Use of dexmedetomidine in children after cardiac and thoracic surgery

Pharmacokinetics of dexmedetomidine in pediatric patients undergoing cardiac surgery with cardiopulmonary bypass

BACKGROUND

Cardiopulmonary bypass can affect the pharmacokinetics of anesthetic agents.

AIMS

We aimed to evaluate the pharmacokinetics of dexmedetomidine for infants and small children undergoing cardiac surgery with cardiopulmonary bypass based on population pharmacokinetics.

METHODS

We enrolled 30 pediatric cardiac surgical patients in this study. After anesthetic induction with atropine (0.02 mg/kg), thiopental sodium (5 mg/kg), and fentanyl (2-3 μg/kg), we administered 1 μg/kg of dexmedetomidine for 10 min, followed by administration of 0.5 μg/kg of dexmedetomidine per hour during surgery. At the initiation of cardiopulmonary bypass, 1 μg/kg of dexmedetomidine was infused over 5 min. Arterial blood was obtained at predefined time points. A pharmacokinetic model was developed using NONMEM. Theory-based allometric scaling with fixed exponents was applied. Weight, age, post-menstrual age, fat-free mass, whether to implement cardiopulmonary bypass and temperature were explored as covariates.

RESULTS

A total of 376 blood samples were obtained from 29 children (age: 20.3 ± 19.3 months, weight: 9.7 ± 4.1 kg). A two-compartment mammillary model with third compartment associated cardiopulmonary bypass procedure best explained the pharmacokinetics of dexmedetomidine. The pharmacokinetic parameter estimates (95% CI) standardized to a 70-kg person were as follows: V₁ (L) = 31.6 (17.9-39.5), V₂ (L) = 90.1 (44.0-330), Cl (L/min) = 1.08 (0.70-1.25), Q (L/min) = 2.0 (1.05-3.46). Volume for third compartment associated cardiopulmonary bypass procedure (L) = 39.4 (19.3-50.9). Clearance was not influenced by the presence of cardiopulmonary bypass in this model.

CONCLUSION

When cardiopulmonary bypass is applied, the plasma concentration of dexmedetomidine decreases due to an increase in the volume of distribution, so a loading dose is required to maintain the previous concentration.

Perioperative dexmedetomidine compared to midazolam in children undergoing open-heart surgery: A pilot randomised controlled trial

Objective

There is a need for evidence on the best sedative agents in children undergoing open heart surgery for congenital heart disease. This study aimed to evaluate the feasibility and safety of dexmedetomidine in this group compared with midazolam.

Design

Double blinded, pilot randomized controlled trial.

Setting

Cardiac operating theatre and paediatric intensive care unit in Brisbane, Australia.

Participants

Infants (≤12 months of age) undergoing their first surgical repair of a congenital heart defect.

Interventions

Dexmedetomidine (up to 1.0mcg/kg/hr) versus midazolam (up to 80mcg/kg/hr), commenced in the cardiac operating theatre prior to surgery.

Main outcome measures

The primary outcome was the time spent in light sedation (Sedation Behavior Scale [SBS] -1 to +1); Co-primary feasibility outcome was recruitment, retention and protocol adherence. Secondary outcomes were use of supplemental sedatives, ventilator free days, delirium, vasoactive drug support, and adverse events. Neurodevelopment and health-related quality of life (HRQoL) were assessed at 12 months post-surgery.

Results

Sixty-six participants were recruited. The number of SBS scores in the light sedation range were greater in the dexmedetomidine group at 24 hours, 48 hours, and overall study duration (0-14 days) versus the midazolam group (24hr: 76/170 [45%] vs 60/178 [34%], aOR 4.14 [95% CI 0.48, 35.92]; 48hr: 154/298 [52%] vs 122/314 [39%], aOR 6.95 [95% CI 0.77, 63.13]; 0-14 days: 597/831 [72%] vs 527/939 [56%], aOR 3.93 [95% CI 0.62, 25.03]). Feasibility was established with no withdrawals or loss to follow-up at 14 days and minimal protocol deviations. There were no differences between the groups relating to clinical, safety, neurodevelopment or HRQoL outcomes.

Conclusions

The use of dexmedetomidine was associated with more time spent in light sedation when compared with midazolam. The feasibility of conducting a blinded RCT of midazolam and dexmedetomidine in children undergoing open heart surgery was also established. The findings justify further investigation in a larger trial.

Clinical trial registration

ACTRN12615001304527.

A comprehensive overview of clinical research on dexmedetomidine in the past 2 decades: A bibliometric analysis

Introduction: Dexmedetomidine is a potent, highly selective α-2 adrenoceptor agonist with sedative, analgesic, anxiolytic, and opioid-sparing properties. A large number of dexmedetomidine-related publications have sprung out in the last 2 decades. However, no bibliometric analysis for clinical research on dexmedetomidine has been published to analyze hot spots, trends, and frontiers in this field. Methods: The clinical articles and reviews related to dexmedetomidine, published from 2002 to 2021 in the Web of Science Core Collection, were retrieved on 19 May 2022, using relevant search terms. VOSviewer and CiteSpace were used to conduct this bibliometric study. Results: The results showed that a total of 2,299 publications were retrieved from 656 academic journals with 48,549 co-cited references by 2,335 institutions from 65 countries/regions. The United States had the most publications among all the countries (n = 870, 37.8%) and the Harvard University contributed the most among all institutions (n = 57, 2.48%). The most productive academic journal on dexmedetomidine was Pediatric Anesthesia and the first co-cited journal was Anesthesiology. Mika Scheinin is the most productive author and Pratik P Pandharipande is the most co-cited author. Co-cited reference analysis and keyword analysis illustrated hot spots in the dexmedetomidine field including pharmacokinetics and pharmacodynamics, intensive care unit sedation and outcome, pain management and nerve block, and premedication and use in children. The effect of dexmedetomidine sedation on the outcomes of critically ill patients, the analgesic effect of dexmedetomidine, and its organ protective property are the frontiers in future research. Conclusion: This bibliometric analysis provided us with concise information about the development trend and provided an important reference for researchers to guide future research.

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.

Efficacy and safety of dexmedetomidine in maintaining hemodynamic stability in pediatric cardiac surgery: a systematic review and meta-analysis

OBJECTIVES

Dexmedetomidine (DEX) is a highly selective alpha-2 adrenergic receptor agonist, which is the main sedative in the intensive care unit. This study aims to investigate the effectiveness and adverse events of DEX in maintaining hemodynamic stability in pediatric cardiac surgery.

SOURCES

Databases such as PubMed, Cochrane, Web of Science, WANFANG STATA and China National Knowledge Infrastructure were searched for articles about the application of DEX in maintaining hemodynamic stability during and after pediatric cardiac surgery up to 18th Feb. 2021. Only randomized controlled trials were included and random-effects model meta-analysis was applied to calculate the standardized mean deviation (SMD), odds ratio (OR) and 95% confidence interval (CI).

SUMMARY OF THE FINDINGS

Fifteen articles were included for this meta-analysis, and 9 articles for qualitative analysis. The results showed that preoperative prophylaxis and postoperative recovery of DEX in pediatric patients undergoing cardiac surgery were effective in maintaining systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and reducing heart rate (HR) (SBP: SMD = -0.35,95% CI: -0.72, 0.01; MAP: SMD = -0.83, 95% CI: -1.87,0.21; DBP: SMD = -0.79,95% CI: -1.66,0.08; HR: SMD = -1.71,95% CI: -2.29, -1.13). In addition, the frequency of Junctional Ectopic Tachycardia in the DEX treatment group was lower than that in the placebo group.

