Metabolic Response: Starvation, Trauma & Sepsis

Metabolic Response to Starvation

• Insulin levels decrease while glucagon levels increase
• Hepatic glycogenolysis and gluconeogenesis increase
• Protein catabolism increases, overall protein and CHO oxidation decreases
• Lipolysis and adaptive ketogenesis increase
• Resting energy expenditure decreases from ~25-30 kcal/kg/day to ~15-20 kcal/kg/day
• After 12 hours of fasting, insulin decreases and glucagon increases
• After 24 hours of starvation, the body depends on muscle glycogen, broken down to lactate and then converted to glucose
• In prolonged fasting, the body relies on fat stores through fat oxidation, producing ketones

Metabolic Response to Trauma and Sepsis

• Sympathetic nervous system activity rapidly increases, leading to increased circulating catecholamine, glucagon, glucocorticoids, GH, and insulin
• Stress hormones increase significantly
• Counter regularity hormones like adrenaline (epinephrine), noradrenaline (norepinephrine), and GH increase
• Energy requirements rise to 40 kcal/kg/day
• Nitrogen requirements increase
• Production and utilization of ketone bodies decreases
• Gluconeogenesis and protein metabolism increase
• Oxidation of lipids is preferential
• Adaptive ketogenesis is lost
• Insulin resistance and glucose intolerance occur, along with fluid retention and hypoalbuminemia

Effect of Metabolic Response to Surgery on Nutrition

• Triggers include pain, immobility, acidosis, tissue damage, hypoxia, and impaired homeostasis
• Metabolic response is affected by fasting, leading to insulin resistance and hyperglycemia
• Insulin resistance causes increased gluconeogenesis and decreased peripheral glycolysis
• Persistence of insulin resistance increases the risk of postoperative infections

Notes About Insulin Resistance

• Pre-existing co-morbidities for insulin resistance: metabolic syndrome, diabetes mellitus, cancer, and obesity
• Methods to counteract insulin resistance: preoperative high glucose intake, minimally invasive techniques, and early mobilization

Malnutrition

• It is a disorder of nutrition or a wasting condition from energy, protein, vitamin, and trace element deficiencies
• Causes include reduced food intake (anorexia, painful swallowing, fasting, physical or mental impairment)
• Malabsorption is also a cause, due to impaired digestion, absorption, or excess loss from the gut
• Altered metabolism caused by trauma, sepsis, surgery, or cancer cachexia induces malnutrition

Adverse Effects of Protein or Calorie Depletion

• Impaired wound healing
• Impaired immune function
• Mental decline (apathy, depression)
• Skeletal muscle loss (fatigue, reduced strength)
• Albumin depletion (edema)
• Small bowel mucosa atrophy, bacterial translocation, malabsorption
• Higher post-operative complications, prolonged recovery
• Thoracic muscle depletion (poor respiration, pneumonia risk)

Intestinal Resection and Short Bowel Syndrome

• The intestine absorbs fluids, nutrients, and electrolytes and adaptation increases absorption capacity
• Decreased intestinal function is from resection or inflammation
• In jejunal resection, ileal and colonic adaptation occurs, no supplements are needed
• Ileal resection results in decreased bile salt absorption, leading to steatorrhea
• Ileal resection increases gastric motility and intestinal transit time, causing diarrhea
• Short Bowel Syndrome is defined as less than 200 cm of intestine, characterized by diarrhea, malabsorption, and dehydration

Stages of Intestinal Resection and Short Bowel Syndrome

• Acute Stage: Occurs in the first few weeks with increased intestinal loss, gastric hypersecretion & hypergastrinemia, leading to acute renal failure and acid-base balance
• Adaptation: Occurs within 1-2 years with structural and functional changes
• Recovery: Requires special diets, supplementation & pharmacological therapy, rehabilitation programs, and intestinal transplantation

Anthropometry

• It is the science of measuring the size, weight, and proportions of the human body
• This can assess level of energy reserves, but cannot identify specific nutrient deficiencies
• Anthropometric assessment includes weight, % of weight changes, BMI, mid-upper arm circumference (MUAC) and triceps skin fold

Biochemistry for Malnutrition

• Markers and their value for detection of subclinical nutritional deficiencies in patients includes:
• Albumin, C reactive protein, WBC are markers of infection and inflammation
• Hemoglobin is a marker of anemia
• Glycosylated hemoglobin is a marker for assessment of blood sugar
• Sodium and urea are for renal assessment
• Calcium and phosphate anticipate refeeding syndrome
• Vitamin D deficiency means mineral bone disease
• Serum albumin and nitrogen balance analysis are also completed
• Creatinine excretion and immunological function assessment are measured

Nitrogen Balance

• Provides an index of protein gain or loss, where 6.25g protein = 1g nitrogen
• Assessed by measuring the difference between nitrogen consumed (mouth, enteral tube or IV) and nitrogen excreted in the urine, feces and other intestinal sources
• Positive nitrogen balance indicates an anabolic state
• Negative nitrogen balance indicates a catabolic state
• Serum albumin level declines due to increased circulating extravascular volume and TNF-α mediated inhibition of albumin synthesis during the acute stress of surgery

Indicators for Changes in Nutritional Status

• Albumin is sensitive but nonspecific and half life is 14-18 days, cut off value is < 35 g/L (< 3.5 g/dL)
• Prealbumin and transferrin (half life of 7 days with a < 200 mg/dL cutoff) are more sensitive indicators of rapid changes in nutritional status

