Dexmedetomidine: therapeutic use for the termination of reentrant supraventricular tachycardia

Application of intranasal dexmedetomidine in magnetic resonance imaging of preterm infants: The ED50, efficacy and safety analysis

BACKGROUND

Infants undergoing magnetic resonance imaging (MRI) often require pharmacological sedation. Dexmedetomidine serves as a novel sedative agent that induces a unique unconsciousness similar to natural sleep, and therefore has currently been used as the first choice for sedation in infants and young children.

OBJECTIVE

To determine the 50% effective dose (ED50) and 95% confidence interval (95%CI) of intranasal dexmedetomidine for MRI in preterm and term infants, and to observe the incidence of adverse events. To explore whether there were differences in ED50 and 95%CI, heart rate (HR) and blood oxygen saturation (SpO2), the induction time and wake-up time and the incidence of adverse events between the 2 groups, so as to provide guidance for clinical safe medication for the meanwhile.

METHODS

A total of 68 infants were prospectively recruited for MRI examination under drug sedation (1 week ≤ age ≤ 23 weeks or weight ≤ 5kg). The children were divided into 2 groups according to whether they had preterm birth experience (Preterm group, Atterm group). The Dixon up-and-down method was used to explore ED50. The basic vital signs of the 2 groups were recorded, and the heart rate and SpO2 were recorded every 5 minutes until the infants were discharged from the hospital. The induction time, wake-up time and adverse events were recorded.

RESULTS

The ED50 (95%CI) of intranasal dexmedetomidine in the Preterm group and the Atterm group were 2.23 (2.03-2.66) μg/kg and 2.64 (2.49-2.83) μg/kg, respectively (P < .05). the wake-up time was longer in Preterm group (98.00min) than in Atterm group (81.00 min) (P < .05), the incidence of bradycardia in Preterm group was 3/33, which was higher than that in Atterm group (1/35). There was no difference in the induction time between the 2 groups (P > .05), and there was no significant difference in other adverse events.

CONCLUSIONS

Intranasal dexmedetomidine can be safely used for sedation in preterm infants undergoing MRI. Compared with term infants, preterm infants have a lower dose of dexmedetomidine, a higher incidence of bradycardia, and a longer weak-up time.

Pharmacological Management of Cardiac Arrhythmias in the Fetal and Neonatal Periods: A Scientific Statement From the American Heart Association: Endorsed by the Pediatric & Congenital Electrophysiology Society (PACES)

Disorders of the cardiac rhythm may occur in both the fetus and neonate. Because of the immature myocardium, the hemodynamic consequences of either bradyarrhythmias or tachyarrhythmias may be far more significant than in mature physiological states. Treatment options are limited in the fetus and neonate because of limited vascular access, patient size, and the significant risk/benefit ratio of any intervention. In addition, exposure of the fetus or neonate to either persistent arrhythmias or antiarrhythmic medications may have yet-to-be-determined long-term developmental consequences. This scientific statement discusses the mechanism of arrhythmias, pharmacological treatment options, and distinct aspects of pharmacokinetics for the fetus and neonate. From the available current data, subjects of apparent consistency/consensus are presented, as well as future directions for research in terms of aspects of care for which evidence has not been established.

Dexmedetomidine Utilization During Air Medical Transport for Agitated Patients

Fixed Wing Air Ambulance providers routinely transport patients agitated from traumatic brain injury sequelae across long distances in a unique environment. The current paradigm limits options available to air medical clinicians to those routinely found on ground based, short distance vehicles, plus whatever a sending facility might be willing to provide. We postulate that dexmedetomidine offers a safe, effective alternative to improve patient care and enhance the safe operation of aircraft.

Preoperative sedation in children with congenital heart disease: 50% and 95% effective doses, hemodynamic effects, and safety of intranasal dexmedetomidine

STUDY OBJECTIVE

To determine the 50% and 95% effective doses (ED50 and ED95, respectively), hemodynamic effects, and safety of intranasal dexmedetomidine for preoperative sedation in pediatric patients with congenital heart disease (CHD) with a left-to-right shunt.

DESIGN

Double-blind sequential allocation trial.

SETTING

Pediatric preoperative waiting area.

PATIENTS

86 pediatric patients ASA physical status II-III scheduled for cardiac surgery, aged1-month to 6-years-old with left-to-right type CHD.

INTERVENTIONS

Children were divided into three groups according to age: infants (1 month-1 year), toddlers (1-3 years), and preschoolers (3-6 years). The first patient in all groups received intranasal dexmedetomidine (2 μg/kg), using the up-and-down Dixon method, and the and the next patient's dose was dependent on the previous patient's response.

