Clinical adverse events to dexmedetomidine: a real-world drug safety study based on the FAERS database

Objective

Adverse events associated with dexmedetomidine were analyzed using data from the FDA's FAERS database, spanning from 2004 to the third quarter of 2023. This analysis serves as a foundation for monitoring dexmedetomidine's safety in clinical applications.

Methods

Data on adverse events associated with dexmedetomidine were standardized and analyzed to identify clinical adverse events closely linked to its use. This analysis employed various signal quantification analysis algorithms, including Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-Item Gamma Poisson Shrinker (MGPS).

Results

In the FAERS database, dexmedetomidine was identified as the primary suspect in 1,910 adverse events. Our analysis encompassed 26 organ system levels, from which we selected 346 relevant Preferred Terms (PTs) for further examination. Notably, adverse drug reactions such as diabetes insipidus, abnormal transcranial electrical motor evoked potential monitoring, acute motor axonal neuropathy, and trigeminal cardiac reflex were identified. These reactions are not explicitly mentioned in the drug's specification, indicating the emergence of new signals for adverse drug reactions.

Conclusion

Data mining in the FAERS database has elucidated the characteristics of dexmedetomidine-related adverse drug reactions. This analysis enhances our understanding of dexmedetomidine's drug safety, aids in the clinical management of pharmacovigilance studies, and offers valuable insights for refining drug-use protocols.

Dexmedetomidine Withdrawal Syndrome in Children in the PICU: Systematic Review and Meta-Analysis

OBJECTIVES

To systematically review literature describing the clinical presentation, risk factors, and treatment for dexmedetomidine withdrawal in the PICU (PROSPERO: CRD42022307178).

DATA SOURCES

MEDLINE/PubMed, Cochrane, Web of Science, and Scopus databases were searched.

STUDY SELECTION

Eligible studies were published from January 2000 to January 2022 and reported clinical data for patients younger than 21 years old following discontinuation of dexmedetomidine after greater than or equal to 24 hours of infusion.

DATA EXTRACTION

Abstracts identified during an initial search were screened and data were manually abstracted after full-text review of eligible articles. The Newcastle-Ottawa Scale was used to assess study quality. Summary statistics were provided and Spearman rank correlation coefficient was used to identify relationships between covariates and withdrawal signs. A weighted prevalence for each withdrawal sign was generated using a random-effects model.

DATA SYNTHESIS

Twenty-three studies (22 of which were retrospective cohort studies) containing 28 distinct cohorts were included. Median cumulative dexmedetomidine exposure by dose was 105.95 μg/kg (range, 30-232.7 μg/kg), median dexmedetomidine infusion duration was 131.75 hours (range, 20.5-525.6 hr). Weighted estimates for proportion (95% CI) of subjects experiencing withdrawal signs across all cohorts were: hypertension 0.34 (range, 0.0-0.92), tachycardia 0.26 (range, 0.0-0.87), and agitation 0.26 (range, 0.09-0.77). Meta-analysis revealed no correlation between dexmedetomidine exposure variables and withdrawal signs. A moderate negative monotonic relationship existed between the proportion of patients who had undergone cardiac surgery and the proportion experiencing hypertension (correlation coefficient, -0.47; p = 0.048) and tachycardia (correlation coefficient, -0.57; p = 0.008), indicating that in cohorts with a higher proportion of patients who were postcardiac surgery, there were fewer occurrences of hypertension and or tachycardia.

CONCLUSIONS

On review of the 2000-2022 literature, dexmedetomidine withdrawal may be characterized by tachycardia, hypertension, or agitation, particularly with higher cumulative doses or prolonged durations. Since most studies included in the review were retrospective, prospective studies are needed to further clarify risk factors, establish diagnostic criteria, and identify optimal management strategies.

Adverse cardiovascular events are common during dexmedetomidine administration in neonates and infants during intensive care

AIM

This study aimed to assess the safety of a commonly used sedative, dexmedetomidine in neonates and infants during intensive care.

METHODS

A retrospective cohort study was conducted in the paediatric intensive care unit at Oulu University Hospital. The study population consisted of all children from birth up to 6 months of age who received dexmedetomidine during 2010-2016. Adverse cardiovascular outcomes were defined as abnormal heart rates or blood pressure values according to the Paediatric Early Warning Score.

