Adult Health Unit 2: Fluid and Electrolytes, IV Therapy, Endocrine Review

Fluid Balance Overview

  • Hypovolemia: Decreased circulating blood volume (fluid deficit), often due to dehydration, hemorrhage, or excessive fluid loss (e.g., severe vomiting, diarrhea, burns). Blood becomes hemoconcentrated, increasing risk for clotting.

    • Indicators: Increased hematocrit, increased blood cell count, increased urine specific gravity, dry mucous membranes, decreased skin turgor, orthostatic hypotension, tachycardia, decreased urine output.

    • Risks: Pulmonary embolism, deep vein thrombosis, hypovolemic shock, acute kidney injury.

  • Hypervolemia: Opposite of hypovolemia, excess fluid in the body (fluid overload), often due to heart failure, kidney failure, excessive IV fluid administration, or liver cirrhosis.

    • Indicators: Decreased hematocrit (hemodilution), distended neck veins, crackles in lungs, peripheral edema, weight gain, elevated blood pressure, bounding pulse.

    • Risks: Pulmonary edema, heart failure exacerbation, electrolyte imbalances.

IV Solutions

  • Isotonic Solutions: Same concentration (osmolality) as blood plasma (250−375 mOsm/L250-375 \text{ mOsm/L}); no net fluid movement between intra- and extravascular spaces when infused. Used for volume expansion (e.g., dehydration, blood loss).

    • Examples: Normal saline (0.9% NaCl0.9\% \text{ NaCl}), Lactated Ringer's (LR), Dextrose 5% in Water (D5W, physiologically isotonic but becomes hypotonic as dextrose is metabolized).

    • Clinical Use: Treat dehydration, expand intravascular volume, administer medications.

  • Hypotonic Solutions: More dilute, fewer particles (osmolality less than blood plasma, <250 \text{ mOsm/L}); causes fluid shift into cells and interstitial space (hydrates cells).

    • Examples: 0.45% NaCl0.45\% \text{ NaCl} (half-normal saline), D5W (after metabolism).

    • Clinical Use: Treat intracellular dehydration (e.g., hypernatremia, diabetic ketoacidosis) and conditions where cells need rehydration. Caution: can cause cellular swelling (cerebral edema).

  • Hypertonic Solutions: More concentrated, pulls fluid from cells and interstitial space into blood vessels (osmolality greater than blood plasma, >375 \text{ mOsm/L}); example: Kool-Aid (due to sugar concentration).

    • Examples: 3% NaCl3\% \text{ NaCl}, 5% NaCl5\% \text{ NaCl}, Dextrose 10% in Water (D10W), Dextrose 5% in 0.45% NaCl0.45\% \text{ NaCl} (D5 1/2 NS), Dextrose 5% in 0.9% NaCl0.9\% \text{ NaCl} (D5NS).

    • Clinical Use: Treat severe hyponatremia, cerebral edema (to decrease intracranial pressure). Caution: risk of fluid volume overload, hypernatremia, and injury to red blood cells if infused too rapidly.

  • Types of IV Fluids:

    • Crystalloids: Clear solutions containing water and electrolytes, easily pass through semipermeable membranes. Used for basic fluid replacement and electrolyte balance.

    • Examples: Normal saline, 3% hypertonic sodium chloride3\% \text{ hypertonic sodium chloride}, Lactated Ringer's.

    • Colloids: Thicker particles (larger molecules like proteins or starches) that do not easily pass through semipermeable membranes, remaining in the intravascular space to increase osmotic pressure and expand volume.

    • Examples: IV albumin, packed red blood cells (PRBCs, used to increase circulating blood volume and oxygen-carrying capacity), fresh frozen plasma (FFP), Dextran, Hetastarch.

    • Clinical Use: Restore osmotic pressure, treat hypovolemic shock, severe burns, protein deficiencies.

Monitoring for Overload

  • Fluid Volume Overload/Circulatory Overload: Refers to excessive fluid in the vascular space, leading to increased hydrostatic pressure.

    • Symptoms: Shortness of breath (dyspnea), crackling lung sounds (rales), elevated blood pressure, bounding pulse, distended neck veins, peripheral edema, weight gain.

    • Nursing Interventions: Assess respiratory status (rate, depth, effort, oxygen saturation), lung sounds, vital signs, I&O, daily weights, and peripheral edema. Elevate head of bed, administer oxygen as prescribed, and monitor IV rates carefully.

    • Importance of monitoring IV rates and changes: Closely regulate infusion rates to prevent overload, especially in vulnerable patients (e.g., elderly, those with cardiac or renal impairment). IV bags should be changed every 24 hours to prevent bacterial growth. IV tubing should be changed every 72-96 hours (or per facility policy) to reduce infection risk.

