title: Fentanyl with ropivacaine infusion for postoperative pain relief in infants and children. Kinetics of epidural fentanyl.
abstract: OBJECTIVE
  The aim of the study was to evaluate pharmacokinetics of fentanyl administered as continuous epidural infusion with 0.2% ropivacaine for postoperative pain relief in infants and toddlers, and older children undergoing major abdominal and urological procedures.
  
  
  METHODS
  Thirteen infants and toddlers (median age 14 [range 3-36] months, 11 [5-17] kg, Group I) and 11 children (68 [45-131] months, 21 [16-52] kg, Group II) participated in the study. Epidural catheter was placed under general anesthesia in the L1-L2, L2-L3, or L3-L4 epidural space and threaded up to 4 cm into the epidural space. Bolus dose of 0.2% ropivacaine, 0.5 ml·kg(-1) and fentanyl, 2 μg·kg(-1) was given, then followed by continuous infusion of 0.2% ropivacaine, 0.15 ml·kg(-1) ·h(-1) with fentanyl 1.12 μg·kg(-1) ·h(-1) . In the postoperative period, fentanyl dose was reduced to 0.375 μg·kg(-1) ·h(-1) .
  
  
  RESULTS
  With this dosing regimen, fentanyl concentration in plasma was within the range of analgesic concentrations, and did not exceed 1.0 ng·ml(-1) . After discontinuation of epidural infusion, pharmacokinetics of fentanyl was complicated by a slight increase in plasma concentration during the elimination phase. Both elimination half-life of fentanyl (t1/2, MRT ) and mean residence time (MRT) were much longer than those observed after single IV bolus dose, and longer in Group I than in Group II (t1/2 MRT 15.9 [3.6-31.5] h vs 8.0 [7.1-13.3] h, P < 0.05, MRTstop-last 22.9 [5.1-45.5] h vs 11.5 [10.2-19.1] h, P < 0.05). Therefore, monitoring of vital signs seems warranted for several hours after the termination of the epidural infusion because risk of respiratory depression may persist, especially in the younger age group.
authors.affiliation: Department of Pediatric Anesthesiology and Intensive Care, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Karas-Trzeciak
authors.affiliation: Polpharma Biologics, Gdansk, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Grabowski
authors.affiliation: Medical Faculty, University of Rzeszow, Rzeszow, Poland.
authors.forename: Bogumila
authors.initials: B
authors.lastname: Woloszczuk-Gebicka
authors.affiliation: The Filab Pharmacokinetic Research Center, Lajski, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Borucka
mesh_terms: D000367:Age Factors; D000577:Amides / Q000008:administration & dosage / Q000627:therapeutic use*; D015360:Analgesia, Epidural / Q000379:methods*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D004359:Drug Therapy, Combination; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D007223:Infant; D008297:Male; D010149:Postoperative Pain / Q000188:drug therapy*; D000077212:Ropivacaine; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D000077212:Ropivacaine; D005283:Fentanyl
keywords: anesthesia; anesthetics; child; epidural; infant; local; pharmacokinetics: fentanyl