CONCLUSIONS

The application of DEX for preoperative prophylaxis and postoperative recovery in pediatric cardiac surgery patients are effective in maintaining hemodynamic stability, and the clinical dose of DEX is not significantly related to the occurrence of pediatric adverse events which may be related to individual differences.

A Minimal Opioid Postoperative Management Protocol in Congenital Cardiac Surgery: Safe and Effective

There is evidence that reducing opioid exposure in children undergoing cardiac surgery may enhance postoperative recovery. We aimed to describe a minimal opioid postoperative management protocol in children undergoing cardiac surgery and our early outcomes with this strategy. We reviewed the medical records of children (6 months-18 years) who underwent elective cardiac surgery through a median sternotomy with cardiopulmonary bypass at our institution between 2016 and 2018. All patients were managed postoperatively using a standardized protocol. 101 children (median age 5 years) were included and 85% were extubated in the operating room. Although most patients (96%) received opioids postoperatively, opioid requirements decreased steadily over time, with 88%, 58%, and 18% of children receiving opioids on postoperative day 1, 2, and 3, respectively; 41% received no opioids after postoperative day 1. The median cumulative opioid exposure was 0.25 morphine milligram equivalents per kg (interquartile range, 0.10-0.75). Greater than mild pain was rare (<10%) at each time point. The rates of operative mortality and major complication were 0% and 3%, respectively. The median postoperative length of stay was 3 days, and 13% required readmission within 30 days. Age, cardiopulmonary bypass time, and number of benzodiazepine doses were independently associated with cumulative opioid exposure. Any complication, chest tube time, and higher STAT Category were independently associated with prolonged postoperative length of stay. A minimal opioid postoperative management protocol can be safe and effective in children undergoing cardiac surgery. Future prospective studies are needed to determine optimal practice and patient selection.

Dexmedetomidine Sedation in Mechanically Ventilated Critically Ill Children: A Pilot Randomized Controlled Trial

OBJECTIVES

To assess the feasibility, safety, and efficacy of a sedation protocol using dexmedetomidine as the primary sedative in mechanically ventilated critically ill children.

DESIGN

Open-label, pilot, prospective, multicenter, randomized, controlled trial. The primary outcome was the proportion of sedation scores in the target sedation range in the first 48 hours. Safety outcomes included device removal, adverse events, and vasopressor use. Feasibility outcomes included time to randomization and protocol fidelity.

SETTING

Six tertiary PICUs in Australia and New Zealand.

PATIENTS

Critically ill children, younger than 16 years old, requiring intubation and mechanical ventilation and expected to be mechanically ventilated for at least 24 hours.

INTERVENTIONS

Children randomized to dexmedetomidine received a dexmedetomidine-based algorithm targeted to light sedation (State Behavioral Scale -1 to +1). Children randomized to usual care received sedation as determined by the treating clinician (but not dexmedetomidine), also targeted to light sedation.

MEASUREMENTS AND MAIN RESULTS

Sedation with dexmedetomidine as the primary sedative resulted in a greater proportion of sedation measurements in the light sedation range (State Behavioral Scale -1 to +1) over the first 48 hours (229/325 [71%] vs 181/331 [58%]; p = 0.04) and the first 24 hours (66/103 [64%] vs 48/116 [41%]; p < 0.001) compared with usual care. Cumulative midazolam dosage was significantly reduced in the dexmedetomidine arm compared with usual care (p = 0.002).There were more episodes of hypotension and bradycardia with dexmedetomidine (including one serious adverse event) but no difference in vasopressor requirements. Median time to randomization after intubation was 6.0 hours (interquartile range, 2.0-9.0 hr) in the dexmedetomidine arm compared with 3.0 hours (interquartile range, 1.0-7.0 hr) in the usual care arm (p = 0.24).

CONCLUSIONS

A sedation protocol using dexmedetomidine as the primary sedative was feasible, appeared safe, achieved early, light sedation, and reduced midazolam requirements. The findings of this pilot study justify further studies of sedative agents in critically ill children.

Dexmedetomidine extraction by the extracorporeal membrane oxygenation circuit: results from an in vitro study

BACKGROUND

Dexmedetomidine is a sedative administered to minimize distress and decrease the risk of life threatening complications in children supported with extracorporeal membrane oxygenation. The extracorporeal membrane oxygenation circuit can extract drug and decrease drug exposure, placing the patient at risk of therapeutic failure.

OBJECTIVE

To determine the extraction of dexmedetomidine by the extracorporeal membrane oxygenation circuit.

MATERIALS AND METHODS

Dexmedetomidine was studied in three closed-loop circuit configurations to isolate the impact of the oxygenator, hemofilter, and tubing on circuit extraction. Each circuit was primed with human blood according to standard practice for Duke Children's Hospital, and flow was set to 1 L/min. Dexmedetomidine was dosed to achieve a therapeutic concentration of ~600 pg/mL. Dexmedetomidine was added to a separate tube of blood to serve as a control and evaluate for natural drug degradation. Serial blood samples were collected over 24 hours and concentrations were quantified with a validated assay. Drug recovery was calculated at each time point.

RESULTS

Dexmedetomidine was highly extracted by the oxygenator evidenced by a mean recovery of 62-67% at 4 hours and 23-34% at 24 hours in circuits with an oxygenator in-line. In contrast, mean recovery with the oxygenator removed was 96% at 4 hours and 93% at 24 hours. Dexmedetomidine was stable over time with a mean recovery in the control samples of 102% at 24 hours.

CONCLUSION

These results suggest dexmedetomidine is extracted by the oxygenator in the extracorporeal membrane oxygenation circuit which may result in decreased drug exposure in vivo.

Fast tracking after repair of congenital heart defects

Fast tracking after repair of congenital heart defects (CHD) is a process involving the reduction of perioperative period by timely admission, early extubation after surgery, short intensive care unit (ICU) stay, early mobilisation, and faster hospital discharge. It requires a coordinated multidisciplinary team involvement. In the last 2 decades, many centres have adopted the fast tracking strategy in paediatric cardiac population, safely and successfully extubating patients in the OR with reported benefits in terms of reduced morbidity and ICU/hospital stay. In this manuscript, we will review the literature available on early extubation after repair of CHD and share our experience with this approach.

Implementation of On-table Extubation After Pediatric Cardiac Surgery in the Developing World

In the recent years there has been increasing trend towards the practice of on-table extubation after pediatric cardiac surgery among practitioner in European and non-European countries. In this article we share our experience with on-table extubation among children after cardiac surgery in the developing world supported with the currently available literature.

Dexmedetomidine Pharmacokinetics and a New Dosing Paradigm in Infants Supported With Cardiopulmonary Bypass

BACKGROUND

Dexmedetomidine is increasingly used off-label in infants and children with cardiac disease during cardiopulmonary bypass (CPB) and in the postoperative period. Despite its frequent use, optimal dosing of dexmedetomidine in the setting of CPB has not been identified but is expected to differ from dosing in those not supported with CPB. This study had the following aims: (1) characterize the effect of CPB on dexmedetomidine clearance (CL) and volume of distribution (V) in infants and young children; (2) characterize tolerance and sedation in patients receiving dexmedetomidine; and (3) identify preliminary dosing recommendations for infants and children undergoing CPB. We hypothesized that CL would decrease, and V would increase during CPB compared to pre- or post-CPB states.

