Daily sedative interruption in mechanically ventilated patients at risk for coronary artery disease*

Creating the animated intensive care unit

Critical care medicine has matured greatly as a field in the past decade. Much has been learned concerning the institution of life support therapies to sustain patients with diverse and multiple organ failures, thus providing patients with a window of opportunity to recover from potentially life-ending insults. The management of critically ill patients has increasingly involved creation of a highly controlled environment by care providers, with patients immobilized, tethered to devices, and receiving multiple drugs to facilitate the entire process. Although it has been assumed that such control of the patient has been necessary to implement essential therapies and to tailor life support systems such as mechanical ventilation, this assumption may be unfounded or at least overplayed, as knowledge of the adverse effects of this approach have been identified and quantified. Extant information, based on observational studies and a few interventional trials, would suggest a radically different approach to care is warranted, even given the difficulties in reversing the current culture of critical care management. Specifically, methods to avoid entirely, or minimize, neuromuscular blockade and sedation are supported by recent literature. These methods include the use of noninvasive ventilation in appropriately selected patients, the development of mechanical ventilators more synchronous with patient efforts and needs, and the use of sedation strategies to avoid drug accumulations with protracted effects. These methods, in turn, afford opportunities to avoid extreme immobilization and institute physiotherapy earlier than previously had been thought possible. In addition to the neuropsychiatric and neuromuscular benefits that could derive from minimizing opiate administration in critically ill patients, gut hypomotility could be avoided. This, in turn, could facilitate earlier and more complete enteral nutrition. Even when opioids have to be administered in generous amounts for control of pain that may accompany critical illness, it is now possible to block the peripheral actions of these medications with the μ-receptor antagonist methylnaltrexone. Other new drugs being introduced into the critical care unit such as dexmedetomidine may also provide a greater ability to achieve analgesia and anxiolysis without some of the adverse concomitant effects seen with more traditional drug regimens. The ultimate goal of this multipronged program to facilitate the maintenance of patients who are more interactive with their care providers, and the life support provided in the intensive care unit would be to speed the pace of recovery and to diminish the need for the protracted rehabilitation that often follows survival from critical illness.

Chronic critical illness

Although advances in intensive care have enabled more patients to survive an acute critical illness, they also have created a large and growing population of chronically critically ill patients with prolonged dependence on mechanical ventilation and other intensive care therapies. Chronic critical illness is a devastating condition: mortality exceeds that for most malignancies, and functional dependence persists for most survivors. Costs of treating the chronically critically ill in the United States already exceed $20 billion and are increasing. In this article, we describe the constellation of clinical features that characterize chronic critical illness. We discuss the outcomes of this condition including ventilator liberation, mortality, and physical and cognitive function, noting that comparisons among cohorts are complicated by variation in defining criteria and care settings. We also address burdens for families of the chronically critically ill and the difficulties they face in decision-making about continuation of intensive therapies. Epidemiology and resource utilization issues are reviewed to highlight the impact of chronic critical illness on our health care system. Finally, we summarize the best available evidence for managing chronic critical illness, including ventilator weaning, nutritional support, rehabilitation, and palliative care, and emphasize the importance of efforts to prevent the transition from acute to chronic critical illness. As steps forward for the field, we suggest a specific definition of chronic critical illness, advocate for the creation of a research network encompassing a broad range of venues for care, and highlight areas for future study of the comparative effectiveness of different treatment venues and approaches.

Current sedation practices: lessons learned from international surveys

Patient outcomes are significantly influenced by the choice of sedative and analgesic agents, the presence of over- or undersedation, poor pain control, and delirium. Individualized sedation management using sedation assessment tools, sedation protocols, and daily sedative interruption can improve clinical outcomes. Despite the publication of randomized trials and numerous guidelines, the uptake of proven strategies into routine practice can be slow. Surveys of clinicians' self-reported practice and prospective practice audits characterize sedation and analgesia practices and provide directions for education and future research. The objective of this review is to present the findings of surveys and practice audits, evaluating the management of sedation and analgesia in mechanically ventilated adults in the intensive care unit, and to summarize international critical care sedation practices.

