title: The use of moderate sedation for the secondary prevention of adverse vasovagal reactions.
abstract: BACKGROUND
  Vasovagal reactions can occur with spine procedures and may result in premature procedure termination or other adverse events.
  
  
  OBJECTIVE
  To evaluate if moderate sedation is an effective means of secondary prevention for vasovagal reactions.
  
  
  METHODS
  Prospectively collected data on 6,364 consecutive spine injections.
  
  
  RESULTS
  Of the 6,364 spine injections, 6,150 spine injections were done without moderate sedation and resulted in 205 vasovagal reactions (3.3% [95% confidence interval {CI} 2.9-3.8%]). One hundred thirty-four spine procedures were performed on patients that had a history of prior vasovagal reaction during a spine procedure. Of these, 90 procedures were performed without moderate sedation, and 21/90 (23.3% [95% CI 15.2-32.1%]) were complicated by a repeat vasovagal reaction. None of 44 repeat injections that utilized moderate sedation experienced a repeat vasovagal reaction (0% [95% CI 0-9.6%]) (χ(2)  = 12.17, P < 0.00048). The rate of vasovagal reaction in patients with a history of prior reaction undergoing repeat injection without conscious sedation was significantly higher (23.3% [95% CI 15.2-32.1%]) than the rate in patients with no such history (3.0% [95% CI 2.6-3.5%] [χ(2)  = 113.4, P < 1.78E-26]).
  
  
  CONCLUSIONS
  A history of vasovagal reaction is a strong predictor of experiencing a vasovagal reaction on subsequent procedures. No vasovagal reactions occurred with the use of moderate sedation, including in the 44 injections in patients that had a history of vasovagal reaction during spine procedures. The overall low rate of vasovagal reactions is low, and greater benefits of moderate sedation were observed when utilized as secondary prevention of repeat vasovagal reactions.
authors.affiliation: Department of Orthopaedics, Stanford University, Redwood City, California, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Kennedy
authors.forename: Byron
authors.initials: B
authors.lastname: Schneider
authors.forename: Matthew
authors.initials: M
authors.lastname: Smuck
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Plastaras
mesh_terms: D016292:Procedural Sedation / Q000379:methods; D005283:Fentanyl / Q000627:therapeutic use; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D007278:Injections, Spinal / Q000009:adverse effects*; D017116:Low Back Pain / Q000628:therapy; D008874:Midazolam / Q000627:therapeutic use; D012189:Retrospective Studies; D055502:Secondary Prevention / Q000379:methods*; D019462:Syncope, Vasovagal / Q000209:etiology / Q000517:prevention & control*
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam; D005283:Fentanyl
keywords: Block; Epidural (Injection Space); Facet Joint; Fluoroscopy; Safety; Sedation; Spine