An open label pilot study of a dexmedetomidine‐remifentanil‐caudal anesthetic for infant lower abdominal/lower extremity surgery: The T REX pilot study

• Published in: Pediatric anesthesia Vol. 29; no. 1; pp. 59 - 67
• Main Authors: Szmuk, Peter, Andropoulos, Dean, McGowan, Francis, Brambrink, Ansgar, Lee, Christopher, Lee, Katherine J., McCann, Mary Ellen, Liu, Yang, Saynhalath, Rita, Bong, Choon Looi, Anderson, Brian J., Berde, Charles, De Graaff, Jurgen C., Disma, Nicola, Kurth, Dean, Loepke, Andreas, Orser, Beverley, Sessler, Daniel I., Skowno, Justin J., von Ungern‐Sternberg, Britta S., Vutskits, Laszlo, Davidson, Andrew, Thomas, Mark
• Format: Journal Article
• Language: English
• Published: France Wiley Subscription Services, Inc 01-01-2019
• Subjects: Anesthesia; anesthesia caudal adverse effects; anesthesia general adverse effects; anesthesia general methods; brain/drug effects; dexmedetomidine; Neurotoxicity; remifentanil; Surgery; anesthesia general adverse effects; dexmedetomidine; anesthesia general methods; remifentanil; brain/drug effects; anesthesia caudal adverse effects
• ISSN: 1155-5645; 1460-9592
• DOI: 10.1111/pan.13544

Summary
Background
Concern over potential neurotoxicity of anesthetics has led to growing interest in prospective clinical trials using potentially less toxic anesthetic regimens, especially for prolonged anesthesia in infants. Preclinical studies suggest that dexmedetomidine may have a reduced neurotoxic profile compared to other conventional anesthetic regimens; however, coadministration with either anesthetic drugs (eg, remifentanil) and/or regional blockade is required to achieve adequate anesthesia for surgery. The feasibility of this pharmacological approach is unknown. The aim of this study was to determine the feasibility of a remifentanil/dexmedetomidine/neuraxial block technique in infants scheduled for surgery lasting longer than 2 hours.
Methods
Sixty infants (age 1‐12 months) were enrolled at seven centers over 18 months. A caudal local anesthetic block was placed after induction of anesthesia with sevoflurane. Next, an infusion of dexmedetomidine and remifentanil commenced, and the sevoflurane was discontinued. Three different protocols with escalating doses of dexmedetomidine and remifentanil were used.
Results
One infant was excluded due to a protocol violation and consent was withdrawn prior to anesthesia in another. The caudal block was unsuccessful in two infants. Of the 56 infants who completed the protocol, 45 (80%) had at least one episode of hypertension (mean arterial pressure >80 mm Hg) and/or movement that required adjusting the anesthesia regimen. In the majority of these cases, the remifentanil and/or dexmedetomidine doses were increased although six infants required rescue 0.3% sevoflurane and one required a propofol bolus. Ten infants had at least one episode of mild hypotension (mean arterial pressure 40‐50 mm Hg) and four had at least one episode of moderate hypotension (mean arterial pressure <40 mm Hg).
Conclusion
A dexmedetomidine/remifentanil neuraxial anesthetic regimen was effective in 87.5% of infants. These findings can be used as a foundation for designing larger trials that assess alternative anesthetic regimens for anesthetic neurotoxicity in infants.