Pain
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Randomized Controlled Trial
Modulation of remifentanil-induced postinfusion hyperalgesia by the β-blocker propranolol in humans.
Acute and chronic exposure to opioids has been associated with hyperalgesia in both animals and humans. A genetic analysis of opioid-induced hyperalgesia in mice linked the β(2)-adrenergic receptor to mechanical sensitization after opioid exposure. In humans, expansion of the area of mechanical hyperalgesia surrounding an experimentally induced lesion after the cessation of remifentanil infusion is a commonly used model of opioid hyperalgesia (remifentanil-induced postinfusion hyperalgesia, RPH). ⋯ Thermal hyperalgesia was not observed after remifentanil infusion. Propranolol infusion at the selected dose had minor hemodynamic effects. Concomitant infusion of propranolol with remifentanil prevented the expression of RPH. β-adrenergic receptor blockade may be a useful pharmacological strategy for preventing hyperalgesia in patients exposed to opioids.
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This study identifies a behavioral and nonpharmacologic means of preventing and reducing newborn pain. Our objective was to determine whether warmth is analgesic in newborn infants undergoing vaccination-a routine painful hospital procedure. We used a prospective randomized controlled trial of 47 healthy full-term newborn infants. ⋯ Heart rate patterns reflected this analgesia. Core temperature did not differ between study groups. Providing natural warmth to newborn infants during a painful procedure decreases the crying and grimacing on par with the "gold" standard treatments of sucrose or pacifier.