Download Fluid and Electrolytes

Fluid and Electrolytes
Homeostasis
 The state of equilibrium in the internal environment of the body
Distribution of body fluids
 Intracellular
o 2/3 of body fluids
o Vital to cells
o Medium for metabolism
 Extracellular
o 1/3 of body fluids
 Interstitial
 Intravascular
 Transcellular
o Medium for transport
 Oxygen, nutrients, and waste
o ECF fluid is the blood – only 5% is in the vessels
Electrolytes
 Electrically charged particles
o Cations: Na+, K+, Ca+, Mg++
o Anions: Cl-, HCO3-, HPO4-, Proteins
 Na+ is the main electrolyte in ECF
 K+ is the main electrolyte in ICF
 More protein in ICF, very little in the interstitial fluid
Fluid and Electrolyte shits
 Cell / capillary membranes
o Separate fluid compartments
o Freely permeable to water, ions, CO2 and O2
o Proteins and glucose cannot move easily
 H2O moves by osmosis
 Electrolyte movement: From high to low concentration
 Water movement: controlled by osmosis and hydrostatic pressure
 Diffusion:
o Simple movement from high to low
 Facilitated Diffusion
o Molecules need helpers to get into cells
 Active Transport
o Movement AGAINST the gradient
o Requires ATP to function
 Osmosis
o H2O moves from high to low
Osmotic pressure
 Pulling power of solution for water
 Greater concentration = greater pull
 Osmolarity / osmolality refers to the concentration of the solution
 Serum osmolality
o 275-295 mOsm / kg (mOsm = milliosmoles)
o ICF and ECF are isotonic to each other
Tonicity of IV fluids
 Isotonic: same osmolality as plasma
o 0.9% NaCl, Ringers, Lactated Ringers
o Isotonic fluids have no net shift
 Hypertonic: higher osmolality than plasma
o 3% saline, 5% saline, 10% dextrose
o Fluid is pulled out of the cells into the bloodstream
o Cells shrink
 Hypotonic: lower osmolality than plasma
o 5% d/w, 0.45% NaCl, 5%D in 0.45% saline
o Fluid moves into the cells from the bloodstream
o Cells swell
o Given for dehydration as a volume booster
 Dextrose is isotonic in the bag
o When metabolized, it becomes hypotonic b/c of the discharge of free water
Body Fluid Movement
 Hydrostatic pressure (BP)
o Pushing force of fluid against the vessel walls
o Pressure generated by heart pumping
o HP down, BP down
o Capillaries push H2O out with hydrostatic
 Colloid (protein) osmotic pressure
o Also called oncotic pressure
o Pulling power of the fluids
o Venules pull H2O back in with osmotic
Fluid Shifts
 Plasma to interstitial fluid (edema)
o Increased venous hydrostatic pressure
o Decreased plasma oncotic pressure
o Increased interstitial oncotic pressure
 Interstitial to plasma
o Increased plasma osmotic/oncotic pressure
o Increased interstitial hydrostatic pressure
Third Spacing
 Vascular fluid moves into an inaccessible space
o Interstitial space (edema) is peripheral
o Transcellular spaces are in the peritoneum and pleura
 Usually occurs due to:
o Decreased plasma proteins
o Decreased capillary permeability
o Blockage in lymphatic drainage
 Patient is considered dehydrated if fluid is in the 3rd spaces
 Change in weight? Can increase or not change
 With correction of the condition, watch for fluid overload
 Give hypertonic solution to pull water back to where it belongs
Fluid balance (I&O)
 Intake
o Oral fluids: 1200 mL
o Foods: 1000 mL
o Metabolism: 500 mL
o Total: 2500 mL
 Output
o Urine: 1500 mL/day
o Feces: 100 mL/day
o Insensible: 900 mL/day
 Sweating / respiratory condensation
o Total: 2500 mL
o If you can see the perspiration, it’s sensible
 These numbers are generalized – not constants
Body Fluids Regulation
 Kidneys are the primary regulator
 Water
o Adjust amount reabsorbed (amount of urine output)
 Electrolytes
o Selective retention or excretion
 Acid / Base
o Excretes H ions, retains bicarbonate
Regulation: Thirst
 Osmoreceptors in hypothalamus
o Sense concentration of body fluids
o Stimulated by increased serum osmolality or fluid deficit
 Increased thirst causes patient to drink
 Mechanism is decreased in elderly people
o The elderly are consistently imbalanced b/c they can’t self-regulate
 What if?
