title: The effect of thoracic epidural analgesia on the occurrence of late postoperative hypoxemia in patients undergoing elective coronary bypass surgery: a randomized controlled trial.
abstract: OBJECTIVE
  To evaluate the effect of perioperative thoracic epidural analgesia followed by postoperative epidural analgesia compared with conventional IV anesthesia on the occurrence of late postoperative hypoxemia in patients undergoing elective coronary bypass graft (CABG) surgery.
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  Cardiac surgery unit at a university hospital.
  
  
  METHODS
  A total of 50 patients undergoing elective CABG surgery.
  
  
  METHODS
  Patients were randomly assigned to receive either conventional IV anesthesia (CON) or general anesthesia combined with thoracic epidural anesthesia followed by postoperative epidural analgesia (TEA) with bupivacaine. Postoperatively, the patients were monitored in the surgical ward with a pulse oximeter for a total of two postoperative nights (the second and third postoperative nights).
  
  
  RESULTS
  The overall incidence of episodic hypoxemia was 56% (28 of 50 patients) on the second postoperative night and 89% (41 of 46 patients) on the third postoperative night. More than 30 episodes of hypoxemia developed on the second night in 22% of patients (11 of 50 patients), and on the third night in 30% of patients (14 of 46 patients). Despite oxygen therapy, 7% of patients (3 of 46 patients) experienced constant hypoxemia on the third night. In general, hypoxemia seemed to be slightly worse on the third postoperative night compared with the second postoperative night. Significantly more patients in the TEA group (25 of 25 patients) experienced episodic hypoxemia on the third postoperative night compared with the CON group (16 of 21 patients; p < 0.05). Otherwise, there were no significant differences between the two regimens.
  
  
  CONCLUSIONS
  Both episodic and constant hypoxemia were common in the late postoperative period in patients on the ward after CABG surgery with no clinically significant intergroup differences. Thus, perioperative epidural anesthesia/analgesia combined with postoperative epidural anesthesia/analgesia was not protective against hypoxemia, and therapy with opioids did not seem to be of importance for the occurrence of late postoperative hypoxemia on nights 2 and 3 after CABG surgery.
authors.affiliation: Department of Thoracic Anesthesiology, The Heart Centre, Rigshospitalet, Copenhagen University, Denmark. lars.hyldborg@dadlnet.dk
authors.forename: Lars Hyldborg
authors.initials: LH
authors.lastname: Lundstrøm
authors.forename: Eigil
authors.initials: E
authors.lastname: Nygård
authors.forename: Lamia Bada
authors.initials: LB
authors.lastname: Hviid
authors.forename: Finn Møller
authors.initials: FM
authors.lastname: Pedersen
authors.forename: Jesper
authors.initials: J
authors.lastname: Ravn
authors.forename: Jan
authors.initials: J
authors.lastname: Aldershvile
authors.forename: Jacob
authors.initials: J
authors.lastname: Rosenberg
mesh_terms: D000368:Aged; D015360:Analgesia, Epidural / Q000009:adverse effects*; D000701:Analgesics, Opioid / Q000009:adverse effects; D000779:Anesthetics, Local / Q000009:adverse effects; D002045:Bupivacaine / Q000009:adverse effects; D001026:Coronary Artery Bypass; D006801:Humans; D000860:Hypoxia / Q000139:chemically induced*; D008875:Middle Aged; D009020:Morphine / Q000009:adverse effects; D013904:Thoracic Vertebrae; D013997:Time Factors
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine