Dexmedetomidine: a review of its use for sedation in mechanically ventilated patients in an intensive care setting and for procedural sedation

Adequate sedation with single-dose dexmedetomidine in patients undergoing transurethral resection of the prostate with spinal anaesthesia: a dose-response study by age group

Background

Dexmedetomidine (DMT), a highly selective α2-adrenoceptor agonist, has been used safely as a sedative in patients under regional anesthesia. The purpose of this study was to determine the 50% effective dose (ED₅₀) of single-dose DMT to induce adequate light sedation in elderly patients in comparison with younger patients undergoing transurethral resection of the prostate (TURP) with spinal anesthesia.

Methods

Forty-two male patients were recruited. The young age group (Group Y) included patients 45 to 64 years old and the old age group (Group O) included patients 65 to 78 years old. After the spinal anesthesia was performed, a pre-calculated dose of DMT was administered for 10 min. The Observer’s Assessment of Alertness/Sedation (OAA/S) scale, bispectral index score (BIS) were assessed then at 2-min intervals for 20 min. A modified Dixon’s up-and-down method was used to determine the ED₅₀ of the drug for light sedation (OAA/S score 3/4). In the recovery room, regression times of the motor and sensory blocks were recorded.

Results

The ED₅₀ of DMT was 0.25 (95% C.I. 0.15-0.35) μg/kg in Group O and 0.35 (95% C.I. 0.35-0.45) μg/kg in Group Y (p = 0.002). The ED₉₅ was 33% lower in Group O compare with Group Y (0.38 (95% C.I. 0.29-0.39) μg/kg vs. 0.57 (95% C.I. 0.49-0.59) μg/kg). The regression time of sensory block was longer in Group O than in Group Y (109.0 ± 40.2 min vs. 80.0 ± 31.6 min) (p = 0.014).

Conclusion

The single-dose of DMT for light sedation was lower by 21% in Group O compare with Group Y underwent TURP with spinal anesthesia.

Trial registration

ClinicalTrials.gov identifier: NCT01665586. Registered July 31, 2012.

Is it prime time for alpha2-adrenocepter agonists in the treatment of withdrawal syndromes?

The need to treat withdrawal syndromes is a common occurrence in outpatient, inpatient ward, and intensive care unit (ICU) settings. A PubMed and Google Scholar search using alpha2-adrenoreceptor agonist (A2AA), specific A2AA agents, withdrawal syndrome and nicotine, and alcohol and opioid withdrawal terms was performed. A2AA agents appear to be able to modulate many of the signs and symptoms of significant withdrawal syndromes but are also capable of significant side effects, which can limit clinical use. Non-opioid oral A2AA agent use for opioid withdrawal has been well established. Pharmacologic combination therapy that utilizes A2AA agents for withdrawal syndromes appears promising but requires further formal testing to better define which other agents, under what condition(s), and at what A2AA doses are needed. The A2AA dexmedetomidine may be useful as an adjunctive agent in treating severe alcohol withdrawal syndromes in the ICU. In general, the current data does not support the routine use of A2AA as the primary or sole agent to treat ethanol/alcohol or nicotine withdrawal syndromes. Specific A2AA agents such as lofexidine has been shown to have a primary role in non-opioid-based treatment of opioid withdrawal syndrome and dexmedetomidine in combination with benzodiazepines has been shown to have potential in the treatment of severe ICU-based alcohol withdrawal syndrome.

Dexmedetomidine added to ropivacaine extends the duration of interscalene brachial plexus blocks for elective shoulder surgery when compared with ropivacaine alone: a single-center, prospective, triple-blind, randomized controlled trial

BACKGROUND AND OBJECTIVES

Research suggests that the addition of dexmedetomidine to local anesthetics can prolong peripheral nerve blocks; however, clinical safety data are limited, and interscalene blocks have not been studied. The present study was designed to test the hypothesis that dexmedetomidine added to ropivacaine would safely enhance the duration of analgesia without adverse effects when compared with ropivacaine alone.