o Client cannot feel thirst / is unable to drink or get H2O / drinks too much? (intoxication)
More regulation mechanisms
 Anti-Diuretic Hormone (ADH): [pituitary gland]
o Works inversely with aldosterone to increase total volume
o Secreted when serum osmolality rises or blood volume is decreased
o Promotes retention of water
 Aldosterone: [adrenal cortex]
o Secreted when decreased renal blood flow is noted
o Promotes retention of sodium and water
 Natriuretic peptides: [cardiac cells]
o Respond to increased pressure and sodium
o Promote excretion of sodium and water
Lifespan factors: Children
 Immature kidneys
 Rapid respiratory rate
 Large body surface area
 Cannot express thirst
 Cannot actively seek fluids
Lifespan factors: Elderly
 Decreased thirst
 Decreased ability of the kidneys to concentrate urine
 Decrease in ICF and total body fluid
 Decreased hormonal response
 Functional changes to body systems
 Other pre-existing medical conditions
Fluid Volume Deficit
 Loss of water and electrolytes
 Intravascular loss = hemorrhage
 Also called hypovolemia
 Causes:
o Loss of body fluids
o Decreased intake
o Third spacing
 EQUAL loss of both water and ‘lytes
 Signs and symptoms:
o Confusion, restlessness – brain cells shrink
o Weakness and thirst; weak/thready but rapid pulse
o Dry skin and mucous membranes
o Decreased BP, but increased pulse and respiratory rates / orthostatic BP as well
o Neck veins flat, especially in the supine position
o Decreased urine output
o Decreased weight
o Labs: increased HCT, increased BUN, increased specific gravity of the urine
o In children?
 Decreased urine, sunken fontanelles, poor turgor, no tears
Fluid volume excess
 Retention of water and sodium
 Increased intravascular pressure
 Causes:
o Excessive intake of fluids (oral or IV)
o Excessive intake of sodium
o Impaired regulation
 Heart failure, renal failure, liver failure, SIADH
 Syndrome of inappropriate ADH release
 Consume a lot of fluids, but output is low
 EQUAL gain of both water and sodium
 Signs and Symptoms:
o Confusion, headache – brain cells swell
o Increased weight
o Peripheral edema
o Increased hydrostatic pressure
o Increased BP, bounding pulse, audible S3 heart sounds
o Neck veins show JVD when standing
o Irritating cough as lungs fill w/ H2O
 Not the same as pneumonia
 White, frothy sputum r/t H2O and air mixing in lungs
o Urine output increased
o Labs: HCT down, BUN down, Urine specific gravity down
o In infants:
 Bulging fontanelles, pedal edema
Dehydration
 Pathophysiology
o Only water is lost
o Inadequate intake
o Increased serum osmolality and sodium
o Leads to cellular dehydration
 Cells shrink and that fluid goes into the blood
o Hyperventilation = pure water loss
 Treatment:
o Monitor pulse, BP, respiratory rate
o Oral rehydration
o Isotonic or hypotonic IV fluids
 Hypotonic makes H2O go back into the cells
o Restrict sodium
 Blood is extremely concentrated
Over hydration
 Pathophysiology
o More water gain
o Decreased serum osmolality and sodium
o Leads to cerebral problems
 Cerebral swelling r/t water shifting INTO cells
o Treatment:
 Check VS and I&O
 Check weight to see fluid shifts
 1 L of fluid = 1 kg
 Watch for increased BP, pedal edema, headache and confusion
 Fluid restrictions
 Diuretic medications
Rehydration in children
 Oral rehydration
o For mild to moderate cases
o 1-3 tsps of oral rehydration fluid every 10-15 minutes
o NO simple sugars (juice, etc)
 Juice is hypertonic and pulls fluid OUT of the cells
 ½ strength juice is cut 50% w/ water
o H2O + salt + glucose = fluid replacement alternative to sports drinks
 IV therapy
o For severe cases when a child is hospitalized
o Delivered with volume control devices or pumps
 VCD provides a backup if pump fails to always get the amount of fluid ordered
o Monitor rate of administration – watch for FVE
o Weight child daily
Nursing responsibilities for Fluid Imbalances