Creatinine Excretion

• Creatinine is a metabolic product of skeletal muscle creatine
• Used as a relative measure of body compartment
• Creatinine High Index (CHI) is used to determine the degree of malnutrition where: CHI = (Actual 24-h creatinine excretion) / (Predicted Creatinine excretion)
• CHI > 80% means no to mid protein depletion
• CHI of 60-80% means moderate depletion
• CHI 60% means severe depletion

Clinical Evaluation

• Includes history taking and physical examination
• History of poor nutrient intake includes anorexia, vomiting
• Loss of body weight with 10-15% means high risk
• Weight loss of 15-20% means malnutrition, 20-30% means severe malnutrition and 30-40%
• Social & economic conditions indicate poverty & malnutrition: inadequate income & drug abuse
• Gastrointestinal symptoms include dysphagia and recurrent vomiting
• Other chronic illnesses may include COPD, cerebral stroke, Parkinson's, or dementia

Enteral Nutrition

• Gut mucosa integrity relies on nutrient provision; prolonged fasting causes mucosal breakdown and villi destruction
• Enteral nutrition preserves gut immunologic function, requires less nursing, and lowers infection rates
• It promotes better insulin response, less water retention, costs less, and improves compliance
• Bacterial translocation can lead to sepsis and is a major cause of multiorgan failure

Contraindications for Enteral Nutrition:

• Intractable vomiting and diarrhea
• Paralytic ileus
• Distal high-output intestinal fistula
• Severe short bowel
• Gl obstruction, ischemia
• The routes are oral supplements, nasogastric tube (NG) and nasojejunal (NJT) tube feeding, and gastrostomy tube feeding

Nasojejunal (NJ) Feeding Tube

• Indicated in gastric stasis
• Placed either blindly or under radiologic or endoscopic guidance
• Used after major/complex operative procedures on the oesophagus, stomach and pancreas
• Witzel (open) is permanent, button jejunostomy, Rouex-en-y is rarely used, and endoscopic
• Complications include perforation, bleeding, peritonitis from leakage, displacement, local sepsis, and epithelialization
• Nasogastric tube is appropriate
• Fine bore feeding tube is preferred if required
• Indications of Nasogastric feeding includes when the stomach emptying is normal and swallowing is impossible or contraindicated
• Start with 20-30 ml/hr, increasing to 75 ml over 2-3 days, with a 4-5 hour break overnight with aspiration performed on a regular basis and If aspirate is 200ml per 2 hours, stop feeding temporarily
• It causes few gastric / esophageal erosions
• Temporary (Stamm) or permanent (Janeway), with complications like perforation, bleeding, and infection

Complications of Enteral Nutrition

• Related to the tube: Malposition and displacement, blockage/leakage/breakage
• Abdominal cramps, Aspiration, Bloating, Nausea, Vomiting, Constipation and Diarrhea
• Electrolyte disorder, vitamin, mineral, trace element deficiency and drug interactions
• Electrolyte imbalance, Diarrhea, dehydration, and Hyperglycemia can result

Parenteral Nutrition

• Delivery of nutrients through an indwelling IV catheter
• It is like dialysis to renal failure & ventilator support to respiratory failure
• The bag contains lipid emulsion, essential & nonessential amino acids, glucose, trace elements, vitamins, increasing the protein content in severely ill patients and decreasing the protein content in renal impairment
• It Should be checked after 28 days during TPN

Parenteral Nutrition Indications

• Prolonged ileus, intestinal obstruction, malabsorption, short cut, inflammatory bowel disease, and highOutput of high intestinal fistulae
• PPN is used to provide calories for 2 weeks, with a low dextrose concentration and amino acid concentrate
• TPN has high dextrose levels, with a Osmolarity of 1000-1900

Sites for Parenteral Nutrition

• Short term Central Access: Subclavian vein
• Long-term central venous lines: Subclavian or internal jugular vein
• Advantage of PPN: can start when you can't use the GI tract
• Contains essential and non-essential AA and variable amounts of electrolytes, with concentrations that depend on the final volume

Advantages of Parenteral Amino Acid Solutions

• No risk of infection
• Branched AA: Beneficial in patients with liver disease
• Glutamine: Improves with stressed patients
• Arginine: Improves function
• Enriched: Beneficial for renal failure individuals
• To monitor ensure all things are checked
• Chest X ray with 2 times/week: Ca+, P, Mg LFT, S.Creat, Albumin
• Daily: Weight & check urine output
• Every 4 Hours- Monitor vital signs

Complications of Parenteral Feeding

• Mechanical: malposition in hemothorax
• Thrombosis for the first 2 weeks
• Electrolyte imbalance with infections
• Overestimation of caloric needs

Overfeeding Syndrome

• Increased oxygen consumption, suppressed leukocyte function, and difficulty removing from ventilator

Liver Dysfunction

• Fatty liver is a common complication and it reduces liver cell production with high fat intake
• It is recommended that you check vitals and electrolytes
• In the first few days in severely malnourished patients, it is recommended to get the patients started on support

Refeeding Syndrome

• Anabolism and electrolyte shift out of the cells, with lower ATP stores
• Patients are a risk if the BMI is 8.5 kg/m^2
• The patient is recommended to get blood sugar checked, and start at a low rate, gradually increasing the high-risk patients for blood
• Bone deficiency and the excess loss of vitamins can result in health
• A regular exam can prevent all the health issues from occurring