Pain
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Randomized Controlled Trial Clinical Trial
Heel lancing in term new-born infants: an evaluation of pain by frequency domain analysis of heart rate variability.
The aim of the investigation was to assess pain by frequency domain analysis of heart rate variability (HRV) during a routine heel lancing procedure in term new-born infants. Beat-to-beat heart rate (HR) was recorded in 23 healthy new-born infants on the maternity ward during blood sampling for neonatal screening. A sham heel prick prior to the sharp lancing procedure was performed randomly in half of the infants. ⋯ A clear stress response was provoked when the heel was squeezed for blood sampling, indicated by an increased HR and a decreased spectral power in the high frequency band (i.e. lower vagal tone). The different stress responses during the lancing and the squeezing of the heel were clearly illustrated when principal component analysis was applied and the vectors for the changes in HR and spectral pattern were indicated. In conclusion, the squeezing of the heel is the most stressful event during the heel prick procedure.
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Age and sex differences were investigated in children's self-report of venipuncture pain. Equal numbers of boys and girls aged 3-15 years (n = 110) made separate ratings of the intensity and unpleasantness of their needle pain, using a paired Visual Analogue Scale (VAS) technique. The parents of these children used the same method to give ratings of predicted pain and unpleasantness before the needle, as well as ratings based on observing their child during the needle. ⋯ The agreement between parental and children's ratings was higher for parents' observed, as opposed to predicted, scores, especially for pain intensity, with no systematic influence of the child's age and sex. In conclusion, it is suggested that age effects in children's self-report of needle pain are predominantly manifest in ratings of sensory intensity, whilst sex effects are predominantly manifest in ratings of an affective (unpleasantness) dimension. It is argued that both age and sex differences are largely the function of pain reporting variables, rather than reflecting fundamental age or sex based variance in nociceptive processing.
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Complex regional pain syndrome (CRPS) is characterized by a triad of sensory, motor and autonomic dysfunctions, with long-standing pain and temperature differences of the affected and contralateral limb as predominant symptoms. The pathogenesis of the disorder still remains unclear. Among the main hypotheses of an underlying pathophysiology we find inflammatory processes and dysfunction of the sympathetic nervous system. ⋯ Wind-up related pain was also significantly enhanced in the affected limb (P < 0.02). The anti-inflammatory agent had no effect. These results indicate a non-inflammatory pathogenesis in CRPS presumably central in origin.
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Comparative Study Clinical Trial
The effect of compression and regional anaesthetic block on referred pain intensity in humans.
The mechanisms underlying local and referred muscle pain are poorly understood. The aim of this experiment was to determine to which degree referred pain is dependent on peripheral or central mechanisms. This was studied by blocking sensory input from the referred pain area. ⋯ In the combined nerve block experiment, a significant reduction of referred pain intensity (38.5%) was seen after 20 min and until the release of the tourniquet. There was no significant difference in the referred pain intensity between the two types of blocks. The present findings suggest that both peripheral and central mechanisms play a role in referred pain and that the myelinated fibres mediate the peripheral component.
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Comparative Study Clinical Trial
Painful and painless peripheral sensory neuropathies due to HIV infection: a comparison using quantitative sensory evaluation.
In order to characterize further, sensory disorders due to HIV-induced distal symmetrical polyneuropathy (DSPN), we compared quantitative sensory testing (QST) and electrodiagnostic parameters in patients presenting with painful or painless DSPN. Forty HIV patients with DSPN were studied and compared with ten seronegative control subjects: 15 patients presented with pains (spontaneous and/or evoked) in the lower limbs and 25 patients, matched for age, sex, duration of HIV and CD4 count, had non-painful symptoms (i.e. paresthesia). QST and nerve conduction studies (NCS) were performed on the lower limbs. von Frey hairs and a thermotest device were used to determine the mechanical- and thermal-, detection and pain thresholds. ⋯ The intensity of mechanical allodynia/hyperalgesia was correlated with the intensity of spontaneous ongoing pain. We conclude that patients with DSPN are characterized by thermal, mechanical and electrophysiological deficits, suggestive of alterations in both small and large peripheral nerve fibers. Patients with a painful neuropathy present with static mechanical allodynia/hyperalgesia, suggestive of a selective alteration in the processing of mechanoreceptive signals, which might have a significant role in the pathophysiology of spontaneous and evoked pains in these patients.