Use of dexmedetomidine in children after cardiac and thoracic surgery

Evaluation of Adverse Events Noted in Children Receiving Continuous Infusions of Dexmedetomidine in the Intensive Care Unit

OBJECTIVES

Dexmedetomidine is an α2-adrenergic receptor agonist with sedative and analgesic effects in mechanically ventilated adults and children. Safety and efficacy data are limited in children. The purpose of this study is to retrospectively identify the incidence and types of adverse events noted in children receiving continuous infusions of dexmedetomidine and evaluate potential risk factors for adverse events.

METHODS

Between July 1, 2006, and July 31, 2007, data were collected on all children (< 18 years) who received continuous infusions of dexmedetomidine. Data collection included demographics, dexmedetomidine regimen, and type/number of adverse events. The primary endpoint was the total number of adverse events noted, including: transient hypertension, hypotension, neurological manifestations, apnea, and bradycardia. Secondary endpoints included categorization of each type of adverse event and an assessment of risk factors. A logistic regression model was used to assess the relationship of adverse events with independent variables including length of ICU stay, cumulative dose, peak infusion rate, duration of therapy, PRISM III score, and bolus dose.

RESULTS

Thirty-six patients received dexmedetomidine representing 41 infusions. The median age was 16 months (range, 0.1–204 months) and median PRISM III score was 2 (range, 0–18). Eighteen (43.9%) patients received a bolus dose of dexmedetomidine. The median cumulative dose (mcg/kg) and peak dose (mcg/kg/hr) were 8.5 (range, 2.2–193.7) and 0.5 (range, 0.2–0.7), respectively. Dexmedetomidine was continued for a median of 20 (range, 3–263) hours. Six (14.6%) patients were slowly tapered off the continuous infusions. Twenty-one adverse events were noted in 17 patients, including 4 neurologic manifestations. Fourteen patients required interventions for adverse events. ICU length of stay was the only independent risk factor (p=0.036) for development of adverse events.

CONCLUSIONS

Several potential adverse events were noted with dexmedetomidine continuous infusions including possible neurological manifestations. Further studies are needed looking at adverse events associated with dexmedetomidine use in the pediatric population.

Dexmedetomidine pharmacokinetics in pediatric intensive care--a pooled analysis

BACKGROUND

Published dexmedetomidine pharmacokinetic studies in children are limited by participant numbers and restricted pathology. Pooling the available studies allows investigation of covariate effects.

METHODS

Data from four studies investigating dexmedetomidine pharmacokinetics after i.v. administration (n = 95) were combined to undertake a population pharmacokinetic analysis of dexmedetomidine time-concentration profiles (730 observations) using nonlinear mixed effects modeling (NONMEM). Estimates were standardized to a 70-kg adult using allometric size models.

RESULTS

Children had a mean age of 3.8 (median 3 years, range 1 week-14 years) and weight of 16.0 kg (median 13.3 kg, range 3.1-58.9 kg). Population parameter estimates (between subject variability) for a two-compartment model were clearance (CL) 42.1 (CV 30.9%) lx h(-1) x 70 kg(-1), central volume of distribution (V1) 56.3 (61.3%) l.70 kg(-1), inter-compartment clearance (Q) 78.3 (37.0%) l x h(-1) x 70 kg(-1) and peripheral volume of distribution (V2) 69.0 (47.0%) l.70 kg(-1). Clearance maturation with age was described using the Hill equation. Clearance increases from 18.2 l x h(-1) x 70 kg(-1) at birth in a term neonate to reach 84.5% of the mature value by 1 year of age. Children given infusion after cardiac surgery had 27% reduced clearance compared to a population given bolus dose. Simulation of published infusion rates that provide adequate sedation for intensive care patients found a target therapeutic concentration of between 0.4 and 0.8 microg x l(-1).

CONCLUSIONS

The sedation target concentration is similar to that described for adults. Immature clearance in the first year of life and a higher clearance (when expressed as l x h(-1) x kg(-1)) in small children dictate infusion rates that change with age. Extrapolation of dose from children given infusion in intensive care after cardiac surgery may not be applicable to those sedated for noninvasive procedures out of intensive care.

Dexmedetomidine use in a pediatric cardiac intensive care unit: can we use it in infants after cardiac surgery?

