Pharmacology and Fluid Volume Lecture (copy)
Pharmacology Review: Diuretics and Electrolytes
Class Review and Practice Questions: The instructor began the session with a QR code-based quiz to review pharmacology material from previous classes to ensure students are making correct clinical connections.
Potassium-Sparing Diuretics Identifying Characteristics: * The nurse caring for a client with heart failure identifies which medication as a potassium-sparing diuretic? Spironolactone. * Note: In the curriculum provided, spironolactone is the primary potassium-sparing diuretic students are responsible for; others mentioned (furosemide, mannitol, hydrochlorothiazide) are potassium-wasting.
Furosemide (Lasix) Education and Patient Teaching: * In a "Select All That Apply" scenario, the following client statements indicate a need for further teaching (wrong statements): * "I will take my medication in the morning and at bedtime." (Correction: Do not take it at bedtime or late at night ( etc.) to avoid being up all night urinating. Afternoon or approximately is better). * "I can drink coffee and tea to get enough fluids." (Correction: Coffee and tea contain caffeine, which acts as a diuretic and may interfere with the medication's controlled effect). * "I should not be concerned if I experience ringing in my ear." (Correction: Ringing in the ears/tinnitus must be reported as it indicates ototoxicity). * Correct patient behaviors include: * Changing positions slowly to prevent falls (orthostatic hypotension). * Notifying the provider about ankle swelling (indicates worsening fluid status).
Renal Insufficiency and Diuretic Selection: * In the emergency department, a client with fluid overload and renal insufficiency would likely be ordered furosemide. * Rationale: Loop diuretics and osmotic diuretics are the only classes that remain effective even when the kidneys are not functioning optimally.
Clinical Contraindications and Lab Values: * Spironolactone: The nurse would hold this medication and contact the provider if the client has a potassium () level of (hyperkalemia), as spironolactone is potassium-sparing. * Sodium Polystyrene Sulfonate (Kayexalate): This is contraindicated if the patient has absent bowel sounds. Elimination occurs through the bowel; if the bowel is not moving, the medication cannot eliminate potassium. It is used specifically for hyperkalemia and can be used regardless of renal function levels.
IV Administration of Bumetanide (Bumex): * Dosage/Route: IV push. * Administration Technique: It should be given undiluted over two minutes. In nursing school contexts, almost no IV push medications are given "as quickly as possible." * Therapeutic Response: The expected therapeutic outcome for a diuretic is increased urine output (e.g., from to ). While blood pressure and potassium levels may drop, these are considered side effects rather than the intended diuretic purpose.
Fluid Volume Deficit (FVD)
Definitions and Clarifications: * Fluid Volume Deficit: A general heading indicating a lack of sufficient fluid. * Hypovolemia: A state of low volume where electrolytes and fluid are lost in the same proportion. * Dehydration: Loss of fluid without an equal loss of sodium, typically resulting in high sodium levels (). * Third Spacing: Fluid is trapped in interstitial spaces where the body cannot use it. The patient may visually appear to have fluid volume excess (edema), but physiologically presents as a fluid deficit (low blood pressure, low urine output). The indicator for third spacing versus general edema is often low blood pressure.
Etiology (Causes): * Gastrointestinal (GI) Losses: Vomiting, diarrhea, and colostomy output (intestines reabsorb fluid; removing part of the tract or increasing transit speed reduces absorption). * Blood Loss: Direct loss of volume. * Polyuria: Increased urination which can stem from various causes. * Burns: Large, traumatic burns cause significant tissue damage, leading to fluid leaking out of the body. * Insufficient Intake: NPO (Nothing by Mouth) status, dysphagia (swallowing difficulties), or lack of access to clean water. * Environmental/Behavioral: Excessive sweating (exercise, heat) and chronic laxative use.
Risk Factors: * Anything preventing oral intake (e.g., stroke/dysphagia). * Lack of access to clean water (rural areas, well water affected by weather). * Diabetic Ketoacidosis (DKA): High glucose causing a fluid and electrolyte deficit. * Increased Respirations: Rapid breathing leads to increased "insensible losses" of fluid. * Renal Failure: Can cause either deficit or excess depending on the specific stage and the body's attempt to compensate.
Clinical Manifestations (The "Decreased" Trend): * Decreased Weight: Daily weight is the best indicator of fluid status. * Decreased Level of Consciousness (LOC): Often related to concurrent electrolyte shifts. * Decreased Skin Turgor: Manifests as "tenting." * Decreased Urine Output: The body activates alarm bells to retain fluid. * Decreased Blood Pressure (Hypotension). * Decreased Warmth to Extremities: Body prioritizes major organs; blood flow to feet/hands is restricted. * Pulse Rate (Exception): Pulse will be increased (tachycardia) as the body attempts to circulate the limited volume, but it will be a weak, thready pulse.
