Continuous intravenous infusions of lorazepam versus midazolam for sedation during mechanical ventilatory support: a prospective, randomized study

Butorphanol versus Propofol in Patients Undergoing Noninvasive Ventilation: A Prospective Observational Study

Background

The present study aimed to explore sedation management in agitated patients who suffered from acute respiratory failure (ARF) and were treated with noninvasive ventilation (NIV).

Patients and Methods

We divided 118 patients undergoing NIV treatment with butorphanol or propofol into two groups: group B (n = 57, butorphanol was initiated at the rate of 0.12 µg/kg/min as a continuous intravenous infusion and then titrated by 0.06 µg/kg/min every half an hour, group P (n = 61, propofol was initiated at the rate of 5 µg/kg/min as a continuous intravenous infusion and then titrated by 1.5 µg/kg/min every half an hour). Score of Sedation Agitation Scale (SAS) in the two groups was maintained between 3 and 4. Medications including sedative, analgesic, and antipsychotic, NIV intolerance score, SAS score, visual analog scale (VAS), medication use and adverse events were recorded repeatedly.

Results

Patients receiving butorphanol required significantly less total amount of fentanyl than patients receiving propofol during NIV to maintain the target VAS [0 (0–0) µg vs 150 (50–200) µg, P< 0.005]. Hemodynamic stability during NIV showed it was better kept in patients treated with butorphanol.

Conclusion

Butorphanol not only decreased the requirements of fentanyl but also enhanced hemodynamic stability in agitated patients suffering from ARF receiving NIV.

Trial Registration

Registered at http://www.chictr.org.cn/ (ChiCTR1800015534).

Evolving targets for sedation during mechanical ventilation

PURPOSES OF REVIEW

Critically ill patients frequently require mechanical ventilation as part of their care. Administration of analgesia and sedation to ensure patient comfort and facilitate mechanical ventilation must be balanced against the known negative consequences of excessive sedation. The present review focuses on the current evidence for sedation management during mechanical ventilation, including choice of sedatives, sedation strategies, and special considerations for acute respiratory distress syndrome (ARDS).

RECENT FINDINGS

The Society of Critical Care Medicine recently published their updated clinical practice guidelines for analgesia, agitation, sedation, delirium, immobility, and sleep in adult patients in the ICU. Deep sedation, especially early in the course of mechanical ventilation, is associated with prolonged time to liberation from mechanical ventilation, longer ICU stays, longer hospital stays, and increased mortality. Dexmedetomidine may prevent ICU delirium when administered nocturnally at low doses; however, it was not shown to improve mortality when used as the primary sedative early in the course of mechanical ventilation, though the majority of patients in the informing study failed to achieve the prescribed light level of sedation. In a follow up to the ACURASYS trial, deep sedation with neuromuscular blockade did not result in improved mortality compared to light sedation in patients with severe ARDS.

SUMMARY

Light sedation should be targeted early in the course of mechanical ventilation utilizing daily interruptions of sedation and/or nursing protocol-based algorithms, even in severe ARDS.

Analgesia, sedation, and delirium in pediatric surgical critical care

The alleviation of discomfort and distress is an essential component of the management of critically ill surgical patients. Pain and anxiety have multifocal etiologies that may be related to an underlying disease or surgical procedure, ongoing medical therapy, invasive monitors, an unfamiliar, complex and chaotic environment, as well as fear. Pharmacologic and non-pharmacologic therapies have complex risk benefit profiles. A fundamental understanding of analgesia, sedation, and delirium is essential for optimizing important outcomes in critically ill pediatric surgical patients. There has been a recent emphasis on goal directed, evidence based, and patient-centered management of the physical and psychological needs of these children. The purpose of this article is to review and summarize recent advances and describe current practice of these important subjects in the pediatric surgical intensive care environment.

A Review of Agents for Palliative Sedation/Continuous Deep Sedation: Pharmacology and Practical Applications

Continuous deep sedation at the end of life is a specific form of palliative sedation requiring a care plan that essentially places and maintains the patient in an unresponsive state because their symptoms are refractory to any other interventions. Because this application is uncommon, many providers may lack practical experience in this specialized area and resources they can access are outdated, nonspecific, and/or not comprehensive. The purpose of this review is to provide an evidence- and experience-based reference that specifically addresses those medications and regimens and their practical applications for this very narrow, but vital, aspect of hospice care. Patient goals in a hospital and hospice environments are different, so the manner in which widely used sedatives are dosed and applied can differ greatly as well. Parameters applied in end-of-life care that are based on experience and a thorough understanding of the pharmacology of those medications will differ from those applied in an intensive care unit or other medical environments. By recognizing these different goals and applying well-founded regimens geared specifically for end-of-life sedation, we can address our patients' symptoms in a more timely and efficacious manner.

