title: Respiratory acidosis prolongs, while alkalosis shortens, the duration and recovery time of vecuronium in humans.
abstract: OBJECTIVE
  To determine the effects of respiratory acidosis and alkalosis by mechanical ventilation on the onset, duration, and recovery times of vecuronium.
  
  
  METHODS
  Randomized, prospective study.
  
  
  METHODS
  Operating rooms in the Sapporo Medical University Hospital and Kitami Red Cross Hospital.
  
  
  METHODS
  90 ASA physical status I and II patients undergoing lower abdominal surgery.
  
  
  METHODS
  Patients were randomly allocated to one of three groups by arterial carbon dioxide tension level (PaCO2; mmHg) after induction: hyperventilation group (PaCO2 = 25-35), normoventilation group (PaCO2 = 35-45), and hypoventilation group (PaCO2 = 45-55). Anesthesia was maintained by spinal block with inhalation of 50% to 66% nitrous oxide in oxygen and intermittent intravenous administration of fentanyl and midazolam with tracheal intubation.
  
  
  RESULTS
  After vecuronium 0.08 mg/kg was given, onset, duration, and recovery time were measured by mechanomyography (Biometer Myograph 2,000, Odense, Denmark). There were significant differences in the duration and recovery time of vecuronium among the normoventilation group (12.7 +/- 3.3 min and 11.8 +/- 2.8 min, respectively), the hyperventilation group (10.6 +/- 3.5 min and 9.2 +/- 2.7 min, respectively; p < 0.01), and the hypoventilation group (14.4 +/- 3.1 min and 15.0 +/- 3.7 min, respectively; p < 0.01) (mean SD). The closest significant correlation in this study was observed between recovery time and arterial blood pH (r = 0.57; p < 0.05).
  
  
  CONCLUSIONS
  In humans, duration and recovery times of vecuronium are prolonged in respiratory acidosis and shortened in respiratory alkalosis.
authors.affiliation: Department of Anesthesiology, Kitami Red Cross Hospital, Japan. yamauchi@sapmed.ac.jp
authors.forename: Masanori
authors.initials: M
authors.lastname: Yamauchi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwasaki
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Namiki
mesh_terms: D000005:Abdomen / Q000601:surgery; D000142:Acidosis, Respiratory; D000472:Alkalosis, Respiratory; D001639:Bicarbonates / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006985:Hyperventilation; D007040:Hypoventilation; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000379:methods*; D013997:Time Factors; D014673:Vecuronium Bromide
chemical_list: D001639:Bicarbonates; D003473:Neuromuscular Nondepolarizing Agents; D002245:Carbon Dioxide; D014673:Vecuronium Bromide