MEASUREMENTS

Assessment using the Modified Observer's Assessment of Alertness/Sedation Scale and the Mask Acceptance Scale was performed before and every 5 min after treatment. Pulse oxygen saturation and heart rate were recorded at baseline, at 10-min intervals, and after admission to the operating room. Systolic pulmonary artery pressure was measured before anesthesia induction.

MAIN RESULTS

The respective ED₅₀ (95% confidence interval [CI]) and ED₉₅ (95% CI) values for preoperative sedation using intranasally administered dexmedetomidine were 3.1 (2.8-3.3) and 3.5 (3.3-4.0) μg/kg for infants; 3.4 (3.2-3.6) and 3.9 (3.7-4.4) μg/kg for toddlers; and 2.4 (2.2-2.6) and 2.9 (2.6-3.3) μg/kg for preschoolers. ED₅₀ was lower for preschoolers than for toddlers (p < 0.001) and infants (p = 0.044). No obvious difference in ED50 was found between infants and toddlers. There was no significant difference in sedation onset time among the groups, and no adverse events were observed during sedation in all patients.

CONCLUSIONS

Intranasal dexmedetomidine can be safety used for preoperative sedation in children with CHD and is effective for sedation when dosed appropriately. Trial registrationclinicaltrials.gov (ChiCTR2100047472); registered 20 June 2021.

Influence of Dexmedetomidine on Post-operative Atrial Fibrillation After Cardiac Surgery: A Meta-Analysis of Randomized Controlled Trials

Background: Previous clinical studies and meta-analysis evaluating the influence of dexmedetomidine on postoperative atrial fibrillation showed inconsistent results. We performed an updated meta-analysis to evaluate the influence of dexmedetomidine on incidence of postoperative atrial fibrillation after cardiac surgery.

Methods: Randomized controlled trials that evaluated the potential influence of dexmedetomidine on the incidence of atrial fibrillation after cardiac surgery were obtained by search of PubMed, Embase, and Cochrane's Library databases from inception to April 12, 2021. A random-effects model incorporating the potential publication bias was used to pool the results. Influences of patient or study characteristics on the efficacy of dexmedetomidine on atrial fibrillation after cardiac surgery were evaluated by meta-regression and subgroup analyses.

Results: Fifteen studies with 2,733 patients were included. Pooled results showed that dexmedetomidine significantly reduced the incidence of atrial fibrillation compared to control (OR: 0.72, 95% CI: 0.55–0.94, p = 0.02) with mild heterogeneity (I² = 26%). Subgroup analysis showed that dexmedetomidine significantly reduced the incidence of atrial fibrillation in studies from Asian countries (OR: 0.41, 95% CI: 0.26–0.66, p < 0.001), but not in those from non-Asian countries (OR: 0.89, 95% CI: 0.71–1.10, p = 0.27; p for subgroup difference = 0.004). Meta-regression analysis showed that the mean age and proportion of male patients may modify the influence of dexmedetomidine on POAF (coefficient = 0.028 and 0.021, respectively, both p < 0.05). Subgroup analysis further showed that Dex was associated with reduced risk of atrial fibrillation after cardiac surgery in studies with younger patients (mean age ≤ 61 years, OR = 0.44, 95% CI: 0.28–0.69, p = 0.004) and smaller proportion of males (≤74%, OR = 0.55, 95% CI: 0.36–0.83, p = 0.005), but not in studies with older patients or larger proportion of males (p for subgroup difference = 0.02 and 0.04).

Conclusions: Current evidence supports that perioperative administration of dexmedetomidine may reduce the risk of incidental atrial fibrillation after cardiac surgery, particularly in Asians.

[Paediatric Life Support]

The European Resuscitation Council (ERC) Paediatric Life Support (PLS) guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations of the International Liaison Committee on Resuscitation (ILCOR). This section provides guidelines on the management of critically ill or injured infants, children and adolescents before, during and after respiratory/cardiac arrest.

Anaesthetic challenges in a patient with Wolff-Parkinson-White (WPW) syndrome for orchidectomy

Wolff-Parkinson-White (WPW) syndrome is an extremely rare congenital cardiac conduction disorder. It is due to an aberrant pathway between the atrium and ventricle. This manuscript entails a man with an underlying WPW who was posted for an elective orchidectomy. We discussed the important perioperative precautions to prevent the precipitation of acute cardiac events.

