fundamentals of fluid and electrolyte balance parenteral solutions adn136 fall 09
TRANSCRIPT
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.
Fluid Transport (cont)
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
Fluid Transport (cont)
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
Fluid Transport (cont)
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
Tonicity of Solution
Hypotonic – contains less salt than the intracellular space 2.5% DWOsmolarity below 250mOsm/L
Hydrates cellsDepletes the circulatory system
Hypotonic Solution
Tonicity of 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
Homeostatic Mechanism
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
Homeostatic Mechanism
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
Fluid Volume Imbalance
Causes of Hypertonic Fluid Dehydration Inadequate fluid intake Decreased water intake results in ECF
solute concentration and leads to cellular dehydration
Fluid Volume Imbalance
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
Fluid Volume Imbalance
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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.
Electrolyte Balance (cont)
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.
Electrolyte Balance (cont)
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.
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
Hyperclacemia: Excessive release of calcium from bone
S & S Neuromuscular symptoms, lethargy, bone pain, flank pain, pathological fractures, constipation, anorexia, N & V, Stone formation.
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
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
Electrolyte Balance (cont)
Other Electrolyte imbalance: Hyperphosphatemia Hypochloremia Hyperchloremia