequential Organ Failure Assessment score, or death) was not different between the 2 groups. The number of alarms per hour was lower with AutoFlow assist-controlled ventilation: 3.3 [1.5 to 17] versus 9.1 [5 to 19], P < 0.0001 (median [quartile range]). In multivariate analysis, a low alarm rate was associated with activation of AutoFlow and a higher midazolam dose.

CONCLUSIONS

This first long-term clinical evaluation of the AutoFlow mode demonstrated its safety with regard to gas exchange and patient outcome. AutoFlow also allowed a very marked reduction in the number of ventilator alarms.

Development and validation of a questionnaire for quantitative assessment of perceived discomforts in critically ill patients

PURPOSE

To develop and validate the IPREA (Inconforts des Patients de REAnimation) questionnaire for the assessment of discomfort perceived by patients related to their intensive care unit (ICU) stay.

METHODS

This was a two step-study comprising a phase of item generation conducted in one ICU and a phase of psychometric evaluation during a multicenter prospective cohort study in 14 ICUs. Patients were unselected consecutive adult surviving ICU patients. On the day of ICU discharge, a nurse asked patients to rate the severity of 16 discomfort sources, from 0 to 100. Ten percent of patients were randomly chosen to be questioned again to assess the reproducibility.

RESULTS

Of 1,380 eligible patients, 1,113 survived and 868 patients could be questioned. The highest scores were for sleep deprivation (35 ± 33), being restrained by tubing, wires, and cables (33 ± 30), pain (32 ± 30), and thirst (32 ± 34). No multidimensional structure was identified. The mean overall score of discomfort was 22 ± 14. Internal consistency was satisfactory using Cronbach's alpha coefficient (0.78). The test-retest reliability study found average measure intraclass correlations ranging from 0.70 to 0.92. The mean duration of the questionnaire administration was 10 ± 7 min.

CONCLUSION

The psychometric properties and acceptability of the IPREA questionnaire make it a potential instrument for measuring discomfort perceived by unselected ICU patients.

Sleep in disorders of consciousness

From a behavioral as well as neurobiological point of view, sleep and consciousness are intimately connected. A better understanding of sleep cycles and sleep architecture of patients suffering from disorders of consciousness (DOC) might therefore improve the clinical care for these patients as well as our understanding of the neural correlations of consciousness. Defining sleep in severely brain-injured patients is however problematic as both their electrophysiological and sleep patterns differ in many ways from healthy individuals. This paper discusses the concepts involved in the study of sleep of patients suffering from DOC and critically assesses the applicability of standard sleep criteria in these patients. The available literature on comatose and vegetative states as well as that on locked-in and related states following traumatic or non-traumatic severe brain injury will be reviewed. A wide spectrum of sleep disturbances ranging from almost normal patterns to severe loss and architecture disorganization are reported in cases of DOC and some patterns correlate with diagnosis and prognosis. At the present time the interactions of sleep and consciousness in brain-injured patients are a little studied subject but, the authors suggest, a potentially very interesting field of research.

Effects of two types of ambient sound during sleep

This field study investigated whether either of two ambient sounds would improve objective sleep (via actigraphy), subjective sleep report, or morning psychomotor performance among 28 adults with self-described disturbed sleep. Nights 1 and 4 were soundless baseline and washout, respectively. On Nights 2 and 3 and 5 and 6, participants listened to double-blind counterbalanced paired nights of novel Sound A and a commercially available Sound B. Compared to baseline and washout, participants reported fewer awakenings during both Sound A and Sound B; actigraphically measured sleep was affected by Sound B but not Sound A. "Improvements" in sleep during the second exposure night probably reflect an increase in homeostatic sleep drive from sleep disturbance on the first exposure night. Differences between sounds were accounted for by user volume settings. Neither sound led to differences in psychomotor performance.

Sedation improves early outcome in severely septic Sprague Dawley rats

INTRODUCTION

Sepsis, a systemic inflammatory response to infective etiologies, has a high mortality rate that is linked both to excess cytokine activity and apoptosis of critical immune cells. Dexmedetomidine has recently been shown to improve outcome in a septic cohort of patients when compared to patients randomized to a benzodiazepine-based sedative regimen. We sought to compare the effects of dexmedetomidine and midazolam, at equi-sedative doses, on inflammation and apoptosis in an animal model of severe sepsis.

METHODS

After central venous access, Sprague Dawley rats underwent cecal ligation and intestinal puncture (CLIP) with an 18 G needle without antibiotic cover and received either saline, or an infusion of comparable volume of saline containing midazolam (0.6 mg.kg-1.h-1) or dexmedetomidine (5 ug.kg-1.h-1) for 8 hours. Following baseline measurements and CLIP, blood was sampled for cytokine measurement (tumour necrosis factor (TNF)-alpha and interleukin (IL)-6; n = 4-6 per group) at 2, 4 and 5 hours, and animal mortality rate (MR) was monitored (n = 10 per group) every 2 hours until 2 hours had elapsed. In addition, spleens were harvested and apoptosis was assessed by immunoblotting (n = 4 per group).