European Resuscitation Council Guidelines 2021: Paediatric Life Support

These European Resuscitation Council Paediatric Life Support (PLS) guidelines, are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidelines on the management of critically ill infants and children, before, during and after cardiac arrest.

Efficacy and safety of dexmedetomidine in patients receiving mechanical ventilation: Evidence from randomized controlled trials

At present, the efficacy and safety of dexmedetomidine in patients receiving mechanical ventilation (MV) is still controversial. Therefore, the purpose of this research was to assess the efficacy and safety of dexmedetomidine in MV patients by reviewing the results of randomized controlled trials (RCT). RCTs evaluating the efficacy of dexmedetomidine in the treatment of MV patients were obtained by searching relevant online databases, including PubMed, EMbase, Web of Science, the Cochrane Library, Medline, OVID, and ClinicalTrials.gov. Literature meeting the inclusion criteria were selected and evaluated by two researchers independently. Risk ratio (RR)/standardized mean difference (SMD) and 95% confidence interval (CI) were used to express the differences between groups. Seven RCTs were included in our study, with 986 participants in the dexmedetomidine group and 862 participants in the control group. Summary analysis results displayed no reduction in 30-day mortality (RR = 0.77, 95% CI: 0.59 to 1.02), delirium (RR = 0.77, 95% CI: 0.57 to 1.03), and adverse events (RR = 1.06, 95% CI: 0.22 to 5.08) in the dexmedetomidine group compared with the control group. As the length of stay in the intensive care unit (ICU) were presented as median and interquartile range (IQR)/standard deviation (SD), descriptive analysis of the results were performed. Generally, for 99.65% (953/986) of patients, dexmedetomidine was not better than the control group in reducing ICU length of stay. Our results demonstrate that for patients requiring MV, dexmedetomidine was not superior to the control group. However, analysis of more RCTs is required to confirm this conclusion.

Supraventricular tachyarrhythmias during the intrauterine, neonatal, and infant period: A 10-year population-based study

BACKGROUND

We aimed to evaluate the incidence, type, and management of supraventricular tachyarrhythmias (SVT) during the first year of life in a retrospective, population-based, single-center study during a 10-year period.

METHODS

The analyzed patient cohort is based on data from the only specialized center managing all cases of neonatal and infant SVTs between 2009 and 2018 in the Slovak Republic (5.5 million population). A total of 116 consecutive patients <366 days old were included in the study.

RESULTS

Calculated SVT incidence ratio was 1:4500 in the first year of life. AV reentry tachycardia was the leading arrhythmia (49%). SVT in this specific population was frequently a transient problem with spontaneous resolution in 87% of patients during a median 3-year follow up. Congenital heart disease was common (16%). Intrauterine treatment by drugs administered to mother was safe and effective in preventing unnecessary cesarean deliveries. In arrhythmia termination, amiodarone and propafenone were equally safe and effective, with possible more favorable pharmacodynamics of the former. For prophylactic treatment, sotalol and propafenone were equally safe and effective and became the preferred basis of long-term drug therapy in our center. However, this therapy requires intensive monitoring during its initiation.

CONCLUSION

The prognosis of SVT in the first year of life is good: with optimized pharmacological treatment, the need for early catheter ablation and mortality rate are low (<1%) and there is a high rate of spontaneous arrhythmia resolution. Heart failure is a possible predictor of arrhythmia persistence with need for ablation in later life.

Association Between Postoperative Dexmedetomidine Use and Arrhythmias in Infants After Cardiac Surgery

BACKGROUND

Dexmedetomidine has been suggested as an arrhythmia prophylactic agent after surgery for congenital heart disease due to its heart rate lowering effect, though studies are conflicting. We sought to study the effect of dexmedetomidine in infants that are at highest risk for arrhythmias.

METHODS

Retrospective cohort study of infants less than six months of age undergoing cardiopulmonary bypass for congenital heart disease. The arrhythmia incidence in the first 48 hours after surgery in infants receiving dexmedetomidine for sedation was compared to those that did not receive dexmedetomidine.

RESULTS

A total of 309 patients were included, 206 patients who did not receive dexmedetomidine and 103 patients who did. The incidence of tachyarrhythmias was similar between the non-DEX group and the DEX group (19% vs 15%, P = .34). When adjusted for baseline differences, the non-DEX group did not have an increased risk of postoperative tachyarrhythmias (odds ratio [OR]: 1.4, 95% confidence interval [CI]: 0.5-3.8). The non-DEX group had an increased need for treatment for arrhythmias (18% vs 8%, P = .012). The three lesions with baseline higher risk for arrhythmias (tetralogy of Fallot, transposition of the great arteries, and complete atrioventricular canal) had an increased incidence of tachyarrhythmias in the non-DEX group (34% vs 6%, P = .027). This risk was not significant in multivariate analysis (OR: 2.5, 95% CI: 0.4-15.5).