METHODS

We conducted a single-center, prospective, randomized, triple-blind, controlled trial of 62 patients undergoing elective shoulder surgery under general anesthesia with an interscalene block. Patients underwent ultrasound-guided interscalene blocks using either 12 mL of 0.5% ropivacaine or 0.5% ropivacaine plus 150-µg dexmedetomidine. The primary outcomes were self-reported duration of the nerve block and safety assessment (adverse effects and neurological sequelae). Data were analyzed in a blinded fashion.

RESULTS

The median duration of the nerve block was 18 hours (95% confidence interval, 18-20) in the dexmedetomidine group and 14 hours (95% confidence interval, 14-16) in the ropivacaine group (P = 0.0001). Dexmedetomidine also lowered pain scores for the first 14 hours postoperatively and significantly hastened the time to sensory (P = 0.04) and motor (P = 0.002) block onset. Dexmedetomidine lowered heart rate but blood pressures were stable. Plasma levels of ropivacaine were not different between groups, and plasma dexmedetomidine levels were relatively low. There were no adverse events or neurological sequelae.

CONCLUSIONS

Dexmedetomidine added to ropivacaine for interscalene blocks increased the duration of the nerve block and improved postoperative pain. These additional efficacy and safety data should encourage further study of peripheral perineural dexmedetomidine in humans.

The pharmacologic management of delirium in children and adolescents

Delirium is a serious and common problem in severely medically ill patients of all ages. It has been less addressed in children and adolescents. Treatment of delirium is predicated on addressing its underlying cause. The management of its symptoms depends on the off-label use of antipsychotics, while avoiding agents that precipitate or worsen delirium. Olanzapine, quetiapine, and risperidone are presently considered first-line drugs, usually replacing haloperidol. Other agents have shown promise, including melatonin to address the sleep disturbance characteristic of delirium, and dexmedetomidine, an α2-agonist, that may facilitate lower doses of benzodiazepines and opioids that may worsen delirium.

The effects of different loading doses of dexmedetomidine on sedation

BACKGROUND

Dexmedetomidine is a useful sedative drug with various uses. We designed this study to investigate the clinical effects and complications of different loading doses, 0.5 and 1.0 µg/kg.

METHODS

Forty six patients, of American Society of Anesthesiologists physical status I and II, who required elective and emergency operation under spinal anesthesia were randomly assigned to group L or group H. Group L received a loading dose of 0.5 µg/kg for 10 minutes while group H received 1.0 µg/kg. Bispectral index (BIS), systolic blood pressure, heart rate, and Ramsay score were recorded at T0 (before loading), TL (just after loading) and T10, 20, 30 (10, 20, 30 minutes after TL). Complications, drug use, lowest BIS and time to reach BIS 80 after termination of dexmedetomidine were recorded during this study.

RESULTS

In group H, BIS value decreased significantly after TL compared to the baseline (T0), while in group L after T10. Between two groups, BIS values showed a significant differences only at T10, BIS of group H was lower than that of group L. Ramsay score showed no significant differences except in TL; the score of group L was significantly lower than that of group H. Other vital signs and complications showed a minimal differences between two groups.

CONCLUSIONS

Higher loading dose (1.0 µg/kg) of dexmedetomidine can lead to faster sedation without any severe complications.

[Interaction between hypnotic agents and the hypothalamic-pituitary-adrenocorticotropic axis during surgery]

During stress, the relationship between the central nervous system and the immune system is essential to maintain homeostasis. The main neuroendocrine system involved in this interaction is the hypothalamic-pituitary-adrenal axis (HPA), which via the synthesis of glucocorticoids will modulate the intensity of the inflammatory response. Anaesthetic agents could be interacting with the HPA axis during surgery. Although etomidate currently remains in the center of the discussions, it seems, at least experimentally, that most hypnotics have the capacity to modulate the synthesis of adrenal steroids. Nevertheless, with the large literature on this subject, etomidate seems to be the most deleterious hypnotic agent on the HPA axis function. Its use should be limited when HPA axis is already altered.