Optimizing sedation in patients with acute brain injury

Daily interruption of sedative therapy and limitation of deep sedation have been shown in several randomized trials to reduce the duration of mechanical ventilation and hospital length of stay, and to improve the outcome of critically ill patients. However, patients with severe acute brain injury (ABI; including subjects with coma after traumatic brain injury, ischaemic/haemorrhagic stroke, cardiac arrest, status epilepticus) were excluded from these studies. Therefore, whether the new paradigm of minimal sedation can be translated to the neuro-ICU (NICU) is unclear. In patients with ABI, sedation has ‘general’ indications (control of anxiety, pain, discomfort, agitation, facilitation of mechanical ventilation) and ‘neuro-specific’ indications (reduction of cerebral metabolic demand, improved brain tolerance to ischaemia). Sedation also is an essential therapeutic component of intracranial pressure therapy, targeted temperature management and seizure control. Given the lack of large trials which have evaluated clinically relevant endpoints, sedative selection depends on the effect of each agent on cerebral and systemic haemodynamics. Titration and withdrawal of sedation in the NICU setting has to be balanced between the risk that interrupting sedation might exacerbate brain injury (e.g. intracranial pressure elevation) and the potential benefits of enhanced neurological function and reduced complications. In this review, we provide a concise summary of cerebral physiologic effects of sedatives and analgesics, the advantages/disadvantages of each agent, the comparative effects of standard sedatives (propofol and midazolam) and the emerging role of alternative drugs (ketamine). We suggest a pragmatic approach for the use of sedation-analgesia in the NICU, focusing on some practical aspects, including optimal titration and management of sedation withdrawal according to ABI severity.

Respiratory depression in the intoxicated trauma patient: are opioids to blame?

Providing effective pain management to acutely intoxicated trauma patients represents a challenge of balancing appropriate pain management with the risk of potential respiratory depression from opioid administration. The objective of this study was to quantify the incidence of respiratory depression in trauma patients acutely intoxicated with ethanol who received opioids as compared with those who did not and identify potential risk factors for respiratory depression in this population. Retrospective medical record review was conducted for subjects identified via the trauma registry who were admitted as a trauma activation and had a detectable serum ethanol level upon admission. Risk factors and characteristics compared included demographics, Injury Severity Score, Glasgow Coma Score, serum ethanol level upon arrival, urine drug screen results, incidence of respiratory depression, and opioid and other sedative medication use. A total of 233 patients were included (78.5% male). Patients who received opioids were more likely to have a higher Injury Severity Score and initial pain score on admission as compared with those who did not receive opioids. Blood ethanol content was higher in patients who did not receive opioids (0.205 vs 0.237 mg/dL, P = .015). Patients who did not receive opioids were more likely to be intubated within 4 hours of admission (1.7% vs 12.1%, P = .02). Opioid administration was not associated with increased risk of respiratory depression (19.7% vs 22.4%, P = .606). Increased cumulative fentanyl dose was associated with increased risk of respiratory depression. Increased cumulative fentanyl dose, but not opioid administration alone, was found to be a risk factor for respiratory depression.

Optimizing Sedation Management to Promote Early Mobilization for Critically Ill Children

Achieving successful early mobilization for the intubated, critically ill child is dependent on optimizing sedation and analgesia. Finding the fine balance between oversedation and undersedation can be challenging. The ideal is for a child to be lucid and interactive during the daytime and demonstrate normal circadian rhythm for sleep with rest at night. Being alert during the day facilitates active participation in therapy including potential ambulation, while decreasing the risk of delirium during mechanical ventilation. An active state during the day with frequent mobilization promotes restorative sleep at night, which brings with it multiple benefits for healing and recovery. Indeed, this ideal may not be physiologically feasible given a child's critical illness and trajectory, but defining it as the "gold standard" for early mobilization provides a consistent goal for the pediatric intensive care unit (PICU) hospitalization. As such, goal-directed, patient-specific sedation plans are integral to creating a culture of mobility in the PICU. We review currently available sedation strategies for mechanically ventilated children for successful implementation of early mobilization in the PICU, as well as pharmacologic considerations for specific classes of sedative-analgesics.

Sedation, sleep promotion, and delirium screening practices in the care of mechanically ventilated children: a wake-up call for the pediatric critical care community*

OBJECTIVES

To examine pediatric intensivist sedation management, sleep promotion, and delirium screening practices for intubated and mechanically ventilated children.

DESIGN

An international, online survey of questions regarding sedative and analgesic medication choices and availability, sedation protocols, sleep optimization, and delirium recognition and treatment.

SETTING

Member societies of the World Federation of Pediatric Intensive and Critical Care Societies were asked to send the survey to their mailing lists; responses were collected from July 2012 to January 2013.

SUBJECTS

Pediatric critical care providers.

INTERVENTIONS

Survey.

MEASUREMENTS AND MAIN RESULTS

The survey was completed by 341 respondents, the majority of whom were from North America (70%). Twenty-seven percent of respondents reported having written sedation protocols. Most respondents worked in PICUs with sedation scoring systems (70%), although only 42% of those with access to scoring systems reported routine daily use for goal-directed sedation management. The State Behavioral Scale was the most commonly used scoring system in North America (22%), with the COMFORT score more prevalent in all other countries (39%). The most commonly used sedation regimen for intubated children was a combination of opioid and benzodiazepine (72%). Most intensivists chose fentanyl as their first-line opioid (66%) and midazolam as their first-line benzodiazepine (86%) and prefer to administer these medications as continuous infusions. Propofol and dexmedetomidine were the most commonly restricted medications in PICUs internationally. Use of earplugs, eye masks, noise reduction, and lighting optimization for sleep promotion was uncommon. Delirium screening was not practiced in 71% of respondent's PICUs, and only 2% reported routine screening at least twice a day.

CONCLUSIONS

The results highlight the heterogeneity in sedation practices among intensivists who care for critically ill children as well as a paucity of sleep promotion and delirium screening in PICUs worldwide.

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.

Should Benzodiazepine Sedation be Delivered by Infusion or Bolus?

