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Surgical Nutrition

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Title: 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.
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