192 - Description of Dexmedetomidine Dosing in Neonates and its Impact on Cardiovascular System

Poster Number: 192
Publication Number: 192.219

Ivonne E. Sierra-Strum, Oklahoma Childrens Hospital at OU Health, Oklahoma City, OK, United States; Jamie Miller, University of Oklahoma College of Pharmacy, Oklahoma City, OK, United States; Patrick J. McNamara, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA, United States; Lise DeShea, University of Oklahoma College of Medicine, Oklahoma City, OK, United States; Adrianne Rahde Bischoff, University of Iowa, Iowa city, IA, United States; Edgardo Szyld, University of Oklahoma College of Medicine, oklahoma city, OK, United States; Marjorie Makoni, OUHSC, Oklahoma City, OK, United States

Background: Delivering an optimal sedative and analgesic regimen for neonates with minimal adverse effects is an essential element of neonatal intensive care. Dexmedetomidine (DEX) is an alpha 2-adrenergic agonist with anxiolytic and sedative effects, but also potential hemodynamic effects such as bradycardia and hypotension. There is a paucity of data on effects in preterm neonates, especially those born < 28 weeks gestational age (GA). 

Objective: Investigate the hemodynamic effects of DEX infusion in neonates admitted to the NICU.   

Design/Methods: A retrospective review of NICU patients who received DEX infusion (0.1-1 mcg/kg/hr) was conducted (01/16 to 03/21). Patients with congenital heart disease and postoperative DEX infusion for < 12hrs were excluded. Serial blood pressure (BP), heart rate, vasoactive inotropic scores (VIS) and DEX dose were recorded at baseline (T0) & post-DEX infusion [T1:1-4hours, T2:5-8hours, T3:9-12hours, T4:24 hours]. Hypotension was defined as SBP, MBP and DBP < 3rd percentile for GA. Patients were divided into 4 GA groups: 1: < 28 weeks, 2: 28-32 weeks, 3: 32-37 weeks and 4: >37 weeks. The primary outcome was changes in BP components over time. Repeated measures ANOVAs were run, except VIS was analyzed with Friedman’s test due to skewness. Comparative evaluation of ventricular function was performed in a subgroup (n=12) with echocardiography 24 hours prior to DEX and within 24 hours of DEX  initiation. LV and RV systolic dysfunction were defined by EF < 55% or FS < 25% and mean TAPSE >1 SD below GA respectively.

Results: A total of 206 neonates were studied;164 (80%) were intubated at baseline (Table 1).  The most common indication for DEX was sepsis (n=49, 24%).  Concomitant analgesic or sedative use was seen in 66.5% [Table 2]. All components of BP fell in group 1, whereas only systolic BP fell in group 3 [Table 3]. These changes were associated with a mean DEX dose of 0.4mcg/kg/hr in group 1, which was maximal at T3. In addition, group 1 had the highest increase in VIS at T3. A consistent fall in heart rate was noted in all groups. Subgroup analysis of infants with serial echo revealed the development of biventricular dysfunction (previously normal) requiring fluid bolus (100%) and/or inotropes/pressor (77%) during DEX infusion. Conclusion(s): Dexmedetomidine infusion was followed by a fall in heart rate across GA subgroups but the greatest reduction in mean, systolic and diastolic BP was noted in patients < 28 weeks GA. These data highlight the need for cautious use in preterm infants and prospective pharmacological studies to appraise hemodynamic impact. 
Baseline Clinical Characteristics
Indications and clinical characteristics surrounding use of DEXPercentages may not sum to 100 because of rounding