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Fentanyl with ropivacaine infusion for postoperative pain relief in infants and children. Kinetics of epidural fentanyl
Author(s) -
KarasTrzeciak Magdalena,
Grabowski Tomasz,
WoloszczukGebicka Bogumila,
Borucka Beata
Publication year - 2015
Publication title -
pediatric anesthesia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.704
H-Index - 82
eISSN - 1460-9592
pISSN - 1155-5645
DOI - 10.1111/pan.12648
Subject(s) - medicine , fentanyl , ropivacaine , anesthesia , bolus (digestion) , pharmacokinetics , analgesic , epidural space , dosing , surgery
Summary Objectives 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 ( t 1/2, 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 ( t 1/2 MRT 15.9 [3.6–31.5] h vs 8.0 [7.1–13.3] h, P < 0.05, MRT stop‐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.