NURS 5031 Study Guide : Fluid/Electrolytes/ABG’s
NURS 5031 Study Guide : Fluid/Electrolytes/ABG’s
- The forces behind the movement of water and electrolytes between the body fluid compartments.
- Hydrostatic Pressure: force of a fluid in a compartment pushing against a cell membrane or vessel wall.
- The BP generated by contraction of the heart
- Pushed H2O out of vascular system into interstitial space
- Hydrostatic - think “push”
- Arterial pressure
- Venous pressure
- Oncotic pressure: osmotic pressure caused by plasma proteins
- Plasma proteins attract H20, pulling fluid from the tissue space to the vascular space
- Osmotic - think “pull”
- Electrolytes
- Blood cells
- Proteins
- Other dissolved substances
- Interstitial oncotic pressure + capillary hydrostatic pressure move water out of capillaries
- Plasma oncotic pressure + interstitial hydrostatic pressure move fluid into capillaries
- Describe the etiology, laboratory diagnostic findings, clinical manifestations, and nursing and interprofessional management of common fluid and electrolyte disorders
- Extracellular fluid volume deficit (hypovolemia):
- Abnormal loss of body fluids (diarrhea, vomiting, hemorrhage, polyuria), inadequate fluid intake, or plasma to interstitial fluid shift
- Clinical manifestations: restlessness, drowsiness, lethargy, confusion, postural hypotension, hypotension, tachycardia, tachypnea, weakness, dizziness, weight loss, seizure, coma, decreased skin turgor and capillary refill, decreased urine output and concentrated urine, dry mucous membranes, thirst, skin warm, dry, wrinkled (cool and moist if severe because vessels constrict to maintain BP)
- Nursing management:
- Correct underlying cause and replace water/electrolytes (orally, blood products (if lost volume from hemorrhage), IV solutions – isotonic (LR and 0.9% saline))
- Monitor daily weights, I&Os, lab findings, cardiovascular care, skin turgor
- Extracellular fluid volume excess (hypervolemia):
- Excess intake of fluids and salty food, excessive administration of isotonic IV fluids, abnormal retention of fluids (heart failure, renal failure), or interstitial to plasma fluid shift (administration of hypertonic solutions
- Clinical manifestations: weight gain, headache, confusion, lethargy, pitting edema, jugular venous distention, bounding pulse, hypertension, dyspnea, crackles, pulmonary edema, muscle spasms, seizures, coma, skin may feel cool because of the fluid accumulation, ascites, 3rd heart sound
- Nursing management:
- Remove fluid without changing electrolyte composition (diuretics, fluid restriction, restriction of sodium, respiratory care for pulmonary edema, edema wraps), IV colloids to get fluid out of interstitial space (dextran, mannitol, hypertonic solutions)
- Sodium restriction
- Monitor daily weights, I&Os, lab findings, cardiovascular care, skin turgor
- Sodium: major role in ECF volume and concentration, generation and transmission of nerve impulses, muscle contractility, acid-base balance
- Hypernatremia: >145mEq/L
- Causes: inadequate water intake à cellular dehydration
- Manifestations: thirst, agitation, restlessness, confusion lethargy, seizures, coma, postural hypotension, tachycardia, weakness
- Nursing management:
- Treat underlying cause
- Primary water deficit: replace fluid orally or IV with isotonic or hypotonic fluids
- Excess sodium: dilute with sodium-free IC and promote excretion with diuretic
- Hyponatremia: <135mEq/L
- Causes: loss of sodium-containing fluids, water excess in relation to the amount of sodium
- Profuse diaphoresis, draining wounds, excessive diarrhea or vomiting, primary adrenal insufficiency
- Manifestations: headache, irritability, difficulty concentrating, confusion, vomiting, seizures, coma
- Nursing management:
- Cause is water excess: treat with fluid restriction, loop diuretics, and IV hypertonic saline if severe symptoms (seizures)
- Cause is abnormal fluid loss: treat with fluid replacement with sodium containing solution, increase oral intake, withhold diuretics, drugs that block ADH
- Potassium: needed for transmission and conduction of nerve and muscle impulses, maintenance of cardiac rhythms (NEUROMUSCULAR AND CARDIAC FUNCTION AFFECTED BY IMBALANCES)
- Hyperkalemia: >5.5mEq/L
- Causes: impaired renal excretion (renal failure, adrenal insufficiency), shift from ICF to ECF (burns, trauma, crush injuries, metabolic acidosis)
- Manifestations: cardiac dysrhythmias, cramping leg pain, weak or paralyzed skeletal muscles, abdominal cramping or diarrhea
- EKG changes:
