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Fluids, Electrolyte, and Acid-Base Balance

Susan L. Maiocco, RN, APN, C

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Fluid Balance– Body Fluid

• Water and dissolved substances

• Electrolytes• Gases• Non-electrolytes

– Homeostasis• Establishes and

maintain equilibrium in the exchange of water among the internal fluid compartments of the body and between the body and the external environment

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Body Fluids

• Water– Most essential nutrient of life

• Provides medium for transporting nutrients to and from cells

• Transports substances such as hormones, enzymes, blood platelets, and red and white blood cells

• Facilitates metabolism and proper cellular chemical functioning

• Acts a s a solvent for electrolytes and non-electrolytes• Maintains normal body temperature• Facilitates digestion and promotes elimination• Acts as a tissue lubricant

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Body Water and Fluid Compartments

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Fluid and Electrolyte Movement

• Cell membranes – Semipermeable

• Allows some particles to pass through while other solutes are not able to be transported

• Osmolarity– Concentration of particles in a solution

(pulling power)

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Osmosis

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Isotonic• Has the same

concentration of particles as plasma (osmolarity)

•If the concentration of solute (salt) is equal on both sides, the water will move back in forth but it won't have any result on the overall amount of water on either side."ISO" means the same

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Hypertonic

•Has greater osmolarity than plasma•The word "HYPER" means more, in this case there are more solute (salt) molecules outside the cell, which causes the water to be sucked in that direction.

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Hypotonic

•Has less osmolarity than plasma

•The word "HYPO" means less, in this case there are less solute (salt) molecules outside the cell, since salt sucks, water will move into the cell.•The cell will gain water and grow larger.

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Diffusion

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Active Transport

• Process that requires energy for the movement of substances through a cell membrane from an area of lesser solute concentration to an area of higher solute concentration

• Adenosine triphosphate or ATP, stored in all cells, is released from a cell and supplies energy for solute movement in and out of the cell.

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Filtration

• The passage of fluid through a permeable membrane.

• Passage is from an area of high pressure to one of lower pressure.

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Fluid Balance

• Adult intake and loss– 1500-3500 ml each 24 hours– Average

• 2500-2600 ml/per day

• Fluid Sources– Ingested liquids– Water contained in food– Metabolism

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Gains and Losses

•Kidneys•Skin•Lungs•GI tract

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Fluid Loss

• Kidneys– Urine

• Intestinal Tract– Feces

• Skin– Perspiration

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Acid-Base Balance

• pH– Unit of measure to describe acid-base balance– Expression of H+ ion concentration and the

resulting acidity or alkalinity of a substance– Acid

• Substance containing H+ ions that can be liberated or released (e.g. carbonic acid)

– Base• Substance that can accept or trap H+ ions (e.g.

bicarbonate)

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An acid releases H+, as follows

A base traps H+, as follows:

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H+ Balance Control

• Respiratory– Lungs are the primary controller of

body’s carbonic supply

• Renal– Kidneys regulate concentration of

bicarbonate in the plasma

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Disturbances in Fluid , Electrolyte, and Acid-Base Balance

• Fluid volume deficit (hypovolemia or isotonic fluid loss)

• Caused by a loss of both water and solutes in the same proportion from the ECF space

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Risk Factors

• Vomiting, diarrhea, suction, fistulas• Hemorrhage• Excessive sweating• Skin trauma, burns, draining wounds• Third-space fluid shifts• Excessive laxative or diuretic use• Polyuria from renal disease or diuretics• Hyperglycemia• Change in mental status

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Assessment

• Thirst• Weight loss over

short period• Weakness, fatigue,

anorexia• Dry mucous

membranes• Postural

hypotension

• Weak, rapid pulse

• Poor skin and tongue turgor

• Sunken eyes• Flat neck veins• Urine output <30

mL/hr• ↑ Urine specific

gravity• ↑Hematocrit• ↑BUN• ↑Serum sodium• Altered sensorium

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Nursing Interventions

• Assess for presence or worsening of FVD.• Administer oral fluids if indicated.• If patient unable to eat and drink,

anticipate TPN or tube feedings to be ordered.

