Safety and population pharmacokinetic analysis of intravenous acetaminophen in neonates, infants, children, and adolescents with pain or Fever

OBJECTIVES

The administration of acetaminophen via the oral and rectal routes may be contraindicated in specific clinical settings. Intravenous administration provides an alternative route for fever reduction and analgesia. This phase 1 study of intravenous acetaminophen (Ofirmev, Cadence Pharmaceuticals, Inc., San Diego, CA) in inpatient pediatric patients with pain or fever requiring intravenous therapy was designed to assess the safety and pharmacokinetics of repeated doses over 48 hours.

METHODS

Neonates (full-term to 28 days) received either 12.5 mg/kg every 6 hours or 15 mg/kg every 8 hours. Infants (29 days to <2 years), children (2 to <12 years) and adolescents (≥12 years) received either 12.5 mg/kg every 4 hours or 15 mg/kg every 6 hours. Both noncompartmental and population nonlinear mixed-effects modeling approaches were used. Urinary metabolite data were analyzed, and safety and tolerability were assessed.

RESULTS

Pharmacokinetic parameters of acetaminophen were estimated using a two-compartment disposition model with weight allometrically expressed on clearances and central and peripheral volumes of distribution (Vds). Postnatal age, with a maturation function, was a significant covariate on clearance. Total systemic normalized clearance was 18.4 L/hr per 70 kg, with a plateau reached at approximately 2 years. Total central and peripheral Vds of acetaminophen were 16 and 59.5 L/70 kg, respectively. The drug was well tolerated based on the incidence of adverse events. The primary and minor pathways of elimination were acetaminophen glucuronidation, sulfation, and glutathione conjugate metabolites across all age groups.

CONCLUSIONS

Intravenous acetaminophen in infants, children, and adolescents was well tolerated and achieved plasma concentrations similar to those achieved with labeled 15 mg/kg body weight doses by oral or rectal administration.

Cardiomyopathy and heart failure in children: anesthetic implications

The purpose of this article is to provide a brief but systematic overview of heart failure and cardiomyopathy in children and the anesthetic management of these patients. We will begin with disease definitions and descriptions of the disorders. Our review will include the epidemiology and etiology of the more prevalent underlying causes of heart failure, the principal pathophysiology of the specific cardiomyopathies, as well as the common therapies in use today in both inpatient and outpatient settings. Important implications for anesthetic management will be highlighted.

A sensitive assay for the quantification of morphine and its active metabolites in human plasma and dried blood spots using high-performance liquid chromatography-tandem mass spectrometry

Opioids such as morphine are the cornerstone of pain treatment. The challenge of measuring the concentrations of morphine and its active metabolites in order to assess human pharmacokinetics and monitor therapeutic drugs in children requires assays with high sensitivity in small blood volumes. We developed and validated a semi-automated LC-MS/MS assay for the simultaneous quantification of morphine and its active metabolites morphine 3β-glucuronide (M3G) and morphine 6β-glucuronide (M6G) in human plasma and in dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution containing the internal standards were the only manual steps. Morphine and its metabolites were separated on a Kinetex 2.6-μm PFP analytical column using an acetonitrile/0.1% formic acid gradient. The analytes were detected in the positive multiple reaction mode. In plasma, the assay had the following performance characteristics: range of reliable response of 0.25-1000 ng/mL (r(2) > 0.99) for morphine, 1-1,000 ng/mL (r(2) > 0.99) for M3G, and 2.5-1,000 ng/mL for M6G. In DBS, the assay had a range of reliable response of 1-1,000 ng/mL (r(2) > 0.99) for morphine and M3G, and of 2.5-1,000 ng/mL for M6G. For inter-day accuracy and precision for morphine, M3G and M6G were within 15% of the nominal values in both plasma and DBS. There was no carryover, ion suppression, or matrix interferences. The assay fulfilled all predefined acceptance criteria, and its sensitivity using DBS samples was adequate for the measurement of pediatric pharmacokinetic samples using a small blood of only 20-50 μL.

