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Nutritional support for
critically ill patients
Dr. Samah AnwarCritical Care & Emergency Nursing
Department
Content outline
• Overview• Physiological principles• Patient at risk to develop malnutrition• Nutritional assessment• Nutritional requirements• Determining nutritional requirement• Methods of nutritional support
• Recognition of the importance of the gastro-intestinal tract and its potential role in the development of multiple organ failure has been increasing over the last 10 years.
Physiological principles
• Protein-Energy Malnutrition (PEM)A pathologic state resulting from a relative or
absolute deficiency of protein and energy• The Hypermetabolic StateAn increase in energy demands that
accompanies any significant physiologic and/or psychological insult
Physiological principles • Protein-Energy Malnutrition (PEM)A pathologic state resulting from a
relative or absolute deficiency of protein and energy
• The Hypermetabolic StateAn increase in energy demands that
accompanies any significant physiologic and/or psychological insult
• The Catabolic State A progressive loss of lean body mass in
response to any significant insult, physiological or psychological
• Body Composition: The Importance of Lean Body Mass and Fat Mass
• Total Body Weight = Lean Body Mass* + Fat Mass
Fat Mass (25%)Adipose Tissue
Lipid
Metabolically Inactive
Contracts If Energy Demand Exceeds
IntakeExpands If Energy Intake in Excess
Stored kcal: 150,000
Lean Body Mass (75%)70% Water, 20% Protein, 10%
MineralsMetabolically Active
Compartment Size Highly Regulated
Essential for Survival
Potential kcal: 40,000
Contains All Skeletal and Smooth MusclesTissue and SkinVisceral Protein
CollagenEnzymes, Antibodies
Growth Factors
Threat
Hypermetabolism, Catabolism, Immune Deficiency
Neurophysiologic Activation System•Pituitary-adrenal Axis
•Sympathetic Nervous System•Corticotropin Release
PhysicalPsychological
Components of nutrition assessment for malnutrition
–Dietary history–Physical
examination–Laboratory
examination–Weight loss–Anthropometric
measurements
–Immunological studies.
–Nitrogen balance studies.
–Determinants of nutritional requirement.
–Indirect Calorimetry
1 ) History: • wt changes over past 6 months • appetite• recent vs. usual food intake• alcohol• dietary/herbal supplements • food intolerances• GI complaints (especially if >2 wk) • changes in functional status
Components of nutrition assessment for malnutrition
Physical Findings associated with Malnutrition: • Cachexia & Muscle wasting• Signs of dehydration• Ascites, edema • Poor hair quality, skin ulcers or rashes, nonhealing
wounds• Pallor or redness of gums, stomatitis, glossitis,
obesity. • Unintentional weight loss of >10% within 6 month
or >5% within 1 month
Components of nutrition assessment for malnutrition
Weight and height
BMI = weight / height2
Triceps or subscapular thickness of skin
fold
Mid-arm muscle circumference and mid-
arm muscle area
Body Composition Parameter
Anthropometric Measurements
• Anthropometry is the measurement of body size , weight , and proportions
• Anthropometry measures can be used to evaluate nutritional status .
• Anthropometry also is considered the method of choice for estimation body composition in a clinical setting .
Height
• Procedure• The client
stands erect with feet flat on the floor and slightly apart, legs and back.
Weight
• Procedure• On the same scale
each time.• At the same time of
day, preferably before breakfast.
• With the same amount of clothing on each time and without shoes. Record the weight immediately
Interpretation
• BMI = weight (kg) height ² (m)² • BMI from 18.5 to 25
• Body Mass Index (BMI) = Wt (kg) Ht (m2)
Weal chair scale
• Use on appropriate scale for client’s mobility status
Mid-Arm Circumference (MAC)
Measures skeletal muscle mass.
Procedure
Interpretation
• Compare measurements to previous MAC to identify any change.
• Measurements less than 90% of reference standard may indicate the need for nutritional support.