RESULTS

Of the 172 infants, 56% had congenital malformation, and 48% had undergone surgery. Neonates and 1-3-month-olds experienced bradycardia (86% vs. 73% in 1-3-month-olds and 50% in 3-6-month-olds, p = 0.001) and severe bradycardia (17% vs. 14% in 1-3-month-olds and 0% in 3-6-month-olds, p = 0.005) more often than older patients. The median maximum rate of dexmedetomidine infusion was 0.86 μg/kg/h (IQR = 0.60-1.71 μg/kg/h). A dose-dependent increase in bradycardia and severe hypotension was found. Adverse cardiovascular events were managed with additional fluid boluses and discontinuation of the infusion.

CONCLUSION

Adverse cardiovascular events were common during dexmedetomidine administration in neonates and infants. Lower dexmedetomidine doses may be required in sedating neonates.

Sinus Arrest Related to Dexmedetomidine Infusion in an Infant; a Case Report and Review of Current Literature

Background: Dexmedetomidine, an alpha 2 agonist, has emerged as a desirable sedative agent in the pediatric intensive care unit due to its minimal effect on respiratory status and reduction in delirium. Bradycardia and hypotension are common side effects, however there are emerging reports of more serious cardiovascular events, including sinus arrest and asystole. These case reports have been attributed to high vagal tone or underlying cardiac conduction dysfunction. Objectives: To describe the development of sinus arrest during sedation with dexmedetomidine in a patient without clinical features of high vagal tone, underlying cardiac conduction dysfunction, or intervening episodes of bradycardia. Case Presentation: An 11 month-old patient requiring sedation during mechanical ventilation for acute respiratory failure secondary to Adenovirus. To facilitate sedation, a dexmedetomidine infusion was initiated at .5 mcg/kg/hr and increased to maximum 1 mcg/kg/hr. Within 8 hours of initiating therapy, the patient had three episodes of sinus arrest. There was no intervening bradycardia between episodes and no further episodes occurred following discontinuation of dexmedetomidine. The patient did not have any clinical features associated with high vagal tone or underlying cardiac conduction dysfunction. Conclusions: As result of these findings, understanding risk factors for bradycardia, or more serious hemodynamic instability with dexmedetomidine infusions, is important to help identify high risk patients and weigh the associated risks and benefits of its administration.

Intranasal dexmedetomidine for transthoracic echocardiography in infants with shunt-dependent single ventricle heart disease

OBJECTIVES

We investigated the efficacy and complication profile of intranasal dexmedetomidine for transthoracic echocardiography sedation in patients with single ventricle physiology and shunt-dependent pulmonary blood flow during the high-risk interstage period.

METHODS

A single-centre, retrospective review identified interstage infants who received dexmedetomidine for echocardiography sedation. Baseline and procedural vitals were reported. Significant adverse events related to sedation were defined as an escalation in care or need for any additional/increased inotropic support to maintain pre-procedural haemodynamics. Minor adverse events were defined as changes from baseline haemodynamics that resolved without intervention. To assess whether sedation was adequate, echocardiogram reports were reviewed for completeness.

RESULTS

From September to December 2020, five interstage patients (age 29-69 days) were sedated with 3 mcg/kg intranasal dexmedetomidine. The median sedation onset time and duration time was 24 minutes (range 12-43 minutes) and 60 minutes (range 33-60 minutes), respectively. Sedation was deemed adequate in all patients as complete echocardiograms were accomplished without a rescue dose. When compared to baseline, three (60%) patients had a >10% reduction in heart rate, one (20%) patient had a >10% reduction in oxygen saturations, and one (20%) patient had a >30% decrease in blood pressure. Amongst all patients, no significant complications occurred and haemodynamic changes from baseline did not result in need for intervention or interruption of study.

CONCLUSIONS

Intranasal dexmedetomidine may be a reasonable option for echocardiography sedation in infants with shunt-dependent single ventricle heart disease, and further investigation is warranted to ensure efficacy and safety in an outpatient setting.

Asystole in 2 Pediatric Patients During Dexmedetomidine Infusion

INTRODUCTION

Bradycardia is a known side effect of dexmedetomidine. Reports of sinus pauses or asystole, however, are rare. We present 2 cases of pediatric patients who developed asystole on a dexmedetomidine infusion.

