fundamentals of fluid and electrolyte balance parenteral solutions adn136 fall 09

Fundamentals of Fluid and Electrolyte Balance

Parenteral Solutions

ADN136Fall 09

Fluid Balance

Body fluid is body water in which electrolytes are dissolved

Bodywater makes up 60% of Total Body weight in young men 50-55% in women 70-80% in infants

Fluid Balance

Fluid Balance (cont)

Homeostasis- Dependent on fluid and electrolyte intake physiologic factors, disease state factors, external environmental factors and pharmacologic intervention. Intracellular fluid (ICF) water in the cells =

40% Extractracellular fluid (ECF) fluid out side

the cells = 20% 15% in tissue space (interstitial) outside the

blood vessel, between cells 5% in plasma (intravascular space)

Percentage of Body Fluid

Fluid Balance

Normal intake 1-3 L/day 200-300 ml produced by oxidation Normal intake and output will

balance approximately every 72 hours

Fluid Balance

Elimination of fluids is considered Sensible (measurable) loss

Skin, Kidneys, Bowels, lungs lose fluid 300-500ml lost through lungs every 24

hrs. 500ml lost with perspiration

Insensible (not measurable) loss Considered to be 500-1000ml/day

Lost through GI tract only 100-200 ml/day

Fluid Balance (cont)

Loss from Diarrhea or intestinal fistula

Significant sweat loss when body temp >101F-38.3C or room temp > 90F

When respirations > 20/min Formula to calculate insensible loss

300-400ml/m2/day

Fluid Function

The fluid in the body has the following function:1. Maintains blood volume2. Regulates body temperature3. Transports material to and from cells4. Serves as an aqueous medium for cellular

metabloism5. Assists digestion of food through hydrolysis6. Acts as a solvent in which solutes are available

for cell function7. Serves as a medium for the excretion of waste

Fluid Transport

4 transport mechanisms Passive transport

Passive diffusion- Osmosis Filtration

Active transport

Fluid Transport

Passive transport- non carrier mediated transport- Fluid moves through membranes with out the expenditure of energy Passive diffusion - movement of water and

other elements in all directions from high concentration to low concentration

Osmosis – passage of water from low particle concentration toward one of higher particle concentration

Normal osmolarity – 280-295 mOsm/L Osmolarity of ICF and ECF is always equal

Fluid Transport (cont)

Filtration – the transfer of water and a dissolved substance from a region of high pressure to a region of low pressure. Force behind it is hydrostatic pressure (the pressure of water at rest) Pumping heat provides hydrostatic

pressure in the movement of water and electrolytes from the arterial capillary bed to the interstitial fluid.


Plasma protein creates and osmotic pressure at the capillary membrane, preventing fluid from plasma leaking into interstitial spaces

Osmotic pressure (created within the plasma) keeps water in the vascular system


Starling’s law of capillaries Under normal circumstances fluid

filtered out of the arterial end of a capillary bed and reabsorbed at the venous end is exactly the same, creating a state of near equilibrium


Active Transport – acts as a concentration gradient ATP – released from the cell to enable

substances to acquire the energy needed to pass through the cell membrane

Active Transport is vital for maintaining the unique composition of both the intracellular and intracellular compartments

Tonicity of Solution

Isotonic - .9% saline, 5% dextrosesame as body fluidsOsmolarity of 250-375mOsm/LRemains within the ECF spaceUsed to expand ECF compartment

Isotonic Solution


Hypotonic – contains less salt than the intracellular space 2.5% DWOsmolarity below 250mOsm/L

Hydrates cellsDepletes the circulatory system

Hypotonic Solution


Hypertonic – causes water from within a cell to move to the ECF compartment Osmolarity of 375mOsm/l or greater Used to replace electrolytes Used to shift EDF from interstitial tissue

to plasma D5W, .9 Normal Saline

Hypertonic Solution

Homeostatic Mechanism Regulation of body water is

maintained Exogenous sources - Intake of food &

Fluids (nurse’s responsibility) Endogenous sources – produce with in

the body through chemical exidation process (various body systems responsible)

Homeostatic Mechanisms Renal System – Kidneys filter 170L l of

plasma/day and excrete 1.5L of urine Regulation of fluid volume and osmolarity by

selective retention and secretion of body fluid Regulation of electrolyte levels by selective

retention of needed substances and excretion of unneeded substances

Regulation of pH of ECF by excretion or retention of hydrogen ions

Excretion of metabolic wastes (primarily acids) and toxic substances

Homeostatic Mechanism Cardiovascular System –

Pumping action of the heart provides circulation of blood through the kidneys under pressure

