Medsurg PP UNIT2

Unit 2 Objectives

• Discuss the function, distribution, movement and regulation of fluid and electrolytes in the body.

• List factors that influence abnormal body fluid and electrolyte balance.

• Recognize clinical signs and laboratory findings of selected fluid and electrolyte disturbances.

• Use the nursing process related to fluid and electrolytes and acid-base when providing care for patients.

• Apply knowledge of anatomy, physiology and pathophysiology to perform an evidence-based assessment for the patient with a disturbance of acid-base balance.

• Interpret assessment findings for the patient experiencing a disturbance of acid-base balance.

• Utilize clinical judgement to assess and implement interventions to prevent and manage systemic complications.

• Implement therapeutic communication to educate clients about transfusion therapy.

• Demonstrate evidence-based practice related to inserting and discontinuing various peripheral intravenous catheter systems.

• Calculate flow rates for parenteral fluids.

• Utilize clinical judgment to assess and implement interventions to prevent and manage systemic complications, and educate clients about IV therapy.

Chapter 13: Concepts of Fluid and Electrolyte Balance

• RNSG 1327

A&P Review Fluid & Electrolyte Balance

• The regulation of body fluid volume, osmolarity, and composition is achieved through processes:

  • Filtration

  • Diffusion

  • Osmosis

  • Selective excretion

• Water constitutes 55-60% of total body weight in younger adults and 50-55% in older adults.

A&P Review: Main Fluid Compartments

• Intracellular Fluid (ICF): Fluid within cells

• Extracellular Fluid (ECF): Fluid outside cells, includes:

  • Interstitial fluid (fluid between cells)

  • Blood

  • Lymph

  • Bone

  • Connective Tissue Water

  • Transcellular fluid (e.g., cerebrospinal fluid (CSF), pleural fluid)

A&P Review: Filtration

• Filtration:

  • Movement of fluid through a membrane due to hydrostatic pressure differences across the membrane.

A&P Review: Diffusion

• Diffusion:

  • Movement of solutes through a permeable membrane from higher to lower concentration areas.

A&P Review: Osmosis

• Osmosis:

  • Movement of water through a semipermeable membrane to achieve equilibrium of osmolarity.

Types of Solutions

• Isotonic:

  • Equal concentration of solutes and solvent.

  • Example: 0.9% NS, Lactated Ringer's, D5W

• Hypertonic:

  • More solutes and less solvent; fluid is pulled out of the cell.

  • Example: 3% NS, 5% NS, D10W, D20W

• Hypotonic:

  • Fewer solutes and more solvent; fluid is pulled into the cell.

  • Example: 0.45% NS, 0.33% NS, 2.5% DW

• Osmolality ranges:

  • Isotonic: 270-300 mOsm/L

  • Hypertonic: >300 mOsm/L

  • Hypotonic: <270 mOsm/L

Fluid & Electrolyte (F&E) Balance

• Electrolytes: Charged ions with specific functions.

• Cations: Positively charged ions

  • Sodium (Na+)

  • Potassium (K+)

  • Calcium (Ca+)

  • Magnesium (Mg+)

• Anions: Negatively charged ions

  • Chloride (Cl-)

Normal Ranges & Significance of Electrolytes

Factors Affecting Fluid Balance

• Age, gender, and amount of fat affect fluid distribution.

• Fluid intake: Regulated by thirst; triggered by increased blood osmolarity or decreased blood pressure.

• Fluid loss:

  • Routes include urine, feces, emesis, sweating.

  • Kidneys: Most significant for water loss; adjust urine output based on hydration status.

  • Insensible water loss occurs through skin and lungs.

Regulation of Fluid Balance: Hormones

• Aldosterone:

  • Secreted by the adrenal cortex; controls sodium and water loss.

  • Stimulates kidneys to reabsorb water and sodium while excreting potassium.

• Antidiuretic Hormone (ADH):

  • Produced by the hypothalamus and released from the posterior pituitary.

  • Responds to blood osmolarity, particularly sodium concentration.

• Natriuretic Peptides (NPs):

  • ANP and BNP secreted in response to increased blood volume and pressure.

Renin-Angiotensin II Pathway

• Initiated by signals of decreased tissue perfusion (e.g., low blood pressure, blood volume, sodium, or oxygen).