Benzodiazepine sedation for mechanically ventilated patients in intensive care (ICU) is common practice worldwide. We performed a literature review to investigate whether benzodiazepine sedation is best delivered by continuous infusion or intermittent bolus. PubMed, Ovid and Cochrane databases were searched. Only four studies, involving 481 patients, were found. Three were randomised controlled trials and one was an observational cohort study; all used different benzodiazepines, sometimes in conjunction with opiates. The studies measured different outcomes including mechanical ventilation duration, length of ICU and hospital stay, quality and complications of sedation and mortality. Use of intermittent sedation or opiate boluses alone reduced mechanical ventilation duration, ICU and hospital length of stay. However such limited data means that the optimal mode of delivery for benzodiazepine sedation remains unresolved.

Sedation for critically ill or injured adults in the intensive care unit: a shifting paradigm

As most critically ill or injured patients will require some degree of sedation, the goal of this paper was to comprehensively review the literature associated with use of sedative agents in the intensive care unit (ICU). The first and selected latter portions of this article present a narrative overview of the shifting paradigm in ICU sedation practices, indications for uninterrupted or prolonged ICU sedation, and the pharmacology of sedative agents. In the second portion, we conducted a structured, although not entirely systematic, review of the available evidence associated with use of alternative sedative agents in critically ill or injured adults. Data sources for this review were derived by searching OVID MEDLINE and PubMed from their first available date until May 2012 for relevant randomized controlled trials (RCTs), systematic reviews and/or meta-analyses and economic evaluations. Advances in the technology of mechanical ventilation have permitted clinicians to limit the use of sedation among the critically ill through daily sedative interruptions or other means. These practices have been reported to result in improved mortality, a decreased length of ICU and hospital stay and a lower risk of drug-associated delirium. However, in some cases, prolonged or uninterrupted sedation may still be indicated, such as when patients develop intracranial hypertension following traumatic brain injury. The pharmacokinetics of sedative agents have clinical importance and may be altered by critical illness or injury, co-morbid conditions and/or drug-drug interactions. Although use of validated sedation scales to monitor depth of sedation is likely to reduce adverse events, they have no utility for patients receiving neuromuscular receptor blocking agents. Depth of sedation monitoring devices such as the Bispectral Index (BIS©) also have limitations. Among existing RCTs, no sedative agent has been reported to improve the risk of mortality among the critically ill or injured. Moreover, although propofol may be associated with a shorter time to tracheal extubation and recovery from sedation than midazolam, the risk of hypertriglyceridaemia and hypotension is higher with propofol. Despite dexmedetomidine being linked with a lower risk of drug-associated delirium than alternative sedative agents, this drug increases risk of bradycardia and hypotension. Among adults with severe traumatic brain injury, there are insufficient data to suggest that any single sedative agent decreases the risk of subsequent poor neurological outcomes or mortality. The lack of examination of confounders, including the type of healthcare system in which the investigation was conducted, is a major limitation of existing pharmacoeconomic analyses, which likely limits generalizability of their results.

Current sedation practices: lessons learned from international surveys

Limitations are inherent to surveys. Most surveys have low response rates, which raises the issue of responder bias. Another limitation of self-report surveys stems from the possible differences between stated and actual practice. That is, what physicians report that they do in surveys often contrasts significantly with what they do in observational studies, as highlighted by the Canadian surveys conducted in 2002 and 2008. Some surveys report estimates provided by ICU nurse managers or physician directors, potentially resulting in inaccurate estimates or data reflecting the individuals practice rather than the entire ICU. Surveys may not reflect how different specialists practice; for example, the German surveys collected data only in ICUs run by anesthesiologists.Notwithstanding these limitations, surveys provide a wealth of information on current practice and determinants of practice, and serve as a useful tool to guide future research and educational interventions. The authors identified substantial international variation in the use of sedative and analgesic drugs, and marked changes over the last 10 years. Overall, there is a trend toward lighter sedation, along with a shift from benzodiazepines toward propofol, and from morphine toward fentanyl and remifentanil. Despite the publication of numerous studies and guidelines for sedation and analgesia, actual practice differs from recommended practice, suggesting that the impact of clinical trials and guidelines on physician practice is quite low. It is clear that there remain substantial barriers to the incorporation of sedation scales, protocols,and daily interruption into routine ICU care.

Sedation and analgesia in the mechanically ventilated patient

Sedation and analgesia are important components of care for the mechanically ventilated patient in the intensive care unit (ICU). An understanding of commonly used medications is essential to formulate a sedation plan for individual patients. The specific physiological changes that a critically ill patient undergoes can have direct effects on the pharmacology of drugs, potentially leading to interpatient differences in response. Objective assessments of pain, sedation, and agitation have been validated for use in the ICU for assessment and titration of medications. An evidence-based strategy for administering these drugs can lead to improvements in short- and long-term outcomes for patients. In this article, we review advances in the field of ICU sedation to provide an up-to-date perspective on management of the mechanically ventilated ICU patient.

Neurodevelopmental outcome following exposure to sedative and analgesic drugs for complex cardiac surgery in infancy

OBJECTIVES/AIM

To determine whether sedation/analgesia drugs used before, during, and after infant cardiac surgery are associated with neurodevelopmental outcome.

BACKGROUND

Animal models suggest detrimental effects of anesthetic drugs on the developing brain. Whether these results can be extrapolated to human neonates is unclear.

