title: Heart rate response to a caudal block in children anesthetized with sevoflurane after ultrasound confirmation of placement.
abstract: BACKGROUND
  Previous studies identified decreasing heart rate (HR) as a predictor of successful caudal placement in children using halothane and isoflurane. No changes were found in HR in the one study using sevoflurane. We documented HR changes in children following a caudal block during sevoflurane anesthesia utilizing ultrasound to confirm successful caudal placement.
  
  
  METHODS
  Seventy-one children (1-82 months) were anesthetized with sevoflurane. A caudal block was placed with confirmation by ultrasound. Four aliquots of bupivacaine 0.2% with epinephrine 5 μg · cc(-1) were administered for a total volume of 1 cc · kg(-1) with HR recorded for 4 min. The outcomes measured were HR changes from the initial baseline and during each 1-min interval. The age-related differences in HR were also analyzed.
  
  
  RESULTS
  Heart rate change from the initial baseline after placing the caudal needle and allowing for equilibration ranged from -10.2% to +8.9% and the HR change from the baseline at the start of each aliquot injection ranged from -9.5% to +8.9%. Most participants (n = 60, 84.5%) experienced at least one HR reduction over the observation period. For patients < 36 months, the HR change ranged from -11 to +12 b · min(-1) (mean -0.3); for patients aged ≥ 36 months, the HR change ranged from -10 to +6 b · min(-1) (mean -1.1).
  
  
  CONCLUSIONS
  Heart rate changes following a caudal block in children ≤ 82 months of age anesthetized with sevoflurane is not a reliable indicator of a successful block. Despite 100% caudal success, many children had no decrease in HR, and in those that did, the decline was of a magnitude indeterminate from beat-to-beat variability.
authors.affiliation: Department of Anesthesiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Adler
authors.affiliation: Department of Anesthesiology, Baystate Medical Center, Springfield, MA, USA.
authors.forename: Donald A
authors.initials: DA
authors.lastname: Schwartz
authors.affiliation: Department of Anesthesiology, Baystate Medical Center, Springfield, MA, USA.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Begley
authors.affiliation: Department of Medicine, Baystate Medical Center, Springfield, MA, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Friderici
authors.affiliation: Department of Anesthesiology, Baystate Medical Center, Springfield, MA, USA.
authors.forename: Neil Roy
authors.initials: NR
authors.lastname: Connelly
mesh_terms: D000763:Anesthesia, Caudal / Q000379:methods*; D000769:Anesthesia, Inhalation / Q000379:methods*; D018685:Anesthetics, Inhalation; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007223:Infant; D008297:Male; D008738:Methyl Ethers; D011446:Prospective Studies; D000077149:Sevoflurane; D018084:Ultrasonography, Interventional
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane
keywords: determination of success; pediatric anesthesiology; regional anesthetic