• Monitor patient's response to fluid intake, either oral or parenteral.

• Be alert for signs of fluid overload.• Provide appropriate skin care.

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Fluid Volume Excess– Fluid volume excess

(hypervolemia or excess of isotonic fluid)

• Excessive retention of water and sodium in ECF in near equal proportions

• May accumulate in intravascular compartments or interstitial spaces

• Accumulation of fluid in interstitial space is known as edema

– Eyes, fingers, ankle, sacral area

– >5% weight gain

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Risk factors

– Compromised regulatory mechanisms: renal failure, CHF, cirrhosis of liver,

– Cushing's syndrome– GI irrigation with hypotonic fluid– Excess IV fluids with sodium– Corticosteroid therapy– Excessive ingestion of sodium-

containing substances in diet or sodium-containing medications

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Assessment• Weight gain over short

period• Peripheral edema

(may be pitting)• Increased BP• Shortness of breath• Crackles and wheezes

in lungs• Full, bounding pulse• Neck vein distention• Polyuria if renal

function is normal

• Ascites, • Pleural effusion• Pulmonary edema• ↓BUN (due to plasma

dilution)• ↓Hematocrit• ↓Serum sodium• ↓Urine specific gravity

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Nursing Interventions

• Assess for presence or worsening of FVE• Encourage adherence to sodium-restricted

and fluid-restricted diet, if ordered.• Avoid OTC drugs or check with physician

or pharmacist about sodium content.• Encourage rest periods.• Monitor patient's response to diuretics.• Teach self-monitoring of weight and intake

and output.• Attentive skin care.• Monitor respiratory status.

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Major Electrolytes

2.7-4.5 mEq/LPO4-

22 - 26 mEq/LHCO3-

98-106 mEq/LCl-

1.5 - 2.5 mEq/LMg2+

8.4 -10.5mg/dLCa2+

3.5 - 5 mEq/LK+

135 -145 mEq/Na+

Normal ValueElectrolyte

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Electrolyte Imbalances

• Deficit or excess of an electrolyte• Indicates dysfunction

– Fluid or acid-base imbalance– Neuromuscular– Cardiac– Renal – Endocrine– Skeletal

• Venous sampling

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Hyponatremia

• Sodium deficit in ECF < 135 mEq/L– Caused by loss of sodium or gain of

water

• Fluid moves from less concentrated ECF to ICF space

• Leads to swelling of cells and cerebral edema

• Watch for seizures

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Hypernatremia

• Surplus of sodium in ECF > 145 mEq/L– Results from excess water loss or excess

of sodium

• Fluids move from the cells causing them to shrink

• CNS are especially affected– Neurological impairment

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Hypokalemia

• Potassium deficit in ECF < 3.5 mEq/L• K+ moves from the cell creating

intracellular K+ deficiency• Skeletal muscles are first to

demonstrate K+ deficiency– Muscle weakness– Leg cramps

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Hyperkalemia

• Excess K+ in ECF > 5.0 mEq/L• Affects nerve conduction, muscle

contractility• Cardiac irregularities, cardiac arrest

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Hypocalcemia

• Calcium deficit in ECF, < 8.4 mg/dL– Inadequate calcium intake– Impaired calcium absorption– Excessive calcium loss

• Sx– Numbness/tingling of fingers– Muscle cramps– Tetany

Chvostek’s Sign

• Elicitation: Tapping on the face at a point just anterior to the ear and just below the zygomatic bone

• Postitive response: Twitching of the ipsilateral facial muscles, suggestive of neuromuscular excitability

• Caused by hypocalcemia

Trousseau’s Sign

• Elicitation: Inflating a sphygmomanometer cuff above systolic blood pressure for several minutes