[Nursing team knowledge on behavioral assessment of pain in critical care patients]

This investigation consisted on a prospective cross-sectional study that aimed to describe the nursing team knowledge on behavioral assessment of pain. The study was conducted in a private hospital in the city of Sao Paulo, Brazil in November 2011, with nursing professionals from a general adult intensive care unit. They answered a questionnaire that contained sociodemographic data and questions related to knowledge about a behavioral assessment of pain. Descriptive data analysis was carried out and the average positive score was compared among categories using the Mann-Whitney test. Out of the 113 participants, over 70% have demonstrated knowledge of the main aspects of this assessment and there was no statistical significant difference among the professional categories. It was concluded that the knowledge of the professionals was satisfactory, but it can be improved.

Interpatient variability in dexmedetomidine response: a survey of the literature

Fifty-five thousand patients are cared for in the intensive care unit (ICU) daily with sedation utilized to reduce anxiety and agitation while optimizing comfort. The Society of Critical Care Medicine (SCCM) released updated guidelines for management of pain, agitation, and delirium in the ICU and recommended nonbenzodiazepines, such as dexmedetomidine and propofol, as first line sedation agents. Dexmedetomidine, an alpha-2 agonist, offers many benefits yet its use is mired by the inability to consistently achieve sedation goals. Three hypotheses including patient traits/characteristics, pharmacokinetics in critically ill patients, and clinically relevant genetic polymorphisms that could affect dexmedetomidine response are presented. Studies in patient traits have yielded conflicting results regarding the role of race yet suggest that dexmedetomidine may produce more consistent results in less critically ill patients and with home antidepressant use. Pharmacokinetics of critically ill patients are reported as similar to healthy individuals yet wide, unexplained interpatient variability in dexmedetomidine serum levels exist. Genetic polymorphisms in both metabolism and receptor response have been evaluated in few studies, and the results remain inconclusive. To fully understand the role of dexmedetomidine, it is vital to further evaluate what prompts such marked interpatient variability in critically ill patients.

Dexmedetomidine for the treatment of alcohol withdrawal syndrome: rationale and current status of research

Dexmedetomidine is currently used in the US in the treatment of alcohol withdrawal syndrome (AWS) in the intensive care unit (ICU) setting, although data to support this practice are limited. Dexmedetomidine targets the noradrenergic system, an important but frequently overlooked secondary mechanism in the development of AWS, and, in doing so, may reduce the need for excessive benzodiazepine use which can increase the risk of γ-aminobutyric acid (GABA)-mediated deliriogenesis and respiratory depression. The purpose of this narrative review is to evaluate available literature reporting on the safety and efficacy of dexmedetomidine for AWS in the ICU setting. An English-language MEDLINE search (1966 to July 2013) was performed to identify articles evaluating the efficacy and safety of dexmedetomidine for AWS. Case series, case reports and controlled trials were evaluated for topic relevance and clinical applicability. Reference lists of articles retrieved through this search were reviewed to identify any relevant publications. Studies focusing on the safety and efficacy of dexmedetomidine for AWS in humans were selected. Studies were included if they were published as full articles; abstracts alone were not included in this review. Eight published case studies and case series were identified. Based on a limited body of evidence, dexmedetomidine shows promise as a potentially safe and possibly effective adjuvant treatment for AWS in the ICU. Prospective, well-controlled studies are needed to confirm the safety and efficacy of the use of dexmedetomidine in AWS.

Preanesthetic dexmedetomidine 1 µg/kg single infusion is a simple, easy, and economic adjuvant for general anesthesia

Background

Dexmedetomidine is an α₂-adrenoreceptor agonist with sedative, analgesic and anxiolytic effects, and it has more selective α₂-adrenergic effect than clonidine. We evaluate the effect of preansethetic dexmedetomidine 1 µg/kg single infusion on sedation, hemodynamics, anesthetic consumption, and recovery profiles during anesthesia.

