Surgical Nutrition

1
Surgical Nutrition

• Vic V.Vernenkar, D.O.
• St. Barnabas Hospital
• Dept. of Surgery

2
Impact on Outcome

• For well nourished or mildly malnourished general
  surgery patients, peri-operative nutritional
  support did not improve outcome and actually was
  associated with increased septic complications
  after surgery both pulmonary and intra-abdominal.
• For severely malnourished patients before a major
  surgical procedure, peri-operative nutritional
  support reduced postoperative complications
  (wound complications, wound failure, prolonged
  hospital stay, ICU days, use of hospital
  resources) by about 10, without significant
  increase in infectious complications.

3
Who will need it?

• Well nourished and mildly malnourished patients
  who cannot take oral food for more than one week
  post operatively to avoid prolonged starvation.
• Severely malnourished patients undergoing general
  surgery procedures.
• All critically ill patients (Sepsis patients,
  Multiple Injury patients Burn patients, etc).
• Patients whom you predict cannot use their gut
  for prolonged period of time (Short gut syndrome,
  EC fistula, etc).

4
When to Start?

• Preoperatively in severely malnourished patient
  undergoing a major surgical operation.
• Immediately postoperatively in severely
  malnourished patients.
• Immediately after major trauma, sepsis, major
  burns.
• Normal or mildly malnourished patient who is
  unable to eat on his own by 7 days after surgery.

5
Metabolism

• Nutritional implications in surgical diseases are
  numerous and include anorexia, sodium and fluid
  retention, accelerated gluconeogenesis,
  hyperglycemia, insulin resistance, and lipid
  intolerance.
• In reviewing body nutrient metabolism, one must
  consider body energy stores.

6
Metabolism

• Triglyceride storage in the typical male consists
  of 140,000 calories.
• Muscle contains 24,000 calories as protein, 2000
  calories as glycogen, 3000 calories as
  triglyceride.
• Liver contains 300 cal as glucose in glycogen
  form, 500 cal as triglyceride.
• Unstressed starvation uses adipose stores.

7
Metabolism (unstressed)

• During the first 48-72 hrs increased use of fat
  stores, and most tissues except RBCs, WBCs, and
  renal medulla oxidize lipid stores.
• Brain has an obligate glucose requirement, over
  3-5 days uses fatty acids for energy.

8
Assessment of Nutritional Status

• Weight loss is a significant indicator
• More than 10 unintentional loss in 6 month
  period.
• 5 loss in 1 month.
• Anorexia, persistent nausea, vomiting, diarrhea,
  malaise.
• Loss of subcutaneous fat, muscle wasting, edema,
  ascites.

9
Evaluation of Nutritional Status(Difficult)

• Weight loss
• Serum markers
• Albumin level T1/2 21 d
• Transferrin T1/2 8 d
• Prealbumin level T1/2 2-3 d
• Immune competence (delayed hypersensitivity
  reaction, total lymphocyte count)

10
Assessment

• Signs of specific nutritional deficiencies.
• Skin rash
• Pallor
• Cheilosis
• Glossitis
• Gingival lesions, hepatomegaly, neuropathy,
  dementia.

11
Evaluation of Body Composition

• Ideal body weight (IBW)
• Men 106lb 6lb for each inch over 5 feet
• Women 100lb 5lb for each inch over 5 ft.
• IBW depends on patient age, body habitus.
• Other measurements include triceps skin fold, arm
  circumference.

12
Body Composition

• BMI characterizes degree of obesity.
• weight(kg)/total body surface area.
• BMI over 40 or over 35 with co-morbid conditions
  are considered candidates for surgical treatment.
• Severe obesity is associated with significant
  increase in morbidity and mortality.

13
Laboratory Markers

• Serum proteins
• Albumin half life 20 days
• Transferrin half life 8.5 days
• Prealbumin half life 1.3 days
• Retinol binding protein 0.4 days
• Severe hypoalbuminemia
• Albumin not a good short term marker

14
Energy Expenditure

• Can be measured by the respiratory quotient.
• RQ CO2 production(VCO2)/O2 consumption (VO2).
• Indirect calorimetry allows for gas analysis and
  calculation of RQ.