METHODS

Open-label, single-center, opportunistic pharmacokinetics (PK) and safety study of dexmedetomidine in patients ≤36 months of age administered dexmedetomidine per standard of care via continuous infusion. We analyzed dexmedetomidine PK data using standard nonlinear mixed effects modeling with NONMEM software. We compared model-estimated PK parameters to those from historical patients receiving dexmedetomidine before anesthesia for urologic, lower abdominal, or plastic surgery; after low-risk cardiac or craniofacial surgery; or during bronchoscopy or nuclear magnetic resonance imaging. We investigated the influence of CPB-related factors on PK estimates and used the final model to simulate dosing recommendations, targeting a plasma concentration previously associated with safety and efficacy (0.6 ng/mL). We used the Wilcoxon rank sum test to evaluate differences in dexmedetomidine exposure between infants with hypotension or bradycardia and those who did not develop these adverse events.

RESULTS

We collected 213 dexmedetomidine plasma samples from 18 patients. Patients had a median (range) age of 3.3 months (0.1-34.0 months) and underwent CPB for 161 minutes (63-394 minutes). We estimated a CL of 13.4 L/h/70 kg (95% confidence interval, 2.6-24.2 L/h/70 kg) during CPB, compared to 42.1 L/h/70 kg (95% confidence interval, 38.7-45.8 L/h/70 kg) in the historical patients. No specific CPB-related factor had a statistically significant effect on PK. A loading dose of 0.7 µg/kg over 10 minutes before CPB, followed by maintenance infusions through CPB of 0.2 or 0.25 µg/kg/h in infants with postmenstrual ages of 42 or 92 weeks, respectively, maintained targeted concentrations. We identified no association between dexmedetomidine exposure and selected adverse events (P = .13).

CONCLUSIONS

CPB is associated with lower CL during CPB in infants and young children compared to those not undergoing CPB. Further study should more closely investigate CPB-related factors that may influence CL.

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.

Use of dexmedetomidine in pediatric cardiac anesthesia

PURPOSE OF REVIEW

In recent years, ultrafast-track anesthesia with on-table extubation and concepts of accelerated postoperative care have gained increasing support in pediatric congenital cardiac surgery. It is believed that such approaches might ideally combine economic benefits with a striving for continuous improvement of patient outcomes. The present review summarizes the role of dexmedetomidine (DEX) in this setting.

RECENT FINDINGS

DEX is a clinical multipurpose drug that mediates its diverse responses through the activation of α2-adrenoreceptors. In pediatric cardiac surgery it has various applications. Used as a premedication, DEX provides arousable sedation and anxiolysis. As an intraoperative adjunctive agent of balanced general anesthesia the primary objectives for its administration are attenuation of the neuro-humoral stress response and facilitation of early extubation. During ICU treatment DEX spares opioids, prevents the risk of postoperative delirium or emergence agitation and impacts on important patient-centered outcomes, such as duration of mechanical ventilation, restart of enteral nutrition or length of ICU stay.

SUMMARY

Due to a favorable mix of beneficial physiologic actions and a limited adverse effect profile, DEX is established in the perioperative pediatric cardiac surgery setting. However, evidence from high-quality randomized controlled trials on the effects of supplemental DEX on meaningful patient outcomes is scarce, and research on the role of DEX in providing cardioprotection, neuroprotection, or renoprotection is still at its beginning. DEX has developed to one of the main agents in the armamentarium of cardiac anesthesiologists and pediatric intensivists, but it should not be regarded as the new 'magic bullet'.

The Efficacy and Safety of Dexmedetomidine Combined with Bupivacaine on Caudal Epidural Block in Children: A Meta-Analysis

BACKGROUND This meta-analysis was conducted to evaluate the analgesics effect and safety of dexmedetomidine (DEX) combined with bupivacaine (BU) on caudal epidural block. MATERIAL AND METHODS Published studies were identified using the PubMed, EMBASE, Web of Science, and the Cochrane Library from inception until October 2017. Relative risk (RR), the standardized mean difference (SMD), and the corresponding 95% confidence interval (CI) were calculated using the STATA 12.0. RESULTS Ten randomized controlled trials (RCTs) were selected for this meta-analysis, involving a total of 691 patients. There was a longer duration of postoperative analgesia in children receiving DEX (SMD=3.19, 95% CI: 2.16-4.22, P<0.001). Furthermore, there was a lower number of patients requiring rescue analgesics in the (BU) + (DEX) group (6 hours: RR=0.09, 95% CI: 0.05-0.17, P<0.001; 12 hours: RR=0.50, 95% CI: 0.32-0.79, P=0.003; 24 hours: RR=0.66, 95% CI: 0.51-0.85, P=0.002). Finally, the occurrence of adverse events, between BU and DEX + BU group, was not statistically significant (RR=0.96, 95% CI: 0.58-1.58, P>0.05). CONCLUSIONS DEX seems to be a promising adjuvant to BU increase duration of caudal analgesia without an increase in side effects in children. However, the result may be influenced by clinical heterogeneity. More large-scale, multicenter, approaching, double-blinded RCTs are required to confirm our results.

Dexmedetomidine is effective and safe during NIV in infants and young children with acute respiratory failure

BACKGROUND

Noninvasive ventilation (NIV) is increasingly utilized in infants and young children, though associated with high failure rates due to agitation and poor compliance, mostly if patient-ventilator synchronization is required.

METHODS

A retrospective cohort study was carried out in an academic pediatric intensive care unit (PICU). Dexmedetomidine (DEX) was infused as unique sedative in 40 consecutive pediatric patients (median age 16 months) previously showing intolerance and agitation during NIV application.

RESULTS

During NIV clinical application both COMFORT-B Score and Richmond Agitation-Sedation Scale (RASS) were serially evaluated. Four patients experiencing NIV failure, all due to pulmonary condition worsening, required intubation and invasive ventilation. 36 patients were successfully weaned from NIV under DEX sedation and discharged from PICU. All patients survived until home discharge.

CONCLUSION

Our data suggest that DEX may represent an effective sedative agent in infants and children showing agitation during NIV. Early use of DEX in infants/children receiving NIV for acute respiratory failure (ARF) should be considered safe and capable of improving NIV, thus permitting both lung recruitment and patient-ventilator synchronization.

Assessment the effect of dexmedetomidine on incidence of paradoxical hypertension after surgical repair of aortic coarctation in pediatric patients

OBJECTIVE

The aim of the study was to assess the effect of dexmedetomidine on the incidence of paradoxical hypertension in patients undergoing aortic coarctation repair.

DESIGN

Randomized observational study.

SETTING

University hospital and cardiac center.

PATIENTS

The study included 108 pediatric patients with isolated aortic coarctation.

METHODS

The patients were classified into two groups (each = 54): Group D: the patients received dexmedetomidine as a loading dose of 0.5 μg/kg over 10 min followed by infusion 0.3 μg/kg/h during surgery and continued for the first 48 postoperative hours. Group C: The patients received an equal amount of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly. The collected data included the heart rate, systolic and diastolic arterial blood pressure, incidence, onset, severity and treatment of paradoxical hypertension, fentanyl dose and end-tidal sevoflurane concentration, amount of blood loss and urine output.

MAIN RESULTS

The heart rate, systolic and diastolic blood pressure decreased significantly with dexmedetomidine than Group C (P < 0.05). The incidence and severity of the paradoxical hypertension was lower with dexmedetomidine than Group C (P = 0.011, P = 0.017, respectively). The onset the paradoxical hypertension was earlier in Group C than dexmedetomidine (P = 0.026). The dose of fentanyl and sevoflurane concentration decreased significantly with dexmedetomidine (P = 0.034, P = 0.026, respectively). The blood loss decreased with dexmedetomidine (P = 0.020) and the urine output increased with dexmedetomidine (P = 0.024). The incidence of hypotension and bradycardia was more with dexmedetomidine (P < 0.05).