Methods

Forty-two female patients with American Society of Anesthesiologists physical status I or II undergoing gynecologic surgery with anticipated operation time of 2 h, were randomly assigned to receive dexmedetomidine 1 µg/kg (Dex group) or saline (control group) iv over 10 min before anesthetic induction. After tracheal intubation with propofol 2 mg/kg, cisatracurium 0.15 mg/kg iv, anesthesia was maintained with sevoflurane, O₂ 50%, N₂O 50% around a BIS value of 40.

Results

After study drug infusion, BIS of Dex group was lower than that of control group (93.9 ± 3.1 vs 51.5 ± 5.2, P < 0.05). Mean arterial pressure (MAP) and heart rate (HR) after intubation were increased in control group, but did not change in Dex group. During maintenance, there was no difference in MAP between groups, but HR of Dex group was lower compared to that of control group. End-tidal concentration (2.0 ± 0.5 vol% vs 1.4 ± 0.3 vol%, P < 0.05) and total cumulative consumption of sevoflurane (34.6 ± 3.8 ml vs 26.5 ± 5.3 ml, P < 0.05) were lower in Dex group than in control group. Recovery profiles, modified Aldrete score, postoperative nausea vomiting, and visual analogue pain score were not significantly different between groups.

Conclusions

Preanesthetic dexmetomidine 1 µg/kg single infusion is a simple, easy, and economic general anesthetic adjuvant that maintains stable hemodynamics and decrease anesthetic consumption without the change of recovery profiles.

Dexmedetomidine infusion associated with transient adrenal insufficiency in a pediatric patient: a case report

Dexmedetomidine is a highly selective α₂-adrenoceptor agonist used for sedation due to its anxiolytic and analgesic properties without respiratory compromise. Due to its structural similarity to etomidate, there has been concern that dexmedetomidine may cause adrenal insufficiency. This concern was initially supported by animal studies, but subsequent human studies demonstrated mixed results. We describe the case of transient adrenal insufficiency in a 1-year-old male who presented with 24% total body surface 2nd degree burns. He required sedation with a prolonged, high-dose dexmedetomidine infusion with a peak infusion dose of 2.7 mcg/kg/hr and duration of 6.5 days. The patient developed lethargy and hypotension four days after discontinuation of his infusion. He had a random cortisol level which was low at 0.4 mcg/dL, and the concern for adrenal suppression was confirmed with an ACTH stimulation test with the baseline cortisol of 0.4 mcg/dL and inappropriate 60 minute post-ACTH stimulation cortisol of 7.8 mcg/dL. While further studies will be needed to clarify the risk of adrenal suppression secondary to dexmedetomidine, this case suggests that caution should be taken when administering dexmedetomidine to pediatric patients and highlights the need for future studies to look at appropriate dosing and duration of dexmedetomidine infusions.

[Indications of dexmedetomidine in the current sedoanalgesia tendencies in critical patients]

Recently, dexmedetomidine has been marketed in Spain and other European countries. The published experience regarding its use has placed dexmedetomidine on current trends in sedo-analgesic strategies in the adult critically ill patient. Dexmedetomidine has sedative and analgesic properties, without respiratory depressant effects, inducing a degree of depth of sedation in which the patient can open its eyes to verbal stimulation, obey simple commands and cooperate in nursing care. It is therefore a very useful drug in patients who can be maintained on mechanical ventilation with these levels of sedation avoiding the deleterious effects of over or infrasedation. Because of its effects on α2-receptors, it's very useful for the control and prevention of tolerance and withdrawal to other sedatives and psychotropic drugs. The use of dexmedetomidine has been associated with lower incidence of delirium when compared with other sedatives. Moreover, it's a potentially useful drug for sedation of patients in non-invasive ventilation.

