Ethan Jackson

The effects of dexmedetomidine on cardiac electrophysiology in children.

BACKGROUND:Dexmedetomidine (DEX) is an &agr;2-adrenergic agonist that is approved by the Food and Drug Administration for short-term (<24 h) sedation in adults. It is not approved for use in children. Nevertheless, the use of DEX for sedation and anesthesia in infants and children appears to be increasing. There are some concerns regarding the hemodynamic effects of the drug, including bradycardia, hypertension, and hypotension. No data regarding the effects of DEX on the cardiac conduction system are available. We therefore aimed to characterize the effects of DEX on cardiac conduction in pediatric patients. METHODS:Twelve children between the ages of 5 and 17 yr undergoing electrophysiology study and ablation of supraventricular accessory pathways had hemodynamic and cardiac electrophysiologic variables measured before and during administration of DEX (1 &mgr;g/kg IV over 10 min followed by a 10-min continuous infusion of 0.7 &mgr;g · kg−1 · h−1). RESULTS:Heart rate decreased while arterial blood pressure increased significantly after DEX administration. Sinus node function was significantly affected, as evidenced by an increase in sinus cycle length and sinus node recovery time. Atrioventricular nodal function was also depressed, as evidenced by Wenckeback cycle length prolongation and prolongation of PR interval. CONCLUSION:DEX significantly depressed sinus and atrioventricular nodal function in pediatric patients. Heart rate decreased and arterial blood pressure increased during administration of DEX. The use of DEX may not be desirable during electrophysiology study and may be associated with adverse effects in patients at risk for bradycardia or atrioventricular nodal block.

Reproductive and teratogenic effects of sufentanil and alfentanil in Sprague-Dawley rats.

The reproductive and teratogenic effects of sufentanil and alfentanil were studied in a total of 168 Sprague-Dawley rats in two separate experiments. Either sufentanil (10, 50, or 100 micrograms.kg-1.day-1) or alfentanil (8 mg.kg-1.day-1) were administered continuously from day 5 through day 20 of pregnancy using subcutaneously implanted osmotic minipumps. Cesarean sections were performed on day 20 of pregnancy, reproductive indexes were determined, and the 1484 fetuses were examined for external, visceral, and skeletal abnormalities. No significant adverse reproductive or teratogenic effects were observed with either narcotic.

A method of rapid robust respiratory synchronization for MRI.

Respiratory motion degrades MRI exams. Adequate detection of respiratory motion with pneumatic respiratory belts in small children is challenging and time-consuming.

Pulmonary hypertensive crisis following ethanol sclerotherapy for a complex vascular malformation

Anhydrous ethanol is a commonly used sclerotic agent for treating vascular malformations. We describe the case of a full-term 15-day-old female with a complex venolymphatic malformation involving the face and orbit. During treatment of the lesion with ethanol sclerotherapy, she suffered acute pulmonary hypertensive crisis. We discuss the pathophysiology of pulmonary hypertension related to ethanol sclerotherapy, and propose that hemolysis plays a significant role. Recommendations for evaluation, monitoring and management of this complication are also discussed.

Reproductive and Teratogenic Effects of Sufentanil and Alfentanil in Sprague-Dawley Rats

The reproductive and teratogenic effects of sufentanil and alfentanil were studied in a total of 168 Sprague-Dawley rats in two separate experiments. Either sufentanil (10, 50, or 100 μg·kg−1·day−1) or alfentanil (8 mg·kg−1 ·day−1) were administered continuously from day 5 through day 20 of pregnancy using subcutaneously implanted osmotic minipumps. Cesarcan sections were performed on day20 of pregnancy, reproductive indexes were determined, and the 1484 fetuses were examined for external, visceral, and skeletal abnormalities. No significant adverse reproductive or teratogenic effects were observed witheither narcotic.