Transcript Surgical Nutrition

Surgical Nutrition
Vic V.Vernenkar, D.O.
St. Barnabas Hospital
Dept. of Surgery
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 intraabdominal.
 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.
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).
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.
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.
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.
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.
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.
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)
Assessment
 Signs of specific nutritional deficiencies.
 Skin rash
 Pallor
 Cheilosis
 Glossitis
 Gingival lesions, hepatomegaly, neuropathy,
dementia.
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.
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.
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 <2 poor outcomes
 Albumin not a good short term marker
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.
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.
Nutritional Requirements
 Total energy requirements.
 Total protein requirements.
 The relative distribution of calories between
carbohydrates, fats, and protein.
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.
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
Stress Factors
Starvation
Postoperative
Cancer
Peritonitis
Sepsis
Multiple Trauma
Burn
0.8
1-1.05
1.1-1.45
1.05-1.25
1.25-1.55
1.25-1.55
1.5-1.7
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.
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).
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.
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.
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.
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.
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)
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.
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.
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.
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.
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.
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.
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.
Deficiencies
 Vitamin A- Wound healing
 Vitamin D- Rickets, osteomalacia
 Vitamin E- Anemia, ataxia, nystagmus,
edema, myopathy.
 Vitamin C- Wound healing
 Thiamine- Encephalopathy
 B6- neuropathy…
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)
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
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 1224hrs.
 But gluconeogenesis continues at
accelerated rate.
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.
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.
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.
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.
Hormonal Response to Injury
 Insulin
 Glucagon
 Catecholamines
 Cortisol
 ADH
 Renin
Protein Synthesis in Critical Illness
Reprioritization
Albumin
Retinol binding protein
Transferrin
Acute phase proteins
Immune proteins
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.
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..
Supplementation
 Relative contraindications to enteral
feeding:
 Mesenteric ischemia
 Bowel obstruction
 Sepsis
 Pancreatitis
 Fistula
 SBS
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
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.
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.
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.
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.
TPN Orders
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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.
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.
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.