- Decreased depolarization à flat P wave, wide QRS complex
- Rapid repolarization à short QT interval, T wave narrow and peaked
- Ventricular fibrillation or cardiac standstill may occur
- Nursing management:
- Monitor EKGs
- Eliminate intake of potassium
- Increase elimination (diuretics, dialysis, Kayexalate (poop out K))
- Force K into ICF with IV insulin
- Administer calcium gluconate IMMEDIATELY if cardiac arrhythmias
- Monitor BP because rapid administration of calcium can cause hypotension
- Hypokalemia:
- Causes: abnormal losses from kidneys (low Mg, diuresing, high aldosterone) or GI (diarrhea, laxative misuse, vomiting, ileostomy drainage), increased shift of K to ICF (insulin and beta adrenergic stimulation, alkalosis), low dietary potassium
- Manifestations: cardiac complications, skeletal muscle weakness, paresthesia, weakness of respiratory muscles (shallow respirations and respiratory arrest), decreased GI motility, hyperglycemia due to impaired insulin secretion
- EKG changes:
- Hyperpolarization à impaired muscle contraction and impaired repolarization: flat T wave, emergence of U wave, peaked P wave, prolonged QRS complex
- Increased incidence of potentially lethal ventricular dysrhythmias
- Nursing management:
- Monitor EKGs
- Oral treatment: KCl supplements and patient education on potassium rich foods
- IV therapy: always dilute IV KCl, never give as push or bolus, should not exceed 10mEq/hr, use infusion pump
- Calcium: functions in formation of teeth and bones, blood clotting, transmission of nerve impulses, myocardial concentrations, muscle contractions, parathyroid hormone increases serum calcium, calcitonin lowers
- Hypercalcemia: >10.3 mg/dL
- Causes: often caused by hyperparathyroidism, tumors (bone destruction by tumor invasion)
- Manifestations: fatigue, lethargy, weakness, confusion, hallucinations, seizures, coma, cardiac dysrhythmias (decreased myocardial excitability
- Nursing management:
- Excretion of calcium with loop diuretic
- Hydration with isotonic saline infusion
- Low calcium diet
- Mobilization
- Bisphosphonates to bind
- IM or SC calcitonin
- Get them up and moving
- Hypocalcemia: <8.5mg/dL
- Causes: surgical removal of parathyroid, multiple blood transfusions (citrate used to anticoagulated blood binds calcium), alkalosis (calcium binds with proteins in high pH), increased calcium loss
- Manifestations: positive Trousseau’s or Chvostek’s sign, hyperreflexia, neuromuscular excitability (laryngeal stridor, dysphagia, tetany, paresthesia around mouth or extremities), cardiac dysrhythmias (EKG: prolonged QT à ventricular tachycardia)
- Nursing management:
- Treat cause
- Diet education about calcium rich foods
- Calcium and vitamin D oral supplements
- IV calcium gluconate
- Change loop diuretic to thiazide
- Rebreathe into paper bag (CO2 retention)
- Treat pain and anxiety to prevent hyperventilation induced respiratory alkalosis
- Phosphorus: essential to function of muscles, RBCs, nervous system, acid-base buffer, ATP production and metabolism, reciprocal relationship with calcium
- Hyperphosphatemia: >4.5mg/dL
- Causes: decreased excretion (kidney injury or disease), excess intake (too many phosphate-containing laxatives, enemas), chemotherapy, hypoparathyroidism
- Manifestations: asymptomatic unless calcium binds to phosphate = signs and symptoms of hypocalcemia, neuromuscular irritability and tetany, calcified deposition in soft tissues à organ dysfunction
- Nursing management:
- Identify and treat underlying cause
- Restrict foods and fluids containing phosphorus
- Oral phosphate-binding agents
- Volume expansion and forced diuresis
- Correct any hypocalcemia
- Hemodialysis
- Hypophosphatemia: <2.8mg/dL
- Causes: malnourishment/malabsorption, diarrhea, use of phosphate-binding antacids, inadequate replacement during parenteral nutrition
- Manifestations: CNS depression, muscle weakness and pain, respiratory and heart failure (all due to impaired cellular energy and oxygen related to deficient ATP)
- Nursing management:
- Monitor phosphate and calcium levels to guide IV therapy
- Monitor for symptomatic hypocalcemia
- Oral supplementation and high phosphorus foods (dairy)
- If severe: administer IV sodium phosphate or potassium phosphate
- Magnesium: activates many enzymes, required for metabolism and synthesis of nucleic acids and proteins, acts on myoneural junction (inhibits Ach, decreased Ca movement into cells), important in normal cardiac function, closely related to Mg and Ca balance – assess all 3 together
