Sources of stress in the NICU include medical
and surgical procedures, pain, pathologic processes,
caregiver interventions, and the physical
environment, especially sound and light. Both
medical/surgical interventions and pathologic processes
can result in pain and place additional
burdens on the infant's fragile resources and available
energy. Neonatal stress leads to energy expenditure,
which may alter healing and recovery
processes and growth. Stress may alter physiologic
processes and CNS organization, influencing developmental
outcomes. The calories and nutrients
infants consume are first used to meet physiologic
demands and the consequences of both immature
function and pathophysiologic events and to respond
to stressors in the environment. Whatever
calories or nutrients are left can then be used for
growth and development. Sammons and Lewis
(1995) proposed a model to visualize this relationship
(Figure 2).