METHODS/MATERIALS

This is a prospective follow-up project conducted in Western Canada. In all infants ≤6 weeks of age having surgery for congenital heart disease between April 2003 and December 2006, demographic and perioperative variables were collected prospectively. Sedation/analgesia variables were collected retrospectively. For each drug class (inhalationals, opioids, benzodiazepines, ketamine, and chloral hydrate), we calculated the cumulative dose received during hospitalization, average dose received per day, and cumulative number of days the patient received the drug. The outcomes at 18-24 months were as follows: General Adaptive Composite and motor scaled scores of the Adaptive Behavior Assessment System, significant mental, motor, and vocabulary delay. Multivariable logistic and linear regression was used to analyze the data.

RESULTS

One hundred and thirty-five neonates underwent open heart surgery; 19 died, 16 had chromosomal abnormality, and five were lost to follow up, leaving 95 survivors for analysis. Multiple linear regression analysis found no evidence of an association between sedation/analgesia variables and ABAS-GAC score or motor scale score. Multiple logistic regression analysis found no evidence of an association between sedation/analgesia variables and significant mental, motor, or vocabulary delay.

CONCLUSION

We found no evidence of an association between dose and duration of sedation/analgesia drugs during the operative and perioperative period and adverse neurodevelopmental outcomes.

Analytic reviews: managing the agitated patient in the ICU: sedation, analgesia, and neuromuscular blockade

Physical and psychological distress is exceedingly common among critically ill patients and manifests generically as agitation. The dangers of over- and undertreatment of agitation have been well described, and the intensive care unit (ICU) physician must strike a balance in the fast-paced, dynamic ICU environment. Identification of common reversible etiologies for distress may obviate the need for pharmacologic therapy, but most patients receive some combination of sedative, analgesic, and neuroleptic medications during the course of their critical illness. As such, understanding key pharmacologic features of commonly used agents is critical. Structured protocols and objective assessment tools can optimize drug delivery and may ultimately improve patient outcomes by reducing ventilator days, ICU length of stay, and by reducing cognitive dysfunction.

Adverse drug events associated with the use of analgesics, sedatives, and antipsychotics in the intensive care unit

As critically ill patients frequently receive analgesics, sedatives, and antipsychotics to optimize patient comfort and facilitate mechanical ventilation, adverse events associated with the use of these agents can affect all organ systems and result in substantial morbidity and mortality. Although many of these adverse effects are common pharmacologic manifestations of the agent, and therefore frequently reversible, others are idiosyncratic and thus unexpected. The critically ill are more susceptible to adverse drug events than nonintensive care unit patients due to the high doses and long periods for which each of these agents are often administered, the frequent use of intravenous formulations that contain adjuvants that may lead to toxicity in some instances, and the high prevalence of end-organ dysfunction that affects the pharmacokinetic and pharmacodynamic response to therapy. This paper will review the most common and serious adverse drug events reported to occur with the use of sedatives, analgesics, and antipsychotics in the intensive care unit; highlight the pharmacokinetic, pharmacodynamic, and pharmacogenetic factors that can influence analgesic, sedative, and antipsychotic response and safety in the critically ill; and identify strategies that can be used to minimize toxicity with these agents.

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.

Sedation and analgesia in the pediatric intensive care unit following laryngotracheal reconstruction

BACKGROUND

Children undergoing laryngotracheal reconstruction (LTR) may remain electively intubated in the pediatric intensive care unit (PICU) for several days following surgery to facilitate wound healing. These patients require sedation and analgesia with or without neuromuscular blockade in order to prevent excessive head and neck movement with resultant tension on the tracheal anastomosis. Achieving this level of immobility features in caring for these children.

AIM

The aims of this article are to describe a variety of commonly used sedation and analgesic agents and to provide guidance as to their optimal use following LTR.

Sedation and analgesia in the pediatric Intensive Care Unit following laryngotracheal reconstruction

Deep levels of sedation and analgesia are needed in the majority of children who require prolonged tracheal intubation after laryngotracheal reconstruction (LTR). Drug doses may be determined most appropriately using validated scoring tools for sedation and analgesia; these scales continue to evolve and are used with increasing regularity in the pediatric intensive care unit (PICU). In this presentation, the validated scoring tools used to assess sedation and analgesia are reviewed, and specific agents used to manage sedation, analgesia, and neuromuscular blockade in the PICU after LTR are discussed.

[Weaning from the ventilator modalities and consequences]

Only few studies have focused on the issues raised by discontinuing sedation in ICU patients. Several lines of evidence allow defining the risk factors for the occurrence of a weaning syndrome due to discontinuation of sedatives and analgesics in ICU patients. These primarily include a prolonged (more than seven days) period of continuous intravenous administration of high doses of hypnotics and opioids. Weaning from sedation is tightly linked to weaning from the ventilator and this area should be the target of research work in the near future.

[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.

Fluid therapy in resuscitated sepsis: less is more

Fluid infusion may be lifesaving in patients with severe sepsis, especially in the earliest phases of treatment. Following initial resuscitation, however, fluid boluses often fail to augment perfusion and may be harmful. In this review, we seek to compare and contrast the impact of fluids in early and later sepsis; show that much fluid therapy is clinically ineffective in patients with severe sepsis; explore the detrimental aspects of excessive volume infusion; examine how clinicians assess the intravascular volume state; appraise the potential for dynamic indexes to predict fluid responsiveness; and recommend a clinical approach.