Dexmedetomidine: pediatric pharmacology, clinical uses and safety

IMPORTANCE OF THE FIELD

Dexmedetomidine is an α(2)-adrenoceptor agonist with sedative, anxiolytic and analgesic properties. It is used off-label in pediatric patients due to its efficacy and lack of adverse respiratory effects. Dexmedetomidine may cause severe circulatory complications in adults. Despite its popularity, the safety of dexmedetomidine in the pediatric population has not been extensively studied.

AREAS COVERED IN THIS REVIEW

This article reviews the current literature (up to 2010) focusing on applications and safety of dexmedetomidine administered to pediatric patients.

WHAT THE READER WILL GAIN

Dexmedetomidine is a useful sedative and anxiolytic drug in the pediatric intensive care unit as well as during diagnostic and therapeutic procedures. Deleterious effects of dexmedetomidine include hypotension and bradycardia. Additionally, hypertension may occur during the "loading dose" or with high infusion rates. Few studies have been performed to evaluate the safety of dexmedetomidine in pediatrics. The development of tolerance and withdrawal has not been studied in children.

TAKE HOME MESSAGE

Despite its favorable respiratory profile, dexmedetomidine may cause deleterious cardiovascular effects. Close monitoring of circulatory dynamics and judicious titration is recommended. Further studies are needed to better define adverse effects following long-term infusions as well as in special populations such as pre-term infants.

Airway responses to desflurane during maintenance of anesthesia and recovery in children with laryngeal mask airways

BACKGROUND

We sought to characterize the airway responses to desflurane during maintenance of and emergence from anesthesia in children whose airways were supported with laryngeal mask airways (LMAs).

METHODS/MATERIALS

Four hundred healthy children were randomized in a 3 : 1 ratio to either desflurane or isoflurane (reference group) during anesthetic maintenance. After induction of anesthesia, anesthesia was maintained with the designated anesthetic. The investigator chose the airway (LMA and facemask), ventilation strategy and when to remove the LMA. The incidence of airway events during maintenance, emergence and recovery was recorded.

RESULTS

Ninety percent of children received LMAs. The frequency of major airway events after desflurane (9%) was similar to that after isoflurane (4%) (number needed to harm [NNH] 20), although the frequency of major events after the LMA was removed during deep desflurane anesthesia (15%) was greater than during awake removal (5%) (NNH 10) (P < 0.006) and during deep isoflurane removal (2%) (NNH 8) (P < 0.03). The frequency of airway events of any severity after desflurane was greater than that after isoflurane (39% vs 27%) (P < 0.05). The frequencies of laryngospasm and coughing of any severity after desflurane were greater than those after isoflurane (13% vs 5% and 26% vs 14%, respectively) (P < 0.05).

CONCLUSIONS

When an LMA is used during desflurane anesthesia in children, fewer airway events occur when it is removed when the child is awake. Although the time to discharge from recovery was not delayed and no child required overnight admission, caution should be exercised when using an LMA in children who are anesthetized with desflurane.

Perioperative complications in children with pulmonary hypertension undergoing general anesthesia with ketamine

BACKGROUND

Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications in children, including pulmonary hypertensive crisis and cardiac arrest. Uncertainty remains about the safety of ketamine anesthesia in this patient population.

AIM

Retrospectively review the medical records of children with PAH to ascertain the nature and frequency of peri-procedural complications and to determine whether ketamine administration was associated with peri-procedural complications.

METHODS

Children with PAH (mean pulmonary artery pressure > or =25 mmHg and pulmonary vascular resistance index > or =3 Wood units) who underwent general anesthesia for procedures during a 6-year period (2002-2008) were enrolled. Details about the patient, PAH, procedure, anesthetic and postprocedural course were noted, including adverse events during or within 48 h of the procedure. Complication rates were reported per procedure. Association between ketamine and peri-procedural complications was tested.

RESULTS

Sixty-eight children (median age 7.3 year, median weight 22 kg) underwent 192 procedures. Severity of PAH was mild (23%), moderate (37%), and severe (40%). Procedures undertaken were major surgery (n = 20), minor surgery (n = 27), cardiac catheterization (n = 128) and nonsurgical procedures (n = 17). Ketamine was administered during 149 procedures. Twenty minor and nine major complications were noted. Incidence of cardiac arrest was 0.78% for cardiac catheterization procedures, 10% for major surgical procedures and 1.6% for all procedures. There was no procedure-related mortality. Ketamine administration was not associated with increased complications.