OBJECTIVE

To assess clinical response of dexmedetomidine alone or in combination with conventional sedatives/analgesics after cardiac surgery.

DESIGN

Retrospective study.

SETTING

Pediatric cardiac intensive care unit.

PATIENTS

Infants and neonates after cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

We identified 80 patients including 14 neonates, at mean age and weight of 4.1 +/- 3.1 months and 5.5 +/- 2 kg, respectively, who received dexmedetomidine for 25 +/- 13 hours at an average dose of 0.66 +/- 0.26 microgxkgxhr. Overall normal sleep to moderate sedation was documented 94% of the time and no pain to mild pain for 90%. Systolic blood pressure (SBP) decreased from 89 +/- 15 mm Hg to 85 +/- 11 mm Hg (p = .05), heart rate (HR) from 149 +/- 22 bpm to 129 +/- 16 bpm (p < .001), and respiratory rate (RR) remained unchanged. When baseline arterial blood gases were compared with the most abnormal values, pH decreased from 7.4 +/- 0.07 to 7.37 +/- 0.05 (p = .006), Po2 from 91 +/- 67 mm Hg to 66 +/- 29 mm Hg (p = .005), and CO2 increased from 45 +/- 8 mm Hg to 50 +/- 12 mm Hg (p = .001). At the beginning of the study, 37 patients (46%) were mechanically ventilated; and at 48 hours, 13 patients (16%) were still intubated and five patients failed extubation. Three groups of patients were identified: A, dexmedetomidine only (n = 20); B, dexmedetomidine with sedatives/analgesics (n = 38); and C, dexmedetomidine with both sedatives/analgesics and fentanyl infusion (n = 22). The doses of dexmedetomidine and rescue sedatives/analgesics were not significantly different among the three groups but duration of dexmedetomidine was longer in group C vs. A (p = .03) and C vs. B (p = .002). Pain, sedation, SBP, RR, and arterial blood gases were similar. HR was higher in group C vs. B (p = .01). Comparison between neonates and infants showed that infants required higher dexmedetomidine doses, 0.69 +/- 25 microgxkgxhr, and vs. 0.47 +/- 21 microgxkgxhr (p = .003) and had lower HR (p = .01), and RR (p = .009), and higher SBP (p < .001).

CONCLUSIONS

Dexmedetomidine use in infants and neonates after cardiac surgery was well tolerated in both intubated and nonintubated patients. It provides an adequate level of sedation/analgesia either alone or in combination with low-dose conventional agents.

Perioperative use of dexmedetomidine in an infant with familial dysautonomia

We present a case of a 10-month-old girl with familial dysautonomia, who was scheduled for the insertion of a gastrotomy tube via laparoscopy under general anaesthesia. We used a total i.v. anaesthetic technique including dexmedetomidine and titrated the drug to patients' haemodynamic status and BIS value. Vital signs remained virtually unchanged during the entire procedure, and the tracheal tube was removed at the end of the procedure. Postoperative course was uneventful. Careful planning of the anaesthetic management, understanding the physiological consequences, and being able to titrate the medications utilized are key to the decrease of complications encountered in these patients. We report the safe use of dexmedetomidine in an infant with this extremely rare condition.

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.

Pharmacologic management of acute pediatric pain

The accurate assessment and effective treatment of acute pain in children in the hospital setting is a high priority. During the past 2 to 3 decades, pediatric pain management has gained tremendous knowledge with respect to the understanding of developmental neurobiology, developmental pharmacology the use of analgesics in children, the use of regional techniques in children, and of the psychological needs of children in pain. A wide range of medications is available to treat a variety of pain types. This article provides an overview of the most common analgesic medications and techniques used to treat acute pain in children.

The use of dexmedetomidine in critically ill children

OBJECTIVE

To describe the use of dexmedetomidine for sedating intubated children in a general medical/surgical pediatric intensive care unit (PICU).

DESIGN

Retrospective, observational study.

SETTING

Multidisciplinary PICU of a tertiary, university-affiliated children's hospital.