SUMMARY OF CASES

An 8-week-old male with RSV bronchiolitis and acute hypoxemic respiratory failure was started on dexmedetomidine for sedation at 0.2 mcg/kg/h with a maximum dose of 0.7mcg/kg/h. On Hospital day (HD) 4, on dexmedetomidine at 0.7 mcg/kg/h, he developed intermittent episodes of bradycardia with heart rates in the 60 s. Echocardiogram on HD 6 showed normal function. On HD 7, he began having periods of asystole lasting up to 6 seconds. Dexmedetomidine was discontinued, with the resolution of episodes of asystole after 6 hours. A 27-month-old male with a congenital left diaphragmatic hernia and pulmonary hypertension who had been weaned off sildenafil 6 months earlier underwent re-repair of left diaphragmatic hernia. Postoperatively he remained intubated and paralyzed. Dexmedetomidine was started at 0.3 mcg/kg/h for sedation, with a maximum dose of 1.2 mcg/kg/h. An echocardiogram on HD 3 showed good function with mild to moderate pulmonary hypertension. That evening, with dexmedetomidine at 1.1 mcg/kg/h, he developed a 15 second period of asystole requiring CPR. Dexmedetomidine was discontinued, and he was started on a midazolam infusion with no further episodes.

DISCUSSION

Both cases occurred in patients without cardiac conduction defects or on negative chronotropic or sympatholytic medications that have been associated with dexmedetomidine-induced asystole. We hypothesize that both episodes of asystole were due to increased patient-related vagal tone exacerbated by dexmedetomidine.

Patient-Specific Factors Associated with Dexmedetomidine Dose Requirements in Critically Ill Children

The objective of this study was to evaluate patient-specific factors associated with dexmedetomidine dose requirements during continuous infusion. A retrospective cross-sectional analysis of electronic health record-derived data spanning 10 years for patients admitted with a primary respiratory diagnosis at a quaternary children's hospital and who received a dexmedetomidine continuous infusion (n = 346 patients) was conducted. Penalized regression was used to select demographic, clinical, and medication characteristics associated with a median daily dexmedetomidine dose. Identified characteristics were included in multivariable linear regression models and sensitivity analyses. Critically ill children had a median hourly dexmedetomidine dose of 0.5 mcg/kg/h (range: 0.1–1.8), median daily dose of 6.7 mcg/kg/d (range: 0.9–38.4), and median infusion duration of 1.6 days (range: 0.25–5.0). Of 26 variables tested, 15 were selected in the final model with days of dexmedetomidine infusion (β: 1.9; 95% confidence interval [CI]: 1.6, 2.3), median daily morphine milligram equivalents dosing (mg/kg/d) (β: 0.3; 95% CI: 0.1, 0.5), median daily ketamine dosing (mg/kg/d) (β: 0.2; 95% CI: 0.1, 0.3), male sex (β: −1.1; 95% CI: −2.0, −0.2), and non-Black reported race (β: −1.2; 95% CI: −2.3, −0.08) significantly associated with median daily dexmedetomidine dose. Approximately 56% of dose variability was explained by the model. Readily obtainable information such as demographics, concomitant medications, and duration of infusion accounts for over half the variability in dexmedetomidine dosing. Identified factors, as well as additional environmental and genetic factors, warrant investigation in future studies to inform precision dosing strategies.

Intranasal dexmedetomidine: the ideal drug for sedation in the pediatric echo lab?

BACKGROUND

Intranasal dexmedetomidine is an attractive option for procedural sedation in pediatrics due to ease of administration and its relatively short half-life. This study sought to compare the safety and efficacy of intranasal dexmedetomidine to a historical cohort of pediatric patients sedated using chloral hydrate in a pediatric echo lab.

METHODS

Chart review was performed to compare patients sedated between September, 2017 and October, 2019 using chloral hydrate and intranasal dexmedetomidine. Vital signs, time to sedation, duration of sedation, need for second dose of medication, rate of failed sedation, and impact on vital signs were compared between groups. Subgroup analysis was performed for those with complex and cyanotic heart disease.

RESULTS

Chloral hydrate was used in 356 patients and intranasal dexmedetomidine in 376. Patient age, complexity of heart disease, and duration of sedation were similar. Rates of failed sedation were very low and similar. Average heart rate and minimum heart rate were lower for those receiving intranasal dexmedetomidine than chloral hydrate. Impact on vital signs was similar for those with complex and cyanotic heart disease. No adverse events occurred in either group.

