Prolonged dexmedetomidine infusion as an adjunct in treating sedation-induced withdrawal

Treatment of benzodiazepine withdrawal syndrome in a severe traumatic brain injury patient

Prolonged exposure to benzodiazepines (BDZ) may contribute towards physical dependence, which is manifested by iatrogenic Benzodiazepine Withdrawal Syndrome (BWS), a condition often underdiagnosed. Current evidence recommends precluding BDZ infusion as sedation in the intensive care unit to avoid possible withdrawal and delirium issues. Administration of dexmedetomidine should be considered to facilitate weaning in patients with BWS.

A Pilot Study Implementing a Protocol Using Dexmedetomidine as a Safe Alternative to Traditional Sedation to Decrease Ventilator Days for Patients Difficult to Extubate

BACKGROUND

Traditional sedation for mechanically ventilated patients causes delirium, which increases the patients' length of stay while hospitalized. When extubation is attempted, these medications must be discontinued because of the side effect of respiratory depression, leaving patients anxious and agitated, delaying extubation and prolonging the need for mechanical ventilation. Dexmedetomidine is a safe alternative sedative that does not cause delirium or respiratory depression. During the weaning process, dexmedetomidine can be continued, allowing the patient to remain calm and successfully extubated.

OBJECTIVES

The aim of this study is to decrease the length of stay for mechanically ventilated patients by implementing a dexmedetomidine protocol for difficult-to-extubate patients during the weaning process.

METHODS

A preintervention/postintervention design pilot study was done comparing the patient mean of length of stay on mechanical ventilation. A Mann-Whitney U test was used because of the small sample size.

RESULTS

Over the 3-month implementation period, 15 patients received dexmedetomidine. None of the patients experienced adverse reactions while on dexmedetomidine. There was a trend of decreasing mechanical ventilation length of stay but no significant difference was noted between the preimplementation and postimplementation groups.

CONCLUSION

Dexmedetomidine was a safe alternative to traditional sedation for difficult-to-extubate patients when a bolus dose was not given.

Sedation options for intubated intensive care unit patients

A common requirement for intubated patients in the intensive care unit (ICU) is sedation and pain management to facilitate patient safety and timely, atraumatic healing. The Society of Critical Care Medicine guidelines for management of pain, sedation, and delirium in adult ICU patients provide assessment scales for pain, sedation, and delirium; medications for sedation and pain management, and protocols for weaning sedation, are discussed. Proficient assessment skills, pharmacologic knowledge of medications administered to provide sedation, and an understanding of the importance of nonpharmacologic interventions can help the registered nurse provide patient advocacy, safety, and improved outcomes.

Pharmacokinetics and pharmacodynamics of dexmedetomidine

Dexmedetomidine is an alpha-2 adrenoceptor agonist and has been used as a general anesthetic, sedative and analgesic for about 30 years. The aim of this paper is to review the pharmacokinetics and pharmacodynamics of dexmedetomidine, evaluate physiological factors that may affect the pharmacokinetics of dexmedetomidine, and summarize the pharmacodynamics of dexmedetomidine at different plasma levels. The pharmacokinetic parameters reported in previous studies according to noncompartmental analyses or population modeling results are compared. We concluded that the pharmacokinetic profile can be adequately described by a two-compartment model in population pharmacokinetic modeling. Body weight, height, albumin level, cardiac output, disease condition and other factors were considered to have significant influence on the clearance and/or distribution volume in different population pharmacokinetic models. The pharmacological effects of dexmedetomidine, such as sedation, heart rate reduction and biphasic change of blood pressure, vary at different plasma levels. These findings provide a reference for individualizing the dose of dexmedetomidine and achieving the desired pharmacological effects in clinical applications.