PATIENTS

All children receiving dexmedetomidine within the PICU during the period of August 2003 to August 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the study period, 121 mechanically ventilated patients, median age 36 months (range 2 months to 21 years), who received dexmedetomidine infusions. The infusion was initiated and adjusted per our PICU protocol. The average dose was 0.55 microg/kg/hr (range 0.15-0.70 microg/kg/hr) and average length of use was 25.8 hours (range 20 minutes to 60 hours). During the dexmedetomidine infusion, the mean decrease in total benzodiazepine and opiate dose as compared with the 24 hours prior was 42% and 36%, respectively. Most patients were able to reduce their benzodiazepine and opiate dose by at least 20% with the dexmedetomidine infusion (70% and 73% of patients, respectively). After discontinuing dexmedetomidine, the average change in total benzodiazepine and opiate dose as compared with the 24 hours before infusion was an increase of 14% and 1.5%, respectively. Fewer patients were able to maintain at least a 20% reduction in benzodiazepine and opiate after cessation of dexmedetomidine compared with the 24 hours before initiation (38% and 40% of patients, respectively). Hypotension and/or bradycardia requiring clinical intervention occurred in 33 of 121 (27%) patients. Discontinuation secondary to clinical concern was necessary in 12 of 121 (10%) patients.

CONCLUSIONS

Our study suggests that many, although not all, mechanically ventilated children may be able to reduce their need for other sedation medications with the use of dexmedetomidine. However, the potential side effects of dexmedetomidine necessitates close hemodynamic monitoring with its use.

Dexmedetomidine sedation for pediatric post-Fontan procedure patients

OBJECTIVE

The hemodynamic, respiratory, and sedative effects of dexmedetomidine (DEX) for pediatric patients post-Fontan surgery.

DESIGN

Retrospective.

SETTING

Single institutional intensive care unit.

PARTICIPANTS

Fourteen patients undergoing Fontan-type surgery.

RESULT

A retrospective review was conducted on 14 pediatric patients who had undergone a Fontan procedure for congenital heart disease. A vital component of postoperative management of these patients is to prevent an increase in pulmonary vascular resistance (PVR) that may lead to a serious reduction in cardiac output. DEX an alpha-2 adrenergic receptor agonist might offer an advantage over current sedation methods in preventing a rise in PVR. Nine patients received sedation with DEX and five patients in a control group were administered standard regimens of sedation and analgesia. The DEX group exhibited no evidence of an increased partial pressure of arterial carbon dioxide postoperatively as opposed to the control group. This lack of respiratory depression made the DEX group less likely to increase their PVR. However, the DEX group did experience a significant incidence of bradycardia that required the use of a cardiac pacemaker.

CONCLUSIONS

The results of this retrospective review of the role of DEX in the management of the post-Fontan surgical pediatric patient indicate some potential advantages.

Efficacy of sedation regimens to facilitate mechanical ventilation in the pediatric intensive care unit: a systematic review

OBJECTIVE

Children admitted to pediatric intensive care units (PICUs) often receive sedatives to facilitate mechanical ventilation. However, despite their widespread use, data supporting appropriate dosing, safety, and optimal regimens for sedation during mechanical ventilation are lacking. Therefore, we conducted a systematic review of published data regarding efficacy of sedation to facilitate mechanical ventilation in PICU patients. Our primary objective was to identify and evaluate the quality of evidence supporting sedatives used in PICUs for this purpose.

DATA SOURCES

We searched MEDLINE, EMBASE, and The Cochrane Registry of Clinical Trials from 1966 to June 2008 to identify published articles evaluating sedation regimens to facilitate mechanical ventilation in PICU patients.

STUDY SELECTION

We included only those studies of intubated PICU or pediatric cardiac intensive care unit patients receiving pharmacologic agents to facilitate mechanical ventilation that reported quality of sedation as an outcome.

DATA EXTRACTION

We analyzed studies separately for study type and by agents being studied. Studies were appraised using criteria of particular importance for reviews evaluating sedatives.

DATA SYNTHESIS

Our search strategy yielded 39 studies, including 3 randomized trials, 15 cohort studies, and 21 cases series or reports. The 39 studies evaluated a total of 39 different sedation regimens, with 21 different scoring systems, in a total of 901 PICU/cardiac intensive care unit patients ranging in age from 3 days to 19 years old. Most of the studies were small (<30 patients), and only four studies compared one or more agents to another. Few studies thoroughly evaluated drug safety, and only one study met all quality criteria.