RESULTS

The 24 hour MR in CLIP animals (90%) was significantly reduced by sedative doses of either dexmedetomidine (MR = 20%) or midazolam (MR = 30%). While both sedatives reduced systemic levels of the inflammatory cytokine TNF-alpha (P < 0.05); only dexmedetomidine reduced the IL-6 response to CLIP, though this narrowly missed achieving significance (P = 0.05). Dexmedetomidine reduced splenic caspase-3 expression (P < 0.05), a marker of apoptosis, when compared to either midazolam or saline.

CONCLUSIONS

Sedation with midazolam and dexmedetomidine both improve outcome in polymicrobial severely septic rats. Possible benefits conveyed by one sedative regimen over another may become evident over a more prolonged time-course as both IL-6 and apoptosis were reduced by dexmedetomidine but not midazolam. Further studies are required to evaluate this hypothesis.

Sleep in the ICU: potential mechanisms and clinical implications

Patients in the ICU are known to have severely disrupted sleep with disturbed circadian pattern, decreased nocturnal sleep time, abnormally increased stages 1 and 2 sleep, and reduced or absent deep sleep. Recent data reveal that a subpopulation of critically ill patients manifests unique EEG sleep patterns. The etiology of sleep disruption in the ICU includes the inherent nature of the environment, medications, ventilator-patient interaction, and the effect of acute illness. How sleep disruption contributes to outcomes in critically ill patients, such as recovery time and weaning from mechanical ventilation, is unknown. This article reviews the literature describing sleep in ICU patients, including recent investigations in patients who require mechanical ventilation, factors that affect sleep in critically ill patients, and the potential mechanisms and clinical implications of disturbed sleep in the ICU setting with directions to consider for future investigations.

Filtering out the noise: evaluating the impact of noise and sound reduction strategies on sleep quality for ICU patients

The review article by Xie and colleagues examines the impact of noise and noise reduction strategies on sleep quality for critically ill patients. Evaluating the impact of noise on sleep quality is challenging, as it must be measured relative to other factors that may be more or less disruptive to patients' sleep. Such factors may be difficult for patients, observers, and polysomnogram interpreters to identify, due to our limited understanding of the causes of sleep disruption in the critically ill, as well as the challenges in recording and quantifying sleep stages and sleep fragmentation in the intensive care unit. Furthermore, most research in this field has focused on noise level, whereas acousticians typically evaluate additional parameters such as noise spectrum and reverberation time. The authors highlight the disparate results and limitations of existing studies, including the lack of attention to other acoustic parameters besides sound level, and the combined effects of different sleep disturbing factors.

Sleep deprivation after septic insult increases mortality independent of age

BACKGROUND

Sleep deprivation is a common problem in the intensive care unit. Animal models have demonstrated that sleep deprivation alone is associated with increased mortality. We have previously shown that septic insult with sleep deprivation results in increased mortality in a murine model. The aging process is known to reduce the restorative phases of sleep. The purpose of this study was to evaluate the effect of age on mortality with sleep deprivation during recovery from septic insult.

METHODS

C57BL/6J male mice aged 2 months (young) or 9 months (old) underwent cecal ligation and puncture (CLP). Animals were randomized to receive sleep interruption (SI) for 48 hours or standard recovery (no SI). Sham animals underwent laparotomy and cecal manipulation without puncture. SI was achieved by securing animal housing to an orbital shaker set to repeatedly cycle at 30 rpm over 120 seconds (30 seconds on/90 seconds off). The primary outcome was survival at 5 days post-CLP. Kaplan-Meier survival analysis with log-rank test was used to explore differences in mortality.

RESULTS

SI resulted in an increase in time awake for both light and dark cycles (p < 0.001). Mortality after CLP with SI (n = 30) was 57% and mortality after CLP without SI (controls; n = 33) was 24%. SI was associated with a greater than 3-fold increase in mortality after CLP (RR = 3.29; 95% CI, 1.42-7.63). Young mice (n = 28) had a mortality of 31% with CLP alone increasing to 67% with SI (p = 0.03). Old mice (n = 35) had a mortality of 18% with CLP alone increasing to 50% with SI (p = 0.05). There was no difference in survival between young and old mice undergoing SI (p = 0.49).

CONCLUSIONS

Sleep deprivation after septic insult increases mortality in both young and old mice. However, sleep deprivation after septic insult does not have a more profound effect on mortality in either age group. These findings suggest that sleep deprivation experienced in the intensive care unit setting during recovery from critical illness may increase mortality. This effect appears independent of increased age. Further studies evaluating extremes of age are warranted.

