Nutritional support in trauma

Question 1

Trauma

Answer 1

An injury or wound to living tissue caused by an extrinsic agent

Question 2

Mortality from trauma phase 1

Answer 2

• Shock
• Develops within 2-6hrs after injury; Lasts 24-48hrs
• Cytokines, catecholamines and cortisol secreted
• Primary aims = stop bleeding, prevent infection
• Peripheral vasoconstriction preserves vital organs

Question 3

Mortality from trauma phase 2

Answer 3

• Catabolic state
• Develops approx. 2 days after injury
• Catecholamines, glucagon, ACTH converted into cortisol
• Primary aims: avoid sepsis, provide adequate nutrition
• Increased lipolysis, Increased glycolysis, Increased neg nitrogen balance, Increased metabolic rate, Increased oxygen consumption

Question 4

Mortality from trauma phase 3

Answer 4

• Anabolic state
• Occurs approx. 3-8days after uncomplicated surgery
• Coincides with beginning of diuresis
  Aims:
• Adequate nutrition supply is critical in this phase
• Refeeding syndrome risk
• May last a few weeks or a few months
• Obesity paradox

Question 5

Inflammatory response at trauma site

Answer 5

1. Bacteria and pathogens enter wound
   2 .Platelets release clotting factors
2. Mast cells secrete factors that mediate vasodilation to increase blood delivery
3. Neutrophils and macrophages phagocytose pathogens
4. Macrophages secrete cytokines to attract immune cells and proliferate the inflammatory response
5. Inflammatory response continues until wound is healed

Question 6

The five cardinal signs of inflammation

Answer 6

1. Heat
2. Redness
3. Swelling
4. Pain
5. Loss of function

Question 7

Endocrine effects of cytokines

Answer 7

• Cytokine mediated secretion of catabolic hormones e.g. IL-1 and TNF-alpha - Catabolic hormones increase energy release
• Cytokine mediated inhibition of anabolic hormones - Anabolic hormones build up molecules the body needs

Question 8

Metabolic response to trauma phase 1

Answer 8

• Supply of glucose and oxygen is interrupted

- Glycogenolysis: 24hrs max; Glycogen glucose

Question 9

Metabolic response to trauma phase 2

Answer 9

• Gluconeogenesis
• Skeletal and secreted protein breakdown; 1kg muscle = 200g protein = 120g glucose
• Amino acids converted to glucose and lactate production
• Nitrogen loss:

Question 10

Metabolic response to trauma phase 3

Answer 10

• Lipolysis and Ketogenesis
• Free Fatty Acid = acetyl CoA = acetoacetate and hydroxybutyrate
• Ketone bodies converted back to Acetyl CoA to make energy
• Gradual change to ketone metabolism by CNS which spares protein stores and muscles

Question 11

Changes in protein after trauma

Answer 11

• Amount of new protein synthesised reduces and profile of proteins synthesised changes
• Increased inflammatory modulators and scavengers
• Decreased albumin
• Skeletal muscle proteolysis increases
• Increased free amino acids, plasma (ammonia)
• More nitrogen loss

Question 12

Lactate production in Hypoxia

Answer 12

• Decreased aerobic metabolism; increased anaerobic metabolism
• Pyruvate reduced to lactate
• Anaerobic metabolism can only continue until lactate becomes toxic, H+ inhibits enzymes

Question 13

Lactate: prognostic marker in trauma

Answer 13

• Failure of blood lactate to return to normal following trauma resuscitation carries a poor prognosis
• Blood lactate (mmol/L):
• <1, mortality: 18%
• 2-4, mortality: 74%
• > or equal to 5: 100%

Question 14

Primary malnutrition

Answer 14

• Protein-calorie undernutrition (starvation)

- Dietary deficiency of specific nutrients e.g. trace elements, water soluble/fat soluble vitamins

Question 15

Secondary malnutrition

Answer 15

• Nutrients present in adequate amounts, but appetite is suppressed
• Nutrients present in adequate amounts, but absorption and utilisation are inadequate
• Increased demand for specific nutrients to meet physiological needs

Question 16

refeeding syndrome

Answer 16

• Reintroduction of nutrients after a period of malnourishment/starvation
• ## Food reintroduced = abrupt shift from fat metabolism back to carb metabolism. Causes insulin secretion to increase. Cells need electrolytes like phosphate to convert glucose to energy, but phosphate is in short supply = hypophosphatemia

Question 17

Symptoms of refeeding syndrome

Answer 17

• Fatigue, confusion, inability to breathe, HBP, seizure, arrhythmias, heart fail, coma and even death

Question 18

Cystic fibrosis main proteins

Answer 18

• Cystic fibrosis transmembrane regulator (CFTR) protein

- cAMP dependent chloride channel

Question 19

CFTR protein function

Answer 19

• CFTR facilitates production of thin, watery, free-flowing mucus
• Lubricating airways and secretory ducts
• Protecting the lining of the: Airway, Digestive system, Reproductive system

Question 20

CFTR dysfunction

Answer 20

• Failure to maintain hydration of macromolecules as they pass through lumen causes they to precipitate and cause obstruction
• Can lead to lung disease as neutrophils die leaving the host more susceptible to Infection and persistent inflammatory state

Question 21

Gastrointestinal disease in CF

Answer 21

• Meconium ileus at birth: 15%
• Bowel obstruction when meconium thicker/stickier than usual
• Pancreatic cysts, exocrine insufficiency = decreased insulin, decreased lipase, decreased proteases
• Poor appetite, failure to thrive, low weight

Question 22

meconium

Answer 22

dark green substance in first faeces