Protocolized and target-based sedation and analgesia in the ICU

Administering sedative and analgesic medications is a cornerstone of optimizing patient comfort and minimizing distress, yet may lead to unintended consequences including delayed recovery from critical illness and slower liberation from mechanical ventilation. The use of structured approaches to sedation management, including guidelines, protocols, and algorithms can promote evidence-based care, reduce variation in clinical practice, and systematically reduce the likelihood of excessive and/or prolonged sedation. Patient-focused sedation algorithms are multidisciplinary, including physician, nurse, and pharmacist development and implementation. Key components of sedation algorithms include identification of goals and specific targets, use of valid and reliable tools to assess analgesia, agitation, and sedation, and incorporation of logical medication selection. Sedation protocols generally focus on a) algorithms that incorporate treating sedation and analgesia based upon escalation, de-escalation, or changing medications according to specific targets, or b) daily interruption of sedative and opioid analgesic infusions. Many published sedation protocols have been tested in controlled clinical trials, often demonstrating benefit such as shorter duration of mechanical ventilation, reduced ICU length of stay, and/or superior sedation management compared to usual care. Implementation of sedation algorithms in ICUs is a challenging process for which sufficient resources must be allocated.

Sedation and analgesia for the mechanically ventilated patient

Mechanically ventilated patients in the intensive care unit routinely require sedative and analgesic medications to manage pain and anxiety. These medications may have unpredictable effects with long-term use. Strategies that may help to improve patient outcomes include thoughtful selection of medications, use of objective sedation and pain scales, and implementation of protocolized sedation.

[Sedation concepts with volatile anaesthetics in intensive care: practical use and current experiences with the AnaConDa system]

The use of volatile anaesthetics in intensive care medicine has so far been limited by the lack of equipment suitable for daily routine use and the need for an anaesthetic machine. The new Anaesthetic Conserving Device (AnaConDa) enables the routine use of volatile anaesthetics for long-term sedation via intensive care ventilators. The Anaesthetic Conserving Device replaces the common heat and moisture exchanger in the ventilation circuit. The volatile anaesthetic is continuously applied in liquid status via a syringe pump to a form of mini-vaporiser where the anaesthetic agent is vaporised. The expired anaesthetic gas is stored in the carbon filter and approximately 90% of the gas is resupplied into the breathing cycle. The current experiences suggest that volatile anaesthetics present an alternative for long-term sedation in intensive care units, providing optimised pathways, from a medical as well as from an economical point of view. It must, however, be emphasized that the use of volatile anaesthetics for longer periods of time is an off-label use and should only undertaken by medical professionals at their own risk.

Sedation management in the mechanically ventilated critically ill patient

Sedation management in the mechanically ventilated critically ill patient is a topic of continuing interest in the critical care literature. The wide variety of clinical practices described in the literature with regard to sedation management has limited the implementation of evidence-based practice guidelines. Common themes for a coherent sedation management strategy include articulation of indications for sedation, initial and daily evaluation of sedation goals, sedation-level assessment, appropriate sedative selection, effective sedation management strategy, and efficient sedation weaning strategy. We provide a summary of the literature on key aspects of sedation in clinical practice. Evidence-based recommendations are provided for clinicians involved in the management of sedation in mechanically ventilated patients.

Sedation practice in the intensive care unit: a UK national survey

INTRODUCTION

The purpose of this study was to evaluate sedation practice in UK intensive care units (ICUs), particularly the implementation of daily sedation holding, written sedation guidelines, sedation scoring tools and choice of agents.

METHODS

A national postal survey was conducted in all UK ICUs.

RESULTS

A total of 192 responses out of 302 addressed units were received (63.5%). Of the responding ICUs, 88% used a sedation scoring tool, most frequently the Ramsey Sedation Scale score (66.4%). The majority of units have a written sedation guideline (80%), and 78% state that daily sedation holding is practiced. A wide variety of sedating agents is used, with the choice of agent largely determined by the duration of action rather than cost. The most frequently used agents were propofol and alfentanil for short-term sedation; propofol, midazolam and morphine for longer sedation; and propofol for weaning purposes.

CONCLUSIONS

Most UK ICUs use a sedation guideline and sedation scoring tool. The concept of sedation holding has been implemented in the majority of units, and most ICUs have a written sedation guideline.