CONCLUSIONS

Sedation with intranasal dexmedetomidine is comparable to chloral hydrate in regards to safety and efficacy for children requiring echocardiography. Consistent with the mechanism of action, patients receiving intranasal dexmedetomidine have a lower heart rate without morbidity.

2022 Society of Critical Care Medicine Clinical Practice Guidelines on Prevention and Management of Pain, Agitation, Neuromuscular Blockade, and Delirium in Critically Ill Pediatric Patients With Consideration of the ICU Environment and Early Mobility

RATIONALE

A guideline that both evaluates current practice and provides recommendations to address sedation, pain, and delirium management with regard for neuromuscular blockade and withdrawal is not currently available.

OBJECTIVE

To develop comprehensive clinical practice guidelines for critically ill infants and children, with specific attention to seven domains of care including pain, sedation/agitation, iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment, and early mobility.

DESIGN

The Society of Critical Care Medicine Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility Guideline Taskforce was comprised of 29 national experts who collaborated from 2009 to 2021 via teleconference and/or e-mail at least monthly for planning, literature review, and guideline development, revision, and approval. The full taskforce gathered annually in-person during the Society of Critical Care Medicine Congress for progress reports and further strategizing with the final face-to-face meeting occurring in February 2020. Throughout this process, the Society of Critical Care Medicine standard operating procedures Manual for Guidelines development was adhered to.

METHODS

Taskforce content experts separated into subgroups addressing pain/analgesia, sedation, tolerance/iatrogenic withdrawal, neuromuscular blockade, delirium, PICU environment (family presence and sleep hygiene), and early mobility. Subgroups created descriptive and actionable Population, Intervention, Comparison, and Outcome questions. An experienced medical information specialist developed search strategies to identify relevant literature between January 1990 and January 2020. Subgroups reviewed literature, determined quality of evidence, and formulated recommendations classified as "strong" with "we recommend" or "conditional" with "we suggest." Good practice statements were used when indirect evidence supported benefit with no or minimal risk. Evidence gaps were noted. Initial recommendations were reviewed by each subgroup and revised as deemed necessary prior to being disseminated for voting by the full taskforce. Individuals who had an overt or potential conflict of interest abstained from relevant votes. Expert opinion alone was not used in substitution for a lack of evidence.

RESULTS

The Pediatric Pain, Agitation, Neuromuscular Blockade, and Delirium in critically ill pediatric patients with consideration of the PICU Environment and Early Mobility taskforce issued 44 recommendations (14 strong and 30 conditional) and five good practice statements.

CONCLUSIONS

The current guidelines represent a comprehensive list of practical clinical recommendations for the assessment, prevention, and management of key aspects for the comprehensive critical care of infants and children. Main areas of focus included 1) need for the routine monitoring of pain, agitation, withdrawal, and delirium using validated tools, 2) enhanced use of protocolized sedation and analgesia, and 3) recognition of the importance of nonpharmacologic interventions for enhancing patient comfort and comprehensive care provision.

Dexmedetomidine in Children on Extracorporeal Membrane Oxygenation: Pharmacokinetic Data Exploration Using Previously Published Models

BACKGROUND

Dexmedetomidine is a sedative and analgesic increasingly used in children supported with extracorporeal membrane oxygenation (ECMO). No data is available to describe the pharmacokinetics (PK) of dexmedetomidine in this population.

METHODS

We performed a single-center prospective PK study. Children <18 years old, supported with ECMO, and on a dexmedetomidine infusion as part of their management were prospectively included. PK samples were collected. Dexmedetomidine dosing remained at the discretion of the clinical team. Six population PK models built in pediatrics were selected. Observed concentrations were compared with population predicted concentrations using the PK models.

RESULTS

Eight children contributed 30 PK samples. None of the PK models evaluated predicted the concentrations with acceptable precision and bias. Four of the six evaluated models overpredicted the concentrations. The addition of a correction factor on clearance improved models' fit. Two of the evaluated models were not applicable to our whole population age range because of their structure.

CONCLUSION

Most of the evaluated PK models overpredicted the concentrations, potentially indicating increased clearance on ECMO. Population PK models applicable to a broad spectrum of ages and pathologies are more practical in pediatric critical care settings but challenging to develop.

Dexmedetomidine and Iatrogenic Withdrawal Syndrome in Critically Ill Children

BACKGROUND

Iatrogenic withdrawal syndrome is a well-known adverse effect of sedatives and analgesics commonly used in patients receiving mechanical ventilation in the pediatric intensive care unit, with an incidence of up to 64.6%. When standard sedative and analgesic treatment is inadequate, dexmedetomidine may be added. The effect of supplemental dexmedetomidine on iatrogenic withdrawal syndrome is unclear.