Allow urine to form Renal perfusion makes renal function

possible

Homeostatic Mechanism

Lymphatic system – Serves as an adjunct to the cardio

vascular system by removing excess interstitial fluid (lymph) and returning it to the circulatory system

Prevents fluid overload


Respiratory System Lungs are vital for maintaining

homeostasis and constitute one of the main regulatory orgnas of fluid and acid base balance

Functions of the lungs Regulation of metabolic alkalosis by

compensatory hypoventilation Regulation of metabolic acidosis by

causing compensatory hyperventilation Removal of 300-500 ml of water daily

through exhalation


Nervous system Master controller in fluid and electrolyte

balance through the regulation of sodium and water

Endocrine system Responsible for aiding homeostasis

through production of various hormones

Antidiuretic hormones (ADH) Parathyroid Hormones Aldosterone Epinephrine

Physical Assessment Vital signs, infusion rate of IV fluids,

intake and output. Neurological - Changes in

orientation, irritability, lethargy, confusion, seizures or coma

Cardiovascular – Quality and rate of pulse Peripheral vein filling Orthostatic hypertension Distended or Flat neck veins

Physical Assessment

Physical Assessment Respiratory

Changes in respiratory rate Tachypnea > 20/min or dysphnea indicate

excess Fluid Volume (FVE) Moist crackles (FVE) Shallow Slow breathing- Metabolic

Acidosis Deep rapid Breathing – Metabolic Alkalosis

Physical Assessment

Skin Appearance & Temperature Access skin turgor Appearance of the tongue

Physical Assessment

Body Weight Weigh Daily – better indicator than I&O

records Loss or gain of 1 kg indicates a loss or

gain of 1 L of body fluid 15% flucation is considered sever

Fluid Volume Imbalance

Fluid Volume Deficit Common Causes of Isotonic Dehydration

Hemorrhage resulting in loss of fluid, electrolytes, proteins and blood cells resulting in inadequate vascular volume

Gastrointestinal losses Fever, environmental heat, profuse sweating Burns Diuretics Third spaced fluids


Causes of Hypertonic Fluid Dehydration Inadequate fluid intake Decreased water intake results in ECF

solute concentration and leads to cellular dehydration


Fluid Volume Excess Primary cause – Cardiovascular dysfunction

secondary to an increase in total body sodium content

Causes of isotonic over hydration Renal failure leading to decrease excretion of

water and sodium Heart failure leading to stasis of blood Excess fluid intake of isotonic IV solution High corticosteroid levels

High Aldosterone levels


Common causes of Hypotonic Over hydration (Water intoxication) More fluid is gained than solute Serum osmolality falls causing cells to swell Repeated water enemas Overuse of hypotonic IV fluids Ingestion of inappropriately prepared formula SIADH causes kidneys to retain large amounts

of water without sodium Treatment- sodium and fluid restriction,

diuretics, treat underlying cause.

Electrolyte Balance

Major electrolytes in body fluid are sodium, potassium, calcium, magnesium, chloride, phosphorus and bicarb

Expressed in meq/liter. Measures chemical activity or combining power rather than weight

Each water compartment of the body contains electrolytes Concentration and composition vary from

compartment to compartment

Electrolyte Balance (cont)

Physiological role of electrolytes Maintaining electroneutrality in fluid

compartments Mediating enzyme reactions Altering cell membrane permeability Regulating muscle contraction and

relaxation Regulating nerve impulse transmission Influencing blood clotting time


Sodium- 135 -145 mEq/L Physiologic role of sodium:

Regulation of fluid distribution in body: water follows sodium

Maintenance of body fluid osmolarity Promotion of neuromuscular response:

Transmission of nerve and muscle impulses depends on sodium, gradient between ECF and ICF

Regulation of acid-base balance: Sodium combines with chloride and bicarbonate to alter pH

Electrolyte Balance (cont) Sodium represents 90% of the

extracellular cations Serum plasma levels of electrolytes are

important in the assessment and management of patients with electrolyte imbalances

Normal daily requirement 100mEq Hyponatermia is a common complication

of adrenal insufficiency Hypernatermia – Serum Sodium excess

great that 145mEq/L can occur with deprivation of water


Signs and Symptoms - Marked thirst, elevated body temperature, swollen tongue. Chronic Hyponatremia: impaired sensation of

taste, anorexia, muscle cramps, feeling of exhaustion, apprehension, feeling of impending doom and focal weakness.