Triceps Skinfold (TSF)
• Measures subcutaneous fat stores and is therefore an index of total body fat, because more than half the total body fat tissubcutaneous.
Triceps skinfold
Biceps skinfold
Sub scapular skinfold
Iliac crest skinfold
Supra spinal skinfold
Abdominal skinfold
Front thigh
Calf skinfold
Other traditional ( chest – axilla )
Estimate of Weight Loss
Usual weight - present weight x 100 = percent of weight change
Estimate of PEM
Mild Moderate Severe
% Wt loss 10% 15%-25% > 25%
Mid-arm muscle circumference (MAMC):
• MAMC (cm) = MAC (cm) − [3.14 × TSF (cm)]
Arm muscle area (AMA)• AMA (cm2) for females = {[MAC- ( x
TSF)] 2 / 4} – 6.5.• AMA (cm2) for males = {[MAC- ( x
TSF)] 2 / 4} – 10.
Laboratory data
• Evaluation of protein level• There are 2 types of protein 1- Somatic protein which found is
skeletal muscle . 2- Visceral protein found in viscera of
body (liver , kidney , pancreas , heart) red blood cell & white blood cell.
Serum protein
1- Albumin
2- Transferin.
3- Prealbumin.
4- Nitrogen balance .
Nitrogen Balance Studies• It is a very important parameter of protein
synthesis & metabolism.• Nitrogen balance = [protein intake (in
grams)] / 6.25 – [24-hour (in grams) urinary urea nitrogen (UUN) + 4]
• If it equals zero nitrogen balance is present.• If it equals a + ve number protein synthesis is
occurring• If it equals a –ve number protein catabolism.
B- Immunological testing
1- Total lymphocyte count ( TLC).
2- Skin antigen testing.
Other tests
• Hemoglobin level iron — contain pigment in red blood cell.
• Hematocric packed red cell volume.• W.B.C&R.B. C.• Fluids & electrolytes level in body .
Determining nutritional requirement• The BMR is the amount of energy
expended at complete rest, shortly after awakening and in a fasting state for 12 to 18 hours. The BMR depends on age, sex, and body size and correlates roughly with body surface area. It is proportional to lean body mass, not to fat. The metabolic rate increases 20% after elective surgery and 110% after a severe burn.
Resting energy expenditure REE, which is often used synonymously with BMR, represents the amount of energy expended 2 hours after a meal under conditions of rest and thermal neutrality. It is generally 10% higher than the BMR.
• The energy requirements can be calculated as:
• Total energy expenditure = BMR x stress factor x activity factor.
• Estimation of energy requirements at rest (basal energy expenditure, BEE) is most often using the equation of Haris.
Basal energy expenditureBEE : Men66.47 + (13.75 weight in kg) + (5.0
height in cm) – (6.76 age in yr.)BEE: Women655.10 + (9.56 x weight in kg) + (1.7 x
height in cm) – (4.68 age in yr.)
Stress factorsLow stress: 1.3 BEEModerate stress: 1.5 BEESevere stress: 2.0 BEECancer: 1.6 BEE
Activity factorsIntubated patients = 1.0 to 1.1 Patients confined to bed = 1.2Patients out of bed = 1.3
Indirect Calorimetry• Indirect calorimetry is a technique that
measures oxygen consumption and carbon dioxide production to calculate resting energy expenditure and respiratory quotient (RQ). One liter of oxygen consumed generates 3.9 kcal (16.32 kJ); 1 L of carbon dioxide produced generates 1.1 kcal (4.60 kJ).
• Indirect calorimetry allows the precise measurement of the daily caloric expenditure.
• Use of a stress factor to account for injury is not necessary because the measured energy expenditure accounts for the effects of disease state, stress, and trauma.
• Because the measurement occurs at rest, it is necessary to multiply by an “activity” factor of 1.0 to 1.3, depending on whether the patient is intubated, at bed rest, or ambulatory.