15
RQ

• RQ of 1.0 predominant glucose utilization.
• RQ of 0.7 and 0.8 consistent with fat and protein
  utilization.
• RQ higher than 1.0 suggests over feeding and
  lipogenesis.

16
Nutritional Requirements

• Total energy requirements.
• Total protein requirements.
• The relative distribution of calories between
  carbohydrates, fats, and protein.

17
Energy Requirements

• Harris-Benedict equation estimates BEE at rest.
• Men 66 (13.7x weight) (5x height) (6.8 x
  age).
• Women 65 (9.6 x weight) (1.7 x height) (4.7
  x age)
• Most require 25-35 kcal/kg/day.
• Stress increases these values.

18
Stress

• Low stress 1.2 x BEE
• Moderate stress 1.2-1.3 x BEE
• Severe stress 1.3-1.5 x BEE
• Major burn injury 1.5-2.0 x BEE
• Requirements are increased by fever, infection,
  activity, burns, head injury, trauma, renal
  failure, surgery.
• Decreased by sedation, paralysis, B blocker

19
Stress Factors
20
Carbohydrate (30-60 of Total)

• Serve as main energy source for cellular
  metabolism when energy is rapidly required
  following stress. Each gram releases 4 kcal.
• Also important in membranes as glycoproteins,
  glycolipids, carbon backbone of essential amino
  acids.

21
Carbohydrate (30-60 of Total)

• Glucose, galactose, fructose main six carbon
  sugars.
• CHO are stored as glycogen in liver (40), muscle
  (60), cardiac muscle.
• Stores depleted in 48hrs (starve), 24 hrs
  (stress).

22
Carbohydrate

• Liver glycogen is only source of free glucose
  available systemically from carbohydrate stores.
• Muscle glycogen is used for muscle itself, and
  not available for other tissues. Does not have
  G-6-P to do this.

23
Protein

• As opposed to CHO, protein absorption in
  intestine is incomplete, leading to a mixture of
  free AA and oligopeptides.
• A major portion of protein digestion products are
  absorbed by luminal cells as small peptides,
  subsequently digested to yield free amino acids
  inside the cell.

24
Protein

• Essential components of all living cells,
  involved in virtually all bodily functions.
• Serve as enzymes, hormones, neurotransmitters,
  immunoglobulins, transport proteins.
• Total protein in a healthy male is 15-18 of body
  weight.
• Protein is not stored, should all be considered
  functional.

25
Protein

• Obligatory turnover rate of proteins.
• 2.5 of total body protein is broken down and
  re-synthesized every 24hrs.
• Half of this is daily digestive process,
  maintenance of immune function, muscle protein
  synthesis, hemoglobin turnover
• Protein yields 3.5 kcal per gram.

26
Protein Requirements

• Most healthy individuals require 0.8-1.0 g
  protein/kg/day.
• Mild stress 1-1.2 g/kg/day.
• Moderate stress 1.3-1.5 g/kg/day.
• Severe stress 1.5-2.5 g/kg/day.
• Renal failure (more)
• Hepatic encephalopathy (less)

27
Nitrogen Balance

• A crude measurement of protein consumption.
• Difference between net nitrogen intake and
  excretion.
• Positive balance indicates more protein ingested
  than excreted.
• Negative balance is catabolism.
• Protein excretion in urine nitrogen x 6.25g.

28
Amino Acids

• Most AA metabolized by liver
• Branched chain AA are metabolized by muscle.
• Patients require at least 20 of their protein
  intake as essential AA.
• Glutamine is most abundant AA in blood, a
  principle food for enterocytes, mucosal
  integrity, macrophage and lymphocyte
  proliferation.

29
Lipids

• Where CHO and protein are fairly soluble, lipids
  are characterized by poor solubility in aqueous
  solutions, good in organic solvents. So
  digestion presents some unique problems.
• Role of lipids include energy source, cell
  membrane structure, lubricant for body surfaces,
  joints, and mucous membranes.

30
Lipids

• Should provide 25-40 of total calories.
• Fatty acids a major source of fuel for heart,
  liver, skeletal muscle.
• Liver oxidation of fatty acids yields ketones
  which are used by the heart, brain, muscle during
  starvation.
• During the fed state, insulin stimulates
  lipogenesis and fat storage, inhibits lipolysis
  in adipocytes.