- Hypermagnesemia: >2.1mEq/L
- Causes: chronic kidney disease and excessive intake of products containing magnesium (excess IV Mg, Maalox)
- Manifestations: lethargy, nausea and vomiting, impaired reflexes, muscle paralysis, respiratory and cardiac arrest, hypotension, facial flushing, urinary retention
- Nursing management:
- Prevention first: restrict Mg intake
- IV CaCl or calcium gluconate if symptomatic to oppose effects of Mg on cardiac muscle
- Fluids and IV furosemide to promote urinary excretion
- Dialysis if impaired renal function
- Hypomagnesemia: <1.3mEq/L
- Causes: prolonged fasting or starvation, chronic alcoholism, prolonged parenteral nutrition without supplementation, diuretics, fluid loss from GI interferes with Mg absorption
- Manifestations: similar to hypocalcemia, hyperactive deep tendon reflexes, muscle cramps, tremors, positive Trousseau’s and Chvostek’s seizures, confusion, vertigo, seizures, cardiac dysrhythmias with wide QRS complexes, corresponding low Ca and K
- Nursing management:
- Treat underlying cause
- Oral supplements
- Increase dietary intake of Mg rich foods
- EKG monitoring
- Parenteral IV or IM magnesium if severe
- Know the difference between crystalloids and colloids, their indications for use, and goals of treatment
- Colloids
- Substances that when they are administered they pull fluid into the vascular space. Colloids stay in the vascular space and increase the osmotic pressure. Colloids include human plasma products (albumin, FFP, blood) and semisynthetics (dextran and starches, Hespan)
- Indications for use-
- Example: If you have a patient with edema, you may give the colloid to pull the fluid back into the vascular space and then administer a diuretic so their kidneys excrete the excess fluid
- Goals of treatment
- Crystalloids
- Can be isotonic, hypotonic, or hypertonic and depending on this will have an effect on the RBCs
- Indications for use
- For maintenance (oral intake inadequate) or replacement (losses have occurred) of fluids
- Goals of treatment- correct any fluid imbalances, maintain or replace fluids in the body
- Review the composition of and indications for common IV fluid solutions.
***Generally, hypertonic solutions have higher osmolality than plasma. So once administered they increase blood serum (ECF) osmolality, which pulls water out of cells and increases ECF volume.
***Generally, hypotonic solutions have less osmolality than the body, so once administered will decrease blood serum (ECF) osmolality, and water will shift into the interstitial and cellular compartments.
***Isotonic solutions have osmolality similar to plasma. Giving fluid only expands ECF and doesn’t pull water into and out of cells - ideal fluid replacement for Pts w/ ECF volume deficits. [0.9% NaCl and Lactated Ringers].
Dextrose in Water
Saline - contains Na+, Cl- and water - no calories
Dextrose in Saline
5% in 0.25% - isotonic
5% in 0.45% - hypertonic
5% in 0.9% -hypertonic
Multiple electrolyte solutions
Ringer's Solution - isotonic, contains Na+, Cl-, K+, Ca+
Used to expand intravascular volume and replace ECF fluid losses
Similar to plasma composition, but no Mg+ or bicarb
No free water or cals
Lactates’ Ringers - Isotonic
, contains Na+, Cl-, K+, Ca+, lactate
Used to treat hypovolemia, burns, GI fluid losses
Similar to plasma but no Mg+
No free water or cals
- Discuss etiology, laboratory findings, clinical manifestations, nursing & collaborative management of acid-base imbalances
- Buffers:
- Bicarbonate – carbonic acid buffer
- First to react, reacts within seconds
- Lungs, kidneys, and cells also buffer
- Respiratory acidosis:
- Manifestations: fatigue, drowsiness, becoming tired easily, confusion, shortness of breath, sleepiness, headache
- Metabolic acidosis:
- Manifestations: rapid and shallow breathing, confusion, fatigue, headache, sleepiness, lack of appetite, jaundice, increased heart rate, breath that smells fruity
- Respiratory alkalosis:
- Manifestations: dizziness, bloating, feeling lightheaded, numbness or muscle spasms in the hands and feet, discomfort in the chest area, confusion, dry mouth, tingling in the arms, heart palpitations, feeling short of breath
- Metabolic alkalosis:
- Manifestations: hypertension, signs of hypocalcemia (tetany, Chvostek’s, Trousseau’s), change in mental status, seizures
- Be able to interpret arterial blood gas findings (ABGs). Remember ROME (Respiratory Opposite Metabolic Equal).
- Base values:
- pH <7.4>
- PCo2 <40>
- HCO3- <24>
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