• In addition, indirect calorimetric data provide, via the RQ (RQ = carbon dioxide production / oxygen consumption).
• The RQ can be useful in altering a patient’s nutritional support regimen. Normal RQ ranges from 0.7 to 1.0.
• An RQ of greater than 1.0 most often indicates overfeeding
• whereas an RQ less than 0.82 is often associated with underfeeding .
Six Ws
Six WsWhy
When
Who
Which
How w
What
Why •do we feed MV patients?
When •should we start to feed them?
Who • are the patients we should feed?
Which • route should we feed by?
How w •can we estimate the amount of feeding we should give?
What •should the feed contain?
Six Ws
Why feed?
• To provide sufficient energy to spare protein• To prevent patient moving from an early stage
of malnourishment to a severe stage.• To optimize management from the nutritional
point to aim for the best outcome• To prevent PEM, and micronutrients
deficiencies
Why • do we feed mechanically ventilated pts?
MalnutritionPatients on admission
Catabolism of illness
Poor outcomes
Wasting of lean body mass
What should we feed critically ill patients?
• Exactly what we should be feeding for optimum recovery remains less clear.
• Enteral nutrition with supplemental arginine, glutamine and omega-3 fatty acid instead of standard enteral diet improved immunological, metabolic and clinical outcomes
• Micronutrients (vitamins & minerals) should be considered
What route?
Enteral nutrition is the route of choice Promote immunocompetence of the gut Overgrowth of gut bacteria Translocation of gut bacteria
• Early feeding usually defined as starting within
the first 48 hours of admission
When • should we start to feed them?
Timing of feeding
• Within 48h in mild to moderate PEM• In severe PEM gradual restoration to avoid
refeeding syndrome• The aims of early feeding are: - Preservation of function - Survive particular episode of illness - Reduction of complications
Early feeding
Starting of feeding within the first 24 hours of admission “ ACCEPT”
Algorithms for Critical Care Enteral and Parenteral Therapy
• All malnourished patients
• All patients who are unlikely to regain normal oral intake within either 2 or 5-7 days depending on your view
Who • are the patients we should feed?
• All hospitalized patients should be screened for risk or presence of malnutrition within 24 hr of admission.
Which • patients should we feed?
Patient at risk to develop malnutrition• Chronic disease• Severe catabolism• Inability to use GIT• I.V support for more than 5 days
– Trauma, Burns– Sepsis, organ failure – Bowel obstruction– Severe digestive or absorptive disorders– Severe pancreatitis– Prolonged NPO or clear liquids – Poor oral health, Dysphagia– Poor functional capacity, elderly.
Conditions associated with Malnutrition Risk
Nutritional Support
• The general goals of nutritional therapy are:• To provide adequate nutrients for anabolism• Maintain fluid balance • Prevent infection and complications
associated with nutritional therapy. • Provide information & emotional support
• Water and electrolytes
• Micronutrients
• Carbohydrate
• lipid
• Nitrogen
• Intact proteins
• Crystalline amino acid solutions
What • should the feed contain?
• Carbohydrates:• Purpose:
– To provide energy.– To spare body proteins.
• I.V source:• Dextrose is the I.V source of
carbohydrates calories. Carbohydrates calories can also be provided by glycerol, sorbitol, or fructose.
• Dextrose 5% 500 ml provides 100 calories, as each 100 ml contains 5 gm of glucose and each gram provides 4 calories.
• 1 gm CHO=4 K cal.
Proteins:• Purpose:• To promote tissue growth repair & replacement of body cells.• I.V source: • Amionsteril which provides 30 gm of amino acids
/500 ml.• • Daily requirement: • The protein requirement of an adult is 0.8 gm /kgm
/day, in disease states this should be increased to 1-3 gm / kgm/day.
• 1 gm of protein provides 4 kilocalories
Protein requirement
• In many critically ill patients, 1.2 - 1.3 g protein/kg of non-edematous weight
• 1.0 g/kg of current edematous weight) suffices to minimize net loss of body protein.