Diagnostic Labs: * BMP/CMP: Checks electrolytes, BUN, and Creatinine. * CBC: Specifically looking at Hemoglobin () and Hematocrit (). These will be higher/elevated in FVD because the blood is more concentrated (like a packet of Kool-Aid made with very little water). * Urine Specific Gravity: Will be high due to concentrated urine.
Nursing Interventions: * Treat the underlying cause (e.g., anti-nausea meds for vomiting). * Fluid Replacement: Oral fluids are preferred because they are the safest and hardest to overcorrect. IV fluids are used for serious deficits or when the patient is NPO. * Rate of Correction: Always replace fluids gradually. Overcorrecting too fast causes more harm than good. * Fluid Challenge: Giving a specific amount of normal saline over a specific time to determine if low output is a kidney problem or volume problem.
Fluid Volume Excess (FVE)
Definition: Also known as hypervolemia; occurs when both water and sodium are retained in the body.
Etiology (Causes): * Heart Failure: Reduced pumping efficiency leads to fluid backup. * Cirrhosis: Hardening of the liver causes fluid to backup, often resulting in ascites (fluid in the abdomen). * Adrenal Gland Disorders: Involving the glands on top of the kidneys. * Corticosteroids: Medications like prednisone lead to sodium and water retention. * Stress: Triggers cortisol release, which causes the body to hold on to sodium and fluid. * Dietary Intake: High salt intake from processed foods (canned soups, cheeses).
Risk Factors: * Preeclampsia: Pregnancy-related condition involving fluid retention and high BP. * IV Therapy/Overcorrection: Nurses must monitor patients carefully to ensure they do not transition from a deficit to an excess.
Clinical Manifestations (The "Increased" Trend): * Increased Blood Pressure: High pressure in the "pipes." * Increased Pulse Rate: Still tachycardia (as in deficit), but the pulse will be bounding (very strong, may even move the nurse's finger). * Edema/Ascites: Visible swelling. * Increased Crackles: Indicates fluid is backing up into the lungs. * Jugular Vein Distension (JVD): Visible bulging of the neck veins when sitting. * Neurological: Confusion, headaches, or seizures due to electrolyte dilution.
Diagnostic Labs: * Liver Function Tests: AST and ALT are monitored if cirrhosis is suspected. * Organ Function: High BUN/Creatinine or Liver enzymes indicate organ failure/dysfunction.
Nursing Interventions: * Restrict Sodium and Fluids: Use mouth swabs, ice ( cup of ice = fluid), or sour candy (stimulates saliva) to help patients tolerate restriction. * Positions: Use Fowlers or High-Fowlers to facilitate breathing. * Skin Integrity: Maintain dryness for legs that are "weeping" fluid through the pores. * Daily Weights: Crucial for monitoring progress.
Lifespan Considerations
Infants: * Highest percentage of water per body surface area; more susceptible to rapid changes. * Immature kidneys do not manage fluid shifts well. * Signs of Deficit: Sunken fontanels (soft spots), crying without tears, weighing diapers for output. * Signs of Excess: Bulging fontanels. * Note: For the first six months, babies should typically only have breast milk or formula; no plain water.
Children and Adolescents: * Otherwise healthy children should not lose weight during growth spurts; weight loss is a red flag for GI bugs or potential eating disorders (laxative use). * More susceptible to dehydration during sports and heat.
Pregnant Individuals: * Hyperemesis Gravidarum: Severe morning sickness requiring hospitalization and IV fluids. * Naturally occurring increase in blood volume is normal, but can lead to hypertension or Polyhydramnios (excessive amniotic fluid threatening fetal growth).
Older Adults: * Diminished Thirst Center: The brain's mechanism for signaling thirst becomes less effective with age. * Reduced Fluid Reserve: Smaller margins for error when sick compared to younger adults. * Behavioral Factors: May avoid drinking to prevent incontinence or because mobility issues make getting to the bathroom difficult/painful. * Cognition: Dementia can cause patients to forget to drink.
Questions & Discussion
Q: Why does increased respiration cause fluid deficit? * A: Because of "insensible losses." Every breath loses a small amount of fluid. Rapid breathing (e.g., during a panic attack) accelerates this loss.
Q: In renal failure, do people excrete more or keep more fluid? * A: It is a staged process. As kidneys start to fail, the body may try to compensate by over-excreting or holding too much. Once in full renal failure, the patient typically holds onto most fluid.
Q: If a patient is bleeding out, is it a fluid volume deficit? * A: Yes. Though we treat it with blood, the symptoms (low BP, fast/weak pulse) remain consistent with a deficit.
Q: What if the patient is on a fluid restriction but receives multiple IV antibiotics? * A: All IV fluids count as intake. The nurse must carefully track INO (I&O) and coordinate with providers regarding the total fluid limit.
Q: What do you do if you hear crackles in a patient receiving IV fluids? * A: Stop the IV pump immediately and notify the physician. Crackles are a sign of fluid overload/pulmonary edema, indicating the patient has been overcorrected.