Define the Stress Response - nutrition during stress?
The terms trauma, stress, shock are very often used interchangeably and encompass a variety of conditions such as sepsis (infection), burns, injury (accidents, wounds), surgery (electiveJemergency) etc. Before we proceed towards understanding the physical and metabolic responses of the human system towards stress, it is important to remember that whether the event is in the form of sepsis (infection), trauma (including bums), or surgery, once the systemic response is activated, the physiologic and metabolic changes that follow are similar and may lead to shock and other outcomes. Variable responses relate to patient's age, previous state of health, pre- existing disease, type of infection and presence/absence of multiple organ dysfunction syndromes (MODS). It has long been recognized that the physiological response of the patient to a stress or disease process will very largely determine the outcome. To an extent this will depend on the extent of the shock and injury; this tends to be minimal for minor surgery or injury and extensive for major accidental or surgical trauma. However, the physiological reserve of the individual is also important. Signals that are initiated in injured or ischaemic tissues communicate the extent of the injury systemicalIy. These stress responses are necessary for the process of recovery from injury.
However, when trauma is severe, the resultant physiological responses are extensive and sustained, such that the same responses may be detrimental and contribute to the progression to critical illness and even death. Stress response means major changes in metabolism that occur after severe injury, illness or infection. The nutrient needs of the body are greatly altered as a result of this response. There is accelerated catabolism of lean body or skeletal mass resulting in muscular wasting and a negative nitrogen balance. The metabolic responses to critical illness have been studied in a variety of critically ill patients, especially those with trauma, bums, or sepsis. The responses are often grouped into phases on the basis of their temporal relation to the injury or insult. The stress response is therefore referred to as a dynamic process that has an ebb phase, a flow phase and an anabolic phase.