Acute severe asthma

Acute severe asthma remains a major economic and health burden. The natural history of acute decompensations is one of resolution and only about 0.4% of patients succumb overall. Mortality in medical intensive care units is higher but is less than 3% of hospital admissions. "Near-fatal" episodes may be more frequent, but precise figures are lacking. However, about 30% of medical intensive care unit admissions require intubation and mechanical ventilation with mortality of 8%. Morbidity and mortality increase with socioeconomic deprivation and ethnicity. Seventy to 80% of patients in emergency departments clear within 2 hours with standardized care. The relapse rate varies between 7 and 15%, depending on how aggressively the patient is treated. The airway obstruction in the 20-30% of people resistant to adrenergic agonists in the emergency department slowly reverses over 36-48 hours but requires intense treatment to do so. Current therapeutic options for this group consist of ipratropium and corticosteroids in combination with beta2 selective drugs. Even so, such regimens are not optimal and better approaches are needed. The long-term prognosis after a near-fatal episode is poor and mortality may approach 10%.

Sedation in the critically ill patient

The goal of critical care medicine is to support organ function and maintain homeostasis until healing can occur. Sedation and analgesia may blunt the physiologic and psychologic sequelae of intensive care unit stress, and support homeostasis. Although a wide variety of agents have been used empirically, the recognition of analgesia, amnesia, and hypnosis as discrete elements comprising the sedated state has facilitated an individualized approach to therapy. Because intensive care unit patients are a highly heterogeneous population with varying levels of end-organ compromise, the development of specific, easily titratable, parenteral agents has made intensive care unit sedation safer. A trend toward refining dosage regimens in order to minimize the total dose of drug administered and to reduce the occurrence of residual sedation is driven by utilization and cost concerns. The capability for simple bedside electrophysiologic monitoring of the level of sedation is expected to improve the ability to provide optimal therapy.

Economic evaluation of sustained sedation/analgesia in the intensive care unit

Lorazepam, midazolam, propofol and opioids are the primary agents that are used for sustained sedation and analgesia of critically ill patients. The choice of agent depends on safety profiles, expected outcomes, cost, patient characteristics and clinical experience. Few studies have comparatively evaluated the sedatives in terms of cost. Many factors, aside from drug costs, influence the total cost of sedation in the intensive care unit. This article reviews the cost parameters of intensive care unit sedation that are specific to the characteristics of commonly used sedatives and analgesics, evaluates economic studies and cost models, summarises alternative methods of sedation and analgesia, and provides practical recommendations for methods of cost containment, including daily sedation interruption, sedation monitoring and protocol implementation.

A randomized trial of intermittent lorazepam versus propofol with daily interruption in mechanically ventilated patients

OBJECTIVE

To compare duration of mechanical ventilation for patients randomized to receive lorazepam by intermittent bolus administration vs. continuous infusions of propofol using protocols that include scheduled daily interruption of sedation.

DESIGN

A randomized open-label trial enrolling patients from October 2001 to March 2004.

SETTING

Medical intensive care units of two tertiary care medical centers.

PATIENTS

Adult patients expected to require mechanical ventilation for >48 hrs and who required > or =10 mg of lorazepam or a continuous infusion of a sedative to achieve adequate sedation.

INTERVENTIONS

Patients were randomized to receive lorazepam by intermittent bolus administration or propofol by continuous infusion to maintain a Ramsay score of 2-3. Sedation was interrupted on a daily basis for both groups.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was median ventilator days. Secondary outcomes included 28-day ventilator-free survival, intensive care unit and hospital length of stay, and hospital mortality. Median ventilator days were significantly lower in the daily interruption propofol group compared with the intermittent bolus lorazepam group (5.8 vs. 8.4, p = .04). The difference was largest for hospital survivors (4.4 vs. 9.0, p = .006). There was a trend toward greater ventilator-free survival for patients in the daily interruption propofol group (median 18.5 days for propofol vs. 10.2 for lorazepam, p = .06). Hospital mortality was not different.

CONCLUSIONS

For medical patients requiring >48 hrs of mechanical ventilation, sedation with propofol results in significantly fewer ventilator days compared with intermittent lorazepam when sedatives are interrupted daily.

Sedation during mechanical ventilation: A trial of benzodiazepine and opiate in combination*

OBJECTIVE

To compare the efficacy of continuous intravenous sedation with midazolam alone vs. midazolam plus fentanyl ("co-sedation") during mechanical ventilation.

DESIGN

A randomized, prospective, controlled trial.

SETTING

A ten-bed medical intensive care unit at a university hospital.

PATIENTS

Thirty patients with respiratory failure who were expected to require >48 hrs of mechanical ventilation and who were receiving a sedative regimen that did not include opiate pain control.

INTERVENTIONS

An intravenous infusion of either midazolam alone or co-sedation was administered by a nurse-implemented protocol to achieve a target Ramsay Sedation Score set by the patient's physician. Study duration was 3 days, with a brief daily "wake-up."

MEASUREMENTS AND MAIN RESULTS

We recorded the number of hours/day that patients were "off-target" with their Ramsay Sedation Scores, the number of dose titrations per day, the incidence of patient-ventilator asynchrony, and the time required to achieve adequate sedation as measures of sedative efficacy. We also recorded sedative cost in U.S. dollars and adverse events including hypotension, hypoventilation, ileus, and coma. Compared with the midazolam-only group, the co-sedation group had fewer hours per day with an "off-target" Ramsay Score (4.2 +/- 2.4 and 9.1 +/- 4.9, respectively, p < .002). Fewer episodes per day of patient-ventilator asynchrony were noted in the co-sedation group compared with midazolam-only (0.4 +/- 0.1 and 1.0 +/- 0.2, respectively, p < .05). Co-sedation also showed nonsignificant trends toward a shorter time to achieve sedation, a need for fewer dose titrations per day, and a lower total sedative drug cost. There was a trend toward more episodes of ileus with co-sedation compared with midazolam-only (2 vs. 0).