Effect of sedation on pain perception

BACKGROUND

Sedation or anesthesia is used to facilitate many cases of an estimated 45 million diagnostic and therapeutic medical procedures in the United States. Preclinical studies have called attention to the possibility that sedative-hypnotic drugs can increase pain perception, but whether this observation holds true in humans and whether pain-modulating effects are agent-specific or characteristic of IV sedation in general remain unclear.

METHODS

To study this important clinical question, the authors recruited 86 healthy volunteers and randomly assigned them to receive one of three sedative drugs: midazolam, propofol, or dexmedetomidine. The authors asked participants to rate their pain in response to four experimental pain tasks (i.e., cold, heat, ischemic, or electrical pain) before and during moderate sedation.

RESULTS

Midazolam increased cold, heat, and electrical pain perception significantly (10-point pain rating scale change, 0.82 ± 0.29, mean ± SEM). Propofol reduced ischemic pain and dexmedetomidine reduced both cold and ischemic pain significantly (-1.58 ± 0.28, mean ± SEM). The authors observed a gender-by-race interaction for dexmedetomidine. In addition to these drug-specific effects, the authors observed gender effects on pain perception; female subjects rated identical experimental pain stimuli higher than male subjects. The authors also noted race-drug interaction effects for dexmedetomidine, with higher doses of drug needed to sedate Caucasians compared with African Americans.

CONCLUSIONS

The results of the authors' study call attention to the fact that IV sedatives may increase pain perception. The effect of sedation on pain perception is agent- and pain type-specific. Knowledge of these effects provides a rational basis for analgesia and sedation to facilitate medical procedures.

Impact of a Protocol Advocating Dexmedetomidine Over Propofol Sedation After Robotic-Assisted Direct Coronary Artery Bypass Surgery on Duration of Mechanical Ventilation and Patient Safety

BACKGROUND

Controversy remains whether propofol or dexmedetomidine is the preferred sedative following cardiac surgery. Dexmedetomidine may offer advantages over propofol among patients undergoing robotic-assisted, minimally invasive, direct coronary artery bypass (MIDCAB) surgery given the rapidity with which this population is usually extubated after surgery.

OBJECTIVE

To measure the impact of a surgery protocol advocating use of dexmedetomidine rather than propofol after MIDCAB surgery on discontinuation of mechanical ventilation and patient safety.

METHODS

The records on consecutive adults undergoing MIDCAB surgery who received postoperative sedation with propofol or dexmedetomidine at a 508-bed academic medical center were analyzed before and after implementation of a post-MIDCAB surgery protocol advocating dexmedetomidine use.

RESULTS

Seventy-three propofol patients were compared with 53 dexmedetomidine patients. The groups were similar, except propofol patients were older (p = 0.002) and more likely to have underlying heart failure that was either moderate or severe (New York Heart Association class III or IV) (p = 0.0001). Time (median [interquartile range]) to extubation (hours) was shorter in the dexmedetomidine group (5.0 [3.6–7.0] vs 9.8 [5.0–16.3]; p = 0.0001). A Cox proportional hazards model revealed that patient age (p = 0.001) and duration of surgery (p = 0.003) influenced time to extubation between the dexmedetomidine and propofol groups but the presence of moderate or severe heart failure (p = 0.438), the number of coronary vessels operated on (p = 0.130), use of an opioid (p = 0.791), or the total dose of morphine administered (p = 0.215) did not. During sedation administration, more propofol-treated patients experienced 1 or more episodes of hypotension (systolic blood pressure ≤80 mm Hg, 11.6% vs 0%; p = 0.02), tachycardia (heart rate ≥120 beats/min, 8.6% vs 0%; p = 0.04), and unarousability (Sedation Agitation Scale score ≤2, 30.0% vs 9.4%; p = 0.03).

CONCLUSIONS

Use of a protocol promoting dexmedetomidine, rather than propofol sedation, after MIDCAB surgery facilitates faster discontinuation of mechanical ventilation and is associated with greater hemodynamic stability and arousability.

