title: The efficacy of perfusion index as an indicator for intravascular injection of epinephrine-containing epidural test dose in propofol-anesthetized adults.
abstract: BACKGROUND
  Perfusion index (PI) is a noninvasive numerical value of peripheral perfusion obtained from a pulse oximeter. In this study, we evaluated the efficacy of PI for detecting intravascular injection of a simulated epidural test dose containing 15 mug of epinephrine in adults during propofol-based anesthesia and compared its reliability with the conventional heart rate (HR) (positive if >or=10 bpm) and systolic blood pressure (SBP) (positive if >or=15 mm Hg) criteria.
  
  
  METHODS
  Forty patients scheduled for elective general surgery under total IV anesthesia were randomized to receive either 3 mL of lidocaine 15 mg/mL with epinephrine 5 microg/mL or 3 mL of saline IV (n = 20 each). HR, SBP, and PI were monitored for 5 min after injection.
  
  
  RESULTS
  Injecting the test dose resulted in an average maximum PI decrease by 65% +/- 13% at 39 +/- 15 s. Moreover, maximal increases in HR and SBP were 19 +/- 8 bpm at 49 +/- 25 s and 17 +/- 7 mm Hg at 102 +/- 34 s after test dose injections, respectively. Using the PI criterion for intravascular injection (positive if PI decreases >or=10% from the preinjection value) the sensitivity, specificity, positive predictive, and negative predictive values were 100% (95% confidence interval [CI]; CI = 83%-100%). On the contrary, sensitivities of 95% (CI = 76%-99%) and 90% (CI = 70%-97%) were obtained based on HR and SBP criteria, respectively.
  
  
  CONCLUSIONS
  PI is a reliable alternative to conventional hemodynamic criteria for detection of an intravascular injection of epidural test dose in propofol-anesthetized adult patients.
authors.affiliation: Department of Anesthesiology, King Fahd University Hospital, PO Box 40081, Al-Khobar 31952, Saudi Arabia. hany_mowafi@hotmail.com
authors.forename: Hany A
authors.initials: HA
authors.lastname: Mowafi
authors.forename: Salah A
authors.initials: SA
authors.lastname: Ismail
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Shafi
authors.forename: Abdulmohsin A
authors.initials: AA
authors.lastname: Al-Ghamdi
mesh_terms: D000328:Adult; D000767:Anesthesia, Epidural; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D001794:Blood Pressure / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000009:adverse effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D010092:Oximetry; D010477:Perfusion / Q000706:statistics & numerical data*; D010991:Plethysmography; D011237:Predictive Value of Tests; D015742:Propofol; D017409:Sufentanil; D014662:Vasoconstrictor Agents / Q000009:adverse effects; D055815:Young Adult
chemical_list: D018686:Anesthetics, Intravenous; D014662:Vasoconstrictor Agents; D017409:Sufentanil; D015742:Propofol; D004837:Epinephrine