title: The effects of epidural anesthesia on ventilatory response to hypoxia.
abstract: OBJECTIVE
  To evaluate the effects of epidural morphine on the ventilatory response to hypoxia in patients having abdominal surgery and to compare the effects of epidural lidocaine.
  
  
  METHODS
  Open-label, randomized study.
  
  
  METHODS
  Shimane Medical University Hospital, Shimane, Japan.
  
  
  METHODS
  Sixteen consenting, unpremedicated ASA physical status I and II patients undergoing abdominal surgery.
  
  
  METHODS
  Patients were administered 2 mg of morphine diluted in 10 ml of saline or 10 ml of 2% lidocaine from an epidural catheter that was inserted the day before surgery.
  
  
  RESULTS
  On the day before surgery, ventilatory parameters consisting of minute expiratory volume (VE), tidal volume (VT), respiratory frequency (f), and oxygen saturation by pulse oximeter (SpO2) were measured during resting state and hypoxic challenge. The same measurements were repeated 30 minutes after the epidural injection before surgery. The slope of VE/SpO2 decreased significantly from 1.6 +/- 0.3 to 1.2 +/- 0.2 after epidural morphine, although ventilatory values such as f, VT, VE, and PaCO2 were unchanged. Epidural lidocaine produced no significant changes in ventilatory response.
  
  
  CONCLUSIONS
  Epidural anesthesia with morphine, but not lidocaine, reduced the ventilatory response to hypoxia indicated by VE/SpO2.
authors.affiliation: Department of Anesthesiology, Shimane Medical University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Saito
authors.forename: S
authors.initials: S
authors.lastname: Sakura
authors.forename: M
authors.initials: M
authors.lastname: Kaneko
authors.forename: Y
authors.initials: Y
authors.lastname: Kosaka
mesh_terms: D000005:Abdomen / Q000601:surgery; D000767:Anesthesia, Epidural; D002245:Carbon Dioxide / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008012:Lidocaine / Q000494:pharmacology*; D008875:Middle Aged; D009020:Morphine / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood; D012123:Pulmonary Ventilation / Q000187:drug effects; D012119:Respiration / Q000187:drug effects*; D013990:Tidal Volume / Q000187:drug effects
chemical_list: D002245:Carbon Dioxide; D009020:Morphine; D008012:Lidocaine; D010100:Oxygen