Sedation and analgesia in mechanically ventilated preterm neonates: continue standard of care or experiment?

Attention to comfort and pain control are essential components of neonatal intensive care. Preterm neonates are uniquely susceptible to pain and agitation, and these exposures have a negative impact on brain development. In preterm neonates, chronic pain and agitation are common adverse effects of mechanical ventilation, and opiates or benzodiazepines are the pharmacologic agents most often used for treatment. Questions remain regarding the efficacy, safety, and neurodevelopmental impact of these therapies. Both preclinical and clinical data suggest troubling adverse drug reactions and the potential for adverse longterm neurodevelopmental impact. The negative impacts of standard pharmacologic agents suggest that alternative agents should be investigated. Dexmedetomidine is a promising alternative therapy that requires further interprofessional and multidisciplinary research in this population.

Sedation in gastrointestinal endoscopy: current issues

Diagnostic and therapeutic endoscopy can successfully be performed by applying moderate (conscious) sedation. Moderate sedation, using midazolam and an opioid, is the standard method of sedation, although propofol is increasingly being used in many countries because the satisfaction of endoscopists with propofol sedation is greater compared with their satisfaction with conventional sedation. Moreover, the use of propofol is currently preferred for the endoscopic sedation of patients with advanced liver disease due to its short biologic half-life and, consequently, its low risk of inducing hepatic encephalopathy. In the future, propofol could become the preferred sedation agent, especially for routine colonoscopy. Midazolam is the benzodiazepine of choice because of its shorter duration of action and better pharmacokinetic profile compared with diazepam. Among opioids, pethidine and fentanyl are the most popular. A number of other substances have been tested in several clinical trials with promising results. Among them, newer opioids, such as remifentanil, enable a faster recovery. The controversy regarding the administration of sedation by an endoscopist or an experienced nurse, as well as the optimal staffing of endoscopy units, continues to be a matter of discussion. Safe sedation in special clinical circumstances, such as in the cases of obese, pregnant, and elderly individuals, as well as patients with chronic lung, renal or liver disease, requires modification of the dose of the drugs used for sedation. In the great majority of patients, sedation under the supervision of a properly trained endoscopist remains the standard practice worldwide. In this review, an overview of the current knowledge concerning sedation during digestive endoscopy will be provided based on the data in the current literature.

Delirium Uncovered

Delirium is defined as an acute confusional state with a disturbance of consciousness and a change in cognition which is fluctuating and self-limited in the vast majority of the cases. It is common in intensive care, most frequently in its hypoactive manifestation, and is associated with increased morbidity and mortality. This article reviews the pathogenesis, risk factors, diagnostic assessment, prevention and management of delirium.

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.

Alcohol withdrawal and delirium tremens in the critically ill: a systematic review and commentary

INTRODUCTION

Alcohol withdrawal is common among intensive care unit (ICU) patients, but no current practice guidelines exist. We reviewed published manuscripts for prevalence, risk factors, screening tools, prophylactic and treatment strategies, and outcomes for alcohol withdrawal syndrome (AWS) and delirium tremens (DT) in the critically ill.

METHODS

The following databases: PubMed, MEDLINE, Embase, Cochrane Database of Systematic Reviews and Central Register of Controlled Trials, CINAHL, Scopus, Web of Knowledge, pain, anxiety and delirium (PAD) Guidelines REFWORKS, International Pharmaceutical Abstracts and references for published papers were searched. Publications with high or moderate Grading of Recommendations Assessment, Development and Evaluation (GRADE) and Oxford levels of evidence were included.

RESULTS

Reported AWS rates range from <1 % in 'all ICU comers' to 60 % in highly selected alcohol-dependent ICU patients. Alcohol dependence and a history of withdrawal are significant risk factors for AWS occurrence. No screening tools for withdrawal have been validated in the ICU. The benefit of alcohol withdrawal prophylaxis is unproven, and proposed regimens appear equivalent. Early and aggressive titration of medication guided by symptoms is the only feature associated with improved treatment outcome.