 Monitor weight and VS
 Maintain accurate I&O
 Monitor neurologic changes
 Review lab results
 Care of skin
 Promote safety
Measurement of electrolytes
 milliequivalents per liter: mEq/L
o Na, K, Mg, Cl, HCO3 (carbonic acid)
o Used because particles are electrically charged
 Milligrams per deciliter: mg/dl
o Ca, PO4
 millimole per liter: mmol/L
o international standard
Normal Lab Results:
 Serum electrolytes
o Na: 135-145 mEq/L
o K: 3.5-5 mEq/L
o Ca: 8.5 – 10.5 mg/dl
o Mg: 1.6 – 2.5 mg/dl
o PO4: 2.5 – 4.5 mg/dl
 CBC, especially HCT
o 40-54% in males
o 37-47% in females
 BUN: 7-18 mg/dl
 Urine specific gravity: 1.010 – 1.025
Fluid imbalances: Diagnoses
 Deficient fluid volume r/t excessive fluid loss (or decreased intake) AEB poor skin turgor, sunken
fontanelles, etc
 Excess fluid volume r/t increased intake of fluid (or fluid retention) AEB bulging fontanelles, etc
Fluid imbalances: Goals
 Restore/regain normal fluid and/or electrolyte balance
 Criteria:
o Client will have <> in time frame
o Good skin turgor, moist mucous membranes
o Adequate urine output
o Stable vital signs
o No evidence of edema
o Clear lung sounds or no adventitious sounds noted
o Maintain normal weight
o Serum electrolytes, HCT, BUN are all within range
 Implementation:
o Educating your patient is one of the best things you can do
o “Push” fluids
 Explain the necessity
 24 hour plan
 What does your patient like/dislike
 Serve or assist your patient with intake
 Encourage further intake
 Monitor I&O
o Restrict fluids
 Explain the necessity
 Help patient with likes and dislikes
 Use small containers
 Provide frequent mouthcare
 Restrict sodium intake
 Monitor I&O
Sodium (Na)
 135-145 mEq/L is the normal value
 Present in most body secretions
 Kidneys regulate sodium balance
 Functions:
o Maintain serum osmolality
o Regulates water balance (ECF volume)
o Transmits nerve impulses
o Contracts muscles
 Foods containing sodium include
 Hyponatremia defined as < 135 mEq/L
o Blood is less concentrated r/t cells shrinking
o Causes:
 Loss of sodium or gain of water
o S/S
 Lethargy, confusion – brain cells shrink
 Muscle spasms
 Abdominal cramps
 Nausea/Vomiting
o Encourage sodium uptake
o Restrict water intake
 Hypernatremia:
o Defined as serum level > 145 mEq/L
o Caused by loss of water or gain of sodium
o S/S
 Thirst, dry mucous membranes
 Weakness, twitching of muscles
 Fatigue, restlessness – brain cells swell
o Encourage fluid intake
o Restrict sodium intake
Potassium (K)
 3.5 mEq/L – 5.0 mEq/L is the normal value
 2.5 mEq/L is a CRITICAL low value
 Must be ingested daily
 Leaves the cells in trauma, acidosis, exercise
 Enters the cell in alkalosis, with insulin, and growth
 Regulated by the kidneys
 Functions:
o Maintains ICF osmolality
o Promotes neuromuscular function
o Regulates cardiac impulse transmissions
 Very important for cardiac muscle function
 Foods rich in potassium: bananas, potatoes, oranges, salt substitutes




Hypokalemia:
o Defined as < 3.5 mEq/L
o Causes:
 Loss of potassium
 Lack of K intake
 Shift into cells
o S/S
 Fatigue, weakness
 Leg cramps
 Nausea / Vomiting
 Decreased bowel sounds / constipation
 Cardiac dysrhythmias
 Weak, irregular pulse
Hyperkalemia:
o Defined as > 5.0 mEq/L
o Causes:
 Retention of potassium
 Excess intake
 Shift out of cells
o S/S
 Irritability, anxiety
 Weakness in lower extremities
 Parasthesia
 Abdominal cramps and diarrhea
 Cardiac dysrhythmias
 Irregular pulse
Check cardiac function CLOSELY with either of these two conditions
Management:
o Hypokalemia:
 Monitor cardiac status, esp. if also on digitalis
 Oral potassium w/ food
 IV <10-20 mEq/hour
 NO IV PUSH – can cause fatal arrhythmia
 Verify renal status prior
 Monitor IV site
 Provide potassium rich diet
 Medication instruction to ensure proper dosing
o Hyperkalemia:
 Monitor cardiac status
 Hold potassium
 Rich foods