CONCLUSIONS

Despite the widespread use of sedatives to facilitate mechanical ventilation in the PICU, we found that high-quality evidence to guide clinical practice is still limited. Pediatric randomized, controlled trials with reproducible methods and assessment of drug safety are needed.

Prolonged use of dexmedetomidine in the paediatric cardiothoracic intensive care unit

BACKGROUND

Dexmedetomidine is an alpha2-adrenergic agonist that causes sleep-like sedation and mild analgesia without narcosis or respiratory depression, and has relative cardiovascular stability. Due to these properties, it may be an effective agent for prolonged use in the sedation of patients in the paediatric cardiothoracic intensive care unit. We reviewed our experience with the drug to detail its safety and efficacy.

METHODS

We conducted a retrospective chart review of all patients who received dexmedetomidine over a six month period in a dedicated paediatric cardiothoracic intensive care unit. Patients were identified from pharmacy records showing administration of drugs. We collected demographic data, information relating to doses of dexmedetomidine, physiologic parameters, and clinical outcomes.

RESULTS

We identified 54 patients who received the drug. The median age of recipients was 6 months, with a range from 1 day to 16 years. The mean duration of administration was 37.3 hours, with a range from 2 to 177 hours. The mean duration of continuation of administration after extubation was 16.7 hours, with a range from zero to 112.5 hours. Physiologically, there were no clinically significant changes in mean arterial pressure, heart rate, respiratory rate, or saturations of oxygen before, during, or after utilization of the drug. Use of dexmedetomidine significantly reduced the need to administer narcotics, and scores using the COMFORT system were not different between patients who received dexmedetomidine and those who did not.

CONCLUSIONS

In this limited and retrospective review, dexmedetomidine was found to be safe and efficacious. Its use as a sedative agent for extended periods of time in critically-ill children deserves investigation in a prospective and controlled manner.

Effect of dexmedetomidine on the characteristics of bupivacaine in a caudal block in pediatrics

BACKGROUND

Dexmedetomidine (DEX) is a highly selective alpha(2)-adrenoceptor agonist that has been used increasingly in children. However, the effect of caudal DEX has not been evaluated before in children. This prospective randomized double-blinded study was designed to evaluate the analgesic efficacy of caudal DEX with bupivacaine in providing pain relief over a 24-h period.

METHODS

Sixty children (ASA status I) aged 1-6 years undergoing unilateral inguinal hernia repair/orchidopexy were allocated randomly to two groups (n = 30 each). Group B received a caudal injection of bupivacaine 2.5 mg/ml, 1 ml/kg; Group BD received the same dose of bupivacaine mixed with DEX 1 microg/kg during sevoflurane anesthesia. Processed electroencephalogram (bispectral index score), heart rate, blood pressure, pulse oximetry and end-tidal sevoflurane were recorded every 5 min. The characteristics of emergence, objective pain score, sedation score and quality of sleep were recorded post-operatively. Duration of analgesia and requirement for additional analgesics were noted.

RESULTS

The end-tidal sevoflurane concentration and the incidence of agitation were significantly lower in the BD group (P < 0.05). The duration of analgesia was significantly longer (P < 0.001) and the total consumption of rescue analgesic was significantly lower in Group BD compared with Group B (P < 0.01). There was no statistically significant difference in hemodynamics between both groups. However, group BD had better quality of sleep and a prolonged duration of sedation (P < 0.05).

CONCLUSION

Caudal DEX seems to be a promising adjunct to provide excellent analgesia without side effects over a 24-h period. It has the advantage of keeping the patients calm for a prolonged time. Implications statement: Caudally administered DEX (1 microg/kg), combined with bupivacaine, was associated with an extended duration of post-operative pain relief.

High-dose dexmedetomidine-induced hypertension in a child with traumatic brain injury

INTRODUCTION

Dexmedetomidine is a centrally acting alpha(2)-adrenergic agonist which is currently FDA-approved for the short-term (less than 24 h) sedation of adults during mechanical ventilation.

DISCUSSION

Given its beneficial physiologic properties, there has been increasing use of this agent in the pediatric population. As with any agent used for sedation in the Pediatric ICU setting, dose escalations may be necessary. Unlike benzodiazepines and opioids, there are limited data regarding the administration of dexmedetomidine above the current package insert dosing recommendations of 0.7 microg/kg/h.