CONCLUSIONS

Treatment of AWS is associated with higher ICU complication rates and resource utilization. The optimal means of identification, prevention and treatment of AWS in order to establish evidence-based guidelines remain to be determined.

Prevention and treatment options for postoperative delirium in the elderly

PURPOSE OF REVIEW

To review recent findings and developments in strategies for prevention and treatment of postoperative delirium.

RECENT FINDINGS

Current advances in the field include improved knowledge about predisposing and precipitating factors, evidence for efficacy of multicomponent prevention programmes, refinement of perioperative procedures, and promising pharmacological approaches for prophylaxis and management of postoperative delirium.

SUMMARY

Postoperative delirium is a common and serious complication in elderly patients. Preoperative assessment of risk profiles and tailored multimodal prevention approaches proved effective and should be integrated into clinical practice. Despite promising recent findings, at present, the routine use of pharmacological prophylaxis cannot be recommended. Validated and easy-to-use bedside diagnostic tools are available and should be regularly applied for delirium screening in the first days after surgery. In patients developing delirium, causal conditions and contributing factors need to be identified and addressed. Whereas administration of antipsychotics may represent an option for symptomatic treatment, further studies are needed to evaluate the effects of pharmacological approaches on long-term outcomes in elderly patients with delirium.

Dexmedetomidine: a guide to its use for sedation in the US

Intravenous dexmedetomidine (Precedex(®)) provides both effective sedation in mechanically ventilated patients in an intensive care setting and effective procedural sedation. In these patient populations, it reduces the need for rescue sedation with intravenous propofol or intravenous midazolam and reduces opioid requirements. In addition, patients receiving dexmedetomidine are calm and easy to arouse and manage. Intravenous dexmedetomidine is generally well tolerated and is not associated with respiratory depression. Although the utilization of dexmedetomidine is associated with hypotension and bradycardia, both usually resolve without intervention.

Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients? a meta-analysis

Introduction

The aim of this study was to explore the use of dexmedetomidine as a safe and efficacious sedative agent in post-cardiac surgery patients.

Methods

A systematic literature search of MEDLINE, EMBASE, the Cochrane Library and Science Citation Index until January 2012 and review of studies was conducted. Eligible studies were of randomized controlled trials or cohort studies, comparing dexmedetomidine with a placebo or an alternative sedative agent in elective cardiac surgery, using dexmedetomidine for postoperative sedation and available in full text. Two reviewers independently performed study selection, quality assessment, and data extraction.

Results

The search identified 530 potentially relevant publications; 11 met selection criteria in this meta-analysis. Our results revealed that dexmedetomidine was associated with a shorter length of mechanical ventilation (mean difference -2.70 [-5.05, -0.35]), a lower risk of delirium (risk ratio 0.36 [0.21, 0.64]), ventricular tachycardia (risk ratio 0.27 [0.08, 0.97]) and hyperglycemia (risk ratio 0.78 [0.61, 0.99]), but may increase the risk of bradycardia (risk ratio 2.08 [1.16, 3.74]). But there was no significant difference in ICU stay, hospital stay, and morphine equivalents between the included studies. Dexmedetomidine may not increase the risk of hypotension, atrial fibrillation, postoperative nausea and vomiting, reintubation within 5 days, cardiovascular complications, postoperative infection or hospital mortality.

Conclusions

Dexmedetomidine was associated with shorter length of mechanical ventilation and lower risk of delirium following cardiac surgery. Although the risk of bradycardia was significantly higher compared with traditional sedatives, it may not increase length of hospital stay and hospital mortality. Moreover, dexmedetomidine may decrease the risk of ventricular tachycardia and hyperglycemia. Thus, dexmedetomidine could be a safe and efficacious sedative agent in cardiac surgical patients.