OBJECTIVE

To explore the potentially preventive effect of dexmedetomidine, used as a supplement to standard morphine and midazolam regimens, on the development of iatrogenic withdrawal syndrome in patients receiving mechanical ventilation in the pediatric intensive care unit.

METHODS

This retrospective observational study used data from patients on a 10-bed general pediatric intensive care unit. Iatrogenic withdrawal syndrome was measured using the Sophia Observation withdrawal Symptoms-scale.

RESULTS

In a sample of 102 patients, the cumulative dose of dexmedetomidine had no preventive effect on the development of iatrogenic withdrawal syndrome (P = .19). After correction for the imbalance in the baseline characteristics between patients who did and did not receive dexmedetomidine, the cumulative dose of midazolam was found to be a significant risk factor for iatrogenic withdrawal syndrome (P < .03).

CONCLUSION

In this study, supplemental dexmedetomidine had no preventive effect on iatrogenic withdrawal syndrome in patients receiving sedative treatment in the pediatric intensive care unit. The cumulative dose of midazolam was a significant risk factor for iatrogenic withdrawal syndrome.

Dexmedetomidine for Prolonged Sedation in the PICU: A Systematic Review and Meta-Analysis

OBJECTIVES

We aimed to systematically describe the use of dexmedetomidine as a treatment regimen for prolonged sedation in children and perform a meta-analysis of its safety profile.

DATA SOURCES

PubMed, EMBASE, Cochrane Library, Scopus, Web of Science, ClinicalTrials.gov, and CINAHL were searched from inception to November 30, 2018.

STUDY SELECTION

We included studies involving hospitalized critically ill patients less than or equal to 18 years old receiving dexmedetomidine for prolonged infusion (≥ 24 hr).

DATA EXTRACTION

Data extraction included study characteristics, patient demographics, modality of dexmedetomidine use, associated analgesia and sedation details, comfort and withdrawal evaluation scales, withdrawal symptoms, and side effects.

DATA SYNTHESIS

Literature search identified 32 studies, including a total of 3,267 patients. Most of the studies were monocentric (91%) and retrospective (88%); one was a randomized trial. Minimum and maximum infusion dosages varied from 0.1-0.5 µg/kg/hr to 0.3-2.5 µg/kg/hr, respectively. The mean/median duration range was 25-540 hours. The use of a loading bolus was reported in eight studies (25%) (range, 0.5-1 µg/kg), the mode of weaning in 11 (34%), and the weaning time in six of 11 (55%; range, 9-96 hr). The pooled prevalence of bradycardia was 2.6% (n = 10 studies; 14/387 patients; 95% CI, 0.3-7.3; I = 75%), the pooled prevalence incidence of bradycardia was 2.6% (n = 10 studies; 14/387 patients; 95% CI, 0.3-7.3; I = 75%), the pooled incidence of hypotension was 6.1% (n = 8 studies; 19/304 patients; 95% CI, 0.8-15.9; I = 84%). Three studies (9%) reported side effects' onset time which in all cases was within 12 hours of the infusion starting.

CONCLUSIONS

High-quality data on dexmedetomidine use for prolonged sedation and a consensus on correct dosing and weaning protocols in children are currently missing. Infusion of dexmedetomidine can be considered relatively safe in pediatrics even when longer than 24 hours.

Perioperative Dexmedetomidine Improves Outcomes of Kidney Transplant

Graft function is crucial for successful kidney transplantation. Many factors may affect graft function or cause delayed graft function (DGF), which decreases the prognosis for graft survival. This study was designed to evaluate whether the perioperative use of dexmedetomidine (Dex) could improve the incidence of function of graft kidney and complications after kidney transplantation. A total of 780 patients underwent kidney transplantations, 315 received intravenous Dex infusion during surgery, and 465 did not. Data were adjusted with propensity scores and multivariate logistic regression was used. The primary outcomes are major adverse complications, including DGF and acute rejection in the early post‐transplantation phase. The secondary outcomes included length of hospital stay (LOS), infection, overall complication, graft functional status, post‐transplantation serum creatinine values, and estimated glomerular filtration rate (eGFR). Dex use significantly decreased DGF (19.37% vs. 23.66%; adjusted odds ratio, 0.744; 95% confidence interval, 0.564–0.981; P = 0.036), risk of infection, risk of acute rejection in the early post‐transplantation phase, the risk of overall complications, and LOS. However, there were no statistical differences in 90‐day graft functional status or 7‐day, 30‐day, and 90‐day eGFR. Perioperative Dex use reduced incidence of DGF, risk of infection, risk of acute rejection, overall complications, and LOS in patients who underwent kidney transplantation.