RESULTS

We report a 2-year-old child with traumatic brain injury who developed hypertension following the administration of a dexmedetomidine infusion at 4 microg/kg/h for several hours. Investigation into the etiology of the hypertension was negative and the blood pressure returned to baseline with a decrease in the infusion rate.

CONCLUSION

Subsequent to this, no further issues with hypertension were noted.

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.

Dexmedetomidine as the primary sedative during invasive procedures in infants and toddlers with congenital heart disease

OBJECTIVE

In this report, we describe the use of dexmedetomidine as the primary sedative agent while performing invasive procedures in infants and toddlers with congenital heart disease who are breathing spontaneously.

DESIGN

Retrospective case review.

SETTING

University Hospital, pediatric cardiac intensive care unit.

PATIENTS

Six spontaneously breathing children, five infants and one toddler, all with congenital heart disease, who received dexmedetomidine as the primary sedative agent while undergoing an invasive procedure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Six patients with congenital heart disease, age 3 days-29 months were included. Five of the patients were <6 months of age. Each patient underwent an invasive procedure including central venous line placement, chest tube insertion, fiberoptic bronchoscopy, and femoral cut-down for Broviac placement. All patients were breathing spontaneously throughout their procedure. Dexmedetomidine was used as the primary sedative agent during the procedure with additional sedation provided with low dose ketamine for patient movement in three of the six patients. The average dexmedetomidine dose used was 1.5 microg/kg (1-3 microg/kg). An additional low dose of ketamine, 0.7 mg/kg (0.3-1.5 mg/kg), was used in 50% of the patients. All patients breathed spontaneously without significant desaturation throughout the procedure, and although there was a trend toward lower blood pressure and heart rate, all patients remained warm and well perfused. Each of the six procedures was successfully completed without any associated complications.

CONCLUSIONS

Our experience suggests that invasive procedures can be successfully performed in spontaneously breathing infants and toddlers with congenital heart disease using dexmedetomidine alone or in combination with low dose ketamine.

Dexmedetomidine: sedation, analgesia and beyond

BACKGROUND

Dexmedetomidine is an alpha-2 adrenoreceptor agonist with sedative, analgesic and anxiolytic properties. Since its release in the US market in late 1999, it has gained remarkable attention in the adult, pediatric and geriatric populations, predominantly because of its minimal respiratory depression. However, beyond its well-known properties, dexmedetomidine has recently been investigated for its potential in many other clinical scenarios, including neuroprotection, cardioprotection and renoprotection, with promising results.

OBJECTIVE

This review provides an outline of the current use of dexmedetomidine in adult and pediatric populations in several clinical settings, including operating room, intensive care unit, postsurgical patients and patients who need sedation and/or analgesia for invasive and noninvasive procedures. Our objectives were to examine the most up-to-date clinical evidence, describe the magnitude of effects, and shed some light on potential future applications.

METHODS

Published, peer-reviewed studies, including preclinical data, were included in this review article.

RESULTS/CONCLUSIONS

Dexmedetomidine is a novel agent with a wide safety margin and excellent sedative and moderate analgesic properties. Though its broadest use is currently in surgical and nonsurgical intensive care unit patients, dexmedetomidine appears to have promising future applications in the areas of neuroprotection, cardioprotection and renoprotection.

Bradycardia During Dexmedetomidine and Therapeutic Hypothermia

Dexmedetomidine is a centrally acting α2-adrenergic agonist which is currently Food and Drug Administration— approved for the short-term (less than 24 hours) sedation of adults during mechanical ventilation. Given its beneficial physiologic effects and limited adverse effect profile, there is growing interest regarding its potential applications in the Pediatric intensive care unit patient including sedation during mechanical ventilation, procedural sedation, the treatment of withdrawal, and prevention of emergence agitation. Although generally safe and effective, occasional hemodynamic effects including bradycardia and hypotension have been reported. Clinical experience has demonstrated that bradycardia may be more common when dexmedetomidine is administered with other medications that have negative chronotropic effects. We report 2 pediatric patients with traumatic brain injury who had good long-term neurologic outcomes, but developed clinically significant bradycardia when therapeutic hypothermia was added to a sedation regimen that included dexmedetomidine and remifentanil. The role of dexmedetomidine as a neuroprotective agent is explored as well as a review presented of previous reports of bradycardia related to dexmedetomidine.