• Postitive response: Muscular contraction including flexion of the wrist and metacarpophalangeal joints, hyperextension of the fingers, and flexion of the thumb on the palm, suggestive of neuromuscular excitability

• Caused by hypocalcemia

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Hypercalcemia

• Excess of calcium in ECF > 10.5 mg/dL– Cancer– Hyperparathyroidism

• Emergency –can lead to cardiac arrest

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Hypomagnesemia

• Magnesium deficit in ECF < 1.5 mEq/L– Chronic alcoholism– Intestinal malabsorption

• Sx– Heart block– AMS– Hyperactive deep tendon reflexes– Respiratory paralysis

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Hypermagnesemia

• Magnesium excess in ECF– early sign

•3-5 mEq/L

– End-stage renal failure• Kidneys fail to excrete magnesium

– Excessive magnesium intake

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Hypophosphatemia

• Below normal serum concentration of phosphorous in the ECF < 2.7mg/dL– Hyperventilation– Insulin release– Absorption problems– Diuretic use

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Hyperphosphatemia

• Above normal serum concentrations of phosphorous in the ECF > 4.5 mg/dL– Impaired kidney excretion– Hypoparathyroidism

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Grading Edema

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What Do We Assess for re: Fluid, Electrolyte, and Acid-Base

Balance………• VS• Intake and Output• Urine

volume/concentration• Body weight• Skin Turgor• Tongue turgor

– Multiple longitudinal furrows

• Moisture and oral cavity• Tearing and salivation

– Absent• Facial appearance

– Pinched and drawn– Sunken eyes

• Neck veins

• Appearance of skin and skin temperature

– Warm, flushed skin (Peripheral

vasodilation)• Edema

– Clinical edema is usually not apparent in the adult until the retention of 5-10 lbs. of excess fluid occurs

• Body temperature• Neuromuscular irritability

– DTR

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Laboratory Studies• CBC

– The complete blood count, the basic screening test, determines the total number of red blood cells and values for hemoglobin and hematocrit. Significant values include the following:

– Increased hematocrit values: found in severe fluid volume deficit and shock (when hemoconcentration rises considerably)

– Decreased hematocrit values: found with acute, massive blood loss, and with hemolytic reaction after transfusion of incompatible blood or with fluid overload

– Increased levels of hemoglobin: found in hemoconcentration of the blood

– Decreased levels of hemoglobin: found with anemia states, severe hemorrhage, and after a hemolytic reaction

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Laboratory Studies

• Serum Electrolytes, BUN, and Creatinine Levels– Determines plasma levels

• Sodium• Potassium, • Chloride, • Bicarbonate ions • BUN and creatinine levels

– Provide information related to the fluid status and the renal function of the patient.

– BUN-10-20 mg/100mL– Creatinine-0.7-1.4 mg/100mL

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Laboratory Studies

• Urine pH and Specific Gravity– dipstick measurement– fresh voided specimen – laboratory analysis. – pH of urine

• 4.5 and 8.2– Specific gravity

• measure of the urine's concentration• Range depends on the patient's state of hydration

and varies with urine volume and the load of solutes to be excreted

• Normal values range from 1.003 to 1.035 (concentrated urine: 1.020–1.030 or more; dilute urine: 1.001–1.010).

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Laboratory Studies• ABG’s determine the

adequacy of oxygenation and ventilation and to assess acid–base status.

• Partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) results directly reflects the adequacy of oxygenation and ventilation.

• When interpreting ABGs, follow these necessary steps:– Determine whether the pH

is alkalotic or acidotic.– Check for the cause of the

change in pH. Is it respiratory (PaCO2) or metabolic (HCO3-)?

