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