Dexmedetomidine as adjunct treatment for severe alcohol withdrawal in the ICU

BACKGROUND

Patients undergoing alcohol withdrawal in the intensive care unit (ICU) often require escalating doses of benzodiazepines and not uncommonly require intubation and mechanical ventilation for airway protection. This may lead to complications and prolonged ICU stays. Experimental studies and single case reports suggest the α2-agonist dexmedetomidine is effective in managing the autonomic symptoms seen with alcohol withdrawal. We report a retrospective analysis of 20 ICU patients treated with dexmedetomidine for benzodiazepine-refractory alcohol withdrawal.

METHODS

Records from a 23-bed mixed medical-surgical ICU were abstracted from November 2008 to November 2010 for patients who received dexmedetomidine for alcohol withdrawal. The main analysis compared alcohol withdrawal severity scores and medication doses for 24 h before dexmedetomidine therapy with values during the first 24 h of dexmedetomidine therapy.

RESULTS

There was a 61.5% reduction in benzodiazepine dosing after initiation of dexmedetomidine (n = 17; p < 0.001) and a 21.1% reduction in alcohol withdrawal severity score (n = 11; p = .015). Patients experienced less tachycardia and systolic hypertension following dexmedetomidine initiation. One patient out of 20 required intubation. A serious adverse effect occurred in one patient, in whom dexmedetomidine was discontinued for two 9-second asystolic pauses noted on telemetry.

CONCLUSIONS

This observational study suggests that dexmedetomidine therapy for severe alcohol withdrawal is associated with substantially reduced benzodiazepine dosing, a decrease in alcohol withdrawal scoring and blunted hyperadrenergic cardiovascular response to ethanol abstinence. In this series, there was a low rate of mechanical ventilation associated with the above strategy. One of 20 patients suffered two 9-second asystolic pauses, which did not recur after dexmedetomidine discontinuation. Prospective trials are warranted to compare adjunct treatment with dexmedetomidine versus standard benzodiazepine therapy.

The effects of dexmedetomidine on mesenteric arterial occlusion-associated gut ischemia and reperfusion-induced gut and kidney injury in rabbits

OBJECTIVE

We assessed the antioxidant activity of dexmedetomidine (Dex) administered during the ischemic period in a rabbit model of mesenteric ischemia/reperfusion (I/R) injury using biochemical and histopathological methods.

METHODS

A total of 24 male New Zealand white rabbits weighing between 2.5 and 3.0 kg were randomly divided into three groups: the sham group (Group S, n = 8), the I/R group (Group I/R, n = 8), and the I/R plus Dex treatment group (Group Dex, n = 8). In the I/R group, ischemia was achieved with 60 min of mesenteric occlusion. The sham group provided normal basal values. The rabbits in Group I/R were operated to achieve I/R. Group Dex received intravenous Dex 30 min after the commencement of reperfusion (10 μg/kg Dex was infused within 10 min, and then a maintenance dose of 10 μg/kg/h Dex was infused intravenously). For the measurement of tissue malondialdehyde, total antioxidant status, total oxidant status, lipid hydroperoxide levels, superoxide dismutase, catalase, and myeloperoxidase activity levels in the renal tissue samples of animals, the rabbits in each group were sacrificed 3 h after reperfusion. The histopathological examination scores were determined using the intestinal and renal tissues.

RESULTS

The mean malondialdehyde, total oxidant status, myeloperoxidase, and lipid hydroperoxide levels were significantly higher in Group I/R than in Groups S and Dex (P < 0.05). There also were significant decreases in the mean total antioxidant status, catalase, and superoxide dismutase activities in Group I/R compared with Groups S and Dex (P < 0.05). The histopathological examination scores of the intestinal and renal tissues were significantly higher in Group I/R compared with Groups S and Dex (P < 0.05).

CONCLUSION

Dex treatment may have biochemical and histopathological benefits by preventing I/R-related cellular damage of intestinal and renal tissues as shown in an experimental mesenteric ischemia model. The preference to use Dex for anesthesia during the mesenteric ischemia procedure may attenuate I/R injury in intestinal and renal tissues.