Sedation withdrawal following single stage laryngotracheal reconstruction: Does dexmedetomidine help?

OBJECTIVES

Single-stage laryngotracheal reconstruction (SS-LTR) requires a period of post-operative intubation, during which time adequate sedation is needed to ensure graft healing. Commonly used agents include benzodiazepines, opioids, and more recently, dexmedetomidine, a centrally-acting α₂ adrenoreceptor. This study aims to compare withdrawal outcomes between various sedation regimens following SS-LTR.

METHODS

Retrospective chart review of 56 patients who underwent SS-LTR between 2008 and 2018 at a tertiary free-standing children's hospital was performed. Of 47 patients with complete records, 18 patients received dexmedetomidine for >75% of their intubation period with midazolam (DexWM), 9 received dexmedetomidine for >75% without midazolam (DexWOM), and 20 received dexmedetomidine for <75% with midazolam (noDex).

RESULTS

There was no significant difference in length of PICU or hospital stay between the groups. The noDex group trended toward a higher re-intubation rate of 25%, as compared with 11% of DexWOM and 5.6% of DexWM (p = 0.21). There was no significant difference in days of oral sedation taper required or Withdrawal Assessment Tool (WAT-1) score for post-extubation days 1 and 3. By post-extubation day 5, 100% of the DexWM group had WAT-1 scores <3 as compared with 71.4% of the noDex group (p = 0.037). Notably, lower average daily doses of dexmedetomidine and midazolam were used in the DexWM group, as compared with the DexWOM and noDex groups, respectively.

CONCLUSION

Dexmedetomidine as a primary sedation agent with midazolam allows for adequate sedation following SS-LTR. The combination of the two drugs in the DexWM group not only reduced the dosage of each drug needed, but also significantly improved WAT-1 scores by post-extubation day 5, as compared with the alternative sedation regimens.

[Application of dexmedetomidine in children with agitation during ventilator weaning]

OBJECTIVE

To study the clinical effect and safety of dexmedetomidine in children with agitation during ventilator weaning.

METHODS

A prospective open observational study was performed for children who were admitted to the intensive care unit and experienced mechanical ventilation between March 2017 and August 2018. They were given dexmedetomidine due to the failure in the spontaneous breathing test (SBT) caused by agitation. A sedation-agitation scale score of ≥5 was defined as agitation. The children were observed in terms of the sedation state at 0.5, 1, 2, 6, and 12 hours after the administration of dexmedetomidine, blood gas parameters before extubation and at 1, 24, and 48 hours after extubation, vital signs (heart rate, respiratory rate and mean arterial pressure) before SBT, before extubation, and at 10, 60, and 120 minutes and 24 hours after extubation, and incidence rates of adverse events related to the use of dexmedetomidine.

RESULTS

A total of 19 children were enrolled in this study. All the children were in a state of agitation at the time of enrollment. At 0.5, 1, 2, 6, and 12 hours after the administration of dexmedetomidine, 12, 17, 17, 18, and 18 children respectively reached the sedation state. There were no significant differences in the oxygenation index, arterial partial pressure of carbon dioxide, heart rate, respiratory rate, and mean arterial pressure at each time point before and after extubation (P>0.05). No adverse events were observed, such as severe hypotension and respiratory depression, and only one child experienced reversible bradycardia.

CONCLUSIONS

Dexmedetomidine is safe and effective in children with agitation during ventilator weaning, but prospective randomized controlled trials are needed for verification.