Treatment: Gradually lower seum sodium level by infusion of hypotonic electrolyte solution .45 Normal Saline or D5W. Level lowered no more than 15 mEq/L in 8 hr.


Potassium: Physiological role Regulation of fluid volume within the cell Promotion of nerve impulse transmission Contraction of skeletal smooth and cardiac

muscle Control of hydrogen ion concentration, acid-

base balance Role of enzyme action for cellular energy

production.


Potassium is an intracellular electrolyte with 98% in ICF and 2% in the ECF

Acquired thru diet and must be ingested daily

Daily requirement is 40 mEq Involved in muscle activity and

transmission of nerve impulses.


Hypokalemia (cont) – Can cause alkalosis S&S fatigue, muscle weakness,

anorexia, nausea and vomiting, irregularity

Treatment – at level less than 3.5mEq/L replacement must be slow to prevent hyperkalemia


Hyperkalemia- Serum plasma level greater than 5.5mEq/L Increased intake of potassium Decreased urinary excretion Movement out of cells into extra cellular space.

Signs & Symptoms Changes shown on ECG Vague muscle weakness Flaccid paralysis Anxiety Nausea and vomiting Cramping and diaherrea


Calcium: Physiological role Maintaining skeletal elements; calcium

is needed for strong bones and teeth Regulating neuromuscular activity Influencing enzyme activity Converting prothrombin to thrombin, a

necessary part of clotting. 99% resides in bones and teeth


Hypocalcemia: reduction in total body calcium levels Because of increase calcium loss, reduced

intake secondary to altered intestinal absorption, altered regulation hypoparathyroidism

S & S: Numbness of fingers, muscle cramps,

hyperactive deep tendon reflexes, positive Trousseaus’s sign and Chevostek’s sign

Treatment with Calcium Gluconate oral or IV


Hyperclacemia: Excessive release of calcium from bone

S & S Neuromuscular symptoms, lethargy, bone pain, flank pain, pathological fractures, constipation, anorexia, N & V, Stone formation.


Magnesium: Physiological role Enzyme action Regulation of neuromuscular activity Regulation of electrolyte balance,

including facilitating transport of sodium and potassium across cell membranes, influencing the utilization of calcium, potassium, and protein.

A major intracellular electrolyte


Hypomagnesemia: often overlooked in critically ill patients

Results from: Chronic alcoholism Malabsorption syndrome Prolonged malnutrition or starvation Prolonged diarrhea Acute pancreatitis Administration of magnesium-free solutions for

more than one week Prolonged NG tube suctioning


S & S Neuromuscular symptoms

Hyperactive reflexes, Coarse tremors Muscle cramps Positive Chvostek’s and Trousseau’s signs Seizures Paresthesia of the feet and legs Painfully cold hands and feet Disorientation dysrhythmias tachycardia

and indreased potential for digitalis toxicity


Hypermagnesemia: renal failure, addison’s disease, and inadequate excretion of magnesium by kidneys

S & S: Neuromuscular symptoms

Flushing and sense of skin warmth Lethargy Sedation Hypoactive deep tendon reflexes, Depressed respiration Weak or absent new born cry

Electrolyte Balance (cont) Phosphorus: physiologic role:

Essential to all cells Role in metabolism of proteins, carbohydrates

and fats Essential to energy, necessary in the formation

of high energy compounds adenosine triphosphate (ATP) and adenosine diphosphate (ADP)

As a cellular building block, it is the backbone of nucleic acids and is essential to cell membrane formation’

Delivery of oxygen; functions information of red blood cell enzyme.

Electrolyte Balance (cont) Approximately 80% is contained in the

bones and teeth 20% is abundant in the ICF Plays and important role in delivery of

oxygen to tissues by regulating the level of 2,3-DPG

Hyphphosphatemia: results from Overzealous refeeding, TPN administered without adequate

phosphorus Malabsorption Alcohol withdrawal Vomiting, chronic diarrhea, and malabsorption

syndromes


Other Electrolyte imbalance: Hyperphosphatemia Hypochloremia Hyperchloremia

fundamentals of fluid and electrolyte balance parenteral solutions adn136 fall 09

Documents

fluid balance body fluid

fluid balance slide

interstitial fluid

fluid function

fundamentals of fluid

percentage of body fluid

fluid transport cont

fluid balance cont loss