Clinical uses of dexmedetomidine in pediatric patients

Dexmedetomidine is being used off-label as an adjunctive agent for sedation and analgesia in pediatric patients in the critical care unit and for sedation during non-invasive procedures in radiology. It also has a potential role as part of anesthesia care to prevent emergence delirium and postanesthesia shivering. Dexmedetomidine is currently approved by the US FDA for sedation only in adults undergoing mechanical ventilation for <24 hours. Pediatric experiences in the literature are in the form of small studies and case reports. In patients sedated for mechanical ventilation and/or opioid/benzodiazepine withdrawal, the loading dose ranged from 0.5 to 1 microg/kg and was usually administered over 10 minutes, although not all patients received loading doses. This patient group also received a continuous infusion at rates ranging from 0.2 to 2 microg/kg/h, with higher rates used in burn patients and those with withdrawal following > or =24 hours of opioid/benzodiazepine infusion. The dexmedetomidine dosage used for anesthesia and sedation during non-invasive procedures, such as radiologic studies, ranged from a loading dose of 1-2 microg/kg followed by a continuous infusion at 0.5-1.14 microg/kg/h, with most patients spontaneously breathing. For invasive procedures, such as awake craniotomy or cardiac catheterization, dosage ranged from a loading dose of 0.15 to 1 microg/kg followed by a continuous infusion at 0.1-2 microg/kg/h. Adverse hemodynamic and respiratory effects were minimal; the agent was well tolerated in most patients. The efficacy of dexmedetomidine varied depending on the clinical situation: efficacy was greatest during non-invasive procedures, such as magnetic resonance imaging (MRI), and lowest during invasive procedures, such as cardiac catheterization. Dexmedetomidine may be useful in pediatric patients for sedation in a variety of clinical situations. The literature suggests potential use of dexmedetomidine as an adjunctive agent to other sedatives during mechanical ventilation and opioid/benzodiazepine withdrawal. In addition, because of its minimal respiratory effects, dexmedetomidine has also been used as a single agent for sedation during non-invasive procedures such as MRI. However, additional studies in pediatric patients are warranted to further evaluate its safety and efficacy in all age ranges.

Use of dexmedetomidine in the pediatric intensive care unit

STUDY OBJECTIVE

To determine the safety, effectiveness, and dosing of dexmedetomidine in intensive care infants and children who require sedation, and the rationale for patient selection.

DESIGN

Prospective observational study.

SETTING

Eleven-bed pediatric intensive care unit in a university-affiliated children's hospital.

PATIENTS

Seventeen infants and children who received dexmedetomidine consecutively between May 4, 2005, and May 4, 2006.

MEASUREMENTS AND MAIN RESULTS

Data were collected on demographics, blood pressure and heart rate measurements, and adverse effects. The rationale for dexmedetomidine use, its dosing, use of other sedatives, and treatment duration were also recorded. Twenty treatment courses in 17 patients (median age 5 mo, range 1 mo-17 yrs) were evaluated. Ten patients (59%) had chronic neurologic impairments (including Down syndrome in nine [53%]). Thirteen (76%) had undergone cardiac surgery, two (12%) had respiratory failure, one (6%) had endocarditis, and one (6%) had undergone scoliosis repair. In 15 (75%) of 20 cases, dexmedetomidine was started to minimize the use of midazolam before extubation; in 13 (87%) of these cases, the patients were extubated within 24 hours. The remaining patients could not tolerate midazolam, and dexmedetomidine was used as an alternative. No loading doses were given. The mean +/- SD starting dose was 0.2 +/- 0.2 microg/kg/hour, with a maximum of 0.5 +/- 0.2 microg/kg/hour. Mean +/- SD duration was 32 +/- 21 hours (range 3-75 hrs); 10 courses exceeded 24 hours. Mean arterial pressures before and after starting treatment were not significantly different (p=0.76), nor were values at discontinuation (p=0.31) or 12 hours later (p=0.29). No significant differences were noted in heart rate at the start (p=0.09), at discontinuation (p=0.06), or 12 hours later (p=0.17). One patient (6%) developed hypotension; no other adverse effects were noted.

