Challenges of judging pain in vulnerable infants

Infants are well endowed to experience pain at birth, and it becomes a common feature of their lives. The supposition of a universally painful birth trauma does not stand up to inspection [1], particularly for standard vaginal delivery, but atypical presentation and the possibility of forceps delivery or vacuum extraction provide possibilities for tissue damage causing pain during the perinatal period. Thereafter, infants are confronted with numerous painful diagnostic and prophylactic procedures such as heel sticks for blood sampling or needle injection for immunization purposes. Older infants also encounter pain and discomfort from the inevitable falls and bumps arising from limited perceptual and motor competence. Less fortunate infants also suffer pain arising from injury, disease, or surgery and related care [2]. Physiologic and behavioral evidence is consistent with expectations that neonates and infants experience pain as a result of these events. Investigations of the developmental neurobiology of pain clearly demonstrate the requisite afferent systems and engagement of autonomic and neuroendocrine systems modulating sensory and emotional experience [3,4]. Fine-grained behavioral observation demonstrates the sensory, distressing, and disruptive impact of pain [5,6]. Thus, the experience of pain in the infant is incontrovertible. Caregivers are faced, however, with the considerable challenges of identifying and delivering appropriate care-essentially social actions. The bioevolutionary and personal significance of pain are often featured, with its interpersonal roles less appreciated. Pain is evident across species and appears to fulfill a primordial role of warning about impending or real tissue damage, thereby motivating escape and withdrawal from activity to convalesce. These biologic and intrapersonal features of pain command the attention of patients, lay and health care practitioners, and scientists, but the social functions of pain also warrant attention. The representation of pain in the cerebral cortex of humans has unique features and may reflect adaptive developments allowing for language and the social complexities of human lifestyles. Pain in one person can alarm others about threats to personal safety, instigate caregiving in the observer, and influence communal bonds. These social functions are particularly important in human infants who have limited intrinsic/personal resources to control and restore homeostasis and rely on adults to nurture them through the extended period of infancy [7]. Survival may depend on the child effectively signaling need states and the parenting adults recognizing and delivering appropriate care. Some infants are biologically and socially more vulnerable than others as a result of premature birth, genetic limitations, congenital challenges, injury, or disease. These infants will encounter not only the usual sources of pain to which all infants are exposed, but their medical conditions may be intrinsically painful; physiologic immaturity may lead to a diminished capacity to modulate and express pain; and various diagnostic and treatment procedures represent added sources of pain [8]. Immaturity or impairments that leave them incapable of adequately signaling painful distress leave caregivers even more challenged with attempting to interpret the source of ambiguous behavioral signals. Because of the infant's fragile condition, caregivers may be even more reluctant to intervene, putting the child at greater risk of morbidity or mortality. Newborns have a minimal capacity to escape pain, with the capability only slowly unfolding during infancy. In consequence, a primary function of their behavioral reactions must be to instigate protection and care from adults. But the infant's capacity for communicating specific needs also is limited, as witnessed by the frustrations parents suffer when attempting to decipher an infant's wail in the middle of the night. In response, most parents exercise considerable caution, become very conservative in decision-making, and attempt to provide all-encompassing and redundant care. They usually do well in caring for their children, but children who are at risk require additional adult sensitivity and care. Better care is specific to states of hunger, fatigue, pain, or other needs. Fortunately, there can be cross-benefits of providing particular interventions for certain conditions; for example, hunger may palliate other distressing states, such as discomfort. But accurate assessment and specific management will be most immediate and effective. Pain is often unresponsive to anything other than exact pain-relieving strategies, and there can be urgency to its accurate identification. The purpose of this article is to describe the complexities of assessment and decision-making processes when adults endeavor to respond to the needs of infants suffering from pain, particularly those who are vulnerable or are at high risk, and to specify practices that may enhance the validity of assessment and improve the quality of care.