Fats:• Purpose:• To provide energy and calories. • To help in absorption of fat soluble vitamins. • To help the patient to gain weight.• I.V source:• Fat emulsion (Intralipids) provide
from 1000 cal / one liter. • 1 gm of fat =9 kilocalories.
Micronutrients:Electrolytes:
– potassium• Purposes:• To transport glucose and amino acid
across the cell membrane. • • Daily requirement:• Approximately 30 to 40 mEq of potassium is
necessary for each 1000 calories provided through parentral route.
Micronutrients:
– Magnesium, soudium, chloride and phosphorus.• Salvical which provide electrolytes and
energy.• Vitamins:• Water soluble and fat-soluble vitamins are added.• E.g. solu vit and cobalamin (B_12).
Micronutrients:Trace elements:• zinc • Purposes: • To promote wound healing.• Copper Purposes:• To assists in iron corporation in
hemoglobin.
How w • can we estimate the amount of feeding we should give?
REE (kcal/d) = 8 x body weight + 14 x height + 32 x minute ventilation + 94 x body temperature - 4834
REE can be measured by indirect calorimetery using metabolic monitor
Harris-Benedict was designed to estimate BEE in healthy, unstressed adults, but more closely
estimates REE
ICU patients rarely have much physical activity.
Chemical neuromuscular paralysis & Heavy sedation decreases energy expenditure by as much as 30%.
Total energy expenditure “TEE”= REE x Stress Factor x Activity Factor
Caloric requirement
• Protein → 10-35% of total caloric intake
• Carbohydrate → 45-65% of total caloric intake
• Fat → 20-35% of total caloric intake
Caloric requirement
Which • route should we feed by?
Enteral Nutrition
• Tube Feeding• Definition: • Tube feeding is the delivery of a liquid feeding
formula directly to the stomach using a feeding tube that is made of silicon, rubber or polyurethane.
• It has a small diameter, and more flexible, so decrease oropharyngeal irritation, distal esophageal irritation, and discomfort from swallowing.
• Purposes: The nurse initiates enteral tube feedings to:1. Administer nutrients to achieve calculated
nutri tional requirements.2. Administer nutrients to achieve the
recommended daily allowance (RDA) of vitamins and minerals.
3. Administer tree water for fluid balance
Indications:• 1-Inability to ingest adequate nutrients
orally• 2-Inability to maintain adequate caloric
needs• 3-For patients with a disturbed level of
consciousness
Contraindications to enteral nutrition
• Absolute contraindications:• Diffuse peritonitis • Intestinal obstruction that prohibits use of the bowel• Intestinal perforation• Paralytic ileus• Severe diarrhea that makes metabolic management
difficult• Relative contraindications:• Severe pancreatitis• Enterocutaneous fistula• Gastrointestinal ischemeia• Severe malabsorption
Methods of delivering formula through feeding tube
Bolus feedings• Bolus feedings are given by a large syringe in volume
as high as 400ml over 5-10 minutes, 5-6 times a day. • The stomach is the preferred site for administration.• It allow patient mobility between feedings because
his freedom from mechanical devices.• Bolus feedings are not well tolerated as a result of
high residuals, so nausea, vomiting, cramping, diarrhea, or aspiration are often accompanied.
• Intermittent feedings
• Intermittent feedings are administered as 300-400 ml by a slow gravity drip 4-6 times a day over a period of 30-60 minutes.
• The preferable site is the stomach. • Intermittent feedings are associated with
decrease the risk for osmotic diarrhea.
Continuous feedings• Continuous feedings are used when the tip of the tube
in the duodenum ,or jejunum ,and are administered over 24 hrs with the aid of a feeding pump to ensure a constant flow rate.
• Continuous pump feedings are the preferred method for intestinal feeding because too rapid delivery may lead to (dumping syndrome) which is characterized by characterized by osmotic diarrhea, abdominal distention, cramp, hyperperstalesis, lightheadness, diaphoresis, and palpitations.
