Pathophysiological basis of orthostatic hypotension in autonomic failure

In patients with autonomic failure orthostatic hypotension results from an impaired capacity to increase vascular resistance during standing. This fundamental defect leads to increased downward pooling of venous blood and a consequent reduction in stroke volume and cardiac output that exaggerates the orthostatic fall in blood pressure. The location of excessive venous blood pooling has not been established so far, but present data suggest that the abdominal compartment and perhaps leg skin vasculature are the most likely candidates. To improve the orthostatic tolerance in patients with autonomic failure, protective measures that reduce excessive orthostatic blood pooling have been developed and evaluated. These measures include physical counter-manoeuvres and abdominal compression

Sleep and temperament in early childhood

Sleep and temperament represent key behaviours in early childhood that reflect underlying individual constitutional differences and influence each other, and many developmental processes over time. This chapter aims to provide the reader with a basic understanding of the early childhood temperament field including definitions, history, and measurement issues. An overview of the key findings in regards to early sleep behaviours and temperament interactions across the first five years of life is provided, and the important role of the parenting environment is briefly explained. While there remain a number of challenges to overcome in the field, two key areas are further developed here. Future work should aim to increase our understanding about why early sleep and temperament are linked, and about the mechanisms involved in transactional developmental systems involving sleep, temperament, genes, and the parenting environment. Multi-disciplinary and creative modelling approaches will be needed to advance the field which should seek to create translatable research findings for the early childhood health and education sectors. Research should contribute to identifying children at the highest risk of ongoing sleep and social-emotional adjustment problems, and address these with appropriately targeted prevention and intervention strategies that support parents, educators, and health practitioners in their roles