Dexmedetomidine in the Treatment of Withdrawal Syndromes in Cardiothoracic Surgery Patients

Dexmedetomidine (Precedex, Abbott Laboratories, Abbott Park, IL) is an• 2adrenergic agonist that possesses a high ratio of specificity for the• 2versus the• 1receptor. It is currently approved for the provision of sedation during mechanical ventilation in adults. Given previous experience with clonidine for the treatment of substance withdrawal and the preliminary anecdotal experience with dexmedetomidine, it appears that dexmedetomidine may be a useful agent for treatment of substance withdrawal in the intensive care setting. The authors present their experience with the use of dexmedetomidine to control withdrawal behavior in 3 patients following cardiothoracic surgery. Previous reports regarding the use of dexmedetomidine to treat withdrawal and its potential application in this clinical arena are reviewed.

Tolerance and Withdrawal Issues with Sedatives in the Intensive Care Unit

Prolonged use of sedative medications continues to be a concern for critical care practitioners, with potential adverse effects including tolerance and withdrawal. The amount of sedatives required in critically ill patients can be lessened and tolerance delayed with the use of pain and/or sedation scales to reach the desired effect. The current recommendation for prolonged sedation is to wean patients from the medications over several days to reduce the risk of drug withdrawal. It is important to identify patients at risk for iatrogenic withdrawal and create a treatment strategy.

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: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Molecular targets and mechanism of action of dexmedetomidine in treatment of ischemia/reperfusion injury

Dexmedetomidine (DEX), a highly specific α2-adrenergic agonist, which exhibits anaesthetic-sparing, analgesia and sympatholytic properties. DEX modulates gene expression, channel activation, transmitter release, inflammatory processes and apoptotic and necrotic cell death. It has also been demonstrated to have protective effects in a variety of animal models of ischemia/reperfusion (I/R) injury, including the intestine, myocardial, renal, lung, cerebral and liver. The broad spectrum of biological activities associated with DEX continues to expand, and its diverse effects suggest that it may offer a novel therapeutic approach for the treatment of human diseases with I/R involvement.

A case-based approach to the practical application of dexmedetomidine in critically ill adults

Dexmedetomidine is a selective α(2) -adrenoceptor agonist that offers unique sedation because patients are readily awakened while administration continues and the drug does not suppress the respiratory center. Limitations of use include higher acquisition cost, inability to produce deep sedation, and bradycardia and hypotension. Using a case-based approach, the purpose of this review was to qualitatively assess the role of dexmedetomidine in the care of the critically ill and in the management of alcohol withdrawal, and to formulate recommendations regarding its clinical application. Sixty-six studies were identified that investigated dexmedetomidine for the provision of sedation. These studies were heterogeneous in design and patient populations; most investigated patients did not require heavy sedation, and few used propofol as the comparator. In general, though, the aggregate results of all studies demonstrate that dexmedetomidine provides comfort, possibly shortens the duration of mechanical ventilation to facilitate extubation, reduces the occurrence of acute brain dysfunction, and facilitates communication, but the drug is associated with hemodynamic instability and requires the supplemental use of traditional sedative and analgesic agents. These outcomes need to be substantiated in additional studies that include assessments of cost-effectiveness. Dexmedetomidine should be considered when patients require mild to moderate levels of sedation of short to intermediate time frames, and they qualify for daily awakenings with traditional sedative therapies. The data for dexmedetomidine in relation to alcohol withdrawal are limited to 12 retrospective reports representing a total of 127 patients. Its role for this indication requires further study, but it may be considered as adjunctive therapy when clinicians are concerned about respiratory suppression associated with escalating doses of γ-aminobutyric acid agonists. Regardless of the indication for dexmedetomidine, the practitioner must closely monitor patient comfort and the occurrence of hemodynamic deviations with the realization that as-needed administration of traditional sedatives and analgesics will be required and some degree of bradycardia and hypotension expected but intervention rarely required.

Management of Autism in the Adult Intensive Care Unit

Autism comprises a growing segment of the population and can be a management challenge in the intensive care unit (ICU). We present the case of a 22-year-old male with severe autism and intellectual disorder who developed respiratory failure and required a prolonged ICU course. This patient exhibited severe distress, aggression, and self-injurious behavior. Management challenges included sedation, weaning from sedation, and liberation from mechanical ventilation. Success was achieved with a multispecialty team and by tailoring the environment and interactions to the patient’s known preferences. The use of dexmedetomidine to wean high-dose benzodiazepines and opiates also permitted successful liberation from mechanical ventilation.

