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Fentanyl blood concentration-analgesic response relationship in the treatment of postoperative pain.
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1988
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FentanylAcute PainPain MedicineSurgeryAnalgesiaIntrasubject VariabilityPain ManagementAnalgesicsAnesthetic PharmacologyHealth SciencesPostoperative Pain ManagementPostoperative PainPerioperative PainConcentration-analgesic Response RelationshipPreoperative PainPharmacologyAbdominal IncisionAnaesthetic AgentPain ResearchPatient SafetyPostoperative Pain ReliefAnesthesiaMedicineAnesthesiology
The study examined inter‑ and intra‑subject variability in the fentanyl blood concentration‑analgesic response relationship using patient‑controlled analgesia in 30 abdominal surgery patients. Patients received a standardized anesthetic regimen and postoperative fentanyl via a Janssen ODAC PCA device (20 µg/hr basal, 20 µg bolus, 5 min lockout), with frequent pre‑dose blood samples collected over an average 50‑hour period to estimate minimum effective concentrations. Results showed higher fentanyl requirements during the first 6 h (83.9 ± 30.1 µg/hr) compared to later periods, an average hourly dose of 55.8 ± 22 µg/hr, cumulative dose of 2739 ± 1191 µg, mean MEC of 0.63 ± 0.25 ng/ml, intrapatient MEC variability of 30.2 %, and stable MEC values over 48 h. Abstract truncated at 250 words.
The inter- and intrasubject variability in blood concentration-analgesic response relationship for fentanyl were investigated using the technique of patient-controlled analgesia (PCA) in 30 consenting patients scheduled for surgical procedures involving an abdominal incision (15 upper and 15 lower abdominal incisions). All patients had a thiopental, nitrous oxide/oxygen, pancuronium anesthetic with 200 microgram fentanyl intraoperatively. Postoperative pain relief was provided with fentanyl from a Janssen On-Demand Analgesic Computer (ODAC) set to provide a basal infusion rate of 20 microgram/hr, a bolus "demand" dose of 20 microgram, and a lockout period of 5 minutes. Frequent blood samples were collected immediately before patients demanded doses, and these were taken as an estimate of the minimum effective concentration (MEC). A mean of 22 samples (range 12 to 45) were collected per patient over a mean study duration of 50 hours (range 24 to 72). The patients required larger hourly fentanyl doses in the first 6-hour period (83.9 +/- 30.1 microgram/hr) than in any other 6-hour period (mean values varied from 37.3 to 63 microgram/hr). The mean (+/- SD) hourly fentanyl dose rate and total cumulative dose were 55.8 +/- 22 microgram/hr (range 28.8 to 136 microgram/hr) and 2739 +/- 1191 microgram (range 900 to 6260 microgram), respectively. The mean (+/- SD) MEC was 0.63 +/- 0.25 ng/ml (five-fold range from 0.23 to 1.18) and the mean intrapatient coefficient of variation in MEC was 30.2% (range 16 to 46%). The MEC values remained relatively constant in all patients over the 48-hour study period. (ABSTRACT TRUNCATED AT 250 WORDS)