CONCLUSION

Dexmedetomidine is safe in pediatric patients undergoing aortic coarctation repair. It minimized the incidence and severity of paradoxical hypertension. It decreased the required antihypertensive medications.

Median effective dose of intranasal dexmedetomidine sedation for transthoracic echocardiography in pediatric patients with noncyanotic congenital heart disease: An up-and-down sequential allocation trial

BACKGROUND

Intranasal dexmedetomidine can provide adequate sedation during short procedures. However, previous literature investigating the single-dose use of intranasal dexmedetomidine for sedation during transthoracic echocardiography in younger children is scarce, and the effects of age on sedation with intranasal dexmedetomidine remain controversial.

OBJECTIVE

This study was to determine the 50% effective dose and estimate the 95% effective dose of single-dose intranasal dexmedetomidine to induce sedation in pediatric patients with noncyanotic congenital heart disease, and also determine the effect of age on the dose required for sedation.

METHODS

Patients were stratified into three age groups of 1-6 months, 7-12 months, and 13-36 months. Intranasal dexmedetomidine started at a dose of 2 μg kg^-1 on the first patient. The dose of dexmedetomidine for each subsequent patient was determined by the previous patient's response using Dixon's up-and-down method with an interval of 0.25 μg kg^-1 . Sedation scale and recovery were assessed by the Modified Observer Assessment of Alertness and Sedation Scale and Modified Aldrete Recovery Score. The 50% effective dose was determined by Dixon's up-and-down method. In addition, both 50% effective dose and 95% effective dose were obtained using a probit regression approach. Other variables included sedation onset time, echocardiography time, wake-up time, discharge time, heart rate, blood pressure, oxygen saturation, respiratory rate, and adverse events such as vomiting, regurgitation, and apnea.

RESULTS

The study population was comprised of 70 patients. The 50% effective dose (95% confidence interval) and the 95% effective dose (95% confidence interval) of intranasal dexmedetomidine for sedation were 1.8 (1.58-2.00) μg kg^-1 and 2.2 (1.92-5.62) μg kg^-1 in patients aged 1-6 months, 1.8 (1.61-1.95) μg kg^-1 and 2.1 (1.90-2.85) μg kg^-1 in patients aged 7-12 months, 2.2 (1.92-2.37) μg kg^-1 and 2.7 (2.34-6.88) μg kg^-1 in patients aged 13-36 months, respectively. The 50% effective dose in age group 13-36 months was higher than those of age group 1-6 months (P = .042) and 7-12 months (P = .043). There were no differences in sedation onset time, echocardiography time, wake-up time, and discharge time between groups. None of the patients experienced oxyhemoglobin desaturation, hypotension, or bradycardia during the procedure. No significant adverse events occurred.

CONCLUSION

Single-dose of intranasal dexmedetomidine was an effective agent for patients under the age of 3 years requiring sedation for transthoracic echocardiography. The 50% effective dose of intranasal dexmedetomidine for transthoracic echocardiography sedation in children aged 13-36 months was higher than in children <13 months.

Retrospective study of intranasal dexmedetomidine as a prophylactic against emergence delirium in pediatric patients undergoing ear tube surgery

OBJECTIVES

This study evaluated the effect of intranasal dexmedetomidine on emergence delirium (ED) in pediatric patients who underwent ear tube surgeries. Due to the brief nature of the surgery and low levels of pain experienced, an IV is rarely needed, limiting the medications available to anesthesiologists to manage postoperative delirium that may arise during recovery from inhalational anesthesia. Intravenous dexmedetomidine is an alpha-2 agonist anesthetic that is used in pediatric patients for the management of ED in various surgical procedures. However, intranasal medication has not been evaluated specifically in ear tube surgeries for ED prevention.

METHODS

We conducted a retrospective chart review of pediatric patients at Nemours Children's Hospital who had undergone ear tube insertion or removal surgery between 2013 and 2015, controlling for confounding variables such as age, surgery duration, and anesthesiologist. We used the post anesthesia emergence delirium (PAED) tool, an instrument created to assess ED in the clinical setting. We analyzed the data for significant differences in PAED score and time in the post anesthesia care unit (PACU) between patients treated with intranasal dexmedetomidine and the control group that did not receive the medication.

RESULTS

We found no significant difference between the PAED scores of those patients treated with intranasal dexmedetomidine prior to ear tube surgeries and those who did not receive the medication, and no difference in the duration of PACU stay.

CONCLUSION

These results conflict with other research on intranasal dexmedetomidine and its potential to prevent ED in pediatric patients. This information should prompt further prospective investigation into the most efficacious use of dexmedetomidine for ED prevention, both in terms of timing and dosage required.

Dexmedetomidine for Sedation During Noninvasive Ventilation in Pediatric Patients

OBJECTIVES

To describe the use of dexmedetomidine for sedation in a large cohort of nonintubated children with acute respiratory insufficiency receiving noninvasive ventilatory support.

DESIGN

Single-center, retrospective, observational cohort study.

SETTING

A large quaternary-care PICU.

PATIENTS

The study cohort included 202 children receiving noninvasive ventilatory and a dexmedetomidine infusion within 48 hours of PICU admission over a 6-month period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary respiratory diagnoses in the cohort (median age, 2 yr) included status asthmaticus (60%) and bronchiolitis (29%). Dexmedetomidine was infused for a median of 35 hours with a median hourly dose across the patient cohort of 0.61 μg/kg/hr (range, 0.4-0.8 μg/kg/hr). The target sedation level was achieved in 168 patients (83%) in the cohort for greater than or equal to 80% of the recorded values over the entire noninvasive ventilatory course, with dexmedetomidine as the only continuously administered sedative agent. While vital signs were frequently abnormal relative to age-based norms, clinical interventions were needed rarely to treat bradycardia (13%), hypotension (20%), and hypopnea (5%). The most frequently used of these interventions was a dexmedetomidine dose reduction, fluid bolus, and titration of noninvasive ventilatory support. Five patients (2.5%) required endotracheal intubation: three due to progression of their respiratory illness, one with septic shock, and one with apnea requiring resuscitation. In 194 of 202 patients (96%), the outcome of the noninvasive ventilatory course was successful with the patient being weaned from noninvasive respiratory support to nasal cannula or room air.

CONCLUSIONS

Dexmedetomidine was often effective as a single continuous sedative infusion during pediatric noninvasive ventilatory. Cardiorespiratory events associated with its use were typically mild and/or reversible with dose reduction, fluid administration, and/or noninvasive ventilatory titration. Prospective studies comparing dexmedetomidine with other agents in this setting are warranted.