Dexmedetomidine infusion to facilitate opioid detoxification and withdrawal in a patient with chronic opioid abuse

Many patients are admitted to the intensive care unit (ICU) for acute intoxication, serious complication of overdose, or withdrawal symptoms of illicit drugs. An acute withdrawal of drugs with addiction potential is associated with a sympathetic overactivity leading to marked psychomimetic disturbances. Acute intoxication or withdrawal of such drugs is often associated with life-threatening complications which require ICU admission and necessitate prolonged sedative analgesic medications, weaning from which is often complicated by withdrawal and other psychomimetic symptoms. Dexmedetomidine, an alpha-2 (α(2)) agonist, has been used successfully to facilitate withdrawal and detoxification of various drugs and also to control delirium in ICU patients. Herein, we report a case of a chronic opioid abuse (heroin) patient admitted with acute overdose complications leading to a prolonged ICU course requiring sedative-analgesic medication; the drug withdrawal-related symptoms further complicated the weaning process. Dexmedetomidine infusion was successfully used as a sedative-analgesic to control the withdrawal-related psychomimetic symptoms and to facilitate smooth detoxification and weaning from opioid and other sedatives.

Perioperative management of the child on long-term opioids

The strategies used to manage children exposed to long-term opioids are extrapolated from adult literature. Opioid consumption during the perioperative period is more than three times that observed in patients not taking chronic opioids. A sparing use of opioids in the perioperative period results in both poor pain management and withdrawal phenomena. The child's pre-existing opioid requirement should be maintained, and acute pain associated with operative procedures should be managed with additional analgesia. This usually comprises short-acting opioids, regional or local anesthesia, and adjuvant therapies. Long-acting opioids, transdermal opioid patches, and implantable pumps can be used to maintain the regular opioid requirement. Intravenous infusion, nurse controlled analgesia, patient-controlled analgesia, or oral formulations are invaluable for supplemental requirements postoperatively. Effective management requires more than simply increasing opioid dose during this time. Collaboration of the child, family, and all teams involved is necessary. While chronic pain or palliative care teams and other staff experienced with the care of children suffering chronic pain may have helpful input, many pediatric hospitals do not have chronic pain teams, and many patients receiving long-term opioids are not palliative. Acute pain services are appropriate to deal with those on long-term opioids in the perioperative setting and do so successfully in many centers. Staff caring for such children in the perioperative period should be aware of the challenges these children face and be educated before surgery about strategies for postoperative management and discharge planning.

Pharmacology of sedative-analgesic agents: dexmedetomidine, remifentanil, ketamine, volatile anesthetics, and the role of peripheral Mu antagonists

In this article, the authors discuss the pharmacology of sedative-analgesic agents like dexmedetomidine, remifentanil, ketamine, and volatile anesthetics. Dexmedetomidine is a highly selective alpha-2 agonist that provides anxiolysis and cooperative sedation without respiratory depression. It has organ protective effects against ischemic and hypoxic injury, including cardioprotection, neuroprotection, and renoprotection. Remifentanil is an ultra-short-acting opioid that acts as a mu-receptor agonist. Ketamine is a nonbarbiturate phencyclidine derivative and provides analgesia and apparent anesthesia with relative hemodynamic stability. Volatile anesthetics such as isoflurane, sevoflurane, and desflurane are in daily use in the operating room in the delivery of general anesthesia. A major advantage of these halogenated ethers is their quick onset, quick offset, and ease of titration in rendering the patient unconscious, immobile, and amnestic.

