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

Insight into Cardioprotective Effects and Mechanisms of Dexmedetomidine

PURPOSE

Cardiovascular disease remains the leading cause of death worldwide. Dexmedetomidine is a highly selective α2 adrenergic receptor agonist with sedative, analgesic, anxiolytic, and sympatholytic properties, and several studies have shown its possible protective effects in cardiac injury. The aim of this review is to further elucidate the underlying cardioprotective mechanisms of dexmedetomidine, thus suggesting its potential in the clinical management of cardiac injury.

RESULTS AND CONCLUSION

Our review summarizes the findings related to the involvement of dexmedetomidine in cardiac injury and discusses the results in the light of different mechanisms. We found that numerous mechanisms may contribute to the cardioprotective effects of dexmedetomidine, including the regulation of programmed cell death, autophagy and fibrosis, alleviation of inflammatory response, endothelial dysfunction and microcirculatory derangements, improvement of mitochondrial dysregulation, hemodynamics, and arrhythmias. Dexmedetomidine may play a promising and beneficial role in the treatment of cardiovascular disease.

Adverse Drug Reactions in Children with Congenital Heart Disease: A Scoping Review

BACKGROUND

Congenital heart disease (CHD) is one of the leading causes of death. Safe and timely medical interventions, especially in children, can prolong their survival. The drugs prescribed for children with CHD are mainly based on the outcomes of drug therapy in adults with cardiovascular diseases, and their adverse drug reactions (ADRs) might be different. Therefore, the aim of this study was to investigate ADRs in children with CHD.

METHODS

This was a scoping review conducted in 2023. PubMed, Web of Science, Scopus, the Cochrane Library, Ovid, ProQuest, and Google Scholar databases were searched. All studies that reported ADRs for children with CHD and were published in English by 1 November 2023 were included in this study. Finally, the results were reported using a content analysis method.

RESULTS

A total of 87 articles were included in the study. The results showed that symptoms/signs/clinical findings, and cardiovascular disorders were the most common ADRs reported in children with CHD. The results also showed that most of the ADRs were reported for prostaglandin E1, amiodarone, prostaglandin E2, dexmedetomidine, and captopril, respectively.

CONCLUSION

The review underscores the wide array of ADRs in children with CHD, particularly in antiarrhythmics, diuretics, beta-blockers, anticoagulants, and vasodilators, which affected cardiovascular, respiratory, endocrine, metabolic, genitourinary, gastrointestinal, and musculoskeletal systems. Tailored treatment is imperative, considering individual patient characteristics, especially in the vulnerable groups. Further research is essential for optimizing dosing, pharmacogenetics, and alternative therapies to enhance patient outcomes in CHD management.

Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus

Cardiovascular disease is a leading cause of morbidity and mortality in individuals with Down syndrome. Congenital heart disease is the most common cardiovascular condition in this group, present in up to 50% of people with Down syndrome and contributing to poor outcomes. Additional factors contributing to cardiovascular outcomes include pulmonary hypertension; coexistent pulmonary, endocrine, and metabolic diseases; and risk factors for atherosclerotic disease. Moreover, disparities in the cardiovascular care of people with Down syndrome compared with the general population, which vary across different geographies and health care systems, further contribute to cardiovascular mortality; this issue is often overlooked by the wider medical community. This review focuses on the diagnosis, prevalence, and management of cardiovascular disease encountered in people with Down syndrome and summarizes available evidence in 10 key areas relating to Down syndrome and cardiac disease, from prenatal diagnosis to disparities in care in areas of differing resource availability. All specialists and nonspecialist clinicians providing care for people with Down syndrome should be aware of best clinical practice in all aspects of care of this distinct population.

Down syndrome and the autonomic nervous system, an educational review for the anesthesiologist

Approximately one in every 700 babies in the United States is born with Down syndrome, or 0.14%. Children with Down syndrome have cognitive impairment and congenital malformations necessitating frequent occurrences of general anesthesia and surgery. The thoughtful perioperative care of children with Down syndrome is relevant and acutely complex for the pediatric anesthesiologist. Behavior, sedation, hypotonia, upper airway obstruction, venous access, and bradycardia are omnipresent concerns apart from the surgical pathology. Down syndrome is also associated with autonomic nervous system dysfunction, a comorbidity that is overlooked in discussions of perioperative care and is described thus far in adults. Autonomic nervous system function or dysfunction may explain the phenotypical features of the perioperative challenges listed above. For this reason, understanding the development and measurement of autonomic nervous system function is important for the pediatric anesthesiologist. Definition and quantification of sympathetic and parasympathetic function will be reviewed.

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.

Sedation With Midazolam After Cardiac Surgery in Children With and Without Down Syndrome: A Pharmacokinetic-Pharmacodynamic Study

OBJECTIVES

To compare the pharmacokinetics and pharmacodynamics of IV midazolam after cardiac surgery between children with and without Down syndrome.

DESIGN

Prospective, single-center observational trial.

SETTING

PICU in a university-affiliated pediatric teaching hospital.

PATIENTS

Twenty-one children with Down syndrome and 17 without, 3-36 months, scheduled for cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

Postoperatively, nurses regularly assessed the children's pain and discomfort with the validated COMFORT-Behavioral scale and Numeric Rating Scale for pain. A loading dose of morphine (100 µg/kg) was administered after coming off bypass; thereafter, morphine infusion was commenced at 40 µg/kg/hr. Midazolam was started if COMFORT-Behavioral scale score of greater than 16 and Numeric Rating Scale score of less than 4 (suggestive of undersedation). Plasma midazolam and metabolite concentrations were measured for population pharmacokinetic- and pharmacodynamic analysis using nonlinear mixed effects modeling (NONMEM) (Version VI; GloboMax LLC, Hanover, MD) software.

MEASUREMENTS AND MAIN RESULTS

Twenty-six children (72%) required midazolam postoperatively (15 with Down syndrome and 11 without; p = 1.00). Neither the cumulative midazolam dose (p = 0.61) nor the time elapsed before additional sedation was initiated (p = 0.71), statistically significantly differed between children with and without Down syndrome. Population pharmacokinetic and pharmacodynamics analysis revealed no statistically significant differences between the children with and without Down syndrome. Bodyweight was a significant covariate for the clearance of 1-OH-midazolam to 1-OH-glucuronide (p = 0.003). Pharmacodynamic analysis revealed a marginal effect of the midazolam concentration on the COMFORT-Behavioral score.

CONCLUSIONS

The majority of children with and without Down syndrome required additional sedation after cardiac surgery. This pharmacokinetic and pharmacodynamic analysis does not provide evidence for different dosing of midazolam in children with Down syndrome after cardiac surgery.

Incidence and risk factors of bradycardia in pediatric patients undergoing intranasal dexmedetomidine sedation

BACKGROUND

Dexmedetomidine is widely used for non-invasive pediatric procedural sedation. However, the hemodynamic effects of intravenous dexmedetomidine are a concern. There has been a growing interest in the application of intranasal dexmedetomidine as a sedative in children.

OBJECTIVE

To investigate the incidence of bradycardia in children undergoing intranasal dexmedetomidine sedation and to identify the associated risk factors.

METHODS

Data pertaining to pediatric patients who underwent intranasal dexmedetomidine sedation for non-invasive investigations at the Kunming Children's Hospital between October 2017 and August 2018 were retrospectively analyzed.

RESULTS

Out of 9984 children who qualified for inclusion, 228 children (2.3%) developed bradycardia. The incidence of bradycardia in the group that received additional dose of dexmedetomidine was higher than that in the group that did not receive additional dose (9.2% vs 16.7%; P = .003). The incidence of bradycardia in males was higher than that in females (2.6% vs 1.8%; P = .007). On multivariate logistic regression, only male gender showed an independent association with the occurrence of bradycardia (odds ratio 1.48; 95% confidence interval 1.11-1.97; P = .008).

CONCLUSIONS

The overall incidence of bradycardia in children after sole use of intranasal dexmedetomidine sedation was 2.3%. Male children showed a 1.48-fold higher risk of bradycardia. However, the blood pressure of the children who developed bradycardia was within the normal range. Simple wake-up can effectively manage bradycardia induced by intranasal dexmedetomidine sedation.

Down Syndrome Reduces the Sedative Effect of Midazolam in Pediatric Cardiovascular Surgical Patients

Down syndrome (DS) is frequently comorbid with congenital heart disease and has recently been shown to reduce the sedative effect of benzodiazepine (BDZ)-class anesthesia but this effect in a clinical setting has not been studied. Therefore, this study compared midazolam sedation after heart surgery in DS and normal children. We retrospectively reviewed patient records in our pediatric intensive care unit (PICU) of pediatric cardiovascular operations between March 2015 and March 2018. We selected five days of continuous post-operative data just after termination of muscle relaxants. Midazolam sedation was estimated by Bayesian inference for generalized linear mixed models. We enrolled 104 patients (average age 26 weeks) of which 16 (15%) had DS. DS patients had a high probability of receiving a higher midazolam dosage and dexmedetomidine dosage over the study period (probability = 0.99, probability = 0.97) while depth of sedation was not different in DS patients (probability = 0.35). Multi regression modeling included severity scores and demographic data showed DS decreases midazolam sedation compared with controls (posterior OR = 1.32, 95% CrI = 1.01-1.75). In conclusion, midazolam dosages should be carefully adjusted as DS significantly decreases midazolam sedative effect in pediatric heart surgery patients.