CONCLUSIONS

Ketamine appears to be a safe anesthetic option for children with PAH. We report rates for cardiopulmonary resuscitation and mortality that are more favorable than those previously reported.

Pharmacokinetic-pharmacodynamic modeling of the hypotensive effect of remifentanil in infants undergoing cranioplasty

OBJECTIVES

Although remifentanil has been used to induce hypotension during surgery in infants, no pharmacokinetic-pharmacodynamic (PKPD) model exists for its quantitative analysis. Our aim was to determine the quantitative relationship between whole blood remifentanil concentration and its hypotensive effect during surgery in infants.

METHODS/MATERIALS

We studied seven infants (age 0.3-1 year) who underwent cranioplasty surgery and received remifentanil delivered by a computer-controlled infusion pump during the maintenance of anesthesia. Arterial blood samples to determine remifentanil concentration and mean arterial blood pressure (MAP) measurements were collected. A simultaneous PKPD mixed-effects model was built in NONMEM.

RESULTS

A total of 77 remifentanil concentrations and 185 MAP measurements were collected. Remifentanil pharmacokinetics was described with a two-compartment model, parameter estimates were 2.99 l x min(-1) x 70 kg(-1) for clearance and 16.23 l x 70 kg(-1) for steady state volume of distribution. Mean baseline MAP was 69.7 mmHg and was decreased as per clinical requirements. A sigmoidal E(max) model driven by an effect compartment described the decrease in MAP, with an estimated concentration to decrease MAP by half (EC(50)) being 17.1 ng x ml(-1).

CONCLUSIONS

Remifentanil is effective in causing hypotension. The final model predicts that a steady state remifentanil concentration of 14 ng.ml(-1) would typically achieve a 30% decrease in MAP.

Population pharmacokinetics of remifentanil in infants and children undergoing cardiac surgery

Background

The aim of this study was to provide a model-based analysis of the pharmacokinetics of remifentanil in infants and children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

Methods

We studied nine patients aged 0.5 to 4 years who received a continuous remifentanil infusion via a computer-controlled infusion pump during cardiac surgery with mildly hypothermic CPB were studied. Arterial blood samples taken prior to, during and after CPB were analyzed for remifentanil concentrations using a validated gas-chromatographic mass-spectrophotometric assay. We used population mixed-effects modeling to characterize remifentanil pharmacokinetics. The final model was evaluated by its predictive performance.

Results

The pharmacokinetics of remifentanil was described by a 1-compartment model with adjustments for CPB. Population mean parameter estimates were 1.41 L for volume of distribution (V) and 0.244 L/min for clearance. V was increased during CPB and post-CPB to 2.41 times the pre-CPB value. The median prediction error and the median of individual median absolute prediction error were 2.44% and 21.6%, respectively.

Conclusion

Remifentanil dosage adjustments are required during and after CPB due to marked changes in the V of the drug. Simulations indicate that a targeted blood concentration of 14 ng/mL is achieved and maintained in 50% of typical patients by administration of an initial dose of 18 μg remifentanil followed by an infusion of 3.7 μg/min before, during and post-CPB, supplemented with a bolus dose of 25 μg given at the start of CPB.

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.

Determination of the pharmacodynamic interaction of propofol and dexmedetomidine during esophagogastroduodenoscopy in children

OBJECTIVES

Propofol is a sedative-hypnotic drug commonly used to anesthetize children undergoing esophagogastroduodenoscopy (EGD). Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist that has been utilized in combination with propofol to provide anesthesia. There is currently no information regarding the effect of intravenous dexmedetomidine on the propofol plasma concentration-response relationship during EGD in children. This study aimed to investigate the pharmacodynamic interaction of propofol and dexmedetomidine when used in combination for children undergoing EGD.

