title: Airway anesthesia alone does not explain attenuation of histamine-induced bronchospasm by local anesthetics: a comparison of lidocaine, ropivacaine, and dyclonine.
abstract: BACKGROUND
  Lidocaine inhalation attenuates histamine-induced bronchospasm while evoking airway anesthesia. Because this occurs at plasma concentrations much lower than those required for intravenous lidocaine to attenuate bronchial reactivity, this effect is likely related to topical airway anesthesia and presumably independent of the specific local anesthetic used. Therefore, the authors tested the effect of dyclonine, lidocaine, and ropivacaine inhalation on histamine-induced bronchospasm in 15 volunteers with bronchial hyperreactivity.
  
  
  METHODS
  Bronchial hyperreactivity was verified by an inhalational histamine challenge. Histamine challenge was repeated after inhalation of dyclonine, lidocaine, ropivacaine, or placebo on 4 different days in a randomized, double-blind fashion. Lung function, bronchial hyperreactivity to histamine, duration of local anesthesia, and lidocaine and ropivacaine plasma concentrations were measured. Statistical analyses were performed with the Friedman and Wilcoxon rank tests. Data are presented as mean +/- SD.
  
  
  RESULTS
  The inhaled histamine concentration necessary for a 20% decrease of forced expiratory volume in 1 s (PC20) was 7.0 +/- 5.0 mg/ml at the screening evaluation. Lidocaine and ropivacaine inhalation increased PC20 significantly to 16.1 +/- 12.9 and 16.5 +/- 13.6 mg/ml (P = 0.007), whereas inhalation of dyclonine and saline did not (9.1 +/- 8.4 and 6.1 +/- 5.0 mg/ml, P = 0.7268). Furthermore, in contrast to saline and lidocaine, inhalation of both ropivacaine and dyclonine significantly decreased forced expiratory volume in 1 s from baseline (P = 0.0016 and 0.0018, respectively). The longest lasting and most intense anesthesia developed after dyclonine inhalation (48 +/- 13 vs. 28 +/- 8 [lidocaine] and 25 +/- 4 min [ropivacaine]).
  
  
  CONCLUSIONS
  Both lidocaine and the new amide local anesthetic ropivacaine significantly attenuate histamine-induced bronchospasm. In contrast, dyclonine, despite its longer lasting and more intense local anesthesia, does not alter histamine-evoked bronchoconstriction and irritates the airways. Thus, airway anesthesia alone does not necessarily attenuate bronchial hyperreactivity. Other properties of inhaled local anesthetics may be responsible for attenuation of bronchial hyperreactivity.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Universität Essen, Germany. harald.groeben@uni-essen.de
authors.forename: H
authors.initials: H
authors.lastname: Groeben
authors.forename: T
authors.initials: T
authors.lastname: Grosswendt
authors.forename: M T
authors.initials: MT
authors.lastname: Silvanus
authors.forename: G
authors.initials: G
authors.lastname: Pavlakovic
authors.forename: J
authors.initials: J
authors.lastname: Peters
mesh_terms: D000328:Adult; D000336:Aerosols; D000577:Amides / Q000097:blood / Q000627:therapeutic use*; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000627:therapeutic use*; D001986:Bronchial Spasm / Q000139:chemically induced / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006632:Histamine / Q000009:adverse effects; D006801:Humans; D008012:Lidocaine / Q000097:blood / Q000627:therapeutic use*; D008297:Male; D011427:Propiophenones / Q000627:therapeutic use*; D000077212:Ropivacaine
chemical_list: D000336:Aerosols; D000577:Amides; D000779:Anesthetics, Local; D011427:Propiophenones; C100063:dyclonine; D000077212:Ropivacaine; D006632:Histamine; D008012:Lidocaine