Clinical Applications of IV Fluids

  • Severe Hyponatremia: Use 3% hypertonic sodium chloride3\% \text{ hypertonic sodium chloride} (a hypertonic solution) cautiously to slowly increase sodium levels and pull fluid from the cells back into circulation. Rapid correction can lead to osmotic demyelination syndrome.

  • Colloids Usage: To restore osmotic pressure. Albumin, for example, helps maintain colloid osmotic pressure (oncotic pressure), drawing fluid into the vascular space and expanding circulating blood volume without as much risk of interstitial edema as crystalloids. Often used in hypovolemic shock or severe burns.

Acid-Base Balance

  • Analyzing ABGs: Arterial Blood Gases are key for exam; kidneys (bicarbonate, HCO<em>3−\text{HCO}<em>3^-) and lungs (carbon dioxide, CO</em>2\text{CO}</em>2) regulate acid-base balance.

    • Normal ABG Values:

    • pH: 7.35−7.457.35-7.45

    • PaCO₂: 35−45 mmHg35-45 \text{ mmHg}

    • HCO₃⁻: 22−26 mEq/L22-26 \text{ mEq/L}

    • PaO₂: 80−100 mmHg80-100 \text{ mmHg}

    • Steps for ABG Interpretation: 1. Check pH (acidosis, alkalosis, normal). 2. Check PaCO₂ (respiratory component). 3. Check HCO₃⁻ (metabolic component). 4. Determine compensation (fully, partially, uncompensated).

  • Anion Gap: Anion Gap=Na+−(Cl−+HCO3−)\text{Anion Gap} = \text{Na}^+ - (\text{Cl}^− + \text{HCO}_3^−)

    • Normal Anion Gap: usually 10−14 mEq/L10-14 \text{ mEq/L}.

    • Elevated anion gap (>14 \text{ mEq/L}) indicates metabolic acidosis due to an accumulation of unmeasured acids (e.g., lactic acid, ketoacids, toxins).

  • Imbalances:

    • Respiratory Acidosis: pH < 7.357.35, PaCO₂ > 45 mmHg45 \text{ mmHg}, HCO₃⁻ may be normal (uncompensated) or elevated (compensated). Impaired CO₂ exchange due to hypoventilation, leading to CO₂ retention. Example causes: COPD exacerbation, opioid overdose, pneumonia, atelectasis.

    • Metabolic Acidosis: pH < 7.357.35, HCO₃⁻ < 22 mEq/L22 \text{ mEq/L}, PaCO₂ may be normal or decreased (compensated). Causes: Anaerobic metabolism (shock/sepsis increases lactic acid), diabetic ketoacidosis (accumulation of ketoacids), renal failure (inability to excrete acids), severe diarrhea (loss of bicarbonate).

    • Respiratory Alkalosis: pH > 7.457.45, PaCO₂ < 35 mmHg35 \text{ mmHg}, HCO₃⁻ may be normal or decreased (compensated). Hyperventilation causes excess CO₂ loss. Example causes: Anxiety, pain, fever, hypoxia, mechanical over-ventilation.

    • Metabolic Alkalosis: pH > 7.457.45, HCO₃⁻ > 26 mEq/L26 \text{ mEq/L}, PaCO₂ may be normal or increased (compensated). Causes: Loss of gastric secretions (e.g., prolonged nausea/vomiting, nasogastric suctioning), diuretic use (loss of potassium and chloride), excessive bicarbonate intake.

Endocrine System Overview

  • Pituitary Gland: Often called the "master gland," it regulates other endocrine glands. Works closely with the hypothalamus which controls pituitary hormone release.

    • Anterior Pituitary Hormones: GH, TSH, ACTH, FSH, LH, Prolactin.

    • Posterior Pituitary Hormones: ADH (Vasopressin), Oxytocin.

  • Thyroid Disorders:

    • Hyperthyroidism (e.g., Grave's Disease): Excessive thyroid hormone production.

    • Symptoms: Exophthalmos (bulging eyes), goiter (enlarged thyroid), weight loss despite increased appetite, tachycardia, anxiety, heat intolerance, diaphoresis, fine hand tremors, insomnia.

    • Graves' Disease: Autoimmune condition, most common cause of hyperthyroidism.

    • Medications: Propylthiouracil (PTU) and methimazole (Tapazole) inhibit thyroid hormone synthesis. Primary side effect: agranulocytosis (severe reduction in WBCs), monitor CBC.

    • Thyrotoxic Crisis (Thyroid Storm): Life-threatening complication, often triggered by stress (e.g., infection, surgery, trauma). Symptoms include hyperthermia (104∘F+104^\circ\text{F}+), severe tachycardia, hypertension, delirium, anxiety, dysrhythmias, vomiting, diarrhea, tremors.

    • Hypothyroidism (e.g., Hashimoto's Thyroiditis): Insufficient thyroid hormone production.