Dexmedetomidine: applications for the pediatric patient with congenital heart disease

This study aimed to provide a general description of the cardiovascular and hemodynamic effects of dexmedetomidine and an evidence-based review of the literature regarding its use in infants and children with congenital heart disease (CHD). A computerized bibliographic search of the literature on dexmedetomidine use in infants and children with CHD was performed. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Adverse cardiovascular effects include occasional episodes of bradycardia, with rare reports of sinus pause or cardiac arrest. Both hypotension and hypertension also have been reported. The latter is related to peripheral α(2B) agonism leading to vasoconstriction. No adverse effects on the pulmonary vasculature have been noted even in patients with preexisting pulmonary hypertension. Although there are no direct effects on myocardial function, decreased cardiac output may result from changes in heart rate or increases in afterload. Although not currently Food and Drug Administration (FDA)-approved for the pediatric population, findings have shown dexmedetomidine to be effective in various clinical scenarios of patients with CHD including sedation during mechanical ventilation, prevention of procedure-related anxiety, prevention of emergence delirium and shivering after anesthesia, and treatment of withdrawal. Although dexmedetomidine may have limited utility for painful or invasive procedures, preliminary data suggest that the addition of ketamine to the regimen may offer benefits. When used during the perioperative period, additional benefits include blunting of the sympathetic stress response with a reduction of endogenous catecholamine release, a decrease in intraoperative anesthetic requirements, and a limitation of postoperative opioid requirements.

Dexmedetomidine use in the setting of cocaine-induced hypertensive emergency and aortic dissection: a novel indication

Aortic dissection is a potentially fatal but rare disease characterized by an aortic intimal tear with blood passing into the media creating a false lumen and with resultant high mortality depending on the location of dissection if not aggressively treated. Cocaine users are known to have a higher incidence of aortic dissection. We report here aortic dissection in a patient with cocaine abuse which did not respond to traditional medication regimes used currently in this setting. Worth mentioning is the use of an alpha-2 receptor selective agonist named Dexmedetomidine as a treatment modality to control hypertension in this patient, which is approved only for sedation of intubated and mechanically ventilated patients in the intensive care settings and for sedation during invasive procedures. This paper illustrates the practical beneficial role of Dexmedetomidine in controling blood pressure in the settings of cocaine-induced sympathetic surge when other treatment modalities fail.

Tolerance and withdrawal from prolonged opioid use in critically ill children

OBJECTIVE

After prolonged opioid exposure, children develop opioid-induced hyperalgesia, tolerance, and withdrawal. Strategies for prevention and management should be based on the mechanisms of opioid tolerance and withdrawal.

PATIENTS AND METHODS

Relevant manuscripts published in the English language were searched in Medline by using search terms "opioid," "opiate," "sedation," "analgesia," "child," "infant-newborn," "tolerance," "dependency," "withdrawal," "analgesic," "receptor," and "individual opioid drugs." Clinical and preclinical studies were reviewed for data synthesis.

RESULTS

Mechanisms of opioid-induced hyperalgesia and tolerance suggest important drug- and patient-related risk factors that lead to tolerance and withdrawal. Opioid tolerance occurs earlier in the younger age groups, develops commonly during critical illness, and results more frequently from prolonged intravenous infusions of short-acting opioids. Treatment options include slowly tapering opioid doses, switching to longer-acting opioids, or specifically treating the symptoms of opioid withdrawal. Novel therapies may also include blocking the mechanisms of opioid tolerance, which would enhance the safety and effectiveness of opioid analgesia.

CONCLUSIONS

Opioid tolerance and withdrawal occur frequently in critically ill children. Novel insights into opioid receptor physiology and cellular biochemical changes will inform scientific approaches for the use of opioid analgesia and the prevention of opioid tolerance and withdrawal.

