Articles: postoperative-pain.
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Randomized Controlled Trial Clinical Trial
Postoperative analgesia with fentanyl: pharmacokinetics and pharmacodynamics of constant-rate i.v. and transdermal delivery.
We have investigated the use of constant-rate delivery of fentanyl by i.v. and transdermal routes for the treatment of pain after major surgery. Forty-five males, ASA I-III, received in a double-blinded fashion either placebo (n = 6) or fentanyl (n = 39) i.v. at one of four dose rates (25, 50, 100 or 125 micrograms h-1). Stable serum concentrations of fentanyl were produced by the end of surgery and were maintained for a total of 24 h. ⋯ Post-operative morphine requirements were minimal (less than 0.5 mg h-1) and PaCO2 remained acceptable in all patients. Serum concentrations of fentanyl increased slowly (15 h to plateau) and decreased slowly (apparent half-life, 21 h). We conclude that delivery of analgesic doses of fentanyl is feasible by the transdermal route.
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Anesthesia and analgesia · Apr 1988
Fentanyl blood concentration-analgesic response relationship in the treatment of postoperative pain.
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. ⋯ 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)
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Twenty-four otherwise healthy patients scheduled for elective major abdominal surgery received general anaesthesia plus lumbar extradural analgesia. A loading dose of 0.5% plain bupivacaine was given to produce sensory analgesia (pin prick) from T4 to S5 and followed by a continuous infusion of 0.5% plain bupivacaine 8 ml h-1. Pain, scored on a 5-point scale, and sensory analgesia were assessed hourly for 16 h after skin incision. ⋯ Only three patients maintained their initial levels of sensory analgesia and a pain score of less than 2. In the remaining patients sensory analgesia decreased at least 5 segments or pain score reached 2 between 4 and 16 h after skin incision. We found a weak correlation between increasing age and the duration of sensory analgesia (r = 0.46, P less than 0.05), but no significant correlations between duration of sensory analgesia and sex, weight, height, body surface area, serum albumin concentration, duration or site of operation.