Robust parameter extraction for decision support using multimodal intensive care data

Digital information flow within the intensive care unit (ICU) continues to grow, with advances in technology and computational biology. Recent developments in the integration and archiving of these data have resulted in new opportunities for data analysis and clinical feedback. New problems associated with ICU databases have also arisen. ICU data are high-dimensional, often sparse, asynchronous and irregularly sampled, as well as being non-stationary, noisy and subject to frequent exogenous perturbations by clinical staff. Relationships between different physiological parameters are usually nonlinear (except within restricted ranges), and the equipment used to measure the observables is often inherently error-prone and biased. The prior probabilities associated with an individual's genetics, pre-existing conditions, lifestyle and ongoing medical treatment all affect prediction and classification accuracy. In this paper, we describe some of the key problems and associated methods that hold promise for robust parameter extraction and data fusion for use in clinical decision support in the ICU.

You are only coming through in waves: wakefulness variability and assessment in patients with impaired consciousness

The vegetative state (VS) is defined as a condition of wakefulness without awareness. Being awake and being asleep are two behavioral and physiological manifestations of the daily cycles of vigilance and metabolism. International guidelines for the diagnosis of VS propose that a patient fulfills criteria for wakefulness if he/she exhibits cycles of eye closure and eye opening giving the impression of a preserved sleep-wake cycle. We argue that these criteria are insufficient and we suggest guidelines to address wakefulness in a more comprehensive manner in this complex and heterogeneous group of patients. Four factors underlying wakefulness, as well as their interactions, are considered: arousal/responsiveness, circadian rhythms, sleep cycle, and homeostasis. The first refers to the arousability and capacity to, consciously or not, respond to external stimuli. The second deals with the circadian clock as a synchronizer of physiological functions to environmental cyclic changes. The third evaluates general sleep patterns, while homeostasis refers to the capacity of the body to regulate its internal state and maintain a stable condition. We present examples of reflex responses, activity rhythms, and electroencephalographic (EEG) measurements from patients with disorders of consciousness (DOC) to illustrate these factors of wakefulness. If properly assessed, they would help in the evaluation of consciousness by informing when and in which context the patient is likely to exhibit maximal responsiveness. This evaluation has the potential to improve diagnosis and treatment and may also add prognostic value to the multimodal assessment in DOC.

Assessment of sleep in ventilator-supported critically III patients

OBJECTIVES

In critically ill patients, sleep derangements are reported to be severe using Rechtschaffen and Kales (R&K) methodology; however, whether such methodology can reliably assess sleep during critical illness is unknown. We set out to determine the reproducibility of 4 different sleep-assessment methods (3 manual and 1 computer-based) for ventilator-supported critically ill patients and also to quantify the extent to which the reproducibility of the manual methods for measuring sleep differed between critically ill and ambulatory (control) patients.

DESIGN

Observational methodologic study.

SETTING

Academic center.

PATIENTS

Critically ill patients receiving mechanical ventilation and age-matched controls underwent polysomnography.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Reproducibility for the computer-based method (spectral analysis of electroencephalography [EEG]) was better than that for the manual methods: R&K methodology and sleep-wakefulness organization pattern (P = 0.03). In critically ill patients, the proportion of misclassifications for measurements using spectral analysis, sleep-wakefulness organization pattern, and R&K methodology were 0%, 36%, and 53%, respectively (P < 0.0001). The EEG pattern of burst suppression was not observed. Interobserver and intraobserver reliability of the manual sleep-assessment methods for critically ill patients (kappa = 0.52 +/- 0.23) was worse than that for control patients (kappa = 0.89 +/- 0.13; P = 0.03). In critically ill patients, the overall reliability of the R&K methodology was relatively low for assessing sleep (kappa = 0.19), but detection of rapid eye movement sleep revealed good agreement (kappa = 0.70).

CONCLUSIONS

Reproducibility for spectral analysis of EEG was better than that for the manual methods: R&K methodology and sleep-wakefulness organization pattern. For assessment of sleep in critically ill patients, the use of spectral analysis, sleep-wakefulness organization state, or rapid eye movement sleep alone may be preferred over the R&K methodology.

Sleep-disordered breathing in patients with decompensated heart failure

Sleep-disordered breathing (SDB) has a higher prevalence in patients with heart failure than in the general middle-aged population. Obstructive sleep apnea (OSA), one of the forms of SBD, promotes poorly controlled hypertension, coronary events, and atrial fibrillation events that can lead to acutely decompensated heart failure (ADHF), and evidence suggests that untreated OSA increases mortality in patients with heart failure. Cheyne-Stokes respiration and central sleep apnea (CSA) have long been associated with heart failure and, in many patients, can coexist with OSA. In this article, we propose a systematic approach to diagnose and treat OSA in patients with ADHF based on current evidence.