The Effect of Dexmedetomidine on Agitation during Weaning of Mechanical Ventilation in Critically ill Patients

Ventilated patients receiving opioids and/or benzodiazepines are at high risk of developing agitation, particularly upon weaning towards extubation. This is often associated with an increased intubation time and length of stay in the intensive care unit and may cause long-term morbidity. Anxiety, fear and agitation are amongst the most common non-pulmonary causes of failure to liberate from mechanical ventilation. This prospective, open-label observational study examined 28 ventilated adult patients in the intensive care unit (30 episodes) requiring opioids and/or sedatives for >24 hours, who developed agitation and/or delirium upon weaning from sedation and failed to achieve successful extubation with conventional management. Patients were ventilated for a median (interquartile range) of 115 [87 to 263] hours prior to enrolment, Dexmedetomidine infusion was commenced at 0.4 μg/kg/hour for two hours, after which concurrent sedative therapy was preferentially weaned and titrated to obtain target Motor Activity Assessment Score score of 2 to 4. The median (range) maximum dose and infusion time of dexmedetomidine was 0.7 μg/kg/hour (0.4 to 1.0) and 62 hours (24 to 252) respectively. The number of episodes at target Motor Activity Assessment Score score at zero, six and 12 hours after commencement of dexmedetomidine were 7/30 (23.3%), 28/30 (93.3%) and 26/30 (86.7%), respectively (P <0.001 for 6 and 12 vs 0 hours). Excluding unrelated clinical deterioration, 22 episodes (73.3%) achieved successful weaning from ventilation with a median (interquartile range) ventilation time of 70 (28 to 96) hours after dexmedetomidine infusion. Dexmedetomidine achieved rapid resolution of agitation and facilitated ventilatory weaning after failure of conventional therapy. Its role as first-line therapy in ventilated, agitated patients warrants further investigation.

α2-Receptor Agonists for Treatment and Prevention of Iatrogenic Opioid Abstinence Syndrome in Critically Ill Patients

Objective:

To review the literature regarding the use of α2-agonists in the treatment and prevention of iatrogenic opioid abstinence syndrome (IOAS) in critically ill patients.

Data Sources:

Primary literature was identified through a search of MEDLINE (1950–June 2009), EMBASE (1988–June 2009), International Pharmaceutical Abstracts (1970–June 2009), and the Cochrane Library (1996–June 2009), using the names of individual α2-agonists and the following key words: children, opioid withdrawal, opioid, and adult. Relevant abstracts from the Society of Critical Care Medicine, reference citations from selected articles, and manufacturers’ product information were also reviewed.

Study Selection and Data Extraction:

All English-language articles identified from the data sources were evaluated. Three retrospective studies and 6 case reports/series representing 44 patients were included for analysis.

Data Synthesis:

Central α2-agonists are thought to minimize symptoms of IOAS by decreasing presynaptic outflow of catecholamines. Successful use of clonidine and dexmedetomidine for management of IOAS has been reported. Lofexidine, an α2-agonist not yet approved in the US, may offer similar withdrawal symptom relief but has yet to be studied in the intensive care setting. Although the quality of studies identified was limited, preliminary evidence does provide some support for the use of transdermal clonidine and injectable dexmedetomidine in the treatment and prevention of IOAS. These agents were shown to facilitate discontinuation of opioids and to minimize withdrawal symptoms with few reported adverse events.

Conclusions:

Central α2-agonists appear to be effective and safe second-line agents for treatment and prevention of IOAS. Further studies should be conducted to determine their role in the therapy of patients with IOAS.

The Safety and Effectiveness of Dexmedetomidine When Used for More Than 24 Hours in an Adult Intensive Care Setting

Dexmedetomidine is a new analgesic and anxiolytic used in the intensive care setting. It has been indicated for use for less than 24 hours to aid in intubation or extubation of a patient. The advantages for dexmedetomidine compared with propofol or benzodiazepines are that it has fewer sedating effects and a short half-life. Several retrospective studies and case reports have reported its use longer than the indicated 24 hours. They reported that dexmedetomidine is safe to use past the 24-hour indicated time of use, with the same or fewer adverse side effects reported.

Hemodynamic and respiratory changes following dexmedetomidine administration during general anesthesia: sevoflurane vs desflurane

BACKGROUND

The current study evaluates the hemodynamic and respiratory effects of dexmedetomidine (DEX) when administered to children anesthetized with sevoflurane (SEVO) or desflurane (DES).

