European journal of pain : EJP
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Randomized Controlled Trial Comparative Study
Does acupuncture activate endogenous analgesia in chronic whiplash-associated disorders? A randomized crossover trial.
Many patients with chronic pain, including those with chronic whiplash-associated disorders (WAD), show features of central sensitization. Randomized trials examining whether treatments are able to influence the process of central sensitization in patients with chronic WAD are emerging. Therefore, the present study aimed at examining whether acupuncture results in activation of endogenous analgesia and relief in symptoms in patients with chronic WAD. ⋯ It was shown that one session of acupuncture treatment results in acute improvements in pressure pain sensitivity in the neck and calf of patients with chronic WAD. Acupuncture had no effect on conditioned pain modulation or temporal summation of pressure pain. Both acupuncture and relaxation appear to be well-tolerated treatments for people with chronic WAD. These findings suggest that acupuncture treatment activates endogenous analgesia in patients with chronic WAD.
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Randomized Controlled Trial
Contextual factors associated with pain response of preterm infants to heel-stick procedures.
Evidence indicates that medical and demographic contextual factors (cFs) impact pain responses in preterm neonates, but the existing evidence is very heterogeneous. ⋯ Higher exposure to painful procedures, male infants and having CPAP or mechanical ventilation were cFs associated with physiological response. The only variables significantly associated with behavioural BPSN scores were Apgar scores but these relationships were inconsistent.
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Randomized Controlled Trial
Hyperbaric oxygen therapy attenuates neuropathic hyperalgesia in rats and idiopathic trigeminal neuralgia in patients.
Neuropathic pain after nerve injury is severe and intractable, and current drug and non-drug therapies offer very limited pain relief. Hyperbaric oxygen (HBO 2) has been clinically used for protection of the nervous system after acute injury. We investigated whether HBO 2 treatment could prevent and/or attenuate neuropathic pain in animals and in patients. ⋯ These findings support that HBO 2 therapy is an effective approach for treating neuropathic pain in both animals and human beings and suggest that neural protection, anti-inflammation and inhibition of nerve injury-induced altered neural activity may contribute to the analgesic effect of HBO 2 therapy.
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Randomized Controlled Trial
Effects of dexmedetomidine on conditioned pain modulation in humans.
Systemic administration of dexmedetomidine (DEX; selective α(2) -adrenoceptor agonist) is found to inhibit diffuse noxious inhibitory control in rats, now referred to as conditioned pain modulation (CPM) in humans. The present study was designed to investigate the effect of intravenous administration of DEX on CPM in humans. ⋯ The present study shows that systemic administration of an α(2) -adrenoceptor agonist (DEX), less than the clinical dose, inhibited CPM in humans. These results may provide some mechanistic insight into why many chronic pain patients show impaired CPM.
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Randomized Controlled Trial
Sex differences in analgesic response to ibuprofen are influenced by expectancy: a randomized, crossover, balanced placebo-designed study.
To determine whether there is a sex difference in placebo and ibuprofen analgesia expectancy. ⋯ We found no sex difference in baseline pain threshold or tolerance levels. When partitioned by sex and expectancy state, analgesia only occurred in males during positive expectancy states at 2, 3 and 4 h post-placebo, and at 1 and 2 h post-ibuprofen. The time course of analgesic action in males was as expected considering the pharmacokinetic profile of ibuprofen. Our study found that dosages of 800 mg of ibuprofen are ineffective in producing analgesia in women regardless of their expectations. We hypothesize that ibuprofen analgesia is produced by a combination of specific pharmacological effects and a non-specific beta endorphin-mediated placebo effect. Whatever the mechanism responsible for the analgesic response seen in males, this research re-emphasizes the importance of psychological factors in determining drug response. It also shows that these factors can differ between men and women, and thus the contribution of psychological factors on analgesia needs to be seriously re-evaluated.