Population Pharmacokinetics of Dexmedetomidine in Infants

Despite limited pharmacokinetic (PK) data, dexmedetomidine is increasingly being used off-label for sedation in infants. We aimed to characterize the developmental PK changes of dexmedetomidine during infancy. In this open-label, single-center PK study of dexmedetomidine in infants receiving dexmedetomidine per clinical care, ≤10 blood samples per infant were collected. A set of structural PK models and residual error models were explored using nonlinear mixed-effects modeling in NONMEM. Covariates including postmenstrual age (PMA), serum creatinine, and recent history of cardiac surgery requiring cardiopulmonary bypass were investigated for their influence on PK parameters. Univariable generalized estimating equation models were used to evaluate the association of hypotension with dexmedetomidine concentrations. A total of 89 PK samples were collected from 20 infants with a median PMA of 44 weeks (range, 33-61). The median maximum dexmedetomidine infusion dose during the study period was 1.8 μg/(kg·h) (0.5-2.5), and 16/20 infants had a maximum dose >1 μg/(kg·h). A 1-compartment model best described the data. Younger PMA was a significant predictor of lower clearance. Infants with a history of cardiac surgery had ∼40% lower clearance compared to those without a history of cardiac surgery. For infants with PMA of 33 to 61 weeks and body weight of 2 to 6 kg, the estimated clearance and volume of distribution were 0.87 to 2.65 L/(kg·h) and 1.5 L/kg, respectively. No significant associations were found between dexmedetomidine concentrations and hypotension. Infants with younger PMA and recent cardiac surgery may require relatively lower doses of dexmedetomidine to achieve exposure similar to older patients and those without cardiac surgery.

Phase IV, Open-Label, Safety Study Evaluating the Use of Dexmedetomidine in Pediatric Patients Undergoing Procedure-Type Sedation

Dexmedetomidine (Precedex™) may be used as an alternative sedative in children, maintaining spontaneous breathing, and avoiding tracheal intubation in a non-intubated moderate or deep sedation (NI-MDS) approach. This open-label, single-arm, multicenter study evaluated the safety of dexmedetomidine in a pediatric population receiving NI-MDS in an operating room or a procedure room, with an intensivist or anesthesiologist in attendance, for elective diagnostic or therapeutic procedures expected to take at least 30 min. The primary endpoint was incidence of treatment-emergent adverse events (TEAEs). Patients received one of two doses dependent on age: patients aged ≥28 weeks' gestational age to <1 month postnatal received dose level 1 (0.1 μg/kg load; 0.05-0.2 μg/kg/h infusion); those aged 1 month to <17 years received dose level 2 (1 μg/kg load; 0.2-2.0 μg/kg/h infusion). Sedation efficacy was assessed and defined as adequate sedation for at least 80% of the time and successful completion of the procedure without the need for rescue medication. In all, 91 patients were enrolled (dose level 1, n = 1; dose level 2, n = 90); of these, 90 received treatment and 82 completed the study. Eight patients in dose level 2 discontinued treatment for the following reasons: early completion of diagnostic or therapeutic procedure (n = 3); change in medical condition (need for intubation) requiring deeper level of sedation (n = 2); adverse event (AE; hives and emesis), lack of efficacy, and physician decision (patient not sedated enough to complete procedure; n = 1 each). Sixty-seven patients experienced 147 TEAEs. The two most commonly reported AEs were respiratory depression (bradypnea; reported per protocol-defined criteria, based on absolute respiratory rate values for age or relative decrease of 30% from baseline) and hypotension. Four patients received glycopyrrolate for bradycardia and seven patients received intravenous fluids for hypotension. SpO₂ dropped by 10% in two patients, but resolved without need for manual ventilation. All other reported AEs were consistent with the known safety profile of dexmedetomidine. Two of the 78 patients in the efficacy-evaluable population met all sedation efficacy criteria. Dexmedetomidine was well-tolerated in pediatric patients undergoing procedure-type sedation.

The Perioperative Use of Dexmedetomidine in Pediatric Patients with Congenital Heart Disease: An Analysis from the Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons Congenital Heart Disease Database

BACKGROUND

Dexmedetomidine is a selective α-2 receptor agonist with a sedative and cardiopulmonary profile that makes it an attractive anesthetic for pediatric patients with congenital heart disease (CHD). Although several smaller, single-center studies suggest that dexmedetomidine use is gaining traction in the perioperative setting in children with CHD, there are limited multicenter data, with little understanding of the variation in use across age ranges, procedural complexity, and centers. The aim of this study was to use the Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons (CCAS-STS) registry to describe patient- and center-level variability in the use of dexmedetomidine in the perioperative setting in children with heart disease.

METHODS

To describe the use of dexmedetomidine in patients for CHD surgery, we analyzed all index cardiopulmonary bypass operations entered in the CCAS-STS database from 2010 to 2013. Patient and operative characteristics were compared between those who received intraoperative dexmedetomidine and those who did not. Selective outcomes associated with dexmedetomidine use were also described.

RESULTS

Of the 12,142 operations studied, 3600 (29.6%) received perioperative dexmedetomidine (DEX) and 8542 did not receive the drug (NoDEX). Patient characteristics were different between the 2 groups with the DEX group generally exhibiting both lower patient and procedural risk factors. Patients who received dexmedetomidine were more likely to have a lower level of Society of Thoracic Surgeons mortality complexity than patient who did not receive it. Consistent with their overall lower risk profile, children in the DEX group also demonstrated improved outcomes compared with patients who did not receive dexmedetomidine.

CONCLUSIONS

We described the growing use of dexmedetomidine in children anesthetized for surgical repair of CHD. Dexmedetomidine appears to be preferentially given to older and larger children who are undergoing less complex CHD surgery. We believe that the data provided in this study are the largest investigating the use of an anesthetic drug in CHD patients. It is also the first analysis of the anesthesia data in the CCAS-STS Congenital Heart Disease database.

Efficacy of Prophylactic Dexmedetomidine in Preventing Postoperative Junctional Ectopic Tachycardia After Pediatric Cardiac Surgery

BACKGROUND

Postoperative junctional ectopic tachycardia is one of the most serious arrhythmias that occur after pediatric cardiac surgery, difficult to treat and better to be prevented. Our aim was to assess the efficacy of prophylactic dexmedetomidine in preventing junctional ectopic tachycardia after pediatric cardiac surgery.

METHODS AND RESULTS

A prospective controlled study was carried out on 90 children who underwent elective cardiac surgery for congenital heart diseases. Patients were randomized into 2 groups. Group I (dexmedetomidine group): 60 patients received dexmedetomidine; Group II (Placebo group): 30 patients received the same amount of normal saline intravenously. The primary outcome was the incidence of postoperative junctional ectopic tachycardia. Secondary outcomes included bradycardia, hypotension, vasoactive inotropic score, ventilation time, pediatric cardiac care unit stay, length of hospital stay, and perioperative mortality. The incidence of junctional ectopic tachycardia was significantly reduced in the dexmedetomidine group (3.3%) compared with the placebo group (16.7%) with P<0.005. Heart rate while coming off cardiopulmonary bypass was significantly lower in the dexmedetomidine group (130.6±9) than the placebo group (144±7.1) with P<0.001. Mean ventilation time, and mean duration of intensive care unit and hospital stay (days) were significantly shorter in the dexmedetomidine group than the placebo group (P<0.001). However, there was no significant difference between the 2 groups as regards mortality, bradycardia, or hypotension (P>0.005).

CONCLUSION

Prophylactic use of dexmedetomidine is associated with significantly decreased incidence of postoperative junctional ectopic tachycardia in children after congenital heart surgery without significant side effects.

Neuroprotection and neurotoxicity in the developing brain: an update on the effects of dexmedetomidine and xenon

Growing and consistent preclinical evidence, combined with early clinical epidemiological observations, suggest potentially neurotoxic effects of commonly used anesthetic agents in the developing brain. This has prompted the FDA to issue a safety warning for all sedatives and anesthetics approved for use in children under three years of age. Recent studies have identified dexmedetomidine, the potent α2-adrenoceptor agonist, and xenon, the noble gas, as effective anesthetic adjuvants that are both less neurotoxic to the developing brain, and also possess neuroprotective properties in neonatal and other settings of acute ongoing neurologic injury. Dexmedetomidine and xenon are effective anesthetic adjuvants that appear to be less neurotoxic than other existing agents and have the potential to be neuroprotective in the neonatal and pediatric settings. Although results from recent clinical trials and case reports have indicated the neuroprotective potential of xenon and dexmedetomidine, additional randomized clinical trials corroborating these studies are necessary. By reviewing both the existing preclinical and clinical evidence on the neuroprotective effects of dexmedetomidine and xenon, we hope to provide insight into the potential clinical efficacy of these agents in the management of pediatric surgical patients.