• Renin release from kidneys converts angiotensinogen to Angiotensin I, then into Angiotensin II.

• Effects of Angiotensin II:

  • Rapid arterial contraction, increasing peripheral resistance.

  • Decreased glomerular filtration in kidneys, promoting aldosterone secretion.

  • Increased kidney reabsorption of water and sodium.

  • Ultimately leading to increased blood volume and pressure.

Assessment of Dehydration

• History: Medication use, medical disorders, fluid intake and output, weight changes.

• Physical assessment:

  • Cardiovascular changes: Heart rate (HR), blood pressure (BP); orthostatic changes; jugular vein distention.

  • Respiratory: Respiratory rate (RR) and signs of hypoxia.

  • Integumentary: Skin turgor and moisture.

  • Neurologic: Mental status changes, lethargy, coma.

  • Renal: Urine output decline (<500ml/day), concentrated urine.

Laboratory & Imaging Assessment for Dehydration

• Increased hemoglobin & hematocrit

• Increased osmolarity (normal: 270-300 mOsm/L)

• Increased glucose (normal: 70-100 mg/dL)

• Increased blood urea nitrogen (normal: 10-20 mg/dL)

• Increased urine specific gravity (normal: 1.015-1.025)

• Increased electrolytes

• Imaging: Ultrasound and echocardiography.

Planning & Implementation for Dehydration

• Focus on preventing further fluid loss, restoring fluid volume, and preventing injury.

• Nursing Priorities:

  • Fluid replacement strategies.

  • Drug therapy where indicated.

  • Ensuring safety of the patient.

  • Patient education and evaluation of effectiveness.

Fluid Overload

• Defined as excess body fluid; primarily hypervolemia.

• Common causes include:

  • Excessive fluid replacement

  • Kidney failure

  • Heart failure

  • Long-term corticosteroid therapy

  • SIADH

  • Psychiatric disorders involving polydipsia

  • Water intoxication

Assessment for Fluid Overload

• Cardiovascular: HR, BP, distended neck and hand veins, weight gain.

• Respiratory: Shallow RR, dyspnea.

• Integumentary: Pitting edema, pale skin.

• Neuromuscular: Altered mental state, headaches, weakness, paresthesia.

• GI: Increased motility.

• Laboratory: Normal electrolytes; decreased hemoglobin & hematocrit.

Interventions for Fluid Overload

• Priority interventions focus on:

  • Ensuring patient safety.

  • Restoring normal fluid balance.

  • Providing supportive care until the imbalance is resolved.

  • Monitoring intake and output (I&O) and daily weight.

Electrolyte Balance

• Electrolyte imbalances can occur in healthy individuals due to fluctuations in fluid intake and output.

• Severe imbalances might lead to life-threatening conditions.

Important Note

• Electrolyte imbalances should not be corrected quickly; adjustments should occur over 24-48 hours to prevent complications.

Specific Electrolyte Conditions

Hyponatremia

• Defined as sodium level < 136 mEq/L.

Common Causes of Hyponatremia include:

• Increased sodium excretion from excessive sweating, diuretics, and renal disease.

• Decreased sodium intake (e.g., dieting, NPO status).

• Dilutional hyponatremia from excessive ingestion of fluids.

• Syndrome of Inappropriate ADH (SIADH).

Assessment for Hyponatremia

• Neurological: Confusion, seizures, altered mental status.

• Cardiovascular: Changes dependent on fluid volume (hypovolemic vs hypervolemic).

• Muscular: General weakness and diminished deep tendon reflexes (DTR).

Interventions for Hyponatremia

• Monitoring patient responses to therapy, focusing on preventing fluid overload.

• Adjusting fluid intake and possibly administering IV solutions (3% or 5% saline).

• Nutrition therapy to increase oral sodium intake.

Hypernatremia

• Defined as sodium level > 145 mEq/L.

Causes of Hypernatremia include:

• Excessive sodium intake, dehydration, kidney failure, hyperaldosteronism.

Assessment for Hypernatremia

• Nervous System Changes: Altered cerebral function; agitation or lethargy depending on fluid volume status.

• Muscle Changes: Vary with severity.