METHODS

A total of 24 children undergoing EGD, ages 3-10 years, were enrolled in this study. Twelve children received dexmedetomidine 1 microg x kg(-1) given over 10 min as well as a continuous infusion of propofol delivered by a computer-assisted target-controlled infusion (TCI) system with target plasma concentrations ranging from 2.8 to 4.0 microg x ml(-1) (DEX group). Another group of 12 children undergoing EGD also received propofol administered by TCI targeting comparable plasma concentrations without dexmedetomidine (control group). We used logistic regression to predict plasma propofol concentrations at which 50% of the patients exhibited minimal response to stimuli (EC50 for anesthesia).

RESULTS

The EC50 +/- SE values in the control and DEX groups were 3.7 +/- 0.4 microg x ml(-1) and 3.5 +/- 0.2 microg x ml(-1), respectively. There was no significant shift in the propofol concentration-response curve in the presence of dexmedetomidine.

CONCLUSION

The EC50 of propofol required to produce adequate anesthesia for EGD in children was unaffected by a concomitant infusion of dexmedetomidine 1 microg x kg(-1) given over 10 min.

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.

Pharmacokinetics And Pharmacodynamics Of Fenoldopam Mesylate For Blood Pressure Control In Pediatric Patients

BACKGROUND

Fenoldopam mesylate, a selective dopamine1-receptor agonist, is used by intravenous infusion to treat hypertension in adults. Fenoldopam is not approved by the FDA for use in children; reports describing its use in pediatrics are limited. In a multi-institutional, placebo controlled, double-blind, multi-dose trial we determined the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and side-effect profile of fenoldopam in children.

METHODS

Seventy seven (77) children from 3 weeks to 12 years of age scheduled for surgery in which deliberate hypotension would be induced were enrolled. Patients were randomly assigned to one of five, blinded treatment groups (placebo or fenoldopam 0.05, 0.2, 0.8, or 3.2 mcg/kg/min iv) for a 30-minute interval after stabilization of anesthesia and placement of vascular catheters. Following the 30-minute blinded interval, investigators adjusted the fenoldopam dose to achieve a target mean arterial pressure in the open-label period until deliberate hypotension was no longer indicated (e.g., muscle-layer closure). Mean arterial pressure and heart rate were continuously monitored and were the primary endpoints.

RESULTS

Seventy-six children completed the trial. Fenoldopam at doses of 0.8 and 3.2 mcg/kg/min significantly reduced blood pressure (p < 0.05) during the blinded interval, and doses of 1.0-1.2 mcg/kg/min resulted in continued control of blood pressure during the open-label interval. Doses greater than 1.2 mcg/kg/min during the open-label period resulted in increasing heart rate without additional reduction in blood pressure. Fenoldopam was well-tolerated; side effects occurred in a minority of patients. The PK/PD relationship of fenoldopam in children was determined.

CONCLUSION

Fenoldopam is a rapid-acting, effective agent for intravenous control of blood pressure in children. The effective dose range is significantly higher in children undergoing anesthesia and surgery (0.8-1.2 mcg/kg/min) than as labeled for adults (0.05-0.3 mcg/kg/min). The PK and side-effect profiles for children and adults are similar.

Ketamine does not increase pulmonary vascular resistance in children with pulmonary hypertension undergoing sevoflurane anesthesia and spontaneous ventilation

BACKGROUND

The use of ketamine in children with increased pulmonary vascular resistance is controversial. In this prospective, open label study, we evaluated the hemodynamic responses to ketamine in children with pulmonary hypertension (mean pulmonary artery pressure >25 mm Hg).

METHODS

Children aged 3 mo to 18 yr with pulmonary hypertension, who were scheduled for cardiac catheterization with general anesthesia, were studied. Patients were anesthetized with sevoflurane (1 minimum alveolar anesthetic concentration [MAC]) in air while breathing spontaneously via a facemask. After baseline catheterization measurements, sevoflurane was reduced (0.5 MAC) and ketamine (2 mg/kg IV over 5 min) was administered, followed by a ketamine infusion (10 microg x kg(-1) x min(-1)). Catheterization measurements were repeated at 5, 10, and 15 min after completion of ketamine load. Data at various time points were compared (ANOVA, P < 0.05).

