title: Effects of EDTA- and sulfite-containing formulations of propofol on respiratory system resistance after tracheal intubation in smokers.
abstract: BACKGROUND
  The formulation of sulfite-containing propofol (SCP) has not been thoroughly investigated in patients with the extensive smoking history for the effects on the total respiratory system resistance after tracheal intubation. However adverse effects, including acute asthma and bronchospasm, have been reported with several other parenteral formulations of drugs containing sulfite as preservative. Therefore, the aim of this prospective randomized and double blind study was to investigate the effects of EDTA-containing propofol (ECP) and SCP on total respiratory system resistance (Rrs) in patients with the prolonged smoking history and undergoing propofol-based total intravenous anesthesia with tracheal intubation.
  
  
  METHODS
  40 patients scheduled for general anesthesia were enrolled into the study. Anesthesia was induced with either 2 mg/kg ECP, or 2 mg/kg SCP followed by vecuronium (0.1 mg/kg) to ensure complete neuromuscular relaxation for the time of the study. Maintenance anesthesia was continued with propofol infusion at 0.15 mg/kg/min for the first 15 min after intubation. Total respiratory system resistance (Rrs), was measured continuously for 10 min postintubation.
  
  
  RESULTS
  The analysis of repeated Rrs measurements taken every minute for 10 min postintubation revealed trend consisting of higher Rrs in the SCP group when compared to the ECP group. The statistical analysis of the data performed using repeated measures analysis of covariance demonstrated statistically significant effect (P < 0.05) of the treatment group factor (SCP vs. ECP) and the time factor (time after intubation) on the postintubation Rrs.
  
  
  CONCLUSIONS
  The total respiratory system resistance measured repeatedly for 10 min after tracheal intubation in patients with smoking history is significantly elevated after induction with SCP than after induction with ECP. The preservative used for propofol formulation may alter the effects of propofol on the total respiratory system resistance in smokers.
authors.affiliation: Department of Anesthesiology, Division of Biostatistics, Nashville, TN 37232, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Rieschke
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: LaFleur
authors.forename: Piotr K
authors.initials: PK
authors.lastname: Janicki
mesh_terms: D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D000465:Algorithms; D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D002614:Chelating Agents / Q000494:pharmacology*; D004311:Double-Blind Method; D004492:Edetic Acid / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D015742:Propofol; D012129:Respiratory Function Tests; D012907:Smoking / Q000503:physiopathology*; D013447:Sulfites / Q000494:pharmacology*
chemical_list: D018686:Anesthetics, Intravenous; D002614:Chelating Agents; D013447:Sulfites; D004492:Edetic Acid; D015742:Propofol