CONCLUSIONS

In mechanically ventilated patients, co-sedation with midazolam and fentanyl by constant infusion provides more reliable sedation and is easier to titrate than midazolam alone, without significant difference in the rate of adverse events.

Complications of sedation and critical illness

Critically ill patients require sedation to reduce anxiety, agitation, and achieve therapeutic goals. Over-sedation in combination with multiple causes for extreme muscle weakness, however, interferes with recovery from critical illness. This article describes contributing factors and explores methods of preventing over-sedation and related sequelae.

Pharmacoeconomic Modeling of Lorazepam, Midazolam, and Propofol for Continuous Sedation in Critically Ill Patients

STUDY OBJECTIVE

To compare the expected costs of short-, intermediate-, and long-term sedation (< 24, 24-72, and > 72 hrs, respectively) with propofol, lorazepam, and midazolam in an intensive care unit.

METHODS

Decision-analysis models were constructed for each sedative and each duration by using institutional costs associated with drug administration and adverse events (including personnel time). Costs were expressed in 2002 U.S. dollars. Adverse events were agitation, hypertriglyceridemia and/or pancreatitis, hypotension, nutritional changes, ventilator-associated pneumonia, and prolonged awakening and/or extubation. MEDLINE and EMBASE databases were searched to obtain durations of sedation, the incidence of outcomes, and cost estimates of outcomes. The ability to maintain specific levels of sedation was assumed equivalent among the sedatives. Univariate sensitivity analyses were conducted to determine the cost-driving variables, and probabilistic sensitivity analyses were conducted by using second-order Monte Carlo simulations.

RESULTS

Weighted mean durations of sedation from 50 studies were 13.46 (short term), 45.27 (intermediate term), and 119.78 (long term) hours. Expected costs for sedation with lorazepam, midazolam, and propofol, respectively, were 497 dollars, 294 dollars, and 272 dollars short term; 932 dollars, 587 dollars, and 674 dollars intermediate term; and 1604 dollars, 1737 dollars, and 2033 dollars long term. Propofol was least costly in 86% of the short-term simulations, midazolam was least costly in 97.5% of the intermediate-term simulations, and lorazepam was least costly in 84% of the long-term simulations. The most important cost-driver for all sedatives was drug cost. Prolonged extubation after sedation was an important cost-driver for lorazepam and midazolam, especially as sedation was lengthened.

CONCLUSION

Propofol, midazolam, and lorazepam had the lowest expected costs for short-, intermediate-, and long-term sedation, respectively. Many factors aside from drug costs influenced the cost of sedation.

Sedation and analgesia in the pediatric intensive care unit

Various clinical situations may arise in the PICU that necessitate the use of sedation, analgesia, or both. Although there is a large clinical experience with midazolam in the PICU population and it remains the most commonly used benzodiazepine in this setting, lorazepam may provide an effective alternative, with a longer half-life and more predictable pharmacokinetics without the concern of active metabolites. However, there are limited reports regarding its use in the PICU population, and concerns exist regarding the potential for toxicity related to its diluent, propylene glycol. Although the synthetic opioid fentanyl frequently is chosen for use in the PICU setting because of its hemodynamic stability, preliminary data suggest morphine may have a slower development of tolerance and may cause fewer withdrawal symptoms than fentanyl. Morphine's safety profile includes long-term follow-up studies that have demonstrated no adverse central nervous system developmental effects from its use in neonates and infants. In the critically ill infant at risk following surgery for congenital heart disease, clinical experience supports the use of the synthetic opioids, given their ability to modulate PVR and prevent pulmonary hypertensive crisis. Alternatives to the benzodiazepines and opioids include ketamine, pentobarbital, or dexmedetomidine. Ketamine may be useful for patients with hemodynamic instability or airway reactivity. There are limited reports regarding the use of pentobarbital in the PICU, with one study raising concerns of a high incidence of adverse effects associated with its use. Propofol has gained great favor in the adult population as a means of providing deep sedation while allowing for rapid awakening; however, its routine use is not recommended because of its potential association with "propofol infusion syndrome." As the pediatric experience increases, it appears that there will be a role for newer agents such as dexmedetomidine.

Adverse Events Associated with Sedatives, Analgesics, and Other Drugs That Provide Patient Comfort in the Intensive Care Unit

Since the 2002 publication of multidisciplinary clinical practice guidelines for intensive care unit (ICU) sedation and analgesia, additional information regarding adverse drug events has been reported. Our understanding of the risks associated with these sedative and analgesic agents promises to improve outcomes by helping clinicians identify and respond to therapeutic misadventures sooner. This review focuses on many issues, including the potentially fatal consequences associated with the propofol infusion syndrome, the evolving understanding of propylene glycol intoxication associated with parenteral lorazepam, new data involving high-dose and long-term dexmedetomidine therapy, haloperidol- and methadone-related prolongation of QTc intervals on the electrocardiogram, adverse events associated with atypical antipsychotics, and the potential for nonsteroidal antiinflammatory drugs to interfere with bone healing.