CONCLUSIONS

High-risk infants had decreased incidence of tachyarrhythmias when receiving dexmedetomidine, though this was not significant after accounting for baseline differences between groups.

Historical and Current Adenosine Receptor Agonists in Preclinical and Clinical Development

Adenosine receptors (ARs) function in the body’s response to conditions of pathology and stress associated with a functional imbalance, such as in the supply and demand of energy/oxygen/nutrients. Extracellular adenosine concentrations vary widely to raise or lower the basal activation of four subtypes of ARs. Endogenous adenosine can correct an energy imbalance during hypoxia and other stress, for example, by slowing the heart rate by A₁AR activation or increasing the blood supply to heart muscle by the A_2AAR. Moreover, exogenous AR agonists, antagonists, or allosteric modulators can be applied for therapeutic benefit, and medicinal chemists working toward that goal have reported thousands of such agents. Thus, numerous clinical trials have ensued, using promising agents to modulate adenosinergic signaling, most of which have not succeeded. Currently, short-acting, parenteral agonists, adenosine and Regadenoson, are the only AR agonists approved for human use. However, new concepts and compounds are currently being developed and applied toward preclinical and clinical evaluation, and initial results are encouraging. This review focuses on key compounds as AR agonists and positive allosteric modulators (PAMs) for disease treatment or diagnosis. AR agonists for treating inflammation, pain, cancer, non-alcoholic steatohepatitis, angina, sickle cell disease, ischemic conditions and diabetes have been under development. Multiple clinical trials with two A₃AR agonists are ongoing.

Spontaneous Conversions of Supraventricular Tachycardia to Sinus Rhythm in Children After Premedication With Intranasal Dexmedetomidine: A Case Report

Intranasal dexmedetomidine administered as premedication before anesthesia and cardioversion appears to have the potential to facilitate the return of sinus rhythm. Two children, 3.5 and 1.5 years old, with recurrent supraventricular tachycardia in need of cardioversion have now on several occasions spontaneously returned to sinus rhythm within 20-40 minutes after intranasal administration of dexmedetomidine (4 μg/kg) with a mucosal atomization device. Both children were observed on all occasions at the pediatric outpatient clinic and could return home within 2 hours of cardioversion. For children with supraventricular tachycardia, a selective α2-agonist might be a valuable alternative to cardioversion with adenosine.

Historical and Current Adenosine Receptor Agonists in Preclinical and Clinical Development

Adenosine receptors (ARs) function in the body's response to conditions of pathology and stress associated with a functional imbalance, such as in the supply and demand of energy/oxygen/nutrients. Extracellular adenosine concentrations vary widely to raise or lower the basal activation of four subtypes of ARs. Endogenous adenosine can correct an energy imbalance during hypoxia and other stress, for example, by slowing the heart rate by A₁AR activation or increasing the blood supply to heart muscle by the A_2AAR. Moreover, exogenous AR agonists, antagonists, or allosteric modulators can be applied for therapeutic benefit, and medicinal chemists working toward that goal have reported thousands of such agents. Thus, numerous clinical trials have ensued, using promising agents to modulate adenosinergic signaling, most of which have not succeeded. Currently, short-acting, parenteral agonists, adenosine and Regadenoson, are the only AR agonists approved for human use. However, new concepts and compounds are currently being developed and applied toward preclinical and clinical evaluation, and initial results are encouraging. This review focuses on key compounds as AR agonists and positive allosteric modulators (PAMs) for disease treatment or diagnosis. AR agonists for treating inflammation, pain, cancer, non-alcoholic steatohepatitis, angina, sickle cell disease, ischemic conditions and diabetes have been under development. Multiple clinical trials with two A₃AR agonists are ongoing.

Anesthetic Management In Electrophysiology Laboratory: A Multidisciplinary Review

Many clinical challenges have been encountered in electrophysiology laboratories (EP) while implanting intracardiac defibrillators for lethal arrhythmias, using pacemakers for bradyarrhythmias, placing pacemakers with multiple leads in patients with heart failure and cardiac ablation procedures. In this environment, anesthesiology plays a very critical role to ensure patients comfort, as well as maintains operator's convenience and facilitate management of undesired situations. EP laboratories are mostly used for diagnosis of certain heart diseases. Meanwhile, with the exponential increase in interventional procedures in our decade, electrophysiologists' need to cooperate with the anesthesiologists more frequently. The literature is still unclear about the effects of anesthetic agents on cardiac conduction pathways, but as we know with our previous data, the most agents we are using currently have more or less effect on the cardiac conduction systems. In this review, we aimed to describe the safe anesthesia methods in cardiac diagnostic procedures and have a closer look up the anesthetic outcomes of these procedures. This article comprehensively reviews the anesthesia practice encountered in electrophysiology laboratories.