Dexmedetomidine Use in Critically Ill Children With Acute Respiratory Failure

OBJECTIVE

Care of critically ill children includes sedation but current therapies are suboptimal. To describe dexmedetomidine use in children supported on mechanical ventilation for acute respiratory failure.

DESIGN

Secondary analysis of data from the Randomized Evaluation of Sedation Titration for Respiratory Failure clinical trial.

SETTING

Thirty-one PICUs.

PATIENTS

Data from 2,449 children; 2 weeks to 17 years old.

INTERVENTIONS

Sedation practices were unrestrained in the usual care arm. Patients were categorized as receiving dexmedetomidine as a primary sedative, secondary sedative, periextubation agent, or never prescribed. Dexmedetomidine exposure and sedation and clinical profiles are described.

MEASUREMENTS AND MAIN RESULTS

Of 1,224 usual care patients, 596 (49%) received dexmedetomidine. Dexmedetomidine as a primary sedative patients (n = 138; 11%) were less critically ill (Pediatric Risk of Mortality III-12 score median, 6 [interquartile range, 3-11]) and when compared with all other cohorts, experienced more episodic agitation. In the intervention group, time in sedation target improved from 28% to 50% within 1 day of initiating dexmedetomidine as a primary sedative. Dexmedetomidine as a secondary sedative usual care patients (n = 280; 23%) included more children with severe pediatric acute respiratory distress syndrome or organ failure. Dexmedetomidine as a secondary sedative patients experienced more inadequate pain (22% vs 11%) and sedation (31% vs 16%) events. Dexmedetomidine as a periextubation agent patients (n = 178; 15%) were those known to not tolerate an awake, intubated state and experienced a shorter ventilator weaning process (2.1 vs 2.3 d).

CONCLUSIONS

Our data support the use of dexmedetomidine as a primary agent in low criticality patients offering the benefit of rapid achievement of targeted sedation levels. Dexmedetomidine as a secondary agent does not appear to add benefit. The use of dexmedetomidine to facilitate extubation in children intolerant of an awake, intubated state may abbreviate ventilator weaning. These data support a broader armamentarium of pediatric critical care sedation.

Dexmedetomidine is Associated with an Increased Incidence of Bradycardia in Patients with Trisomy 21 After Surgery for Congenital Heart Disease

This study aimed to evaluate adverse cardiac events using dexmedetomidine in infants with trisomy 21 and those without (controls) and examined potential risk factors in infants after cardiovascular surgery. We conducted a single-center retrospective cohort study. The medical records of 124 consecutive infants who had undergone cardiovascular surgery between April 1, 2013, and October 31, 2015, were enrolled. Clinical characteristics, usage of dexmedetomidine, and perioperative medications were analyzed. Adverse cardiac events were assessed with the Naranjo score and World Health Organization-The Uppsala Monitoring Centre (WHO-UMC) criteria. In total, 124 consecutive infants (30 patients and 94 controls) met the inclusion criteria. Eight of 30 (26.7 %) patients with trisomy 21 and 12 of 94 (12.8 %) controls experienced adverse cardiac events (i.e., hypotension, transient hypertension, and bradycardia) during dexmedetomidine with median Naranjo score of 6, and causality categories of WHO-UMC criteria were "certain" or "probable." Of those, the incidence of bradycardia occurred at a higher rate in patients with trisomy 21 than in controls (P = 0.011). Multiple logistic regression analysis revealed that the presence of trisomy 21 was an independent risk factor for adverse cardiac events of dexmedetomidine after cardiovascular surgery (odds ratio 4.10, 95 % CI 1.17-11.19, P = 0.006). Dexmedetomidine is associated with an increased incidence of bradycardia in patients with trisomy 21 after surgery for congenital heart disease. Physicians using dexmedetomidine should know a great deal about the characteristics of patients with trisomy 21, and hemodynamic monitoring should be closely observed.

The efficacy of pre-emptive dexmedetomidine versus amiodarone in preventing postoperative junctional ectopic tachycardia in pediatric cardiac surgery

OBJECTIVE

The objective of this study was to assess the effectiveness of pre-emptive dexmedetomidine versus amiodarone in preventing junctional ectopic tachycardia (JET) in pediatric cardiac surgery.

DESIGN

This is a prospective, controlled study.

SETTING

This study was carried out at a single university hospital.

SUBJECTS AND METHODS

Ninety patients of both sexes, American Society of Anesthesiologists Physical Status II and III, age range from 2 to 18 years, and scheduled for elective cardiac surgery for congenital and acquired heart diseases were selected as the study participants.

INTERVENTIONS

Patients were randomized into three groups (30 each). Group I received dexmedetomidine 1 mcg/kg diluted in 100 ml of normal saline intravenously (IV) over a period of 20 min, and the infusion was completed 10 min before the induction followed by a 0.5 mcg/kg/h infusion for 72 h postoperative, Group II received amiodarone 5 mg/kg diluted in 100 ml of normal saline IV over a period of 20 min, and the infusion was completed 10 min before the induction followed by a 10-15 mcg/kg/h infusion for 72 h postoperative, and Group III received 100 ml of normal saline IV. Primary outcome was the incidence of postoperative JET. Secondary outcomes included vasoactive-inotropic score, ventilation time (VT), pediatric cardiac care unit stay, hospital length of stay, and perioperative mortality.

MEASUREMENTS AND MAIN RESULTS

The incidence of JET was significantly reduced in Group I and Group II (P = 0.004) compared to Group III. Heart rate while coming off from cardiopulmonary bypass (CPB) was significantly low in Group I compared to Group II and Group III (P = 0.000). Mean VT, mean duration of Intensive Care Unit stay, and length of hospital stay (day) were significantly short (P = 0.000) in Group I and Group II compared to Group III (P = 0.000).

CONCLUSION

Perioperative use of dexmedetomidine and amiodarone is associated with significantly decreased incidence of JET as compared to placebo without significant side effects.

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.

Emergency Corrective Surgery of Congenital Diaphragmatic Hernia With Pulmonary Hypertension: Prolonged Use of Dexmedetomidine as a Pharmacologic Adjunct

INTRODUCTION

Underdevelopment of the lung parenchyma associated with abnormal growth of pulmonary vasculature in neonates with congenital diaphragmatic hernia results in pulmonary hypertension which mandates smooth elective mechanical ventilation in postoperative period, for proper alveolar recruitment and oxygenation, allowing lungs to mature enough for its functional anatomy and physiology. Dexmedetomidine is sympatholytic, reduces pulmonary vascular resistance and exerts sedative and analgesic property to achieve stable hemodynamics during elective ventilation. Neonatal experience with dexmedetomidine has been predominately in the form of short term or procedural use as a sedative.

CASE PRESENTATION

The preliminary clinical experience with pre-induction to 48 hours postoperative use of dexmedetomidine infusion as a pharmacologic adjunct in the emergency corrective surgery of three such neonates are presented.