    • Symptoms: Fatigue, weight gain, cold intolerance, constipation, bradycardia, dry skin, hair loss, depression, slowed mental processes.

    • Treated with Synthroid (Levothyroxine): Synthetic thyroid hormone (T4). Administer on an empty stomach, typically in the morning, 30-60 minutes before food. Do not take with antacids or iron supplements. Lifelong therapy.

    • Risk of Myxedema Coma: Life-threatening complication, severe hypothyroidism. Symptoms: extreme hypothermia, hypotension, hypoventilation, bradycardia, altered mental status (lethargy, coma). Requires immediate IV thyroid hormone replacement.

Parathyroid Gland

  • Four small glands located on the posterior thyroid gland, primarily regulate calcium and phosphate balance through parathyroid hormone (PTH).

  • Hyperparathyroidism: Overproduction of PTH leading to high calcium levels (hypercalcemia) and low phosphate levels (hypophosphatemia).

    • Symptoms: "Stones, bones, abdominal moans, and psychic groans" - kidney stones, bone pain/fractures, abdominal pain, constipation, depression, fatigue.

    • Treatment: Parathyroidectomy often, encourage hydration, cautious ambulation.

  • Hypoparathyroidism: Underproduction of PTH leading to low calcium levels (hypocalcemia) and high phosphate levels (hyperphosphatemia).

    • Symptoms: Tetany (muscle spasms, tingling, numbness), irritability, seizures, laryngeal spasm, cardiac dysrhythmias (prolonged QT interval).

    • Chvostek’s sign: Facial muscle twitching when facial nerve is tapped.

    • Trousseau’s sign: Carpal spasm caused by inflating a blood pressure cuff above systolic pressure for a few minutes.

    • Treatment: Calcium gluconate IV for severe deficits (acute tetany), vitamin D supplements and oral calcium for chronic management. Monitor airway carefully.

Adrenal Gland Disorders

  • Adrenal Insufficiency (Addison's Disease): Underproduction of adrenal cortex hormones (cortisol, aldosterone).

    • Symptoms: Fatigue, muscle weakness, weight loss, hypotension, hyperpigmentation (bronze skin), abdominal pain, nausea/vomiting, hyponatremia, hyperkalemia, hypoglycemia.

    • Treatment: Lifelong corticosteroid replacement (e.g., hydrocortisone, fludrocortisone).

    • Adrenal Crisis (Addisonian Crisis): Acute, life-threatening exacerbation triggered by stress (infection, surgery, trauma) or abrupt withdrawal of corticosteroids. Symptoms: severe hypotension, hypovolemic shock, hypoglycemia, profound weakness, pain. Requires immediate IV corticosteroids, fluids, and glucose.

  • Cushing's Syndrome: Adrenal gland hyperfunction or prolonged exposure to high levels of exogenous corticosteroids; results in excess cortisol.

    • Symptoms: Central obesity ("buffalo hump," "moon face"), thin extremities, thin fragile skin, striae, hypertension, hyperglycemia, easy bruising, muscle weakness, personality changes, susceptibility to infection, hypokalemia.

    • Treatment: Dependent on cause; surgery (adrenalectomy) for tumors, tapering exogenous corticosteroids. Diet low in sodium, high in potassium and protein.

Blood Transfusion Protocol

  • Pre-transfusion: Obtain informed consent, verify physician's order, obtain baseline vital signs and assessment, ensure patent IV access (usually 18−20 gauge catheter18-20 \text{ gauge catheter}), ensure proper blood product compatibility (type and screen/crossmatch), gather equipment (appropriate tubing, normal saline). Two-nurse verification of patient identity and blood product (type, Rh, unit number, expiration date) at the bedside is crucial.

  • During Transfusion: Stay with the patient for the first 15 minutes of infusion. Monitor for allergic reactions or other transfusion reactions: flushing, shortness of breath, itching, rash, hives, chills, fever, back pain, anxiety.

    • Start transfusion slowly (25-50 mL/hr) initially for the first 15-30 minutes. If no reaction, increase to prescribed rate. Typically, one unit of PRBCs should infuse within 2-4 hours, but no longer than 4 hours (risk of bacterial growth).

  • In case of Transfusion Reaction: Immediately stop the transfusion. Maintain an open IV line with normal saline (using a new tubing set) to keep the vein patent and prevent hypovolemia as per facility policy. Notify the physician and blood bank. Return the blood bag, tubing, and any attached components to the blood bank for testing. Monitor vital signs and administer medications as prescribed (e.g., antihistamines, antipyretics, vasopressors).

  • Types of Reactions: Febrile non-hemolytic, acute hemolytic, allergic, anaphylactic, circulatory overload, sepsis, TRALI (transfusion-related acute lung injury).

  • Post-transfusion: Monitor vital signs and patient for effectiveness and any delayed reactions (e.g., delayed hemolytic reaction, hepatitis).