Content area
Full Text
Pain assessment in neonates is among the most difficult challenges faced by health professionals and clinical researchers. All existing tools for neonates were developed for acute or postoperative pain. 1-4 They are helpful for identifying an acute painful event or comparing analgesic treatments used to combat procedural pain. A large number of responses to pain were described in the course of the development of these tools, providing valuable semiological data.
However, several lines of evidence indicate that preterm infants are subjected to not only acute pain but also prolonged pain. Firstly, neonatal intensive care involves many painful procedures. For instance, Barker & Rutter 5 found that the number of procedures performed during the neonatal intensive care unit (NICU) stay of an infant weighing 560 g at birth was 488. Secondly, hormonal or metabolic responses indicative of stress have been reported in neonates with hyaline membrane disease or recent surgery, and abated with analgesic treatment. 6-8 Thirdly, preterm babies often spend a considerable time in hospital: in a recent study, for instance, the median duration of assisted ventilation in a cohort of 182 very low birthweight infants was 36 days, and the median hospital stay was 105 days. 9 Intensive care provided over such a long period constitutes a prolonged painful experience.
No tools are available for assessing prolonged pain-that is, lasting several hours or days-in preterm babies. Clearly, there is a clinical need for such a tool. 10 In a previous study, we began to describe prolonged pain semiology. 11 Now, we seek to meet this need by developing and validating a new pain scale suitable for clinical practice.
Methods
Development of the EDIN (Échelle Douleur Inconfort Nouveau-Né, neonatal pain and discomfort scale) was a two phase process. In the first phase, useful indicators of pain were identified, the scale was drafted, and its content validity was evaluated. The data were gathered by observation over one year of preterm infants born at 25-36 weeks gestational age and admitted to an NICU or a conventional neonatal unit (CNU). Severity of illness was the main difference between the patients in these two units: critically ill neonates were admitted to the NICU and neonates requiring simple care to the CNU. Newborns with cerebral hypoxia-ischaemia were excluded because...