31
Triglycerides

• Long Chain must be emulsified by bile salts to
  for micelles.
• Must be hydrolyzed by pancreatic lipase in the
  proximal small bowel for absorption to occur.
• Medium Chain absorbed directly by enterocytes,
  thru portal system to liver.
• Readily absorbed despite severe deficiencies in
  pancreatic function. Less steatorrhea.

32
Essential Fatty Acids

• During parenteral nutrition, at least 3-5 of
  total calories as fat is necessary to prevent
  essential fatty acid deficiency.
• Linoleic and Linolenic acid are precursors to
  prostaglandins and eicosanoids.
• Deficiencies result in dermatitis,ecchymosis,
  alopecia, anemia, edema, thrombo, respiratory
  distress.
• Manifestations occur in 4-6 weeks.

33
Vitamins

• Deficiencies can occur in severely malnourished
  patients, chronic nutritional support.
• Impaired wound healing can be a direct result of
  deficiencies in Vitamin A, C, and zinc.

34
Deficiencies

• Vitamin A- Wound healing
• Vitamin D- Rickets, osteomalacia
• Vitamin E- Anemia, ataxia, nystagmus, edema,
  myopathy.
• Vitamin C- Wound healing
• Thiamine- Encephalopathy
• B6- neuropathy

35
Stress

• The same events as starvation.
• Much more accentuated tissue protein breakdown in
  order to
• Supply increased demands of energy
• Supply building blocks for acute phase reactant
  proteins by the liver.
• This accentuated protein breakdown is stimulated
  by
• Increased steroid production
• Cytokines associated with acute stress response
• Nitrogen loss
• 5-8 gm/d normally
• 2-4 gm/d after several days of unstressed
  starvation
• 30-50 gm/d under severe stress (multiple trauma,
  sepsis, burns)

36
Critical Illness

• Metabolic rate is increased
• While patients are in negative nitrogen balance,
  protein synthesis is active centrally
• Fat not as available as energetic substrate
• Cortisol and catecholamines block lipolysis and
  oxidation of fatty acids to ketone bodies

37
Metabolism (stressed)

• Hypermetabolism associated with major catabolic
  illness, trauma, major surgery is a significant
  change.
• Increase in ACTH, epinephrine, glucagon, cortisol
  production.
• As in unstressed, glycogen is used up in
  12-24hrs.
• But gluconeogenesis continues at accelerated rate.

38
Metabolism (stressed)

• Muscle protein, in addition to providing a source
  for gluconeogenesis, serves as a substrate for
  acute phase protein synthesis by providing
  necessary AA.
• Liver reprioritizes to produce acute phase
  proteins rather than visceral proteins.
• Increased glutamine and alanine released from
  muscle for gut and liver respectively.
• Hyperglycemia common because of gluconeogenesis
  and insulin resistance.

39
Alterations During Stress

• CHO ACTH, cortisol, catecholamines, glucagon.
• Hyperglycemia frequently present during stress
  secondary to relatively low insulin level and
  peripheral insulin resistance.
• Insulin inhibited by catecholamines, sympathetic
  nervous system, somatostatin.
• Catecholamines and cortisol contribute to insulin
  resistance peripherally.

40
Alterations During Stress

• Liver glycogenolysis, gluconeogenesis stimulated
  by catecholamines, cortisol, glucagon.
• The glucose produced is essential for RBCs, WBCs,
  renal medulla, neural tissue, wound tissue.
• Protein synthesis increases during stress
• Net proteolysis and negative nitrogen balance are
  characteristic of severe stress.

41
Alterations During Stress

• Alanine release from peripheral tissue increases
  as it is the major source of AA substrate for
  gluconeogenesis in the liver.
• During severe sepsis, muscle protein loss may
  occur at 240 g protein per day.
• IL-1 may play a role in stimulating proteolysis
  in this setting.
• Lipids During severe stress, lipolysis is
  stimulated by increased cortisol, catecholamines,
  glucagon, GH, ACTH, sympathetic activity.