• Continuous feedings can decrease the risk of aspiration , and allow more time for nutrients to be absorbed.
• Cyclic feedings • Cyclic feedings are continuous feedings that
deliver the total daily nutritional requirements in a shorter time frame over 8-12 hrs to allow patient freedom from 24 hrs continuous feedings.
• Cyclic feeding of high density & high volume are given at night to allow hunger to develop during the day.
Route Advantages Disadvantages
NasogastricShort term (less than 6 weeks) with functional GIT
Stomach is normal reservoir for food.Presence of hydrochloric acid in stomach helps destroy microorganism possibly reduce infection. Intermittent feeding into stomach are better tolerated than those into small intestine.
Not as appropriate for patients on long term tube feeding.Contraindicated for patients with history of aspiration pneumonia and those at high risk for aspiration. Some tubing materials are uncomfortable.
Route Advantages Disadvantages
Naso duodenalShort term with functional GIT may be used post operatively following gastric surgery.
May carry less risk for aspiration.May allow feeding after gastric surgery
Not desirable for long term tube feeding.Contraindicated for Patients with history of aspiration pneumonia and those at risk for aspiration. Difficult to place and maintain in the small intestine.Some tubing materials are uncomfortable.
Route Advantages Disadvantages
GastrostomyFor long-term tube feeding into the stomach for patient with alterations in swallowing secondary to neurologic disease or brain injury.
Same as nasogastric but more comfortable. Can not be misplaced into trachea.Easier to confirm tube placement. Usually inserted under anesthesia.
Percutaneous endoscopic gastrostomy (PEG) is contraindicated for patient’s with peritonitis, ascites, esophageal obstruction or severe gastroesophageal reflux.General anesthesia may be contraindicated.Possible aspiration risk for patient’s with gastric reflux or those who are weak and debilitated.Risk of skin break down around tube if the site is not properly cared for.Tube dislodgment before tract is mature may lead to peritonitis.
How to give Medication via N.G.T correctly?
Medications are a frequent cause of tube blockage. To minimize the problem, follow these guidelines:-• Administer the drug’s liquid formulation when ever possible.• Dilute the drug adequately before giving it. Viscous solution
increases the risk for clogging.• If the drug is available only as a tablet or capsule, ask the
pharmacist whether if it can be rushed or can be opened. Never crush or open enteric coated medications.
• Flush the tube with warm not hot water before and after giving the medication.
• If you are giving more than one medication, do not mix them together flush the tube with 5 - l0 ml of water between medications.
• Do not mix the medication with the formula.
Enteral feedingComplications:I- Mechanical (related to the tube size).• Pulmonary aspiration • Esophageal erosion• Esophageal reflux
Continue Mechanical complications (related to the tube size).
• Tube obstruction• Depressed cough
• Otatis media• Impaired gas exchange ( if aspiration
occurs). • Parotitis (an inflammation of one or both
parotid glands, the major salivary glands located on either side of the face)
II- GIT complications (10 %-20%)• Diarrhea
• Mal-absorption• High gastric residuals (return of at least
half the amount given over an hour) • Distension• Nausea & vomiting • Abdominal cramp
III- Metabolic • Hyper or hypoglycemia• or fat & albumin• or mineral or vitamin• Pre renal azotemia• Fluid & electrolyte alteration• Essential fatty acids deficiency• Hyperosmolar • coma
Parenteral nutrition1- Peripheral parenteral nutrition• Is the administration of macro-& micro-
nutrients necessary to maintain health in the form of liquid solution suitable for direct intravenous administration.
Purposes
• To improve the patient's nutritional status, provide calories, replaces essential vitamins, electrolytes and minerals.
• To restore nitrogen balance.• To meet the patient's energy requirements.• To improve wound healing promotes tissue
synthesis.• To promote weight gain.• To promote anabolism.• To allow bowel rest and healing.• To improve tolerance to surgery.