Sedation, analgesia, and neuromuscular blockade for high-frequency oscillatory ventilation

OBJECTIVE

To provide a comprehensive review of the issue related to the administration of sedative, analgesic, and neuromuscular blocking agents (NMBA) to patients who are receiving ventilatory support for acute respiratory distress syndrome (ARDS) with high-frequency oscillatory ventilation.

RESULTS

Sedative, analgesic, and NMBA are used with great frequency in patients with severe ARDS who are undergoing high-frequency oscillatory ventilation. In particular, the use of NMBA has been higher than for other ARDS populations. Important considerations for effective treatment include careful patient evaluation, patient-based medication selection, identification of treatment goals with periodic re-assessment, titration of medications to objective parameters such as sedation scales and peripheral nerve stimulation, use of intermittent therapy when feasible, implementation of drug interruption strategies, and discontinuation of medications at the earliest possible time. It is important to recognize that patients evolve from severe ARDS through phases of recovery to the resolution of respiratory failure and that ventilatory management, as well as sedative and related medication requirements, will vary markedly over the course of this process.

CONCLUSIONS

A multidisciplinary, structured approach that is based on the considerations described should help achieve optimal results in this challenging patient population.

Analgesie und Sedierung in der Intensivmedizin

Sedation and analgesia are relevant aspects for the adequate treatment of patients in an intensive care unit. Recent drug developments and new strategies for ventilation provide improved sedation management allowing better adaptation to the clinical background and individual needs of the patient. This article provides an overview on the application of different substance groups. Focus is placed on newly developed pharmaceuticals such as dexmedetomidine. Another aspect is scoring system-related and EEG-based monitoring of depth of sedation. Modern concepts of analgesia and sedation for ICU patients have been developed based on the interaction of different parameters such as adaptive sedation and analgesia management (ASAM).

Severe exacerbations of asthma

All asthmatics regardless of their perceived severity, are at risk of exacerbation, particularly if they are suboptimally treated in the outpatient arena. Fortunately most patients recover after administration of bronchodilators and anti-inflammatory medications, but preventable deaths continue to occur and refractory cases result in hospitalization and need for mechanical ventilation. We begin this article by reviewing the pathophysiology of acute exacerbations to build a foundation for the assessment of clinical status and to provide the rationale for a carefully contemplated and evidence-based therapeutic approach. We end this article with an in-depth examination of the particular problems that are encountered during mechanical ventilation and offer a strategy that helps minimize complications. In the final analysis, however, the greatest gains in the field of acute asthma will come not from its treatment but from its prevention by enhanced educational and environmental efforts and by the delivery of optimal medications at home.

The interplay of lorazepam-induced brain oscillations: microstructural electromagnetic study

OBJECTIVE

The effects on cortical rhythms of a single-dose (30 microg/kg) administration of the GABAA agonist lorazepam were examined in a randomized, double-blind, cross-over, placebo-controlled study with 8 healthy volunteers using simultaneous electroencephalography (EEG) and magnetoencephalography (MEG).

METHODS

The oscillations were assessed by means of adaptive classification of short-term spectral patterns.

RESULTS

Lorazepam (a) decreased the percentage of EEG/MEG segments with fast-theta, delta-alpha, fast-theta-alpha and alpha activity and increased percentage of EEG/MEG segments with delta, delta-slow-theta, delta-beta, slow-theta and polyrhythmic activity; (b) decreased diversity of EEG/MEG signals (in terms of spectral patterns) and increased the general instability of the signal; (c) increased stabilization periods of the spectral patterns (reduced brain information processing); (d) maintained larger maximum periods of temporal stabilization for delta, slow-theta, delta-slow-theta, delta-beta and polyrhythmic activity (in terms of spectral patterns); (e) did not increase power in the independent beta rhythm.

CONCLUSIONS

Lorazepam caused significant reorganization of the EEG/MEG microstructure. These results suggest also that adaptive classification analysis of single short-term spectral patterns may provide additional information to conventional spectral analyses.

Management of agitation in the intensive care unit

Although the effective evaluation and management of agitated patients often receives less attention than other aspects of critical illness, it is among the most important and rewarding challenges that face critical care physicians. Key features of effective management include a thorough, organized search for potentially dangerous and correctable causes; a sound understanding of the pharmacology of analgesics and sedatives; and keeping a steady eye on appropriate management goals. In turn, the reward for excellent care will be shorter lengths of stay, more rapid liberation from mechanical ventilation, improved cognition, cost savings, and, perhaps, improved survival.

Sedation during mechanical ventilation: a systematic review

OBJECTIVE

A systematic review was performed to determine the most effective agent with which to sedate adult patients who have respiratory failure that requires mechanical ventilation in the medical intensive care unit.

DATA SOURCES

A computerized literature search of MEDLINE, a U.S. National Library of Medicine online database, from 1966 to August 1998 was conducted. All selected articles were reviewed to identify other relevant articles.

STUDY SELECTION

Inclusion criteria were as follows: a) population-adults with respiratory failure who received mechanical ventilation in a medical intensive care unit; b) design-prospective, randomized controlled trial; c) intervention-sedation; and d) primary outcome-successful sedation.

DATA EXTRACTION

Of 71 potentially relevant articles, only 15 randomized trials fulfilled all four selection criteria.

DATA SYNTHESIS

Clinical heterogeneity among studies precluded statistical pooling of results.

CONCLUSIONS

More research is needed to determine the most effective agent with which to sedate adult patients who have respiratory failure that requires mechanical ventilation in the medical intensive care unit.