In respiratory acid–base imbalances, the pH and PaCO2 values are inversely abnormal (move in opposite directions):

– Respiratory acidosis:• ↓ pH < 7.35 ↑ PaCO Normal HCO3-

– Respiratory alkalosis:• ↑ pH > 7.45 ↓ PaCO2

Normal HCO3-

In metabolic acid–base imbalances, the pH and HCO3-values are both high or both low:

– Metabolic acidosis:• ↓ pH < 7.35 ↓ HCO3-

Normal PaCO2– Metabolic alkalosis:

• ↑ pH > 7.45 ↑ HCO3- Normal PaCO2

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How do you know if the patient is in some type of compensated

process……..• Anytime PaCO2 and HCO3- are going the

same direction (either both high or both low), it is a compensated process - such as partially compensated respiratory acidosis (both PaCO2 and  HCO3- are high)– Respiratory

• Renal system ↑ or ↓ HCO3-

– Metabolic• Respiratory system regulates CO2 levels

• The focus of compensation efforts is to return the pH to normal range

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Sum It All Up• Look at pH and determine if it is high or low (alkalosis or

acidosis) • Examine the PaCO2 and determine if it indicates acidosis

or alkalosis– If pH is low it is some type of acidosis

• If PaCO2 is high, it’s respiratory acidosis • If HCO3 is low it’s metabolic acidosis

– If pH is high it is some type of alkalosis • If  PaCO2 is low, its respiratory alkalosis • If  HCO3 is high, its metabolic alkalosis

• Identify the origin of the acid-base disturbance as respiratory or metabolic– Circle the acidosis or alkalosis that matches the pH

• Determine whether the patient is in compensation– If the pH is normal, and values for respiratory and metabolic

components outside their normal ranges but in opposite directions, the patient is fully compensated

– If the pH is not normal, look at the value not circled. If within normal limits, the patient is uncompensated; if outside the normal limits, patient is compensated

– Anytime PaCO2 and HCO3 are going the same direction (either both high or both low), it is a compensated process - such as partially compensated respiratory acidosis (both PaCO2 and HCO3 are high)

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Nursing Process

• Identifying patients at high risk for fluid, electrolyte, and acid–base imbalance

• Determining that a specific imbalance is present and identifying the nature of the imbalance along with its severity, etiology, and defining characteristics or assessment findings

• Determining the plan of care, including the appropriate nursing diagnosis/es or collaborative problem/s, followed by the identification of specific outcomes, associated interventions, and the evaluation of the effectiveness of the plan of care

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Nursing Diagnosis

1. Excess Fluid Volume2. Deficient Fluid Volume3. Risk for Imbalanced Fluid Volume

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Intravenous Therapy• Maintain strict aseptic

technique• Examine the solution for

type, amount, expiration date, character of the solution, and lack of damage to container

• Select and prepare an IV infusion pump, as indicated

• Monitor for IV patency before administration of IV medication

• Perform IV site checks according to agency policy

• Maintain occlusive dressing• Flush IV lines between

administration of incompatible solutions

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IV Administration

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Vascular Access Devices• Peripheral Venous Catheters• Central Venous Access Devices

– Peripherally inserted central catheters (PICCs)– Nontunneled percutaneous central venous

catheters• Shorter dwell time• Introduced through skin into jugular, subclavian,

femoral veins and sutured in place– Tunneled central venous catheters

• Long term use• Implanted into internal jugular subclavian or

femoral vein• Tunneled in subclavian tissue under skin and

sutured in place– Implanted ports– Requires aseptic technique with mask R/T

dressing, tubing, cap changes

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CVAD

• Provides access for IV fluids, medications, blood products, and TPN solutions

• Means for hemodynamic monitoring and blood sampling

• CVAD is usually introduced into the subclavian or internal jugular vein and passed to the superior vena cava just above the right atrium

• All CVADs require radiographic confirmation of position.

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PICC

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Triple Lumen CVC (nontunneled)

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Implanted Port

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Peripheral IV Sites

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Infusion Site Care• Maintain patency• Observe site for complications• Regular dressing changes (aseptic technique) and tubing

replacements are important means of preventing infection. – 2% chlorhexidine-based solution is recommended for skin

antisepsis for central venous catheter site care (CDC, 2002).