Anesthesia in the Electrophysiology Laboratory

The electrophysiology suite is a foreign location to many anesthesiologists. The initial experience was with shorter procedures under conscious sedation, and the value of greater tailoring of the sedation/anesthesia by anesthesiologists was not perceived until practice patterns had already been established. Although better control of ventilation with general anesthesia may be expected, suppression of arrhythmias, blunting of the hemodynamic adaptation to induced arrhythmias, and interference by muscle relaxants with identification of the phrenic nerve may be seen. We review a range of electrophysiology procedures and discuss anesthetic approaches that balance patient safety and favorable outcomes.

Dexmedetomidine sedation reduces atrial fibrillation after cardiac surgery compared to propofol: a randomized controlled trial

BACKGROUND

Atrial fibrillation occurs frequently in patients following cardiac surgery and can be a cause of increased morbidity and mortality. The use of dexmedetomidine to prevent atrial fibrillation is unclear. The present study was designed to evaluate the effect of dexmedetomidine sedation on the incidence of atrial fibrillation after cardiac surgery.

METHODS

Upon arrival to the intensive care unit (ICU), cardiac surgery patients without prior atrial fibrillation or flutter were randomized to receive either dexmedetomidine (0.2-1.5 μg/kg/h) or propofol (0.3-3 mg/kg/h) open-label titrated to a target Richmond agitation-sedation scale of 0 to -3. Our primary endpoint was the incidence of postoperative atrial fibrillation, and the secondary end points were the length of ICU stay, length of hospital stay, and hospital costs.

RESULTS

Atrial fibrillation occurred in 6 of 44 patients (13.6 %) in the dexmedetomidine group compared to 16 of 44 patients (36.4 %) in the propofol group (odds ratio = 0.28; 95 % confidence interval, 0.10, 0.80; P = 0.025). The median (interquartile range) length of ICU stay in the dexmedetomidine group was significantly lower than in the propofol group (2.9 (2.4-3.5) vs 3.5 (2.7-4.5 days, P = 0.008), with a trend toward a decrease in median hospital costs (86,367 vs 77,874 Chinese yuan; P = 0.068). The incidence of hypotension was higher in the dexmedetomidine group than in the propofol group (25/44 (56.8 %) vs 13/44 (29.5 %); P = 0.017).

CONCLUSIONS

Dexmedetomidine sedation reduced the incidence of new-onset postoperative atrial fibrillation and shortened the length of ICU stay in patients after cardiac surgery compared to propofol sedation. Dexmedetomidine treatment was associated with more episodes of hypotension.

TRIAL REGISTRATION

chictr.org.cn: ChiCTR-IPR-16008231 , retrospectively registered: April 6, 2016. This trial was not prospectively registered due to a lack of importance applied to trial registration.

Sedation and Analgesia in Pediatric Cardiac Critical Care

OBJECTIVES

This review will focus on the pharmacokinetics (with an emphasis on the context-sensitive half-time), pharmacodynamics, and hemodynamic characteristics of the most commonly used sedative/hypnotic, analgesic, and IV anesthetics used in cardiac intensive care. In addition, the assessment of pain and agitation and withdrawal will be reviewed.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSIONS

Children in the cardiac ICU often require one or more components of general anesthesia: analgesia, amnesia (sedation and hypnosis), and muscle relaxation to facilitate mechanical ventilation, to manage postoperative pain, to perform necessary procedures, and to alleviate fear and anxiety. Furthermore, these same children are often vulnerable to hemodynamic instability due to unique underlying physiologic vulnerabilities. An assessment of hemodynamic goals, postoperative procedures to be performed, physiologic vulnerabilities, and the intended duration of mechanical ventilation should be made. Based on this assessment, the optimal selection of sedatives, analgesics, and if necessary, muscle relaxants can then be made.