Indications:• A 10% deficit in body weight in short period of time
(3-6 months).– Excessive vomiting.– Anorexia nervosa.– Malabsorption.
• Inability to take oral feeding or fluid within 7 days post operative.
• Gastrointestinal problem: as intestinal obstruction & pancreatitis.
• Ulcerative colitis.
Hyper-catabolic state.• Trauma.• Sever burns.• Immunocompromised states as: bone marrow
depression &Aids.• Cancer.• Major infection with fever.
Parenteral nutrition medication additives
• Insulin is considered to be chemically stable in nutrition; insulin is responsible for adequate metabolism of carbohydrates. As hyperglycemia is the most common complication of TPN which is due to high concentration of glucose.
• Heparin doses of 100 to300 unit / liter have been routinely used to decrease the incidence of subclavian vein thrombosis.
• Cimetedine can be added to the TPN solution as prophylactic measure against development of stress ulcer.
Methods of TPN administration
Peripheral parenteral nutrition:• Indications:• Patients in whom central venous access is
either impossible or contraindicated.• Patients with fluid restrictions.• Patients expected to resume enteral
feeding within 7 to 10 days.
Types of solutions administered
• Dextrose 5% and 10%.• Crystalline amino acids• Electrolyte, trace elements and vitamins.• Fat emulsions
Advantages
• Avoids insertion and maintenance of central catheter.
• Delivers less hypertonic solution than venous TPN.
• Reduces the chance of metabolic complication than central venous TPN
Disadvantages
• Can't be used in nutritionally depleted patients.
• Does not generally increase a patient's weight.• May cause phlebitis due to osmolarity of
solutions
Central parenteral nutritionIndications:• Large volume of fluids.• High concentration and hyperosmolarity solutions. Advantages:• Useful for long term therapy (usually longer than 3
weeks).• Useful for patients with large caloric &nutrient needs.• Decrease the incidence of phlebitis.• Examples:• 8.5-10% amino acids.• 50-70%dextrose
Disadvantages:• Requires a minor surgical to insert central line.• May cause metabolic complication as glucose
intolerance, electrolyte imbalance and essential fatty acid deficiency.
Complications:I- Upon insertion1- Mechanical• Pneumothorax• S.C emphysema• Misplacement of the tip of the catheter
2- Vascular• Subclavian or carotid injury• Subclavian hematoma• Thorax duct injury• Cardiac damage (perforation)• Hemothorax• Venous injury
3- Neurological damage• Brachial plexus injury• Phrenic nerve injury• Horner’s syndrome ( if sympathetic
trunk injury)• Ptosis, myosis, anhydrosis,
exophthalmus.
II- During maintenance1- Infection• Catheter sepsis• Septicemia• Endocarditis2- Venous thrombosis• Local (central thrombosis)• Distal • Thromboembolism
3- Serious cavity problems• Hydrothorax• Cardiac tamponade4- Metabolic • As enteral feeding• Respiratory distress (carbohydrate produces
carbon dioxide & water. In patients with respiratory disease, the increase in Co2 production from the metabolism of the hypertonic glucose solutions in TPN may not tolerated
5- Others• A.V fistula• Air embolism• Catheter embolism
Nursing considerations:• Assess for sharp chest pain or decreased
breath sounds• Assess the LOC, presence of paralysis,
seizures and tremors.• Check for increased or decreased blood
pressure, decreased urinary output, presence of fever, distended neck veins, wheezes, edema, nausea or vomiting, and diarrhea.
• Full aseptic precautions should be used during any manipulation of any lumen of the catheter, in line care, and in dressing changes and solution preparation.
• Inspect insertion site q shift for potential phlebitis.
• Inspect oral mucosa at least once daily for signs of potential painful oral mucosa, gingivitis and/or xerostomia
Parenteral versus Enteral nutrition