title: Anticholinergic premedication to prevent bradycardia in combined spinal anesthesia and dexmedetomidine sedation: a randomized, double-blind, placebo-controlled study.
abstract: OBJECTIVE
  When dexmedetomidine is used in patients undergoing spinal anesthesia, high incidence of bradycardia in response to parasympathetic activation is reported. Therefore, we aimed to evaluate the effectiveness of atropine premedication for preventing the incidence of bradycardia and the hemodynamic effect on patients undergoing spinal anesthesia with sedation by dexmedetomidine.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled study.
  
  
  METHODS
  Operating room.
  
  
  METHODS
  One hundred fourteen patients (age range, 2-65 years; American Society of Anesthesiology class I-II) participated in this study, willing to be sedated and to undergo spinal anesthesia.
  
  
  METHODS
  The patients were divided into 2 groups: group A and group C. After performing spinal anesthesia, dexmedetomidine was infused at a loading dose of 0.6 μg/kg for 10 minutes, followed by an infusion at 0.25 μg/(kg h). Simultaneously with the loading dose of dexmedetomidine, patients in group A received an intravenous bolus of 0.5 mg atropine, whereas patients in group C received an intravenous normal saline bolus.
  
  
  METHODS
  Data on administration of atropine and ephedrine were collected. Hemodynamic data including heart rate, systolic blood pressure, diastolic blood pressure (DBP), and mean blood pressure (MBP) were also recorded.
  
  
  RESULTS
  The incidence of bradycardia requiring atropine treatment was significantly higher in group C than group A (P=.035). However, the incidence of hypotension needing ephedrine treatment showed no significant difference between the 2 groups (P=.7). Systolic blood pressure and heart rate showed no significant differences between the 2 groups (P=.138 and .464, respectively). However, group A showed significant increases in DBP and MBP, and group C did not (P=.014 and .008, respectively).
  
  
  CONCLUSIONS
  Prophylactic atropine reduces the incidence of bradycardia in patients undergoing spinal anesthesia with dexmedetomidine sedation. However, DBP and MBP showed significant increases in patients when prophylactic atropine was administrated. Therefore, atropine premedication should be administered cautiously.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea.
authors.forename: Eun Jin
authors.initials: EJ
authors.lastname: Ahn
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea.
authors.forename: Jun Ha
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea.
authors.forename: Hyo Jin
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea.
authors.forename: Kyung Woo
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea.
authors.forename: Hey Ran
authors.initials: HR
authors.lastname: Choi
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul Paik Hospital of Inje University, Seoul, Republic of Korea. Electronic address: sira1045@naver.com.
authors.forename: Si Ra
authors.initials: SR
authors.lastname: Bang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000775:Anesthesia, Spinal / Q000009:adverse effects* / Q000379:methods; D001285:Atropine / Q000008:administration & dosage / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D002648:Child; D002675:Child, Preschool; D018680:Cholinergic Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000009:adverse effects*; D004311:Double-Blind Method; D004809:Ephedrine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000009:adverse effects*; D007022:Hypotension / Q000139:chemically induced; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010277:Parasympathomimetics / Q000008:administration & dosage / Q000009:adverse effects*; D011292:Premedication / Q000379:methods*; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D018680:Cholinergic Antagonists; D006993:Hypnotics and Sedatives; D018727:Muscarinic Antagonists; D010277:Parasympathomimetics; D020927:Dexmedetomidine; D001285:Atropine; D004809:Ephedrine
keywords: Bradycardia; Dexmedetomidine; Spinal anesthesia