CONCLUSIONS

Hemodynamics remained virtually stable during the whole procedure and post-operative pain relief and recovery profile were satisfactory. The prolonged infusion was well tolerated with a gradual trend towards improved oxygen saturation. Careful planning of the anesthetic management and the ability to titrate the adjunct utilized for smooth postoperative ventilation are the keys to ameliorate the complications encountered and favorable outcomes achieved in such patients.

Effect of dexmeditomidine on postoperative junctional ectopic tachycardia after complete surgical repair of tetralogy of Fallot: A prospective randomized controlled study

Introduction:

Incidence of junctional ectopic tachycardia (JET) after repair of tetralogy of Fallot (TOF) is 5.6–14%. Dexmeditomidine is a α-2 adrenoceptor agonist modulates the release of catecholamine, resulting in bradycardia and hypotension. These effects are being explored as a therapeutic option for the prevention of perioperative tachyarrhythmia. We undertook this study to examine possible preventive effects of dexmedetomidine on postoperative JET and its impact on the duration of ventilation time and length of Intensive Care Unit stay.

Methods:

After obtaining approval from the hospitals ethics committee and written informed consent from parents, this quasi-randomized trial was initiated. Of 94 patients, 47 patients received dexmedetomidine (dexmedetomidine group) and 47 patients did not receive the drug (control group).

Results:

Dexmedetomidine group had more number of complex variants like TOF with an absent pulmonary valve or pulmonary atresia (P = 0.041). Hematocrit on cardiopulmonary bypass (CPB), heart rate while coming off from CPB and inotrope score was significantly low in the dexmedetomidine group compared to control group. The incidence of JET was significantly low in dexmedetomidine group (P = 0.040) compared to control group.

Conclusions:

Dexmedetomidine may have a potential benefit of preventing perioperative JET.

Noncardiac Challenges in the Cardiac ICU: Feeding, Growth and Gastrointestinal Complications, Anticoagulation, and Analgesia

Outcomes following cardiac intensive care unit (CICU) admission are influenced by many factors including initial cardiac diagnosis, surgical complexity, and burden of critical illness. Additionally, the presence of noncardiac issues may have a significant impact on outcomes and the patient experience during and following an intensive care unit stay. This review focuses on three common noncardiac areas which impact outcomes and patient experience in and beyond the CICU: feeding and growth, pain and analgesia, and anticoagulation. Growth failure and feeding dysfunction are commonly encountered in infants requiring cardiac surgery and have been associated with worse surgical and developmental outcomes. Recent studies most notably in the single ventricle population have demonstrated improved weight gain and outcomes when feeding protocols are implemented. Children undergoing cardiac surgery may experience both acute and chronic pain. Emerging research is investigating the impact of sedatives and analgesics on neurodevelopmental outcomes and quality of life. Improved pain scores and standardized management of pain and withdrawal may improve the patient experience and outcomes. Effective anticoagulation is a critical component of perioperative care but may be complicated by inflammation, multiorgan dysfunction, and patient factors. Advances in monitoring of anticoagulation and emerging therapies are reviewed.

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.

Cardiac Arrest in a Heart Transplant Patient Receiving Dexmedetomidine During Cardiac Catheterization

Dexmedetomidine is an α-2 agonist with a sedative and cardiopulmonary profile that makes it an attractive anesthetic in pediatric cardiac patients. Cardiac transplant patients may suffer from acute cellular rejection of the cardiac conduction system and, therefore, are at an increased risk of the electrophysiological effect of dexmedetomidine. We present such a patient who had a cardiac arrest while receiving dexmedetomidine during cardiac catheterization. Because acute cellular rejection of the cardiac conduction system is difficult to diagnose, dexmedetomidine should be used with caution in pediatric heart transplant patients.

Dexmedetomidine decreases the emergence agitation in infant patients undergoing cleft palate repair surgery after general anesthesia

Background

To determine whether continuous intravenous infusion of dexmedetomidine (DEX) can affect the incidence of Emergence Agitation (EA) after general anesthesia in infant undergoing cleft palate repair surgery.

Methods

Forty infants underwent cleft palate repair surgery under general anesthesia were randomly divided into the DEX (D) group and Placebo (P) groups. Patients in group D received continuous intravenous infusion of DEX 0.8 μg · kg-1 · min-1 after the induction. Patients in group P were administered with continuous intravenous infusion of the equivalent volume of normal saline. Both groups were induced with fentanyl 0.005 mg/Kg, propofol 2 mg/Kg and cisatracurium 0.2 mg/Kg. Anaesthesia was maintained with continuous intravenous infusion of propofol (2 mg/Kg · h), remifentanil (0.1 μg/Kg · h), and inhalation of 1 to 3 % sevoflurane.

Result

The heart rate (HR) in group P was significant higher than that in group D at the time of operation (P < 0.05), postoperative 15 min, 30 min and the time of extubation (P < 0.01). The mean arterial pressure (MAP) in group P was higher comparing with MAP in group D at the time of extubation (P < 0.05). The spontaneous eye opening times and spontaneous arm or leg motion times were longer in group D (P < 0.05). The mean agitation scores of patients in group D were significantly lower than that in group P (P < 0.01). However, the incidence of EA in group P and group D was 90 % and 15 % (P <0.05).

Conclusion

The continuous intravenous infusion of DEX after induction could significantly reduce the occurrence of EA.

Trial registration

The Chinese Clinical Trial Register ChiCTR-TRC-13003865

Pain and Sedation Management in Mechanically Ventilated Children

Assessing and managing pain and agitation in critically ill children can be challenging. Multiple factors contribute to the challenges of management, including prior medication exposure, surgical and procedural interventions, pharmacokinetics, and age-related pharmacodynamics making the population heterogeneous. Therefore, individualizing treatment approaches embedded with frequent assessments is likely to improve the management of pain and agitation in critically ill children. Novel approaches to manage pain and agitation continue to evolve and will require ongoing evaluation prior to widespread adoption.

Perioperative Considerations for Children With Right Ventricular Dysfunction and Failing Fontan

The survival of patients with congenital heart diseases (CHD) has increased in the past decades, resulting in the identification of new characteristics of chronic comorbidities observed in pediatric and adults with CHD. Patients with CHD can present with a broad clinical spectrum of manifestations of congestive heart failure (CHF) at any point throughout their lives that may be related to anatomical or surgical variables. This article focuses on the perioperative assessment of patients with CHD and CHF, with an emphasis on pathophysiologic, diagnostic, and therapeutic alternatives in patients with right ventricular failure and failing Fontan circulation. We also provide descriptions of the effects of sedatives and anesthetics commonly used in this population in diagnostic or invasive procedures.

Efficacy and Safety of Postoperative Dexmedetomidine Administration in Infants and Children Undergoing Cardiac Surgery: A Retrospective Cohort Study

In this retrospective cohort study, we describe efficacy and safety of dexmedetomidine administration in the cardiac intensive care unit, in children undergoing cardiac surgery. This study consisted of pediatric patients 3 days to 17.5 years of age, undergoing cardiac surgery from April 2010 to April 2011. In addition to a scheduled opioid, usually fentanyl, 107 patients received dexmedetomidine postoperatively, including 19 (18%) patients diagnosed with trisomy 21 and 9 (8%) neonates/newborns. Median dexmedetomidine starting dose was 0.45 µg/kg/h and overall median dose higher than previously published, ranging from 0.8 µg/kg/h to 2.17 µg/kg/h. We compared infants (younger than 1 year) with older children (1-17 years of age). Median duration of administration was 1.6 days (0-23.9 days) and duration to extubation in infants was 46.5 hours, and in the older children it was 22.6 hours. Seven patients (6.5%) were discontinued dexmedetomidine due to adverse events, most commonly bradycardia. Neonates experienced more pronounced heart rate reduction (no bradycardia) and received lower maintenance doses than older infants (0.56 vs. 0.77 µg/kg/h). The face, leg, activity, cry, consolability pain scale and the state behavioral scale scores indicated adequate sedation and good analgesia. The most common adverse reaction postdiscontinuation was agitation, more frequent in the infant group (20 vs. 11.2%). Thirty patients (28.3%) received prolonged infusion (>72 hours). Patients with and without trisomy 21 did not differ with dose, safety, efficacy, or adverse events. Dexmedetomidine, as part of multimodal management, appears to be a safe, efficacious agent providing analgesia and sedation throughout all pediatric age groups following cardiac surgery. Overall, dexmedetomidine is well tolerated and safe with higher doses than previously noted, and is well tolerated by neonates, infants, and patients with trisomy 21. Withdrawal effects were noted in patients following prolonged infusion.

