title: Is a fall in baseline heart rate a reliable predictor of a successful single shot caudal epidural in children?
abstract: BACKGROUND
  This study was designed to investigate whether a fall in heart rate (HR) with injection of local anesthetic into the caudal space can be used as a predictor of correct needle placement.
  
  
  METHODS
  Two hundred and twenty pediatric patients undergoing infraumbilical surgery were recruited to the study. After induction of general anesthesia, baseline HR was recorded and caudal block was performed using 0.75-1 ml x kg(-1) 0.25% bupivacaine, which was injected at a rate of 1 ml x 3 s(-1). The change in HR while injecting an initial 0.2 ml x kg(-1) of drug and during total drug injection was recorded. HR reduction of > or = 3 b x min(-1) was considered a positive test for correct needle placement. The success of block was judged by HR response to skin incision, endtidal halothane concentration required for maintenance of anesthesia and postoperative pain scores.
  
  
  RESULTS
  Caudal block was successful in 209/220 (95%) patients. Mean HR following the initial drug injection (111 +/- 17.7, P < 0.01) and entire drug injection (108.8 +/- 17.2, P < 0.01) was significantly lower than baseline (116.2 +/- 17.5). HR reduction of > or = 3 b x min(-1) was present in 190/209 and 199/209 successful block following initial drug injection and total drug injection respectively. The analysis of study data showed that a fall in HR is a predictor of successful caudal block, with a sensitivity of 90.9%, specificity of 100% and a positive predictive value of 100% after initial injection of local anesthetic.
  
  
  CONCLUSIONS
  We conclude that decrease in HR with drug injection is a simple, objective and reliable test to predict success of caudal block.
authors.affiliation: Department of Anaesthesia and Intensive Care, Post Graduate Institute of Medical Education and Research, Chandigarh, India. ghaibabita@hotmail.com
authors.forename: Babita
authors.initials: B
authors.lastname: Ghai
authors.forename: Jeetinder Kaur
authors.initials: JK
authors.lastname: Makkar
authors.forename: Bikram Kishore
authors.initials: BK
authors.lastname: Behra
authors.forename: Krishna Prasad
authors.initials: KP
authors.lastname: Rao
mesh_terms: D000763:Anesthesia, Caudal / Q000379:methods*; D000768:Anesthesia, General / Q000379:methods; D000772:Anesthesia, Local / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007223:Infant; D008297:Male; D010149:Postoperative Pain / Q000188:drug therapy; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D000779:Anesthetics, Local