Arrhythmias in Cardiac Critical Care

OBJECTIVES

Here, we characterize the frequency, mechanisms, clinical impact, and potential treatment options for several arrhythmias commonly encountered in pediatric cardiac critical care.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSIONS

Arrhythmias among children in the cardiac critical care setting are common and clinically important, associated independently with prolonged mechanical ventilation, critical care unit stay, and an increase in mortality. The precise characterization of an arrhythmia may provide clues as to an underlying mechanism as well as serve to guide treatment. Arrhythmia therapy, pharmacologic or otherwise, is directed toward addressing the underlying mechanism, and as such may be applicable to the treatment of more than one specific rhythm disturbance. Decisions concerning therapy must call into consideration an arrhythmia's underlying etiology, mechanism, and associated hemodynamic embarrassment, along with the potential for adverse effects of treatment.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care: Sedation, Analgesia and Muscle Relaxant

OBJECTIVE

This article reviews pharmacotherapies currently available to manage sedation, analgesia, and neuromuscular blockade for pediatric cardiac critical patients.

DATA SOURCES

The knowledge base of an expert panel of pharmacists, cardiac anesthesiologists, and a cardiac critical care physician involved in the care of pediatric cardiac critical patients was combined with a comprehensive search of the medical literature to generate the data source.

STUDY SELECTION

The panel examined all studies relevant to management of sedation, analgesia, and neuromuscular blockade in pediatric cardiac critical patients.

DATA EXTRACTION

Each member of the panel was assigned a specific subset of the studies relevant to their particular area of expertise (pharmacokinetics, pharmacodynamics, and clinical care) to review and analyze.

DATA SYNTHESIS

The panel members each crafted a comprehensive summary of the literature relevant to their area of expertise. The panel, as a whole, then collaborated to cohesively summarize all the available, relevant literature.

CONCLUSIONS

In the cardiac ICU, management of the cardiac patient requires an individualized sedative and analgesic strategy that maintains hemodynamic stability. Multiple pharmacological therapies exist to achieve these goals and should be selected based on the patient's underlying physiology, hemodynamic vulnerabilities, desired level of sedation and analgesia, and the projected short- or long-term recovery trajectory.

Inhibition of the cardiac Na⁺ channel α-subunit Nav1.5 by propofol and dexmedetomidine

Propofol and dexmedetomidine are very commonly used sedative agents. However, several case reports demonstrated cardiovascular adverse effects of these two sedatives. Both substances were previously demonstrated to quite potently inhibit neuronal voltage-gated Na(+) channels. Thus, a possible molecular mechanism for some of their cardiac side effects is an inhibition of cardiac voltage gated Na(+) channels. In this study, we therefore explored the effects of propofol and dexmedetomidine on the cardiac predominant Na(+) channel α-subunit Nav1.5. Effects of propofol and dexmedetomidine were investigated on constructs of the human α-subunit Nav1.5 stably expressed in HEK-293 cells by means of whole-cell patch clamp recordings. Both agents induced a concentration-dependent tonic inhibition of Nav1.5. The calculated IC50 value for propofol was 228 ± 10 μM, and for dexmedetomidine 170 ± 20 μM. Tonic block only marginally increased on inactivated channels, and a weak use-dependent block at 10 Hz was observed for dexmedetomidine (16 ± 2 % by 100 μM). The voltage dependencies of fast and slow inactivation as well as the time course of recovery from inactivation were shifted by both propofol and dexmedetomidine. Propofol (IC50 126 ± 47 μM) and dexmedetomidine (IC50 182 ± 27 μM) blocked the persistent sodium current induced by veratradine. Finally, the local-anesthetic (LA)-insensitive mutant Nav1.5-F1760A exhibited reduced tonic and use-dependent block by both substances. Dexmedetomidine was generally more potent as compared to propofol. Propofol and dexmedetomidine seem to interact with the LA-binding site to inhibit the cardiac Na(+) channel Nav1.5 in a state-dependent manner. These data suggest that Nav1.5 is a hitherto unrecognized molecular component of some cardiovascular side effects of these sedative agents.

Association between perioperative dexmedetomidine and arrhythmias after surgery for congenital heart disease

BACKGROUND

Dexmedetomidine is commonly used after congenital heart surgery and may be associated with a decreased incidence of postoperative tachyarrhythmias. Using a large cohort of patients undergoing congenital heart surgery, we examined for an association between dexmedetomidine use in the immediate postoperative period and subsequent arrhythmia development.