[Management of the sedated patient]

A sedation strategy aimed at minimizing alteration of consciousness once comfort, analgesia and adaptation to the ventilator have been ensured is feasible in critically-ill patients requiring mechanical ventilation, even if, in patients with severe ARDS or ICH, the high dosages of sedatives and analgesics transiently required to provide perfect adaptation to the ventilator often preclude preservation of consciousness. The main components of a sedation algorithm include a clear objective of sedation-analgesia, regular assessments of patient status using validated clinical tools and a precise yet simple dosage adaptation schedule. Development and implementation of a sedation algorithm requires a multidisciplinary approach and an important input from both physicians and nurses. However, several methodologically-correct interventional studies have shown that using an algorithm to administrate sedatives and analgesics results in a significant reduction of MV duration, reaching 50% in some studies. This might translate into a real benefit for the patient point of view provided that preserving patient's comfort remains a constant concern for the caregivers. There is no reliable evidence to date to use propofol rather than midazolam as a sedative agent. Indeed, the way the sedative drug is used, as part of a sedation algorithm, is very likely more important than the selection of the drug itself. Analgesia-based sedation, promoting the use of morphinics alone before the adjunction of hypnotics, represents a new alternative to the traditional combined administration of hypnotics and morphinics. However data on the impact of analgesia-based sedation on patients' outcomes remain sparse to date.

Perceived barriers to the use of sedation protocols and daily sedation interruption: a multidisciplinary survey

BACKGROUND

Although use of sedation protocols and daily sedation interruption (DSI) improve outcome, their current use and barriers affecting their use are unclear.

METHODS

We designed a multidisciplinary, Web-based survey to determine current use of sedation protocols and DSI and the perceived barriers to each, and administered it to members of the Society of Critical Care Medicine.

RESULTS

The 904 responders were physicians (60%), nurses (14%), or pharmacists (12%); 45% worked in a university hospital. Of 64% having a sedation protocol, 78% used it for >or=50% of ventilated patients. Reasons for lack of protocol use included no physician order (35%), lack of nursing support (11%), and a fear of oversedation (7%). Daily sedation interruption was used by only 40%. Barriers to DSI included lack of nursing acceptance (22%), concern about risk of patient-initiated device removal (19%), and inducement of either respiratory compromise (26%) or patient discomfort (13%). Clinicians who prefer propofol were more likely to use DSI than those who prefer benzodiazepines (55% vs 40, P < .0001).

CONCLUSIONS

Current intensive care unit sedation practices are heterogeneous, and the barriers preventing the use of both sedation protocols and DSI are numerous. These barriers should be addressed on an institutional basis to boost the use of these evidence-based practices.

[ICU-acquired neuromyopathy, delirium and sedation in intensive care unit]

ICU-acquired neuromyopathy (NMAR) and delirium are the two most frequent and severe neurological complications of intensive care medicine. Their mechanisms still remain to be elucidated. The objective of this review is to address the potential role of sedation in occurrence of these complications. There is no evidence that sedation is involved in NMARs. However, the hypothesis that muscle inactivity induced by sedation fosters NMAR is an argument to discontinue or reduce sedatives infusion whenever possible. It is also recommended not to administer propofol more than 48 h at an infusion rate above 5 mg/kg per hour in patients with systemic inflammatory response syndrome, because of the risk of propofol infusion syndrome, which includes notably rhabdomyolysis. The relationship between delirium and sedation are controversial because in most studies, patients were considered delirious though being still sedated and multivariate analysis was lacking. One study showed that lorazepam given continuously was an independent risk factor for daily transition to delirium 24 h later with a 20% increase risk of every unit dose (expressed as log(e)mg). The impact of deepness, daily interruption or titration of sedation on the prevalence of delirium has never been assessed but it seems that deep sedation has to be avoided.