• Cardiovascular Changes: Measure and monitor BP, heart rate in regards to fluid volumes.

Interventions for Hypernatremia

• Focus on monitoring cardiovascular function and patient safety, with interventions including administering isotonic IV fluids and possible nutritional changes.

Hypokalemia

• Defined as potassium level < 3.5 mEq/L.

Common Causes of Hypokalemia include:

• Gastrointestinal losses (diarrhea, vomiting).

• Medications (diuretics).

• Renal losses due to high levels of aldosterone.

Assessment for Hypokalemia

• Respiratory: Weakness due to respiratory muscle involvement.

• Cardiovascular: Weak peripheral pulses, dysrhythmias, orthostatic hypotension.

• Neurological: Confusion, potential changes in LOC due to imbalances.

• Intestinal Changes: Decreased bowel sounds, constipation, abdominal distention.

Interventions for Hypokalemia

• Administer potassium supplementation, monitor respiratory function, and evaluate patient safety strategies.

Hyperkalemia

• Defined as potassium level > 5.0 mEq/L.

Common Causes of Hyperkalemia include:

• Renal failure, acidosis, excessive potassium intake, and tissue damage.

Assessment for Hyperkalemia

• Cardiovascular: Monitor for bradycardia and ECG changes.

• Neuromuscular: Monitor muscle tone and strength, assess for twitching.

Interventions for Hyperkalemia

• Administer medications to shift potassium into cells (like insulin), provide cardiac monitoring and emergency measures as needed.

Hypocalcemia

• Defined as calcium level < 9.0 mg/dL.

Causes of Hypocalcemia include:

• Vitamin D deficiency, hypoparathyroidism, and malabsorption disorders.

Assess Cardiovascular changes: Heart rate variations, potential for hypotension or prolonged ECG intervals.

Interventions for Hypocalcemia

• Administer calcium supplements, manage environment to reduce stimuli, assess for negative signs (e.g., Trousseau’s and Chvostek’s signs).

Hypercalcemia

• Defined as calcium level > 10.5 mg/dL.

Assessment for Hypercalcemia

• Monitor for cardiovascular changes (decreased contractility) and neuromuscular concerns (muscle weakness).

Interventions for Hypercalcemia

• Promote hydration and administer medications to decrease serum calcium levels.

Hypomagnesemia

• Defined as magnesium level < 1.8 mEq/L.

Causes include malnutrition and the use of diuretics.

Assessment and Interventions focused on correcting imbalance and managing related risks.

Hypermagnesemia

• Defined as magnesium level > 2.6 mEq/L.

Assessment should include cardiovascular and neuromuscular monitoring.

Acid-Base Balance

Overview

• Acids are substances that elevate free hydrogen ions in solution (lowering pH).

• Bases bind free hydrogen ions (increasing pH).

• Buffers help maintain pH by reacting as either acids or bases depending on fluid pH.

Abnormal pH Levels

• Disrupt the function of hormones, enzymes, and the activity of the heart, nerves, muscles, and GI tract.

Regulatory Mechanisms

Chemical Buffers

• Immediate responders to acid-base imbalances.

Respiratory

• Regulate pH by controlling CO2 levels via breathing rate.

Renal

• Slow but powerful mechanism that adjusts bicarbonate levels.

Acid-Base Imbalances

Types

• Metabolic acidosis

• Respiratory acidosis

• Metabolic alkalosis

• Respiratory alkalosis

Laboratory Assessment

• Indicators of acidosis vs alkalosis based on pH, bicarbonate, and CO2 levels in arterial blood gas (ABG) tests.

Interventions Overview

• Focus on correcting underlying issues and patient safety monitoring.

Case Studies

• Assessing patients for acid-base disturbances, using ABG interpretation to guide nursing interventions.

Infusion Therapy

Overview

• The delivery of medications and fluids through IV therapy to correct imbalances and administer medications.

Types of IV Fluids

• Isotonic (e.g., NS), hypertonic, and hypotonic solutions and their respective clinical uses.

Transfusion Therapy

Overview

• Process of transferring blood components, generally requiring precautions for safety and monitoring for adverse reactions.

Responsibilities

• Pretransfusion checks including blood type matching, patient identification, IV setup, and ongoing monitoring during the transfusion process to ensure safety.