METHODS AND RESULTS

A total of 1593 surgical procedures for congenital heart disease were performed. Dexmedetomidine was administered in the immediate postoperative period after 468 (29%) surgical procedures. When compared with 1125 controls, the group receiving dexmedetomidine demonstrated significantly fewer tachyarrhythmias (29% versus 38%; P<0.001), tachyarrhythmias receiving intervention (14% versus 23%; P<0.001), bradyarrhythmias (18% versus 22%; P=0.03), and bradyarrhythmias receiving intervention (12% versus 16%; P=0.04). After propensity score matching with 468 controls, the arrhythmia incidence between groups became similar: tachyarrhythmias (29% versus 31%; P=0.66), tachyarrhythmias receiving intervention (14% versus 17%; P=0.16), bradyarrhythmias (18% versus 15%; P=0.44), and bradyarrhythmias receiving intervention (12% versus 9%; P=0.17). After excluding controls exposed to dexmedetomidine at a later time in the hospitalization, dexmedetomidine was associated with increased odds of bradyarrhythmias receiving intervention (odds ratio, 2.18; 95% confidence interval, 1.02-4.65). Furthermore, there was a dose-dependent increase in the odds of bradyarrhythmias (odds ratio, 1.04; 95% confidence interval, 1.01-1.07) and bradyarrhythmias receiving intervention (odds ratio, 1.05; 95% confidence interval, 1.01-1.08).

CONCLUSIONS

Although dexmedetomidine exposure in the immediate postoperative period is not associated with a clinically meaningful difference in the incidence of tachyarrhythmias after congenital heart surgery, it may be associated with increased odds of bradyarrhythmias.

Retrospective Evaluation of the Epidemiology and Practice Variation of Dexmedetomidine Use in Invasively Ventilated Pediatric Intensive Care Admissions, 2007-2013

OBJECTIVES

The study assessed dexmedetomidine utilization and practice variation over time in ventilated pediatric intensive care unit (PICU) patients; and evaluated differences in hospital outcomes between high- and low-dexmedetomidine utilization hospitals.

STUDY DESIGN

This serial cross-sectional analysis used administrative data from PICU admissions in the pediatric health information system (37 US tertiary care pediatric hospitals). Included admissions from 2007 to 2013 had simultaneous dexmedetomidine and invasive mechanical ventilation charges, <18 years of age, excluding neonates. Patient and hospital characteristics were compared as well as hospital-level severity-adjusted indexed length of stay (LOS), charges, and mortality.

RESULTS

The utilization of dexmedetomidine increased from 6.2 to 38.2 per 100 ventilated PICU patients among pediatric hospitals. Utilization ranged from 3.8 to 62.8 per 100 in 2013. Few differences in patient demographics and no differences in hospital-level volume/severity of illness measures between high- and low-utilization hospitals occurred. No differences in hospital-level, severity-adjusted indexed outcomes (LOS, charges, and mortality) were found.

CONCLUSION

Wide practice variation in utilization of dexmedetomidine for ventilated PICU patients existed even as use has increased sixfold. Higher utilization was not associated with increased hospital charges or reduced hospital LOS. Further work should define the expected outcome benefits of dexmedetomidine and its appropriate use.

Pain management in newborns

As a standard of care for preterm/term newborns effective pain management may improve their clinical and neurodevelopmental outcomes. Neonatal pain is assessed using context-specific, validated, and objective pain methods, despite the limitations of currently available tools. Therapeutic approaches reducing invasive procedures and using pharmacologic, behavioral, or environmental measures are used to manage neonatal pain. Nonpharmacologic approaches like kangaroo care, facilitated tucking, non-nutritive sucking, sucrose, and others can be used for procedural pain or adjunctive therapy. Local/topical anesthetics, opioids, NSAIDs/acetaminophen and other sedative/anesthetic agents can be incorporated into NICU protocols for managing moderate/severe pain or distress in all newborns.

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

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

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

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

The Year in Review

Congenital cardiac anesthesiology is a young and rapidly growing subspecialty. It embraces a large spectrum of congenital and acquired heart diseases, which now affect the entire life span of patients from “cradle to grave.” One of the challenges faced by congenital cardiac anesthesiologists is reading the large amount of relevant literature from the fields of cardiology, cardiac surgery, intensive care medicine, and anesthesiology. This review highlights some of the current themes in the literature during the past year.

A dose-response study of dexmedetomidine administered as the primary sedative in infants following open heart surgery

OBJECTIVE

To evaluate the dose-response relationship of dexmedetomidine in infants with congenital heart disease postoperative from open heart surgery.

DESIGN

Prospective open-label dose-escalation pharmacokinetic-pharmacodynamic study.

SETTING

Tertiary pediatric cardiac ICU.

PATIENTS

Thirty-six evaluable infants, 1-24 months old, postoperative from open heart surgery requiring mechanical ventilation.