Strategies to optimize analgesia and sedation

Achieving adequate but not excessive sedation in critically ill, mechanically ventilated patients is a complex process. Analgesics and sedatives employed in this context are extremely potent, and drug requirements and metabolism are unpredictable. Clinicians must have heightened awareness of the potential for enduring effects and are encouraged to employ strategies that maximize benefit while minimizing risk. Successful sedation protocols have three basic components: frequent assessments for pain, anxiety, and agitation using a reproducible scale; combination therapy coupling opioids and sedatives; and, most importantly, careful communication between team members, with a particular recognition that the bedside nurse must be empowered to pair assessments with drug manipulation. In recent years, two broad categories of sedation protocols have achieved clinical success in terms of decreasing duration of mechanical ventilation and intensive care unit length of stay by minimizing drug accumulation. Patient-targeted sedation protocols (the first category) rely on structured assessments to guide a careful schema of titrated drug escalation and withdrawal. Variation exists in the assessment tool utilized, but the optimal goal in all strategies is a patient who is awake and can be readily examined. Alternatively, daily interruption of continuous sedative infusions (the second category) may be employed to focus care providers on the goal of achieving a period of awakening in the earliest phases of critical illness possible. Newer literature has focused on the safety of this strategy and its comparison with intermittent drug administration. Ongoing investigations are evaluating the broad applicability of these types of protocols, and currently one may only speculate on whether one strategy is superior to another.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSIONS

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Liberation from mechanical ventilation: what monitoring matters?

Over the past 2 decades, the art of "weaning" from mechanical ventilation has been informed by increasing published basic science and outcomes studies. Although monitoring technologies can provide vast amounts of information before, during, and after liberation from mechanical ventilation, little data exists on how to maximally harness even routinely monitored, basic physiologic parameters. Overdependence on technology and derived variables, without data to demonstrate benefit, may even inhibit the patient's progress if it is used inappropriately. We review the scientific evidence for best using routinely available physiologic data and a few more sophisticated and invasive monitoring technologies during weaning. We also suggest future study designs that would better inform the process of liberation from the ventilator and endotracheal extubation.

Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial): a randomised controlled trial

BACKGROUND

Approaches to removal of sedation and mechanical ventilation for critically ill patients vary widely. Our aim was to assess a protocol that paired spontaneous awakening trials (SATs)-ie, daily interruption of sedatives-with spontaneous breathing trials (SBTs).

METHODS

In four tertiary-care hospitals, we randomly assigned 336 mechanically ventilated patients in intensive care to management with a daily SAT followed by an SBT (intervention group; n=168) or with sedation per usual care plus a daily SBT (control group; n=168). The primary endpoint was time breathing without assistance. Data were analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00097630.

FINDINGS

One patient in the intervention group did not begin their assigned treatment protocol because of withdrawal of consent and thus was excluded from analyses and lost to follow-up. Seven patients in the control group discontinued their assigned protocol, and two of these patients were lost to follow-up. Patients in the intervention group spent more days breathing without assistance during the 28-day study period than did those in the control group (14.7 days vs 11.6 days; mean difference 3.1 days, 95% CI 0.7 to 5.6; p=0.02) and were discharged from intensive care (median time in intensive care 9.1 days vs 12.9 days; p=0.01) and the hospital earlier (median time in the hospital 14.9 days vs 19.2 days; p=0.04). More patients in the intervention group self-extubated than in the control group (16 patients vs six patients; 6.0% difference, 95% CI 0.6% to 11.8%; p=0.03), but the number of patients who required reintubation after self-extubation was similar (five patients vs three patients; 1.2% difference, 95% CI -5.2% to 2.5%; p=0.47), as were total reintubation rates (13.8%vs 12.5%; 1.3% difference, 95% CI -8.6% to 6.1%; p=0.73). At any instant during the year after enrolment, patients in the intervention group were less likely to die than were patients in the control group (HR 0.68, 95% CI 0.50 to 0.92; p=0.01). For every seven patients treated with the intervention, one life was saved (number needed to treat was 7.4, 95% CI 4.2 to 35.5).

INTERPRETATION

Our results suggest that a wake up and breathe protocol that pairs daily spontaneous awakening trials (ie, interruption of sedatives) with daily spontaneous breathing trials results in better outcomes for mechanically ventilated patients in intensive care than current standard approaches and should become routine practice.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the GRADE system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost), or clearly do not. Weak recommendations indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include: early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures prior to antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for post-operative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B) targeting a blood glucose < 150 mg/dL after initial stabilization ( 2C ); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper GI bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include: greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSION

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.