Pain
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Meta Analysis
Systematic review of factors affecting the ratios of morphine and its major metabolites.
In a systematic review of 57 studies with information on 1232 patients we examined the effect of age, renal impairment, route of administration, and method of analysis on the ratios of morphine-3-glucuronide:morphine (M3G:M) and morphine-6-glucuronide:morphine (M6G:M) and the relative concentrations of M3G and M6G. Across all studies the range of the ratios of metabolites to morphine was wide (0.001-504 for M3G:M, and 0-97 for M6G:M). Neonates produced morphine glucuronides at a lower rate than older children or adults. ⋯ There was no evidence of differences between methods of assay. There was a high correlation between the two glucuronide metabolites in spite of the different situations studied, supporting a single glucuronidating enzyme. Morphine was present in CSF at a fourfold higher concentration than the glucuronide metabolites.
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Dorsal horn neurons that respond to noxious cold also respond to noxious heat, suggesting the hypothesis that pain evoked by temperature extremes, whether hot or cold, may be processed similarly in the CNS. In this study, we tested perceptual consequences of this hypothesis by comparing characteristics of heat and cold pain, as well as of innocuous warm and cool. Eight healthy subjects performed psychophysical tasks involving hot and cold cutaneous stimuli. ⋯ Perceived stimulus intensity was compared to temperature recordings from intradermal and skin surface thermocouples. Heat pain, cool and warmth appeared to depend on surface temperature, whereas cold pain was related to subcutaneous temperature, suggesting different receptors for noxious heat and noxious cold. These data, combined with results of human brain imaging and primate electrophysiological studies, suggest that the unpleasantness associated with both heat pain and cold pain is processed similarly in the CNS, whereas differential information about stimulus quality is preserved in the cerebral cortex.
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Randomized Controlled Trial Comparative Study Clinical Trial
Ketorolac potentiates morphine in postoperative patient-controlled analgesia.
The authors conducted a prospective randomised double-blind comparison of patient-controlled analgesia (PCA), with a combination of morphine and ketorolac versus morphine alone and ketorolac alone in the management of postoperative pain after orthopaedic surgery. Forty-two patients were randomly assigned to three groups. Group 1 was given 1 mg/ml morphine, group 2 was given 3 mg/ml ketorolac and group 3 half-doses of each. ⋯ The incidence of urinary retention was highest in the group given morphine alone. The combination of half-doses of morphine and ketorolac is more effective in controlling postoperative pain than either drug alone. This combination also reduces analgesic consumption and morphine-related adverse events.
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Randomized Controlled Trial Comparative Study Clinical Trial
Psychological approaches during conscious sedation. Hypnosis versus stress reducing strategies: a prospective randomized study.
Stress reducing strategies are useful in patients undergoing surgery. Hypnosis is also known to alleviate acute and chronic pain. We therefore compared the effectiveness of these two psychological approaches for reducing perioperative discomfort during conscious sedation for plastic surgery. ⋯ Vital signs were significantly more stable in the HYP group. Patient satisfaction score was significantly higher in the HYP group (P < 0.004). This study suggests that hypnosis provides better perioperative pain and anxiety relief, allows for significant reductions in alfentanil and midazolam requirements, and improves patient satisfaction and surgical conditions as compared with conventional stress reducing strategies support in patients receiving conscious sedation for plastic surgery.