Articles: analgesia.
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Regional anesthesia · Sep 1991
Randomized Controlled Trial Clinical TrialEpidural butorphanol augments lidocaine sensory anesthesia during labor.
To determine the efficacy and safety of epidural butorphanol combined with lidocaine, 50 healthy parturients were studied during labor and delivery. All patients received a test dose of 3 ml 1.5% lidocaine with 1:200,000 epinephrine. Patients were then randomly assigned to receive 7 ml of one of two epidural regimens in a double-blind fashion: Group 1 patients received 1.5% lidocaine plus 1 mg butorphanol plus 1:300,000 epinephrine; Group 2 patients received 1.5% lidocaine plus 1:300,000 epinephrine. ⋯ There were no difference between groups in duration of first and second stages of labor, method of delivery or neonatal outcome. Umbilical cord acid-base status and neurologic adaptive capacity scores did not differ significantly between the two groups. The authors conclude that adding small doses of butorphanol to epidural lidocaine during labor is effective and safe.
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A series of studies with humans as well as experiments carried out on animals have shown that physical exercise leads to temporary hypoalgesia. Reduced sensitivity to pain is not only demonstrable after long-distance exercise (such as a marathon run) but also during and after intensive physical exercise on a laboratory ergometer. In a double blind study (20 mg naloxone versus placebo) experimental pain thresholds (electrical intracutaneous finger and dental pulp stimulation) and plasma hormone levels (beta-endorphin, cortisol, and catecholamines) were measured in ten healthy athletic men before, during, and after physical exercise on a cycle ergometer. ⋯ Central pain inhibitory systems are probably thereby activated by the stimulation of afferent nerves endings (group III and IV) in the skeletal muscle. The same trigger mechanism also plays a role as a release stimulus for hormones which are secreted in increased measure during physical exercise (catecholamines, pituitary hormones). Plasma beta-endorphin is probably not directly involved in the exercise-induced hypoalgesia but is rather a "marker" for the activating of central analgesia mechanisms.
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Experiments using measurement of electrical-current threshold as a nociceptive test in the skin of the tail and neck in rats demonstrated that fentanyl, ketocyclazocine and midazolam caused spinally mediated antinociception when the drugs were administered intrathecally via chronically implanted lumbar subarachnoid catheters. The benzodiazepine antagonist flumazenil selectively suppressed the midazolam response, indicating that this benzodiazepine exerted its segmental antinociceptive effect via spinal-cord benzodiazepine receptors. ⋯ The dose of naloxone which suppressed the midazolam response was similar to that required to suppress the response to the kappa-opioid agonist. We suggest that the segmental antinociceptive effects of fentanyl and midazolam are mediated via different pathways; the benzodiazepine exerts its antinociceptive action via a spinal-cord opioid pathway which does not involve mu-receptors.
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Randomized Controlled Trial Clinical Trial
Effect of epidural clonidine on analgesia and pharmacokinetics of epidural fentanyl in postoperative patients.
Epidural clonidine produces postoperative analgesia in patients and potentiates opioid analgesia in animals. The aim of the current study was to assess the effect of epidural clonidine on the plasma concentrations and analgesic effect of fentanyl after epidural administration. Twenty ASA physical status 2 or 3 patients recovering from abdominal surgery were allocated randomly to receive either epidural fentanyl (100 micrograms in 10 ml isotonic saline; EF group) or epidural fentanyl (same dose) plus epidural clonidine (150 micrograms; EF + C group) in isotonic saline solution. ⋯ Peak plasma fentanyl concentrations (Fmax) and the time to reach Cmax (Tmax) were comparable in the two groups (0.29 +/- 0.15 ng.ml-1 at 16.2 +/- 14.8 min in the EF group and 0.27 +/- 0.11 ng.ml-1 at 8.3 +/- 5.5 min in the EF + C group), as were plasma concentrations at each definite time of measurement. Drowsiness and hypotension were noticed in the EF + C group. Thus, epidural clonidine appears to prolong epidural fentanyl analgesia without affecting its plasma concentration.
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Int J Obstet Anesth · Sep 1991
A comparison of epidural diamorphine with intramuscular papaveretum following caesarean section.
Following caesarean section carried out under epidural blockade using local anaesthetic only, 40 consenting women were randomly allocated to receive either epidural diamorphine 2.5-5 mg in 10 ml physiological saline and intramuscular saline or epidural saline and intramuscular papaveretum 10-20 mg, dosage depending on weight, when the pain returned. When analgesia was next requested the alternative treatment was given. A visual analogue pain score was recorded before and 15, 30, 60, 120, 180 and 240 min after the first treatment. ⋯ No difference in respiratory rate was noted but side-effects were more frequent with epidural diamorphine. Despite this more women preferred this treatment. Because of enhanced mobility provided by good analgesia epidural diamorphine is worth offering to women following caesarean section.