title: A pulsatile pressure waveform is a sensitive marker for confirming the location of the thoracic epidural space.
abstract: OBJECTIVE
  The purpose of this study was to assess the validity of using a pulsatile, pressure waveform transduced from the epidural space through an epidural needle or catheter to confirm correct placement for maximal analgesia and to compare 3 different types of catheters' ability to transduce a waveform.
  
  
  METHODS
  A single-center, prospective, randomized trial.
  
  
  METHODS
  A tertiary-referral hospital.
  
  
  METHODS
  Eighty-one patients undergoing posterolateral thoracotomy who required a thoracic epidural catheter for postoperative pain management.
  
  
  METHODS
  Each epidural needle and each epidural catheter was transduced to determine if there was a pulsatile waveform exhibited.
  
  
  RESULTS
  Sensitivity of the pulsatile waveform transduced through an epidural needle to identify correct placement of the epidural needle and the sensitivity of each catheter type to identify placement were compared. In 79 of 81 cases (97.5%), the waveform transduced directly through the epidural needle had a pulsatile characteristic as determined by blinded observers. In a total of 53 of 81 epidural catheters (65.4%), the transduced waveform displayed pulsations. Twenty-four of 27 catheters in group S-P/Sims Portex (Smiths Medical MD, Inc, St Paul, MN) (88.9%) transduced a pulsatile tracing from the epidural space, a significantly greater percentage than in the other 2 groups (p = 0.02).
  
  
  CONCLUSIONS
  The technique of transducing the pressure waveform from the epidural needle inserted in the epidural space is a sensitive and reliable alternative to other techniques for confirmation of correct epidural catheter placement. The technique is simple, sensitive, and inexpensive and uses equipment available in any operating room.
authors.affiliation: Department of Anesthesia, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada. pamela.lennox@vch.ca <pamela.lennox@vch.ca>
authors.forename: Pamela H
authors.initials: PH
authors.lastname: Lennox
authors.forename: Hamed S
authors.initials: HS
authors.lastname: Umedaly
authors.forename: Raymer P
authors.initials: RP
authors.lastname: Grant
authors.forename: S Adrian
authors.initials: SA
authors.lastname: White
authors.forename: Brett G
authors.initials: BG
authors.lastname: Fitzmaurice
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Evans
mesh_terms: D000368:Aged; D000767:Anesthesia, Epidural / Q000379:methods*; D002404:Catheterization; D004594:Electrophysiology / Q000379:methods; D004824:Epidural Space / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D011446:Prospective Studies; D011673:Pulsatile Flow / Q000502:physiology*; D013904:Thoracic Vertebrae; D013908:Thoracotomy