Median Effective Dose of Intranasal Dexmedetomidine for Transthoracic Echocardiography in Children with Kawasaki Disease Who Have a History of Repeated Sedation

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Median Effective Dose of Dexmedetomidine Inducing Bradycardia in Elderly Patients Determined by Up-and-Down Sequential Allocation Method

Purpose: When dexmedetomidine is used in elderly patients, high incidence of bradycardia is reported. Given age-related physiological changes in this population, it is necessary to know the safety margin between the loading dose of dexmedetomidine and bradycardia. Therefore, we conducted this study to investigate the median effective dose (ED50) of dexmedetomidine causing bradycardia in elderly patients. Methods: Thirty patients with ages over 65 years undergoing elective general surgery were enrolled. The Dixon and Massay sequential method were applied to determine the loading dose of dexmedetomidine, starting from 1.0 µg/kg. The dose for the follow-up subjects increased or decreased according to the geometric sequence with the common ratio 1.2, based on the 'negative' or 'positive' response of the previous subject. Positive mean that the subject developed bradycardia during the test. Hemodynamic data including heart rate and systolic blood pressure were recorded. The level of sedation was assessed with the Observer Assessment of Alertness and Sedation Scale (OAA/S). Results: Bradycardia occurred in 13 patients (43.3%). The ED50 of dexmedetomidine causing bradycardia was 1.97 µg/kg (95% CI, 1.53-2.53 µg/kg). OAA/S scores at 10 min after the beginning of the dexmedetomidine infusion and 10 min after the termination of dexmedetomidine administration showed no significant differences between the positive and negative groups (P > 0.05). Conclusion: The ED50 of dexmedetomidine causing bradycardia in our cohort was higher than clinical recommended dose. A higher loading dose appears acceptable for a faster onset of sedation under careful hemodynamic monitoring. Trial registration: ChiCTR 15006368.

ED50 of Intranasal Dexmedetomidine Sedation for Transthoracic Echocardiography in Children with or without a History of Cardiac Surgery for Cyanotic Congenital Heart Disease

Methods

This prospective single-blinded clinical trial included 72 ASA I-II stage children aged 1-36 months with cCHD who were scheduled to undergo TTE under sedation. Children were assigned to group A (n = 37) with a previous history of cardiac surgery and group B (n = 35) with no history of cardiac surgery. Doses of intranasal DEX were analyzed by up-down sequential allocation at an initial dose of 2.3 μg/kg and an increase in steps of 0.2 μg/kg. Intranasal DEXED50 values were analyzed by the up-and-down method of Dixon-Massey and probit regression to determine ED50 and 95% confidence interval (CI) for sedation. The time to effective sedation, time to regaining consciousness, vital signs, oxygen saturation, time of performing TTE, clinical adverse effects, and characteristics of regaining consciousness were compared between the two groups.

Results

ED50 of intranasal DEX sedation was 2.530 μg/kg (95% CI, 1.657-4.156) in group A and 2.500 μg/kg (95% CI, 1.987-3.013) in group B. There was no significant difference in sedation onset time and time to regaining consciousness between the two groups. Additionally, no significant adverse hemodynamic or hypoxemic effect was observed. There was no significant difference in sedation-onset time and wake-up time between the two groups (15 ± 4 min vs.16 ± 5 min; 50 ± 11 min vs.48 ± 10 min). This trial is registered with the China Clinical Trials Registry (ChiCTR-IOR-1800015038).

Conclusions

ED50 of intranasal DEX sedation for TTE is similar in children with and without a history of cardiac surgery for cCHD.