CONCLUSION

With careful patient selection and a conservative approach to dosing, dexmedetomidine was a useful sedative in children requiring mechanical ventilation. It allowed for a reduction or elimination of other sedatives, and it was particularly useful in children with chronic neurologic impairments. Dexmedetomidine was well tolerated, with no clinically significant effects on blood pressure or heart rate.

Use of dexmedetomidine for sedation of children hospitalized in the intensive care unit

BACKGROUND

Dexmedetomidine is a potentially useful sedative for hospitalized children, but there is little published data regarding its safety, dosage, or efficacy.

OBJECTIVE

To report our experience with dexmedetomidine for the sedation of hospitalized children.

DESIGN

Retrospective case series.

SETTING

Pediatric ICU of a university-affiliated children's hospital.

PATIENTS

We retrospectively examined data from the medical records of all children who received dexmedetomidine for sedation between December 2003 and October 2005.

INTERVENTION

None.

RESULTS

Dexmedetomidine was administered 74 times to 60 children (median age 1.5 years, range 0.1-17.2 years). The most common indications for ICU admission were respiratory distress/failure (53%), status-postcorrective cardiac surgery (19%), and other postoperative patients (18%). In 53% of cases dexmedetomidine was used to supplement ongoing sedation judged inadequate and in 41% of cases it was used as a bridge to extubation while other sedatives were weaned or discontinued. Among all the children, the median dose to maintain adequate sedation was 0.7 microg/kg per hour (range 0.2-2.5 microg/kg per hour), with a median duration of therapy of 23 hours (range 3-451 hours). Most children (80%) experienced no adverse effects from the sedation, with hypotension (9%), hypertension (8%), and bradycardia (3%) the most common adverse events. For 93% of children who experienced a side effect, it resolved either without treatment or by withholding the infusion.

CONCLUSIONS

In this cohort of children hospitalized in the ICU, dexmedetomidine appeared to be effective and to have few adverse effects. Dexmedetomidine may have a potentially useful role to play in sedating hospitalized children.

Use of dexmedetomidine in patients with trisomy 21 after cardiac surgery

Children with trisomy 21 have a high incidence of congenital heart disease that frequently requires surgical repair. These patients often require multiple and higher dosage sedatives during the postoperative period. Dexmedetomidine is an alpha(2)-adrenergic receptor agonist that has sedative, analgesic, and anxiolytic properties. We report the successful use of dexmedetomidine in patients with trisomy 21 following surgical repair of congenital heart disease.

Characterization of spinal alpha-adrenergic modulation of nociceptive transmission and hyperalgesia throughout postnatal development in rats

BACKGROUND AND PURPOSE

The selective alpha(2)-adrenergic agonist dexmedetomidine is used clinically for analgesia and sedation, but effects in early life are not well characterized. Investigation of age-related effects of dexmedetomidine is important for evaluating responses to exogenously administered analgesics and provides insight into postnatal function of noradrenergic pathways.

EXPERIMENTAL APPROACH

We examined effects of epidural dexmedetomidine in anaesthetized rat pups (3, 10 and 21 postnatal days) using a quantitative model of nociception and C-fibre induced hyperalgesia. Electromyographic recordings of withdrawal responses to hindpaw mechanical stimuli measured effects of dexmedetomidine upon the baseline reflex and the response to mustard oil application on the hindpaw (primary hyperalgesia) or hindlimb (secondary hyperalgesia). In addition, we compared epidural with systemic administration, examined effects of spinal transection and evaluated heart rate changes following dexmedetomidine.

KEY RESULTS

Epidural dexmedetomidine dose-dependently prevented mustard oil-induced hyperalgesia at all ages but dose requirements were lower in the youngest pups. Higher doses also suppressed the baseline nociceptive reflex when given epidurally, but had no effect when given systemically. Analgesic efficacy was the same for primary and secondary hyperalgesia, and was not diminished by spinal cord transection.

CONCLUSIONS AND IMPLICATIONS

Our laboratory studies predict that spinally mediated alpha(2)-agonist analgesia would be effective throughout postnatal development, dose requirements would be lower in early life and selective anti-hyperalgesic effects could be achieved with epidural administration at doses lower than associated with antinociceptive or cardiovascular effects. Clinical trials of alpha(2) agonists in neonates and infants should consider developmentally regulated changes.

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.