Sex differential effect of dexmedetomidine on fear memory extinction and anxiety behavior in adolescent rats

Exposure to stressful stimuli, including fear and anxiety, modulates the central noradrenergic system. Dexmedetomidine is a commonly used α2-adrenoreceptor agonist. Because the effect of fear acquisition varies between sexes, the present study was designed to investigate sex-related differences in the effects of dexmedetomidine on fear memory and anxiety-like behavior. We conducted a fear test and an elevated plus maze test in 6-8-week-old male and female rats. Two doses of dexmedetomidine (20 and 40 μg/kg) were injected intraperitoneally three times at 24 h intervals after the tests: after fear expression, extinction 1, and extinction 2. The repeated administration of dexmedetomidine showed significant acceleration of fear memory extinction in female rats but not in male rats; the effect increased proportionally to concentrations of dexmedetomidine. Compared to male rats, female rats treated with both concentrations of dexmedetomidine showed significant anxiolytic behavior after 1 week. Dexmedetomidine accelerated the fear memory extinction and reduced anxiety; it was more effective in female rats than in male rats. Our results suggest that dexmedetomidine may exert protective effects against fear-related and anxiety-like behaviors in rats with fear memory after repeated administration, and the sex-specific effects of dexmedetomidine should be considered.

Dexmedetomidine Use in a Tertiary Care NICU: A Descriptive Study

BACKGROUND

Continuous infusions of dexmedetomidine are increasingly used for sedation in critically ill pediatric patients. Emerging data suggest potential benefits when used for sedation in neonates, including reduced sedative requirements and earlier enteral feeds.

OBJECTIVE

To describe the use, adverse effects, and signs of withdrawal in a cohort of neonates receiving dexmedetomidine, the majority of whom were receiving concomitant opioids.

METHODS

This was a retrospective, descriptive review of 38 neonates receiving dexmedetomidine in a medical surgical neonatal intensive care unit, including data on duration of use, dose, adverse effects, weaning, and signs of withdrawal.

RESULTS

Dexmedetomidine was used for a median of 183 hours, at a median maximum dose of 0.5 µg/kg/h. Premature infants were started on dexmedetomidine at a later chronological age than term infants (41 vs 9 days, P = 0.004). Of 18 patients receiving an opioid infusion at the time of dexmedetomidine initiation, 67% had a dose reduction in opioids by 24 hours. The majority (89%) of neonates had at least 1 potentially related adverse effect during the dexmedetomidine infusion, though no discontinuations were needed as a result. In all, 80% of patients had their dexmedetomidine gradually weaned off, and 71% had at least 1 sign of withdrawal.

CONCLUSIONS AND RELEVANCE

In this cohort, dexmedetomidine was often used in a postsurgical setting, with concomitant opioids, over prolonged periods. These factors appear to affect and likely confound the rates of adverse effects and withdrawal signs from dexmedetomidine. Clinicians considering the use of dexmedetomidine in a similar population can draw guidance from our data.

Sedative Plasma Concentrations and Delirium Risk in Critical Illness

BACKGROUND

The relationship between plasma concentration of sedatives and delirium is unknown.

OBJECTIVE

We hypothesized that higher plasma concentrations of lorazepam are associated with increased delirium risk, whereas higher plasma concentrations of dexmedetomidine are associated with reduced delirium risk.

METHODS

This prospective cohort study was embedded in a double-blind randomized clinical trial, where ventilated patients received infusions of lorazepam and dexmedetomidine. Plasma concentrations of these drugs and delirium assessments were measured at least daily. A multivariable logistic regression model accounting for repeated measures was used to analyze associations between same-day plasma concentrations of lorazepam and dexmedetomidine (exposures) and the likelihood of next-day delirium (outcome), adjusting for same-day mental status (delirium, coma, or normal) and same-day fentanyl doses.

RESULTS

This critically ill cohort (n = 103) had a median age of 60 years (IQR: 48-66) with APACHE II score of 28 (interquartile range [IQR] = 24-32), where randomization resulted in assignment to lorazepam (n = 51) or dexmedetomidine (n = 52). After adjusting for same-day fentanyl dose and mental status, higher plasma concentrations of lorazepam were associated with increased probability of next-day delirium (comparing 500 vs 0 ng/mL; odds ratio [OR] = 13.2; 95% CI = 1.4-120.1; P = 0.02). Plasma concentrations of dexmedetomidine were not associated with next-day delirium (comparing 1 vs 0 ng/mL; OR = 1.1; 95% CI = 0.9-1.3; P = 0.45).

CONCLUSIONS

In critically ill patients, higher lorazepam plasma concentrations were associated with delirium, whereas dexmedetomidine plasma concentrations were not. This implies that the reduced delirium risk seen in patients sedated with dexmedetomidine may be a result of avoidance of benzodiazepines, rather than a dose-dependent protective effect of dexmedetomidine.