title: Buffered lidocaine as a local anesthetic: an investigation of shelf life.
abstract: OBJECTIVE
  To determine whether buffered lidocaine must be prepared just before use.
  
  
  METHODS
  Randomized, double-blind, prospective trial.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Twenty-four adult volunteers.
  
  
  METHODS
  Three buffered lidocaine solutions prepared seven days, one day, and just before use were compared with a control solution. Subjects received 0.5 mL intradermal injections of each solution. Pain of infiltration and extent and duration of anesthesia were measured.
  
  
  RESULTS
  Pain of infiltration was less with all buffered solutions than control (P less than .0001). Mean maximum diameter of anesthesia ranged from 29 to 33 mm for the buffered solutions compared with 31 mm for control. Mean duration of anesthesia was 33 minutes for control and 30 minutes for all of the buffered solutions. There was no statistically significant difference in extent or duration of anesthesia for any of the solutions (P greater than .5, beta = .15 for delta = 10%).
  
  
  CONCLUSIONS
  Buffered lidocaine stays effective for up to one week after preparation. It is therefore convenient to use in emergency settings.
authors.affiliation: Department of Emergency Medicine, Albany Medical College, New York.
authors.forename: J M
authors.initials: JM
authors.lastname: Bartfield
authors.forename: P J
authors.initials: PJ
authors.lastname: Homer
authors.forename: D T
authors.initials: DT
authors.lastname: Ford
authors.forename: P
authors.initials: P
authors.lastname: Sternklar
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D004355:Drug Stability; D004356:Drug Storage; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007271:Injections, Intradermal; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use; D010146:Pain / Q000209:etiology / Q000517:prevention & control; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D008012:Lidocaine