Pain
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Randomized Controlled Trial Clinical Trial
Topical capsaicin selectively attenuates heat pain and A delta fiber-mediated laser-evoked potentials.
Cutaneous stimulation with CO2 laser pulses activates A delta of nociceptive afferents and evokes late cerebral potentials (LEPs), the amplitude of which correlates parametrically with the perceived magnitude estimation of laser pulses. Capsaicin is known to desensitize the nociceptive terminals of C fibers. In this double-blind, vehicle-controlled experiment, we tested the hypothesis that topical capsaicin would inactivate A delta afferents and lead to an attenuation of the LEPs. ⋯ It indicated that topical capsaicin caused a definite functional and reversible inactivation of A delta nociceptive afferent transmission. The decline in the magnitude estimation of laser pulses concomitantly with the attenuation of LEP amplitudes supports the hypothesis that some A delta afferents mediate noxious heat in humans. These findings demonstrate the usefulness of LEP in the physiological evaluation of nociceptive pathways and its potential usefulness in objectively documenting the effect of pharmacological treatment on pain perception.
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Pain is highly prevalent in individuals with HIV disease, yet is often overlooked as a symptom requiring clinical intervention. We evaluated the adequacy of analgesic management for pain and identified predictors of pain undertreatment in a sample of 366 ambulatory AIDS patients using a prospective cross-sectional survey design. Two hundred and twenty-six of the 366 ambulatory AIDS patients surveyed reported "persistent or frequent" pain over the 2 week period prior to the survey. ⋯ Women, less educated patients, and patients who reported injection drug use as their HIV transmission risk factor were most likely to have received inadequate analgesic therapy. These results demonstrate the alarming degree of undertreatment of pain in ambulatory patients with AIDS, and indicates the need to improve the management of AIDS-related pain in this underserved population. Future research should elucidate the factors that impede adequate pain management in order to overcome obstacles to adequate treatment.
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Randomized Controlled Trial Clinical Trial
Sufentanil does not preempt pain after abdominal hysterectomy.
We compared the effect of intravenous (i.v.) sufentanil on postoperative pain and analgesic requirements, when given before or after abdominal hysterectomy. Patients were assigned in a random blind manner to receive 1 microgram/kg of sufentanil 5 min before induction of anaesthesia (group A, n = 18) or after ligation of the round ligaments of the uterus (group B, n = 21). General anaesthesia was induced with midazolam, thiopental and vecuronium and maintained with isoflurane and N2O in oxygen. ⋯ Pain was assessed with VAS and a verbal rating scale (VRS: 1 = no pain and 6 = intolerable pain) immediately before the first analgesic administration and 4, 8, 12, and 24 h postoperatively. VAS or VRS scores did not differ between the two groups at any time: neither did propoxyphene, paracetamol, and pethidine requirements. These results suggest that preinjury i.v. sufentanil is not more beneficial for postoperative pain control than the postinjury administration.
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Accuracy and errors in judges' attempts to differentiate facial expressions that displayed genuine pain, no pain or were dissimulated (i.e., masked and exaggerated) were examined. Judges were informed that misrepresentations in the facial expressions were present and were asked to rate their confidence in classifying these expressions. Detailed, objective coding of the patients' facial reactions (e.g., brow lowering, mouth opening) were related to judges' decisions. ⋯ Judges consistently used rules of thumb based on specific facial cues when making judgments. Certain cues were effectively discriminative. Systematic training in the use of specific cues or the use of articulated decision rules may be helpful in improving judges' accuracy.
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The objective of this study was to describe the health care utilization and prospective predictors of high-cost primary-care back pain patients. In the primary-care clinics of a large, staff model health maintenance organization in western Washington State, 1059 subjects were selected from consecutive patients presenting for back pain. The design was a 1-year prospective cohort study. ⋯ A minority of primary-care back pain patients accounted for a majority of health-care costs. Patients with high back pain costs accounted for more back pain-related health-care utilization than did patients with high total costs. Factors predicting subsequent high costs suggest behavioral interventions targeting dysfunction, pain persistence, and depression may reduce health-care utilization and prevent accumulation of high health-care costs among primary-care back pain patients.