Articles: analgesia.
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alpha(2)-Adrenoceptor agonists like clonidine, dexmedetomidine, and ST-91, inhibit nociceptive reflex activity predominantly by a spinal mode of action. They mimic the action of the inhibitory transmitter noradrenaline, which is released from the terminals of bulbospinal monoaminergic pathways. The inhibition by noradrenaline is due partly to hyperpolarization of the postsynaptic neuronal membrane; however, the selective antinociceptive effect of the alpha(2)-adrenoceptor agonists results from reduction of the release of the excitatory transmitters such as glutamate and substance P, blockade of the binding of substance P to spinal neurones, and enhancement of the action of the inhibitory transmitter, 5-hydroxytryptamine. ⋯ Moreover, impulse conduction in C fibres of peripheral nerves is far more reduced by these compounds than that in A fibres. Antinociceptive effects are reported to occur in various models of clinical pain, e.g. the formalin test, adjuvans-induced arthritis, autotomy following deafferentation, and "hyperalgesia" after nerve ligation. Therefore, the mechanisms involved in antinociception may also be responsible for the analgesia produced by alpha(2)-adrenoceptor agonists.
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Obstetrics and gynecology · Nov 1995
Randomized Controlled Trial Comparative Study Clinical TrialRandomized trial of epidural versus intravenous analgesia during labor.
To compare the effects of epidural analgesia with intravenous (IV) analgesia on the outcome of labor. ⋯ Although labor epidural analgesia is superior to meperidine for pain relief, labor is prolonged, uterine infection is increased, and the number of operative deliveries are increased. A two- to fourfold increased risk of cesarean delivery is associated with epidural treatment in both nulliparous and parous women.
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Anesthesia and analgesia · Nov 1995
Randomized Controlled Trial Clinical TrialAnalgesia after thoracotomy: effects of epidural fentanyl concentration/infusion rate.
After thoracotomy some patients have discomfort, primarily in the rostral portion of their incisions. In this prospective, randomized study in 66 patients after lateral thoracotomy we evaluated whether, for equal fentanyl dosage in micrograms per kilogram, epidural infusion (lumbar catheter) of fentanyl 5 micrograms/mL provided better segmental analgesia (including the rostral portion of the incision) than a 10-micrograms/mL concentration infused at a rate half that used in the 5-micrograms/mL group. Ketorolac was used as an analgesic adjunct for nonincisional pain. ⋯ There were no significant differences in demographics, surgical procedure, intraoperative fentanyl dose, side effects, rates of epidural fentanyl infusion, or total epidural fentanyl doses at 12, 24, 36, 48, and 60 h postbolus. Analgesia was effective in both groups. Although overall comfort levels were lower (i.e., indicated greater comfort) in the 5-micrograms/mL group in 6 of 8 visual analog scores (VASs) for comfort level and 20 of 24 VRSs for comfort level scores, and mean VRSs for the rostral portion of the incision were lower (i.e., indicated greater comfort) in the 5-micrograms/mL group at 21 of 24 evaluation subsets (one statistically significant), statistical significance was achieved in only six evaluation subsets.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Cost-effectiveness analysis of patient-controlled analgesia, intramuscular q.i.d. injection and p.r.n. injection for postoperative pain relief.
We conclude that the intravenous PCA method is a cost-effective technique. Although the PCA device is expensive, the cost-effectiveness analysis should give explicit figures for physicians and the hospital administrators to decide whether they should use the PCA instead of the conventional method.
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Respiratory monitoring, using a novel flow sensor based on an acoustic principle, has been investigated in 30 patients during postoperative analgesia. Each patient was subjected to monitoring and human observation for 8 hr. The study was performed by independent observers at three clinics. ⋯ More than 800 apnea alarms were noted, using an alarm setting of 30 sec; 61% of the categorized alarms were noted by the observers as true apneas. From the recordings it was shown that the number of alarms can be reduced by a factor of four if the alarm setting is changed to 45 sec. We conclude that the suggested technique, with slight modifications, provides adequate respiratory monitoring of patients during postoperative analgesia.