Pain
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Randomized Controlled Trial
Pain relief by applying transcutaneous electrical nerve stimulation (TENS) on acupuncture points during the first stage of labor: a randomized double-blind placebo-controlled trial.
Transcutaneous electrical nerve stimulation (TENS) is one of the non-pharmacological means of pain relief for labor and delivery. We aimed to investigate the efficacy and safety of TENS on specific acupuncture points for reducing pain in the first stage of labor. In this double-blind, placebo-controlled trial, we randomly assigned healthy full-term parturients in active phase of first-stage labor to either TENS on four acupuncture points (Hegu [Li 4] and Sanyinjiao [Sp 6]) (n=52) or the TENS placebo (n=53). ⋯ Willingness of using the same analgesic method for a future childbirth was also significantly different (TENS: 48/50 [96%] vs TENS placebo: 33/50 [66%], P<0.001). Operative delivery was increased in the TENS group (12/50 [24%] vs 4/50 [8%], P=0.05), but the neonatal outcomes were not different. The application of TENS on specific acupuncture points could be a non-invasive adjunct for pain relief in the first stage of labor.
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Sympathetically maintained pain could either be mediated by ephaptic interactions between sympathetic efferent and afferent nociceptive fibers or by catecholamine-induced activation of nociceptive nerve endings. We report here single fiber recordings from C nociceptors in a patient with sympathetically maintained pain, in whom sympathetic blockade had repeatedly eliminated the ongoing pain in both legs. We classified eight C-fibers as mechano-responsive and six as mechano-insensitive nociceptors according to their mechanical responsiveness and activity-dependent slowing of conduction velocity (latency increase of 0.5+/-1.1 vs. 7.1+/-2.0 ms for 20 pulses at 0.125 Hz). ⋯ Moreover, their activity-dependent slowing was typical for mechano-insensitive nociceptors. We conclude that sensitized mechano-insensitive nociceptors can be activated by endogenously released catecholamines and thereby may contribute to sympathetically maintained pain. No evidence for ephaptic interaction between sympathetic efferent and nociceptive afferent fibers was found.
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Disrupted sleep has long been associated with physical functioning and disability in chronic pain populations and recent research shows that patterns of sleep and rest can predict physical disability, independent of depression and pain levels in this group. However, it is unknown whether sleep quality may independently predict disability in this way. The aim of the present study was to examine the self-reported relationship between sleep and disability in 155 chronic pain patients attending a pain management service. ⋯ These findings highlight the important role of sleep in chronic pain suffering. However, due to the cross sectional nature of this study, the mediation pathways proposed require testing by further research adopting a prospective design. Ideally, future research should evaluate whether targeted interventions to improve sleep can reduce pain severity, depression and ultimately, pain-related disability.