RESULTS

Fifteen patients (age 147, 108 mo; median, interquartile range) were studied. Diagnoses included idiopathic pulmonary arterial hypertension (5), congenital heart disease (9), and diaphragmatic hernia (1). At baseline, median (interquartile range) baseline pulmonary vascular resistance index was 11.3 (8.2) Wood units; 33% of patients had suprasystemic mean pulmonary artery pressures. Heart rate (99, 94 bpm; P = 0.016) and Pao2 (95, 104 mm Hg; P = 007) changed after ketamine administration (baseline, 15 min after ketamine; P value). There were no significant differences in mean systemic arterial blood pressure, mean pulmonary artery pressure, systemic or pulmonary vascular resistance index, cardiac index, arterial pH, or Paco2.

CONCLUSIONS

In the presence of sevoflurane, ketamine did not increase pulmonary vascular resistance in spontaneously breathing children with severe pulmonary hypertension.

The use of dexmedetomidine during laryngoscopy, bronchoscopy, and tracheal extubation following tracheal reconstruction

We report the use of dexmedetomidine for laryngoscopy, rigid bronchoscopy, and tracheal extubation in the operating room in two children who had undergone tracheal reconstruction 1 week previously. Dexmedetomidine in combination with propofol provided appropriately deep anesthesia during these brief but stimulating procedures without cardiovascular or respiratory depression.

Opioid analgesia in neonates following cardiac surgery

Pain in the newborn is complex, involving a variety of receptors and mechanisms within the developing nervous system. When pain is generated, a series of sequential neurobiologic changes occur within the central nervous system. If pain is prolonged or repetitive, the developing nervous system could be permanently modified, with altered processing at spinal and supraspinal levels. In addition, pain is associated with a number of adverse physiologic responses that include alterations in circulatory (tachycardia, hypertension, vasoconstriction), metabolic (increased catabolism), immunologic (impaired immune response), and hemostatic (platelet activation) systems. This "stress response" associated with cardiac surgery in neonates could be profound and is associated with increased morbidity and mortality. Neonates undergoing cardiac operations are exposed to extensive tissue damage related to surgery and additional painful stimulation related to endotracheal and thoracostomy tubes that may remain in place for variable periods of time following surgery. In addition, postoperatively neonates endure repeated procedural pain from suctioning of endotracheal tubes, placement of vascular catheters, and manipulation of wounds (eg, sternal closure) and dressings. The treatment and/or prevention of pain are widely considered necessary for humanitarian and physiologic reasons. Improved clinical and developmental outcomes underscore the importance of providing adequate analgesia for newborns who undergo major surgery, mechanical ventilation, and related procedures in the intensive care unit. This article reviews published information regarding opioid administration and associated issues of tolerance and abstinence syndromes (withdrawal) in neonates with an emphasis on those having undergone cardiac surgery.

Modified and conventional ultrafiltration during pediatric cardiac surgery: Clinical outcomes compared

OBJECTIVE

This prospective study compared clinical outcomes after heart surgery between three groups of infants with congenital heart disease. One group received dilutional conventional ultrafiltration (group D), another received modified ultrafiltration (group M), and a third group received both dilutional conventional and modified ultrafiltration (group B). We hypothesized that group B patients would have the best clinical outcome.

METHODS

Children younger than 1 year undergoing heart surgery for biventricular repair by the same surgeon were randomly allocated to one of the three study groups. Patient management was standardized, and intensive care staff were blinded to group allocation. Primary outcome measure was duration of postoperative mechanical ventilation. Other outcome measures recorded included total blood products transfused, duration of chest tube in situ, chest tube output, and stays in intensive care and in the hospital.

RESULTS

Sixty infants completed study protocol. Mean age and weight were as follows: group D (n = 19), 61 days, 4.3 kg; group M (n = 20), 64 days, 4.5 kg; and group B (n = 21), 86 days, 4.4 kg. Preoperative and intraoperative characteristics were similar between groups. Ultrafiltrate volumes obtained were 196 +/- 93 mL/kg in group D, 105 +/- 33 mL/kg in group M, and 261 +/- 113 mL/kg in group B. There were no significant differences between groups for any outcome variable. Technical difficulties prevented completion of modified ultrafiltration in 2 of 41 infants.