 Sparing diuretics
 Administer:
 Glucose and insulin
 Potassium wasting diuretics / initiate dialysis
 Kayexalate by enema
 Calcium gluconate IV
Calcium (Ca)
 8.5 – 10.5 mg/dl is the normal value
 Absorbed in GI tract, excreted by the kidneys
 Regulated by PTH, Vitamin D, and calcitonin
 Inverse relationship with phosphorus
 With aging and poor absorption, pt. is more prone to osteoporosis
 Functions:
o Forms bones and teeth
o Nerve impulse transmission, muscle contractions
o Maintains cardiac pacemaker
o Necessary for blood clotting
 Calcium rich foods:
 Hypocalcemia:
o Defined as serum level < 8.5 mg/dl
o Causes:
 Hypoparathyroidism, increased phos. level, Vitamin D deficiency, chronic alcoholism
o S/S
 Numbness, tingling around mouth
 Muscle tremors, cramps, tetany (constant spasms)
 Cardiac arrhythmias
 Positive Trousseau’s and Chvostek’s signs
 Hyperactive deep tendon reflexes
 Confusion, anxiety
o Treatment:
 Oral or parenteral calcium (by IV – NO IM ADMINISTRATION)
 Calcium rich diet + vit. D
 Monitor cardiac status
 Control pain and anxiety
 Safety measures to prevent injury
 IM or non-patent IV administration can cause tissue necrosis
 Hypercalcemia:
o Defined as serum level > 10.5 mg/dl
o Causes:
 Hyperparathyroidism, malignancy, Vit. D overdose, prolonged immobility
o S/S
 Confusion, decreased memory
 Depressed DTR’s
 Muscle weakness, fatigue
 Bone pain, fractures
 Constipation, anorexia, nausea and vomiting
 Cardiac dysrhythmias
 Renal calculi – kidney stones
o Treatment:
 Loop diuretic, isotonic IV fluids, calcitonin
 3000-4000 ml oral fluids daily and encourage acid fluids (cranberry juice)
 Low calcium diet and begin weight bearing exercise ASAP
Magnesium (Mg)
 1.6 – 2.5 mEq/L is the normal value
 ICF cation
 Conservation and excretion by the kidneys
 Intestinal absorption increased by Vit. D and PTH
 Functions:
o Intracellular metabolism (ATP production)
o Transmits nerve impulses
o Regulates cardiac function
 Mg rich foods:
 Hypomagnesemia
o Defined as < 1.6 mEq/L
o Causes:
 Prolong fasting or starvation
 Diarrhea, N&V, NG suction
 Chronic alcoholism
o S/S
 Confusion, tremors, seizures
 Hyperreflexia, + Trousseau’s and Chvostek’s signs
 Tachycardia, HTN, dysrhythmias
 Dysphagia
o Treatment:
 Oral supplements
 Mg rich foods
 Monitor for seizures, cardiac status
 Assess swallowing
 Alcohol rehabilitation
 Hypermagnesemia
o Defined as serum level > 2.5 mEq/L
o Causes:
 Retention of Mg (renal failure)
 Treatment with Mg
o S/S
 Lethargy, drowsiness
 N&V
 Hypotension, bradycardia, flushing
 Muscle weakness, paralysis
 Depressed DTR’s
 Respiratory and cardiac arrest
o This is the MAIN CAUSE of kidney failure
o Treatment:
 IV calcium chloride or gluconate
 Dialysis for patients in renal failure
 Focus on prevention
 Renal patients should limit their intake
Phosphorus
 2.5 – 4.5 mg/dl is the normal value
 Excreted by the kidneys
 Reciprocal relationship with calcium (inverse)
 Functions:
o Cellular metabolism (ATP)
o Essential to function of muscle, RBC’s, and nervous system
o Metabolism of fat, protein, and carbs
 Rich foods:
 Hypophosphatemia:
o Defined as serum level < 2.5 mg/dl
o Causes:
 Malnourishment
 Alcohol withdrawal
 IV glucose
o S/S
 Parasthesia, weakness
 Mental changes
 Cardiac dysrhythmias
o Treatment:
 Oral or IV Phos.
 Diet rich in Phos
 Hyperphosphatemia:
o Defined as serum levels > 4.5 mg/dl
o Causes:
 Renal failure
 Excessive ingestion
 Malignancy
o S/S
 Numbness, tingling around the mouth
 Tetany
o Treatment:
 Restrict intake
 Give phosphate binding gel
 Correct hypocalcemia
Promoting F&E balance:
 Explain diet should be well balanced
 Provide additional education
 Benefits of exercise
 Patient should consume six to eight 8 oz glasses of water daily
 Increase intake after exercise
 Limit tea/coffee/salt/sugar
 Avoid alcohol
 Know side effects of each imbalance
 Know signs and symptoms of imbalance