Sedation in the intensive care unit

Although the administration of sedatives is a commonplace activity in the ICU, few guidelines are available to aid the clinician in this practice. The first principle of sedative administration is to define the specific problem requiring sedation and to rationally choose the drug and depth of sedation appropriate for the indication. Next, the clinician must recognize the diverse and often unpredictable effects of critical illness on drug pharmacokinetics and pharmacodynamics. Failure to recognize these effects may lead initially to inadequate sedation and subsequently to drug accumulation. Drug accumulation may result in prolonged encephalopathy and mechanical ventilation and may mask the development of neurologic or intra-abdominal complications. Daily interruption of continuous sedative infusions is a simple and effective way of addressing this problem. A glossary of sedative drugs commonly used in the ICU is included in this review.

Advances and Controversies in Adult ICU Sedation, Part 3: Evolving Pharmacological Treatment Issues

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient—an area of health care that has become increasingly complex. It will review recent advances (including evolving and controversial data) in drug therapy for adult ICU patients and assess these new modalities in terms of clinical, humanistic, and economic outcomes.

Correlation between midazolam and lignocaine pharmacokinetics and MEGX formation in healthy volunteers

AIMS

The objectives of the present investigation were: (a) to determine the correlation between lignocaine and midazolam pharmacokinetics following intravenous administration in healthy volunteers, (b) to determine the effects of treatment with an inhibitor of CYP3A4 (erythromycin) on this correlation and (c) to assess the precision of the MEGX-test as a sole predictor of lignocaine and midazolam pharmacokinetics.

METHODS

The study was conducted in four male and four female healthy volunteers, aged between 21 and 26 years, who received 1 mg kg-1 lignocaine HCl i.v. on days 1, 3, 5, 9 and 10 of the investigation. On days 5 and 10 they also received midazolam, 0.075 mg kg-1 i.v. and from days 6-10 they took erythromycin 500 mg orally, four times daily. Following administration of lignocaine and midazolam, frequent venous blood samples were obtained for determination of the concentrations of lignocaine, MEGX and midazolam.

RESULTS

In the absence of erythromycin a statistically significant linear correlation was observed between the clearance of lignocaine and midazolam (CL(midazolam)= 0.41 x CL(lignocaine)+ 1.2; r(2) = 0.857; P < 0.001). Erythromycin cotreatment resulted in a loss of the correlation between the two clearances (r(2) = 0.39; P = 0.1). Erythromycin caused a statistically significant reduction in midazolam clearance from the original value of 3.8 to 2.5 (95% CI for the difference -2.27, -0.35) ml kg-1 min-1. Interestingly there was no significant change in the clearance of lignocaine (6.4 vs 5.8 (95% CI for the difference -2.74, -1.51) ml kg-1 min-1). Furthermore no correlation at all was observed between the MEGX-test and lignocaine or midazolam clearances. Considering the data on day 1, 3 and 5 the intra-individual coefficient of variation in the MEGX-test was 45.3% at 15 min and 23.5% at 30 min, respectively.

CONCLUSIONS

It is concluded that there is a significant correlation between lignocaine and midazolam clearances but this correlation is lost after CYP3A4 inhibition by erythromycin. The MEGX-test is of no value in assessing intra- and inter-individual variability in midazolam clearance.

Analysis of pharmacoeconomics of sedation and analgesia

Intravenous sedation and analgesia are cornerstones of the pharmacologic management of the critically ill, mechanically ventilated adult patient. No conclusive evidence exists to support any single optimal sedative or analgesic regimen in this heterogeneous population. The role of cost effectiveness in the process of selecting a regimen is explored with a review of the literature, followed by proposed cost-effectiveness models and recommendations for the clinical practitioner.

Benzodiazepines in the intensive care unit

The effects of BZ drugs result from interaction at the GABAA receptor within the CNS, producing anxiolysis, hypnosis, and amnesia in a dose-dependent fashion. These sedative effects are best titrated to reproducible clinical endpoints, using scoring systems such as the Ramsay scale. All BZs exhibit similar pharmacologic effects, but the important differences in pharmacokinetics and pharmacodynamics should be recognized to use these drugs safely and effectively within the ICU. Diazepam is the classic anxiolytic, amnestic, and sedative agent, but the presence of long-acting active metabolites that depend on the kidneys for elimination limits its use in many ICU patients. Lorazepam is the most potent BZ used in the ICU; it has stable pharmacokinetics and relatively low cost. This drug is best reserved for situations in which rapid onset is not essential and long-term sedation is anticipated. Midazolam has the shortest t1/2 of the commonly used BZs, generates few active metabolites, and is water soluble at physiologic pH. Thus, it is well suited for continuous infusion in the ICU, and the recent introduction of generic formulations of midazolam has decreased the drug-acquisition cost for many hospitals. Optimal sedation for ICU patients often requires BZ and concomitant therapy with drugs such as haloperidol, dexmedetomidine, opioids, and so forth, to reduce untoward side effects and, perhaps, overall drug costs. Flumazenil, a specific BZ antagonist, can be used for diagnostic or therapeutic reversal of BZ agonists when appropriate. Most experienced intensivists recommend an individualized approach to sedation and titration of anxiolysis to maximize efficacy, minimize side effects, and optimize cost effectiveness in the ICU. New CNS monitors of the EEG, such as the BIS or entropy EEG monitors, may refine titration algorithms further in the near future.