Neonatal Pain

Abstract

During the last three decades, important research has led to significant advances in the understanding of pain mechanisms, description of anatomical and functional development of pain structures, recognition of short and long term consequences of pain, measurement of neonatal responses to pain, and assessment of the efficacy and safety of numerous pharmacological and non-pharmacological interventions to relieve pain. Notwithstanding this progress, data still show that a large gap exists between published research results and routine clinical practice. Proven and safe therapies are currently under-used for routine minor, yet painful procedures as well as for continuous or prolonged pain. Nociceptive-related brain activity can be measured non-invasively in human neonates using neurophysiological and haemodynamic measures such as scalp electroencephalography (EEG), Near InfraRed Spectroscopy (NIRS) and functional magnetic resonance imagery (fMRI). They display distinguishable responses to noxious and non-noxious stimuli. Accurate pain assessment is essential for adequate pain management. Based on behavioural and physiological responses to nociception, more than 40 tools have been developed to assess pain in neonates. In the future, the inclusion of cortical measures may provide a more objective measurement of pain. Invasive painful procedures are extremely numerous in infants admitted to NICUs. Studies using skin-breaking procedures as a proxy of nociception have shown that repeated neonatal pain leads to poorer cognition and motor function, impaired brain development, and altered pain responses. Consequently, systematic invasive procedures should be avoided and only absolutely necessary procedures should be performed. The least painful procedure is the one that is never performed. Non-pharmacological approaches and pharmacological treatments are effective for pain management in the neonate. For procedures, the analgesic efficacy of oral sweet solutions, non-nutritive sucking, skin-to-skin contact, and breastfeeding have clearly been shown. Opioids are the most common pharmacologic agents used for pain relief in hospitalised neonates, with morphine and fentanyl most often used, especially for persistent pain. Paracetamol has been shown to provide analgesia for continuous pain, but not for procedural pain in neonates. Evidence to support the effectiveness of topical anaesthetics is neonates is limited. The alleviation of pain is a basic need and human right regardless of age; units caring for neonates should have protocols and guidelines to assess, prevent and treat pain.