INTERVENTIONS

Cohorts of 12 infants were enrolled sequentially to one of the three IV loading doses of dexmedetomidine (0.35, 0.7, and 1 mcg/kg) over 10 minutes followed by respective continuous infusions (0.25, 0.5, and 0.75 mcg/kg/hr) for up to 24 hours.

MEASUREMENTS AND MAIN RESULTS

Dexmedetomidine plasma concentrations were obtained at timed intervals during and following discontinuation of infusion. Pharmacodynamic variables evaluated included sedation scores, supplemental sedation and analgesia medication administration, time to tracheal extubation, respiratory function, and hemodynamic parameters. Infants achieved a deeper sedation measured by the University of Michigan Sedation Scale score (2.6 vs 1) despite requiring minimal supplemental sedation (0 unit doses/hr) and fewer analgesic medications (0.07 vs 0.15 unit doses/hr) while receiving dexmedetomidine compared with the 12-hour follow-up period. Thirty-one patients were successfully extubated while receiving the dexmedetomidine infusion. Only one patient remained intubated due to oversedation during the infusion. While receiving dexmedetomidine, there was a decrease in heart rate compared with baseline, 132 versus 161 bpm, but there was an increase in heart rate compared with postinfusion values, 132 versus 128 bpm. There was no statistically or clinically significant change in mean arterial blood pressure.

CONCLUSIONS

Dexmedetomidine administration in infants following open heart surgery can provide improved sedation with reduction in supplemental medication requirements, leading to successful extubation while receiving a continuous infusion. The postoperative hemodynamic changes that occur in infants postoperative from open heart surgery are multifactorial. Although dexmedetomidine may play a role in decreasing heart rate immediately postoperative, the changes were not clinically significant and did not fall below postinfusion heart rates.

Dexmedetomidine for patients undergoing diagnostic cardiac procedures: a noninferiority study

When anesthetizing children with congenital heart disease for diagnostic cardiac catheterization, anesthesiologists and cardiologists seek to use anesthetic regimens that yield minimal hemodynamic changes and allow for spontaneous ventilations. Recently, dexmedetomidine has been used as an anesthesia adjunct because of its sedative and analgesic properties and minimal ventilatory depressive effects. We tested the hypothesis that the combination of sevoflurane and dexmedetomidine is non-inferior to sevoflurane alone as it refers to hemodynamic measurements during diagnostic cardiac catheterization in children with a transplanted heart, one ventricle (Fontan procedure), or normal cardiac physiology. Patients were anesthetized with inhalation of sevoflurane in nitrous oxide/oxygen and, after baseline hemodynamic measurements, successive boluses of dexmedetomidine followed by continuous infusion were administered. In this study, non-inferiority was shown when differences at steady-state (dexmedetomidine + sevoflurane) compared to baseline (sevoflurane alone) and its associated 95% confidence interval fell completely within the range of plus or minus 20%. Forty-one (26 normal physiology, 9 cardiac transplantation, and 6 Fontan) patients were enrolled. Non-inferiority of sevoflurane + dexmedetomidine compared with sevoflurane alone was shown for heart rate, but not for arterial blood pressure in patients with normal and cardiac transplant physiology. In patients with normal cardiac physiology, non-inferiority was demonstrated for bispectral index. Therefore, while the lack of depressive respiratory effects and non-inferiority for heart rate are desirable, the lack of non-inferiority of dexmedetomidine + sevoflurane combination for arterial blood pressure do not justify the routine use of this combination compared with sevoflurane alone for children with congenital heart disease undergoing cardiac catheterization.

Dexmedetomidine: antiarrhythmic effects in the pediatric cardiac patient

This report aims to provide a general description of the cardiovascular effects of dexmedetomidine, emphasizing its effects on conduction, and to give an evidence-based review of the literature regarding the use of dexmedetomidine to treat and prevent tachyarrhythmias in infants and children. A computerized bibliographic search of the literature on the use of dexmedetomidine to treat and prevent arrhythmias in infants and children was conducted. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Growing experience, mostly in the pediatric population, has demonstrated the potential therapeutic applications of dexmedetomidine in the acute treatment of arrhythmias. Additionally, its use during cardiac surgery has been associated with a decreased incidence of postoperative ventricular and supraventricular tachyarrhythmias. Although dexmedetomidine is not currently approved by the Food and Drug Administration for the pediatric population, findings have shown it to be effective in various clinical scenarios for sedation. In addition, recent studies show that dexmedetomidine may have promising properties for the acute treatment and prevention of tachyarrhythmias.