The brain protective effect of dexmedetomidine during surgery for paediatric patients with congenital heart disease

Objective

To study the brain protective effect of dexmedetomidine (DEX) during surgery in paediatric patients with congenital heart disease (CHD).

Methods

This randomized single-blind controlled study enrolled paediatric patients aged 0–3 years with CHD who underwent surgery and randomized them into two groups: one group received DEX and the control group received 0.9% NaCl during anaesthesia. Demographic data, heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were recorded. Levels of neuron specific enolase (NES) and S-100β protein were determined using enzyme-linked immunosorbent assays.

Results

The study enrolled 80 paediatric patients with CHD. Compared with the control group, HR, MAP and CVP were significantly lower in the DEX group at all time-points except for T0. At all time-points except for T0, the levels of jugular venous oxygen saturation in the DEX group were significantly higher compared with the control group. At all time-points except for T0, the levels of arterial venous difference and cerebral extraction of oxygen were significantly lower in the DEX group compared with the control group. Levels of NES and S-100β protein in the DEX group were significantly lower compared with the control group at all time-points except for T0.

Conclusion

DEX treatment during surgery for CHD improved oxygen metabolism in brain tissues and reduced the levels of NES and S-100β protein.

Sedation methods for transthoracic echocardiography in children with Trisomy 21-a retrospective study

BACKGROUND

Many children with Trisomy 21 have neurologic or behavioral problems that make it difficult for them to remain still during noninvasive imaging studies, such as transthoracic echocardiograms (TTEcho). Recently, intranasal dexmedetomidine sedation has been introduced for this purpose. However, dexmedetomidine has been associated with bradycardia. Children with Trisomy 21 have been reported to have a higher risk of bradycardia and airway obstruction with sedation or anesthesia compared to children without Trisomy 21.

OBJECTIVE

Our aim was to quantify the incidence of age-defined bradycardia and other adverse effects in patients with Trisomy 21 under sedation for TTEcho using a variety of sedation and anesthesia techniques available and utilized at our institution in this challenging patient population, including intranasal dexmedetomidine, oral pentobarbital, general anesthesia with propofol, and general anesthesia with sevoflurane. Our primary hypothesis was that intranasal dexmedetomidine sedation would result in a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens.

METHODS

This is a retrospective, observational study of 147 consecutive patients with Trisomy 21 who were sedated or anesthetized for transthoracic echocardiography. Efficacy of sedation was defined as no need for rescue sedation or conversion to an alternate technique. Lowest and highest heart rate, systolic blood pressure, oxygen saturation, and PR interval from formal electrocardiograms were extracted from the electronic medical record. These data were compared to age-defined normal values to determine adverse events.

RESULTS

Four methods of sedation or anesthesia were utilized to perform sedated transthoracic echocardiography: general anesthesia with sevoflurane by mask, general anesthesia with sevoflurane induction followed by intravenous propofol maintenance, oral pentobarbital, and intranasal dexmedetomidine. Intranasal dexmedetomidine 2.5 mcg·kg^-1 was an effective sedative as a single dose for TTEcho in 37 of 41 (90%) cases. Oral pentobarbital 5 mg·kg^-1 as a single dose for young children with Trisomy 21 was effective in 55 of 75 (73%) cases. Intranasal dexmedetomidine sedation was not associated with a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens, when compared to oral pentobarbital for patients under 2 years of age and general anesthesia for children 3 years and older. The two general anesthesia groups showed lowest heart rates of 66.9 ± 15.9 min^-1 for sevoflurane and 69.0 ± 11.5 min^-1 for sevoflurane-propofol. Hypotension was present in all groups ranging between an incidence of 56% in the sevoflurane group to 11% in the oral pentobarbital group. Oxygen saturation and clinically significant desaturation occurred in 14% of the oral pentobarbital group.

CONCLUSION

Intranasal dexmedetomidine sedation was not associated with a significantly higher risk of bradycardia in patients with Trisomy 21, compared with other sedative or anesthetic regimens.