METHODS

After tracheal intubation and spontaneous ventilation, DEX (0.5 microg x kg(-1)) was administered over 5 min. Heart rate (HR), systolic blood pressure (sBP), diastolic blood pressure (dBP), and endtidal carbon dioxide (P(E)CO(2)) were monitored and recorded prior to DEX (time 0) and again at 5, 10, and 15 min after DEX.

RESULTS

The cohort included 80 children (1-12 years of age) anesthetized with SEVO (n = 40) or DES (n = 40). The lowest HR from time 0 to time 15 was less in patients anesthetized with SEVO compared with DES (104 +/- 16 b x min(-1) in the SEVO/DEX group vs 120 +/- 17 b x min(-1) in the DES/DEX group, < 0.01). Although both sBP and dBP decreased following the administration of DEX to patients anesthetized with either SEVO or DES, there was no difference in sBP or dBP between the two groups. Likewise, no evidence was found for changes in the P(E)CO(2) during the study period.

CONCLUSIONS

The administration of DEX (0.5 microg x kg(-1)) results in a lower HR in patients anesthetized with SEVO compared with DES. No evidence was found for differences in sBP, dBP, or P(E)CO(2) during spontaneous ventilation with 1 MAC of SEVO vs DES.

Dexmedetomidine: applications in pediatric critical care and pediatric anesthesiology

OBJECTIVE

To provide a general descriptive account of the end-organ effects of dexmedetomidine and to provide an evidence-based review of the literature regarding its use in infants and children.

DATA SOURCE

A computerized bibliographic search of the literature regarding dexmedetomidine.

MAIN RESULTS

The end-organ effects of dexmedetomidine have been well studied in animal and adult human models. Adverse cardiovascular effects include occasional episodes of bradycardia with rare reports of sinus pause or cardiac arrest. Hypotension has also been reported as well as hypertension, the latter thought to be due to peripheral alpha2B agonism with peripheral vasoconstriction. Although dexmedetomidine has no direct effects on myocardial function, decreased cardiac output may result from changes in heart rate or increases in afterload. There are somewhat conflicting reports in the literature regarding its effects on ventilatory function, with some studies (both human and animal) suggesting a mild degree of respiratory depression, decreased minute ventilation, and decreased response to CO2 challenge whereas others demonstrate no effect. The central nervous system effects include sedation and analgesia with prevention of recall and memory at higher doses. Dexmedetomidine may also provide some neuroprotective activity during periods of ischemia. Applications in infants and children have included sedation during mechanical ventilation, prevention of emergence agitation following general anesthesia, provision of procedural sedation, and the prevention of withdrawal following the prolonged administration of opioids and benzodiazepines.

CONCLUSIONS

The literature contains reports of the use of dexmedetomidine in approximately 800 pediatric patients. Given its favorable sedative and anxiolytic properties combined with its limited effects on hemodynamic and respiratory function, there is growing interest in and reports of its use in the pediatric population in various clinical scenarios.

Dexmedetomidine: an updated review

OBJECTIVE

To review recent literature on the safety and efficacy of dexmedetomidine.

DATA SOURCES

Articles were identified through searches of MEDLINE (1966-January 2007). Key words included dexmedetomidine, medetomidine, alpha(2)-agonist, and sedation. References from selected articles were reviewed for additional references.

STUDY SELECTION AND DATA EXTRACTION

Experimental and observational studies that focused on the safety and efficacy of dexmedetomidine in humans were selected.

DATA SYNTHESIS

Dexmedetomidine is an alpha(2)-agonist for short-term sedation in critically ill patients. In postoperative patients, dexmedetomidine produced similar levels of sedation and times to extubation, with less opioid requirements compared with propofol. Dexmedetomidine has also been studied for sedation in critically ill medical and pediatric patients, as adjunct to anesthesia, and for procedural sedation. Hypotension, hypertension, and bradycardia are common adverse effects. Although dexmedetomidine is labeled only for sedation less than 24 hours, it has been administered for longer than 24 hours without apparent development of rebound hypertension and tachycardia.