42
Hormonal Response to Injury

• Insulin
• Glucagon
• Catecholamines
• Cortisol
• ADH
• Renin

43
Protein Synthesis in Critical IllnessReprioritiza
tion

• Albumin
• Retinol binding protein
• Transferrin
• Acute phase proteins
• Immune proteins

44
Nutritional Supplementation

• Benefits high risk patients such as severely
  malnourished, critically ill, burns, severe
  trauma.
• Delayed oral intake 7-10 days.
• Enteral route is indicated in all patients with
  an intact, functioning GI tract.
• Prevents intestinal atrophy, gut immune function,
  inhibition of stress induced increase in
  intestinal permeability.

45
Nutritional Supplementation

• Oro-enteric, naso-enteric, gastrostomy,
  jejunostomy.
• Small bore NG tubes can be use for short period
  of time.
• Gastrostomy and jejunostomy for long term.
• Complications in placement, organ injury,
  aspiration, malfunction, leaks, sinusitis,
  erosion..

46
Supplementation

• Relative contraindications to enteral feeding
• Mesenteric ischemia
• Bowel obstruction
• Sepsis
• Pancreatitis
• Fistula
• SBS

47
Role of Gut in Critical Illness

• Mice fed TPN
• Reduced GALT T- and B-Cells
• Reduced IgA production in GI AND Respiratory
  Tracts
• Reduced immunity to respiratory tract infectious
  challenges - viral and bacterial
• Enteral feeding
• Restored GALT cell lines
• Restores immune function
• Restores ability to resist URI challenges
• Ann Surg, 1997

48
Enteral Feeding

• The most frequently cited advantage of enteral
  feeds is relative decreased infection rate in
  critically ill patients.
• Glutamine- mucosal integrity, immune function.
  Levels fall significantly during severe stress
  and sepsis.
• Arginine- improves N balance, T-cell
  responsiveness, reduces infection complications.
• Omega-3 fatty acids- precursors for eicosanoids,
  immunoregulatory role possible.

49
Over Feeding

• Detected if respiratory quotient (RQ) is above 1
  (determined by the metabolic cart). That means
  that there is lipogenesis.
• Has adverse effects
• Respiratory failure due to excess CO2 production
  during lipogenesis.
• Hepatic failure due to excess fatty liver
  infiltration and cholestasis.
• Overfeeding has to be completely avoided as it is
  harmful to the patient.

50
Parenteral Feeds

• TPN- indicated when GI tract is unavailable or
  nonfunctional.
• Via Central catheter due to hyperosmolarity of
  the solutions.
• Complications related to catheters frequent.
• Severe metabolic complications can occur.
• Hyperglycemia, hypoNa, hypoK, hypoMg, hypoP,
  hypereverything.

51
Parenteral Feeds

• Refeeding Syndrome- may develop rapidly in
  severely malnourished patients started on TPN.
• Most frequently associated with admin of high
  calorie supplements, supplements with high
  carbohydrates.

52
TPN Orders

• Calculate VOLUME requirements/24h.
• Determine PROTIEN requirements g/kg/d.
• Calculate daily CALORIES kcal/kg/d.
• Determine to be given as protein, CHO, fats.
• Add ELECTROLYTES, TRACE ELEMENTS.
• Co-administer Lipids to prevent fatty acid
  deficiency.
• Lipids give more calories in less volume
• A 10 lipid sol. 1.1kcal/ml, 20 is 2.0 kcal/ml.

53
Take Home Messages

• Nutritional supplementation reduces the risk of
  complications if given to severely malnourished
  patients undergoing major surgical procedures and
  in patients with severe sepsis, trauma and burns
  (by 10) but does not impact the mortality.
• Nutritional supplementation is not indicated in
  healthy subjects postoperatively until one week
  postoperatively or in patients who are predicted
  not to be not able to eat to avoid prolonged
  starvation.

54
Take Home Messages

• Enteral feeding must be the first choice always
  for nutritional supplementation.
• Parenteral nutrition is an important tool in the
  armamentarium, however it has a lot of inherited
  problems. Only used when enteral feeding cannot
  be done.
• Overfeeding is very harmful for patients and must
  be avoided and looked for.