Dexmedetomidine utilisation and outcomes of children with trisomy 21 undergoing congenital heart disease surgery

INTRODUCTION

The diagnosis of trisomy 21 in children has been associated with failed extubation after CHD surgery. Dexmedetomidine may be a useful agent to improve postoperative outcomes in these patients, such as ventilator time, ICU length of stay, or hospital length of stay.

MATERIALS AND METHODS

The Pediatric Health Information System database was queried from January, 2008 to December, 2010 for patients with trisomy 21 who underwent CHD surgery. Patients who received dexmedetomidine were matched to patients who did not by propensity score. The primary outcome was ventilator days charged, and secondary outcomes included ICU and hospital length of stay.

RESULTS

A total of 1088 patients (544 matched pairs) met inclusion criteria. Patient characteristics were similar, with the exception of more patients in the dexmedetomidine group undergoing repair of complete atrioventricular canal and fewer undergoing mechanical valve replacement (p<0.01). More patients in the dexmedetomidine group were administered milrinone, epinephrine, vasopressin, benzodiazepines, opiates, and adjunct pain and sedative medications (p<0.01). The dexmedetomidine group had greater time on the ventilator [7 (4.5-11) versus 6 (4-10) days (median, interquartile range) p<0.01] and similar ICU length of stay, hospital length of stay, and mortality compared with controls. Mixed-effects modelling clustered on institution did not show beneficial effect of dexmedetomidine on ventilator time, ICU stay, or hospital length of stay.

CONCLUSIONS

The use of dexmedetomidine was not associated with the decreased ventilatory time. Routine use of dexmedetomidine is not warranted in this patient population.

Intraoperative dexmedetomidine reduces postoperative mechanical ventilation in infants after open heart surgery

OBJECTIVE

The inclusion of dexmedetomidine in the operative and postoperative management of infants with congenital heart defects has lessened the need for opioids that may cause respiratory depression. Our objective was to show that a dexmedetomidine bolus at or about the time of sternal closure is associated with a decrease in the use of mechanical ventilation in the immediate postoperative period.

DESIGN

Retrospective cohort study.

SETTING

Single pediatric tertiary cardiac center.

PATIENTS

Infants undergoing surgical intervention for congenital heart defects requiring cardiopulmonary bypass, age 30-365 days in a 5-year time period from June 1, 2008, to December 31, 2012.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 1,057 total encounters, 441 met inclusion criteria and were evenly distributed over the 5-year time period. Dexmedetomidine had been given at or about the time of sternal closure in 57% of patients. When the exposed and unexposed groups were compared in terms of mechanical ventilation immediately postoperative, there was a statistically significant effect of using dexmedetomidine on the odds of receiving mechanical ventilation (p = 0.0019). This difference remained significant after adjusting for covariates affecting the decision for mechanical ventilation, including year of the procedure, age and weight of subject, cardiopulmonary bypass time, the use of deep hypothermic circulatory arrest, intraoperative fentanyl dose, and the Risk Adjustment for Congenital Heart Surgery Score 1 (p = 0.0317). The odds of receiving mechanical ventilation are estimated to be two times higher for patients who did not receive dexmedetomidine than for patients who received dexmedetomidine after adjusting for variables.

CONCLUSION

The use of dexmedetomidine bolus in the operating room at the time of sternal closure in infants undergoing open heart surgery is associated with reduced need for mechanical ventilation in the immediate postoperative period.

Electrocardiographic and electrophysiologic effects of dexmedetomidine on children

BACKGROUND

Dexmedetomidine (DEX) is a highly selective alpha-2-adrenergic agonist approved for short-term sedation and monitored anesthesia care in adults. Its effects on the electrocardiography and cardiac conduction tissue are not well described in the literature. Therefore, we aimed to characterize the electrocardiographic and electrophysiologic effects of DEX in children.

METHODS

Twenty children (11 boys and nine girls) between the ages of eight and 17 undergoing electrophysiology study and ablation of the supraventricular tachycardia had hemodynamic and cardiac electrophysiologic variables measured before and during the administration of DEX (1 microgram/kg IV over 10 minutes followed by a 10-minute continuous infusion of 0.5 microgram/kg/h).

RESULTS

A significant decrease in heart rate was seen after the administration of DEX, but the systolic-diastolic-mean arterial pressure, respiratory rate, and end-tidal carbon dioxide did not change. Corrected sinus node recovery times and baseline sinus cycle lengths, which are markers of sinus nodal function, were both lengthened with the administration of DEX. Atrioventricular (AV) nodal function, as evidenced by the Wenckebach cycle length, the ventriculoatrial block cycle length, and AV nodal effective refractory periods, was lengthened significantly. We also found that DEX increased the atrial refractory period and diminished atrial excitability.

CONCLUSIONS

DEX significantly depressed sinus and AV nodal function in pediatric patients without significant electrocardiogram interval changes, other than a trend toward lower heart rates. Although no spontaneous AV nodal block and no clinically significant bradycardia were seen, we recommend that DEX be used with caution in patients at risk for bradycardia and/or AV nodal dysfunction due to its associated comorbidities.

Dexmedetomidine and fentanyl exhibit temperature dependent effects on human respiratory cilia

BACKGROUND

Dexmedetomidine (dex) is commonly used in intensive care due to its effective sedation and analgesia with few adverse effects and minimal respiratory depression. However, we recently observed that exposing mouse epithelial respiratory cells to dex decreased ciliary beat frequency (CBF), suggesting dex may pose pulmonary risk.

OBJECTIVE

The purpose of this study is to determine the effects of dex at clinically relevant doses on CBF in human respiratory epithelia.

METHODS

Human nasal epithelial cilia were obtained from the inferior nasal turbinate with a rhinoprobe and placed in culture medium at 15°C and 37°C. At 5 and 30 min, video-microscopy was used to assess CBF, either without (control) or with different concentrations (1, 5, and 10 nM) of dex, fentanyl (fen), and dex + fen combination.

RESULTS

At 15°C, CBF was lower in the dex group compared to controls at 5 and 30 min. At 37°C, there was a significant increase in CBF with dex at 5 and 30 min, except for dex at 5 nM after 5 min, which showed a significant decrease. At 15°C the combination of dex + fen showed a positive interaction, causing less ciliary inhibition as expected. In contrast, no interaction between drugs was seen between dex and fen at 37°C.

CONCLUSION

At low temperatures, dex reduces CBF in human respiratory epithelia, whereas dex increases CBF at physiologic temperature in vitro. Whether these effects translate into clinical consequences during hypothermia, as with cardiopulmonary bypass surgery will require further studies.