– For peripheral catheter site care, chlorhexidine is preferred.

– Iodine, iodophor, and 70% alcohol are considered acceptable alternatives (Hadaway, 2003).

– Transparent membrane dressings are used most commonly to protect the insertion site.

– Transparent dressings (eg, Tegaderm or OpSite IV) allow easy inspection of the IV site, permit evaporation of moisture that accumulates under the dressing, and help to secure the catheter.

• Agency policy generally determines the type of dressing and the intervals for dressing change.

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Complications• Infiltration: the escape of

fluid into the subcutaneous tissue – Dislodged needle

Penetrated vessel wall – Swelling, pallor, coldness,

or pain around the infusion site; significant decrease in the flow rate

• Sepsis: microorganisms invade the bloodstream through the catheter insertion site – Poor insertion technique– Red and tender insertion

site Fever, malaise, other vital sign changes

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Complications• Phlebitis: an inflammation

of a vein– Mechanical trauma from

needle or catheter– Chemical trauma from

solution– Septic (due to

contamination)– Local, acute

tenderness; redness, warmth, and slight edema of the vein above the insertion site

• Thrombus: a blood clot – Symptoms similar to

phlebitis – IV fluid flow may cease

if clot obstructs needle

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Complications

• Speed shock: the body's reaction to a substance that is injected into the circulatory system too rapidly – Too rapid a rate of fluid infusion into circulation– Pounding headache, fainting, rapid pulse rate,

apprehension, chills, back pains, and dyspnea

• Fluid overload: the condition caused when too large a volume of fluid infuses into the circulatory system– Too large a volume of fluid infused into circulation– Engorged neck veins, increased blood pressure, and

difficulty in breathing (dyspnea)

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Complications

• Air embolus: air in the circulatory system– Break in the IV system above the heart level allowing air

in the circulatory system as a bolus – Respiratory distress– Increased heart rate– Cyanosis– Decreased blood pressure– Change in level of consciousness – Pinch off catheter or secure system to prevent entry of

air.Place patient on left side in Trendelenburg position.Call for immediate assistance.Monitor vital signs and pulse oximetry.

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Blood Products• Typing and Cross-Matching• Blood Types

– A, B, AB, and O• Rh Factor • Donate their own blood for transfusion

(autologous transfusion) • Group AB

– Universal Recipient• Have no agglutinins for A or B antigens

• Group-O– Universal Donor

• Have neither A or B antigens

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Blood Components• Packed red blood cells

– Patient with anemia (a reduction in red blood cells or hemoglobin)

– Patient with cardiovascular failure, with a need to increase blood volume and red blood cells while avoiding cardiovascular overload

– Patient with GI bleeding, with a need to maintain adequate hemoglobin levels without increasing blood pressure, which would likely lead to more bleeding

• Fresh-frozen plasma – When only plasma is required, such as when plasma

protein or the blood's clotting factor is low. • Platelet infusion

– is indicated for the treatment or prevention of bleeding associated with deficiencies in the number or function of a patient's platelets

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Transfusion Reactions

• Allergic reaction: allergy to transfused blood

• Febrile reaction: fever develops during infusion

• Hemolytic transfusion reaction: incompatibility of blood product

• Circulatory overload: too much blood administered

• Bacterial reaction: bacteria present in blood

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TPN• Total parenteral nutrition (TPN)

– Highly concentrated nutrient solution consisting of dextrose, amino acids, and select electrolytes, vitamins, minerals, and trace elements that must be infused through a central vein because of its hypertonic nature

• Hypertonic• Monitor glucose levels/lytes• Should infuse by itself-designated lumen

– Given to patients who are unable to meet their nutritional needs through the oral or enteral routes.

– Complication• Catheter related infection• Electrolyte imbalances

– Must not be stopped suddenly causes hypoglycemic reaction