Articles: pain.
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Because of the likely involvement of central convergence of afferent inputs in mechanisms underlying referred pain, the activity of single neurones was recorded in the cat's trigeminal (V) subnucleus caudalis (medullary dorsal horn) to test for the presence and extent of convergent inputs to the neurones. In chloralose-anaesthetized or decerebrate unanaesthetized cats, electrical stimuli were applied to afferents supplying facial skin, oral mucosa, canine and premolar tooth pulp, laryngeal mucosa, cervical skin and muscle, and jaw and tongue muscles, and tactile and noxious mechanical and thermal stimuli were applied to skin and mucosa. Considerable proportions of caudalis neurones which could be functionally classified on the basis of their cutaneous receptive field properties as low-threshold mechanoreceptive (LTM), wide-dynamic-range (WDR), or nociceptive-specific (NS) neurones, could be excited by electrical stimulation of several of these afferent inputs. ⋯ On the basis of antidromic activation, 15% of these WDR and NS neurones were shown to have a direct projection to the contralateral thalamus. The findings question the use of terminology and classifications of somatosensory neurones based only on the cutaneous receptive field properties of the neurones since distinctions between the different neuronal populations become less obvious when properties other than those related to cutaneous afferent inputs are taken into account. Moreover, the observations of extensive convergence of different types of afferents, which was especially apparent in cutaneous nociceptive neurones, also suggest a role for these neurones in mediating deep pain and in spread and referral of pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
A multiple-dose comparison of ketorolac tromethamine with diflunisal and placebo in postmeniscectomy pain.
The efficacy of oral ketorolac 5 mg and 10 mg taken qid was compared in a randomized double-blind study with that of oral diflunisal 500 mg bid (interleaved with placebo twice daily) and of placebo, in 120 patients suffering at least moderate pain following meniscectomy. The trial comprised two phases: (1) an acute phase (the first postoperative day) and (2) a chronic phase (days 2-5 postoperatively). Acutely, pain was assessed before drug administration, and then 0.5, 1.0, 2.0, 3.0, 4.0, 6.0, 8.0, and 9.0 hours after the first dose. ⋯ Over the chronic phase, ketorolac 5 mg and placebo showed similar results, with diflunisal showing the least pain relief and ketorolac 10 mg the most. All the active treatments showed a low incidence of side effects and, in an overall evaluation, no one treatment was distinguishable. Ketorolac would seem to be an acceptable therapy for acute postoperative pain.
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During a period of one year, 119 patients with chronic pain received injections of opioids via a catheter inserted in the lumbar epidural space. Twenty-three patients (19%) showed evidence of tolerance and were given droperidol 1.25-5.0 mg epidurally. ⋯ One patient given an accidental overdose of droperidol developed reversible Parkinsonism. It is concluded that epidural administration of the dopamine antagonist droperidol may be beneficial as supplementary medication to epidural opioids when tolerance develops.
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Chronic pain in the perineum is a difficult neurosurgical problem. This article evaluates the effectiveness of sacrococcygeal rhizotomy in 28 patients who had cancer-related pain or coccydynia, underwent rhizotomy, and were followed for an average of 3 years. Good pain relief was obtained in 53% (10 of 19 patients) with malignant pain, as opposed to 22% (2 of 9 patients) with nonmalignant pain. Sacral rhizotomy is a reasonable treatment for cancer-related perineal pain, but it is ineffective for coccydynia and other benign perineal pain problems.
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Acta Anaesthesiol Scand · Nov 1986
Randomized Controlled Trial Clinical TrialLow-dose ketamine infusion for analgesia during postoperative ventilator treatment.
In a randomized, double-blind study with placebo, ketamine was used as an analgesic during ventilator treatment in the period of recovery after major abdominal surgery. Forty patients were orally intubated and ventilated by means of a volume-controlled ventilator. Twenty of them received an i.v. bolus of 30 mg of ketamine followed by an 8-h infusion of 1 mg per minute. ⋯ Dreams and hallucinations were recalled in three patients in the control group and five in the ketamine group. Only one control and two ketamine patients experienced these as unpleasant. In this investigation, ketamine infusion in a low dose appeared to offer satisfactory analgesia and to permit tolerance of the orotracheal tube.