CONCLUSIONS

Dexmedetomidine is a safe and effective agent for sedation in critically ill patients. Further, well designed studies are needed to define its role as a sedative for critically ill medical, neurosurgical, and pediatric patients, as an adjunct to anesthesia, and as a sedative during procedures.

Prolonged use of dexmedetomidine in an infant with respiratory failure following living donor liver transplantation

We used dexmedetomidine for more than 2 months in a mechanically ventilated infant without serious adverse effects. An infant with liver cirrhosis of unknown cause underwent living donor liver transplantation at the age of 9 months. Long-term mechanical ventilation was required postoperatively, and midazolam with fentanyl had been used to sedate the patient. They required increase to 1.7 mg.kg(-1).h(-1) and 3.5 microg.kg(-1).h(-1), respectively, which were still inadequate. On postoperative day 29, dexmedetomidine was added. The rate of dexmedetomidine infusion was increased gradually to 1.4 microg.kg(-1).h(-1). It was discontinued temporarily to exclude drug-induced liver dysfunction. However, without dexmedetomidine, adequate sedation level was unattainable. Liver dysfunction was likely to be attributed to cytomegalovirus infection and after restarting dexmedetomidine, the respiratory condition improved. He was extubated 10 weeks after the operation. Dexmedetomidine was successfully tapered off over the following 2 weeks with no signs of withdrawal. Dexmedetomidine was a useful sedative for an infant who required mechanical ventilation for a prolonged period of time.

Repeated dexmedetomidine infusions, a postoperative living-donor liver transplantation patient

Here we report on a postoperative living-donor liver transplantation (LDLT) patient who received nightly infusions of dexmedetomidine (DEX), a specific alpha2-adrenergic receptor agonist, to treat agitation and insomnia during an intensive care unit stay. The infusion rate was adjusted according to the Ramsay sedation score. The actual plasma concentrations were higher than the values predicted by RugLoop software package simulation 9 h after the DEX infusion. However, all of the measurements were within the therapeutic range for DEX. Thus, DEX infusion could be safely used in the postoperative LDLT patient by employing a simple consciousness scale.

The use of dexmedetomidine to facilitate acute discontinuation of opioids after cardiac transplantation in children

OBJECTIVE

To report the use of dexmedetomidine to facilitate rapid opioid and benzodiazepine withdrawal in children with transplanted hearts and to review the receptor physiology and pharmacodynamic impact of dexmedetomidine on the denervated heart.

DESIGN

Case series.

SETTING

Intensive care unit at a tertiary pediatric medical center.

PATIENTS

The series included a 6-month-old infant with pulmonary atresia who had a 3-month exposure to high-dose opioids and benzodiazepines and had undergone cardiac transplantation 4 wks before the use of dexmedetomidine and a 7-yr-old boy who had been sedated while undergoing extracorporeal membrane oxygenation for 3 wks before transplantation and started to receive dexmedetomidine 3 days after transplantation.

INTERVENTION

Administration of dexmedetomidine to facilitate the discontinuation of opioids and benzodiazepine.

MAIN RESULT

Successful rapid withdrawal from opioids and benzodiazepines while maintaining hemodynamic stability.

CONCLUSION

To our knowledge, this report describes the first use of dexmedetomidine to facilitate opioid withdrawal in children with a cardiac transplant. Dexmedetomidine allowed for the preservation of satisfactory hemodynamic parameters during acute withdrawal from opioids in children with denervated hearts.

Tolerance and Withdrawal Issues with Sedation

The stay in an ICU is a complex mixture of providing optimal care while keeping the patient safe. Means of reducing the anxiety associated with the ICU stay include frequent reorientation and maintenance of patient comfort with sedation supplemented by analgesia as needed. The most common agents used to provide sedation include benzodiazepines, propofol, and the newer dexmedetomidine. Others include barbiturate agents, neuroleptics, clonidine, etomidate, ketamine, and supplemental opioid analgesics for pain control. A common complication of sedation is tolerance, which can lead to withdrawal if the sedation is discontinued hastily. This article evaluates the occurrence of tolerance and withdrawal in the most commonly used sedatives in critically ill patients.

