Le nouveau-né hospitalisé est exposé de manière répétée à des procédures douloureuses ou stressantes pouvant entraîner des conséquences neurodéveloppementales à court et long terme. La prévention de la douleur procédurale est essentiellement basée sur l’utilisation de traitements non pharmacologiques parmi lesquels les solutions sucrées possèdent un niveau de preuve élevé. Cependant, leur efficacité a récemment été remise en cause et leurs mécanismes d’action restent mal compris. Enfin, la dissociation parfois retrouvée entre les réponses comportementales et corticales suggère de monitorer la douleur de manière multimodale. Les objectifs de ce travail étaient : 1) de comparer l’efficacité de l’allaitement maternel et du sucrose sur la douleur procédurale en analysant spécifiquement les réponses corticales, 2) d’étudier les effets périphériques des solutions sucrées au niveau de neurones sensoriels de ratons, 3) d’évaluer l’intérêt d’un modèle d’évaluation multimodale de la douleur chez le nouveau-né à terme et prématuré. Aucune différence entre le sucrose et l’allaitement maternel n’a pu être objectivée sur les réponses corticales(NIRS) à la douleur chez des nouveau-nés à terme à 3 jours de vie. Nous avons objectivé un effet périphérique du glucose et du sucrose sur des neurones sensoriels de ratons nouveau-nés, médié par TRPV1. L'effet du glucose était associé à une diminution de la libération de la substance P. L’évaluation multimodale de la douleur retrouvait des corrélations faibles à modérées entre le score NFCS et la conductance cutanée, le cortisol salivaire et les changements d’ [HbT] mesurés en NIRS. L’étude menée chez les nouveau-nés prématurés nous permettra de préciser l’intérêt de l’utilisation de la variabilité de la fréquence cardiaque (indice NIPE instantané) dans cette indication afin de proposer un modèle multimodal fiable pour de futurs essais randomisés contrôlés. / Hospitalized newborns are exposed to repeated painful or stressful procedures that can lead to short- and long-term neurodevelopmental sequellae.The prevention of procedural pain is essentially based on the use of nonpharmacological treatments among which the sweet solutions appear to be among the most effective. However, their effectiveness has recently been challenged and their mechanisms of action remain poorly understood. Finally, the dissociation frequently found between behavioural and cortical responses shows the importance of monitoring pain in a multimodal way. The objectives of this work were 1) to compare the efficacy of breastfeeding and sucrose on procedural pain by specifically analyzing cortical responses, 2) to study the peripheral effects of sweet solutions on sensory neurons of newborn rats and 3) to evaluate the contribution of a multimodal pain assessment model in term and preterm neonates. No difference between sucrose and breastfeeding was measured on pain-evoked cortical responses (NIRS) in term neonates at 3 days of life.We reported a peripheral effect of glucose and sucrose on afferent sensory neurons from newborns rats mediated byTRPV1. The effect for glucose was associated with a decrease of substance P release.The multidimensional assessment of pain found mild to moderate correlations between the NFCS score, skin conductance, salivary cortisol and changes in [HbT] measured in NIRS.The study conducted in preterm newborns will specify the reliability of heart rate variability (instant NIPE index) in thisindication to provide a suited multimodal pain assessment model for future randomized controlled trials.

Thesis (MNutr (Human Nutrition))--Stellenbosch University, 2008. / INTRODUCTION: The best known reference standards used to evaluate the growth and development of infants and children are the 1977 National Centre for Health Statistics (NCHS) - , the 2000 Centres for Disease Control and Prevention (CDC) - and the World Health Organization (WHO) (2006). The NCHS reference standards were used to analyse anthropometric data from the 1999 National Food Consumption Survey (NFCS). It was anticipated that using the 2000 CDC and the 2006 WHO reference standards may lead to differences in the previously estimated prevalences of stunting, wasting, underweight, risk of overweight, overweight and obesity in the study population. AIM: To compare the anthropometric status of children aged 12 - 60 months when using the 1977 NCHS -, the 2000 CDC -, and the 2006 WHO reference standards. METHODS: A secondary analysis of anthropometric data from the 1999 NFCS was conducted using different reference standards to compare anthropometric status in terms of the prevalences of stunting, wasting, underweight, risk of overweight, overweight and obesity. Relationships between anthropometric status and other variables such as breastfeeding, maternal education level and type of housing were explored. RESULTS: The prevalences of stunting, obesity and overweight were significantly higher and the prevalence of underweight and wasting were lower when using the 2006 WHO compared to the 1977 NCHS and the 2000 CDC reference standards. A significant relationship was found between weight-forheight and breastfeeding when using any one of the reference standards and between BMI-for-age and breastfeeding when using the 2006 WHO reference standard. A significant relationship was shown between maternal education level and height-for-age and weight-for-age when using any one of the three reference standards and a significant association was found between weight-for-height and BMI-for-age and the type of housing when using any of the three reference standards. CONCLUSIONS: The prevalences of stunting and obesity were higher when using the 2006 WHO reference standards compared to the 1977 NCHS and 2000 CDC reference standards. This may be due to the linear growth and rate of weight gain of breastfed infants differing from formula fed infants and the 2006 WHO reference made use of the exclusively and predominantly breastfed infant living under normal healthy conditions as the normative model which is a prescription of how children should not grow and .not an indication of how children are growing. In conclusion, the 2006 WHO reference standard must be the only reference standard used nationally and internationally when assessing the growth and nutritional status of infants and children.