CONCLUSION

There was no clinical advantage in combining conventional and modified ultrafiltration. Because clinical outcomes were similar across groups, relative risks of the ultrafiltration strategies may influence choice.

Lung isolation in a child with unilateral necrotizing Clostridium perfringens pneumonia

OBJECTIVE

To describe lung isolation and the selective application of continuous positive airway pressure using an endobronchial blocker in a patient with sickle cell disease and unilateral necrotizing Clostridium perfringens pneumonia.

DESIGN

Case report.

SETTING

Pediatric intensive care unit.

PATIENT

A 12-yr-old male with sickle cell disease developed persistent necrotizing pneumonia of the left lung following exchange transfusion for acute chest syndrome and hyper-hemolytic syndrome.

INTERVENTIONS

An endobronchial blocker was placed into the left main stem bronchus for lung isolation and application of continuous positive airway pressure to the left lung for 48 hrs.

MEASUREMENTS AND MAIN RESULTS

After 14 days of persistent atelectasis of the left lung despite thorascopic decortication and multiple bronchoscopies, our patient had substantial lung aeration within 48 hrs of continuous positive airway pressure applied via the endobronchial blocker. Lung resection was avoided and the patient was successfully extubated 2 days after removal of the blocker.

CONCLUSIONS

This case report demonstrates a therapeutic application of prolonged lung isolation and differential ventilation in a patient with an airway too small for commercially available double-lumen endotracheal tubes. The apparent success of this intervention suggests the feasibility of selective ventilation in pediatric patients and highlights a novel application of the bronchial blocker.

A comparison of three methods for estimating appropriate tracheal tube depth in children

BACKGROUND

Estimating appropriate tracheal tube (TT) depth following tracheal intubation in infants and children presents a challenge to anesthesia practitioners. We evaluated three methods commonly used by anesthesiologists to determine which one most reliably results in appropriate positioning.

METHODS

After IRB approval, 60 infants and children scheduled for fluoroscopic procedures requiring general anesthesia were enrolled. Patients were randomly assigned to one of three groups: (1) deliberate mainstem intubation with subsequent withdrawal of the TT 2 cm above the carina ('mainstem' method); (2) alignment of the double black line marker near the TT tip at the vocal cords ('marker' method); or (3) placement of the TT at a depth determined by the formula: TT depth (cm) = 3 x TT size (mmID) ('formula' method). TT tip position was determined to be 'appropriate' if located between the sternoclavicular junction (SCJ) and 0.5 cm above the carina as determined by fluoroscopy. Risk ratios were calculated, and data were analysed by the chi-square test accepting statistical significance at P < 0.05.

RESULTS

The mainstem method was associated with the highest rate of appropriate TT placement (73%) compared with both the marker method (53%, P = 0.03, RR = 1.56) and the formula method (42%, P = 0.006, RR = 2.016). There was no difference between the marker and formula methods overall (P = 0.2, RR = 1.27). Analysis of age-stratified data demonstrated higher success with the marker method compared with the formula method for patients 3-12 months (P = 0.0056, RR = 4.0).

CONCLUSIONS

Deliberate mainstem intubation most reliably results in appropriate TT depth in infants and children.

Prolonged infusion of dexmedetomidine for sedation following tracheal resection

Dexmedetomidine is a centrally acting alpha-2 adrenergic agonist that is currently approved by the US Food and Drug Administration for short-term use (< or = 24 h) to provide sedation in adults in the ICU. This drug has been shown to be efficacious in adult medical and surgical patients in providing sedation, anxiolysis, and analgesia. Dexmedetomidine has been associated with rapid onset and offset, hemodynamic stability, and a natural, sleep-like state in mechanically ventilated adults. To date, there are few publications of the use of this drug in children, and prolonged infusion has not been described. We report our use of dexmedetomidine in a child during a 4-day period of mechanical ventilation following tracheal reconstruction for subglottic stenosis.