Dexmedetomidine in anaesthesia

PURPOSE OF REVIEW

The development of dexmedetomidine, a potent and highly selective alpha2-adrenoceptor agonist, has created new interest in the use of alpha2-adrenoceptor agonists, and has led to its evaluation in various yet non-approved perioperative settings. The current review focuses on the usefulness of dexmedetomidine in anaesthesia practice.

RECENT FINDINGS

Recently acquired knowledge and experience with dexmedetomidine in perioperative use will be presented and discussed in the context of known pharmacological properties.

SUMMARY

Dexmedetomidine offers beneficial pharmacological properties, providing dose-dependent sedation, analgesia, sympatholysis and anxiolysis without relevant respiratory depression. The side-effects are predictable from the pharmacological profile of (2-adrenoceptor agonists. In particular, the unique sedative properties of dexmedetomidine resulted in several interesting applications in anaesthesia practice, promising benefits in the perioperative use of this compound. However, dexmedetomidine was approved for sedation in the intensive care unit in the USA in 1999, and administration in anaesthesia practice remains an 'off-label' use. Further studies are needed to establish the role of dexmedetomidine in the perioperative period.

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.

The use of dexmedetomidine to facilitate opioid and benzodiazepine detoxification in an infant

Prolonged use of opioids and benzodiazepines for the care of critically ill infants and children can generate physical dependence. We present a case of an 8-mo-old infant with Hunter's syndrome who was maintained on very large doses of fentanyl and midazolam and who could not be weaned from these drugs by conventional taper. We used dexmedetomidine, an alpha(2)-adrenergic agonist, to facilitate opioid and benzodiazepine withdrawal. A processed electroencephalogram (Bispectral Index) was used to guide the titration of dexmedetomidine in this neurologically impaired infant. This is the first report of this drug being used in an infant to manage chemical dependence withdrawal.

IMPLICATIONS

Dexmedetomidine was used to facilitate opioid and benzodiazepine withdrawal in an 8-mo-old infant. A processed electroencephalogram (Bispectral Index) was used to guide the titration of dexmedetomidine in this neurologically impaired infant. This is the first report of dexmedetomidine use in an infant to manage chemical dependence withdrawal.

Comparing Dexmedetomidine Prescribing Patterns and Safety in the Naturalistic Setting Versus Published Data

BACKGROUND:

In clinical practice, new drugs may be used differently than the product labeling recommends. Furthermore, it often takes several years of use before adverse drug reactions (ADRs) are reported.

OBJECTIVE:

To compare prescribing patterns and safety of the newly released drug dexmedetomidine as observed in clinical practice with published data on the drug.

METHODS:

Information from a convenience sample of adults receiving dexmedetomidine as part of routine patient care at 10 institutions was retrospectively collected from June 27, 2001, to May 31, 2002. Investigators reviewed medical records daily and entered dosing information, patient demographics, and predefined categories of ADR severity and probability anonymously via the Internet on a secure server.

RESULTS:

Only 33% of the total sample (n = 136) of patients received a loading infusion of dexmedetomidine; however, maintenance dosing was usually within product labeling guidelines. Of note, 27.2% of patients received dexmedetomidine above the maximum dose and 33.8% received the drug beyond 24 hours. Some patients (15.4%) were never mechanically ventilated, while 59.5% received dexmedetomidine following extubation for an average of 11.3 hours. ADRs were reported in 30% of patients: 20% of the reactions required treatment or increased length of stay. Hypotension was the most common ADR, occurring in 22.7% of patients. Bradycardia was reported in 4.4% of patients. The rate and type of ADRs were similar in patients receiving dexmedetomidine >24 hours compared with the total population.

CONCLUSIONS:

Dexmedetomidine is prescribed within product labeling guidelines except for low use of a loading dose, some patients received the drug at doses above the maximum, and others received it for longer than 24 hours. Since ADR rates are similar to those of other published reports, dexmedetomidine maintained its expected safety profile in our patients.