Pain
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Controlled Clinical Trial
Altered quantitative sensory testing outcome in subjects with opioid therapy.
Preclinical studies have suggested that opioid exposure may induce a paradoxical decrease in the nociceptive threshold, commonly referred as opioid-induced hyperalgesia (OIH). While OIH may have implications in acute and chronic pain management, its clinical features remain unclear. Using an office-based quantitative sensory testing (QST) method, we compared pain threshold, pain tolerance, and the degree of temporal summation of the second pain in response to thermal stimulation among three groups of subjects: those with neither pain nor opioid therapy (group 1), with chronic pain but without opioid therapy (group 2), and with both chronic pain and opioid therapy (group 3). ⋯ Among clinical factors, daily opioid dose consistently correlated with the decreased heat pain threshold and exacerbated temporal summation of the second pain in group 3 subjects. These results indicate that decreased heat pain threshold and exacerbated temporal summation of the second pain may be characteristic QST changes in subjects with opioid therapy. The data suggest that QST may be a useful tool in the clinical assessment of OIH.
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Controlled Clinical Trial
Influence of heterotopic noxious conditioning stimulation on spontaneous pain and dynamic mechanical allodynia in central post-stroke pain patients.
In 10 patients with central post-stroke pain (CPSP), the influence of ischemia-induced heterotopic noxious conditioning stimulation (HNCS) on the intensity of spontaneous ongoing- and brush-evoked pain was examined. In addition, the modulating effect of ongoing pain and HNCS on pain sensitivity in a remote pain-free area was explored. A semi-quantitative brushing technique was employed in combination with a computerized visual analogue scale (VAS) to monitor the allodynic percept over time, by calculating the area under the VAS curve as the total brush-evoked pain intensity. ⋯ During HNCS, higher pressure pain thresholds were demonstrated in patients and controls alike (P<0.001), whereas in controls only decreased sensitivity to suprathreshold pressure pain was found (P<0.05). Lack of influence from HNCS on ongoing- and brush-evoked pain on a group level, indicates inability of modulation from endogenous pain controlling systems on nociceptive activity generated in the brain. Increased pressure pain sensitivity at baseline suggests alteration in corticofugal control of nociceptive sensitivity due to the brain lesion, whereas patients during HNCS seemed to activate modulatory systems interacting with nociceptive input from the spinal level equal to controls.
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Controlled Clinical Trial
Psychological determinants of problematic outcomes following Total Knee Arthroplasty.
The primary objective of the present study was to examine the role of pain-related psychological factors in predicting pain and disability following Total Knee Arthroplasty (TKA). The study sample consisted of 75 (46 women, 29 men) individuals with osteoarthritis of the knee who were scheduled for TKA. Measures of pain severity, pain catastrophizing, depression, and pain-related fears of movement were completed prior to surgery. ⋯ The results of this study add to a growing literature highlighting the prognostic value of psychological variables in the prediction of post-surgical health outcomes. The results support the view that the psychological determinants of post-surgical pain severity differ from the psychological determinants of post-surgical disability. The results suggest that interventions designed to specifically target pain-related psychological risk factors might improve post-surgical outcomes.
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Pain assessment and treatment is influenced by patient demographic characteristics and nonverbal expressions. Methodological challenges have limited the empirical investigation of these issues. The current analogue study employed an innovative research design and novel virtual human (VH) technology to investigate disparities in pain-related clinical decision-making. ⋯ This study demonstrates the application of VH technology and lens model methodology to the study of disparities in pain-related decision-making. Assessment and treatment of acute post-surgical pain often varies based on VH demographic and facial expression cues. These data contribute to the existing literature on disparities in pain practice and highlight the potential of a novel approach that may serve as a model for future investigation of these critical issues.
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Procedural pain in the neonatal intensive care unit triggers a cascade of physiological, behavioral and hormonal disruptions which may contribute to altered neurodevelopment in infants born very preterm, who undergo prolonged hospitalization at a time of physiological immaturity and rapid brain development. The aim of this study was to examine relationships between cumulative procedural pain (number of skin-breaking procedures from birth to term, adjusted for early illness severity and overall intravenous morphine exposure), and later cognitive, motor abilities and behavior in very preterm infants at 8 and 18 months corrected chronological age (CCA), and further, to evaluate the extent to which parenting factors modulate these relationships over time. Participants were N=211 infants (n=137 born preterm 32 weeks gestational age [GA] and n=74 full-term controls) followed prospectively since birth. ⋯ The number of skin-breaking procedures as a marker of neonatal pain was closely related to days on mechanical ventilation. In general, greater overall exposure to intravenous morphine was associated with poorer motor development at 8 months, but not at 18 months CCA, however, specific protocols for morphine administration were not evaluated. Lower parenting stress modulated effects of neonatal pain, only on cognitive outcome at 18 months.