# Homeostasis

Homeostasis

Homeostasis is the concept of  maintaining a constant internal environment that allows cellular processes to function optimally . Many aspects of  surgery , trauma and injury a ff ect homeostasis and can lead to organ dysfunction. Traditionally the metabolic response to injury is divided into an initial period of catabolism (which may include a period of  shock) followed by an anabolic phase of  repair and tissue healing. The catabolic phase begins at the time of  injury and is characterised by hypovolaemia, decreased basal metabolic rate, reduced cardiac output, hypothermia and lactic acidosis. The main physiological role of this phase is to conserve both circulating volume and energy stores and thus maximise sur - vival chances for future recovery . A series of  neurohormonal responses accompany these e ff ects and trigger a systemic inflammatory response syndrome (SIRS), where body stores are mobilised for recover y and repair. The catabolic e ff ects include muscle breakdown, weight loss and hyperglycaemia, which themselves increase the risk of  complications, especially sepsis. As the catabolic phase subsides, an anabolic (rebuilding) phase develops, which may last for weeks if  extensive recovery and repair are required following serious injury . 

Avoidable factors that compound the metabolic response
•
to injury
How the metabolic response to injury in
/f_l
uences surgical
•
outcomes
Concepts behind optimal perioperative care
•

Homeostasis

Homeostasis is the concept of  maintaining a constant internal environment that allows cellular processes to function optimally . Many aspects of  surgery , trauma and injury a ff ect homeostasis and can lead to organ dysfunction. Traditionally the metabolic response to injury is divided into an initial period of catabolism (which may include a period of  shock) followed by an anabolic phase of  repair and tissue healing. The catabolic phase begins at the time of  injury and is characterised by hypovolaemia, decreased basal metabolic rate, reduced cardiac output, hypothermia and lactic acidosis. The main physiological role of this phase is to conserve both circulating volume and energy stores and thus maximise sur - vival chances for future recovery . A series of  neurohormonal responses accompany these e ff ects and trigger a systemic inflammatory response syndrome (SIRS), where body stores are mobilised for recover y and repair. The catabolic e ff ects include muscle breakdown, weight loss and hyperglycaemia, which themselves increase the risk of  complications, especially sepsis. As the catabolic phase subsides, an anabolic (rebuilding) phase develops, which may last for weeks if  extensive recovery and repair are required following serious injury . 

Avoidable factors that compound the metabolic response
•
to injury
How the metabolic response to injury in
/f_l
uences surgical
•
outcomes
Concepts behind optimal perioperative care
•

Homeostasis

Homeostasis is the concept of  maintaining a constant internal environment that allows cellular processes to function optimally . Many aspects of  surgery , trauma and injury a ff ect homeostasis and can lead to organ dysfunction. Traditionally the metabolic response to injury is divided into an initial period of catabolism (which may include a period of  shock) followed by an anabolic phase of  repair and tissue healing. The catabolic phase begins at the time of  injury and is characterised by hypovolaemia, decreased basal metabolic rate, reduced cardiac output, hypothermia and lactic acidosis. The main physiological role of this phase is to conserve both circulating volume and energy stores and thus maximise sur - vival chances for future recovery . A series of  neurohormonal responses accompany these e ff ects and trigger a systemic inflammatory response syndrome (SIRS), where body stores are mobilised for recover y and repair. The catabolic e ff ects include muscle breakdown, weight loss and hyperglycaemia, which themselves increase the risk of  complications, especially sepsis. As the catabolic phase subsides, an anabolic (rebuilding) phase develops, which may last for weeks if  extensive recovery and repair are required following serious injury . 

Avoidable factors that compound the metabolic response
•
to injury
How the metabolic response to injury in
/f_l
uences surgical
•
outcomes
Concepts behind optimal perioperative care
•