Nursing Assessment IV Fluids and Electrolytes

Fundamentals of Nursing: Fluids and Electrolytes

• Fluid and electrolyte balance is the body's maintenance of homeostasis of fluid volume and electrolytes.
• Mechanisms include osmosis, diffusion, active transport, and capillary filtration.
• Water is the primary body fluid and water content varies with age, sex, and adipose tissue.
• Electrolytes have an electrical charge when dissolved in water.
• Nonelectrolytes do not conduct electricity (e.g., glucose, urea).
• Fluid intake is primarily through drinking fluids, and 20% from food and metabolism. Recommendations for daily intake are 2700 mL/day for women, and 3500 mL/day for men.
• Fluid intake is regulated by thirst and changes in plasma osmolality, controlled by the hypothalamus.
• Fluid output includes urine, skin (perspiration), lungs (exhalation), and feces. Typical daily urinary output is 1500 mL and fecal loss is 100-200 mL/day. Insensible losses include skin perspiration and water vapor from the lungs. Noticeable losses include sweat and loss through intestines. Minimal obligatory loss is 500 mL of urine in 24 hours or 30 mL in an hour.
• Hormonal Regulation:
  • Antidiuretic hormone (ADH) from the pituitary gland causes kidneys to retain fluid.
  • Renin-angiotensin system causes kidneys to release renin and aldosterone when fluid volume decreases, increasing sodium and water reabsorption, and potassium excretion, thereby increasing plasma volume and kidney perfusion.

Body Fluid Imbalances

• Fluid Volume Excess (FVE): Hypervolemia (one of the most important nursing diagnoses). Common causes are excess sodium intake, kidney or liver disease, or heart failure (decreased cardiac output). Clinical manifestations include elevated blood pressure, bounding pulse, edema, ascites, pulmonary crackles, and rapid weight gain.
• Fluid Volume Deficit (FVD): Hypovolemia or dehydration. Clinical Manifestations: Thirst, decreased skin turgor, dry mucous membranes, increased pulse, orthostatic hypotension, muscle weakness, decreased urine output, concentrated urine, hypernatremia (sodium greater than 145 mEq/L), and elevated BUN.

Diagnostic Laboratory Values

• Blood Urea Nitrogen (BUN): Normal level: 7-20 mg/dL. Primarily used to evaluate fluid balance, liver and kidney function. Elevated BUN levels can signify less-than-optimal kidney filtering, low fluid balance, and high protein intake/breakdown. Low levels typically indicate malnutrition due to poor protein intake.
• Creatinine: Normal level: 0.6-1.2 mg/dL (varies slightly by sex). Evaluates kidneys’ filtering waste, and associated disorders can result in raised levels of creatinine. Used to monitor kidney function. When levels rise, Acute kidney injury (AKI) is potentially indicated

Fluid & Electrolyte Imbalances (Specific)

• Hypovolemia & Dehydration (FVD): Causes: inadequate fluid intake, excessive fluid loss, excessive heat, altered mental status, infections. Interventions: Prevention, Encourage oral intake [2-3 litres per day] (contraindicated if necessary), limit sodium intake, monitor intake and output. Daily weights, IV fluid (slow-moderate)

• Hypervolemia (FVE): Causes: excess fluids (excess sodium intake, kidney or liver disease, or heart failure (decreased cardiac output). Interventions: Monitor I & O, daily weights, IV fluid regulation, limit fluid intake.

IV Fluid Types

• Isotonic: Balanced with blood, stays in the vascular space (e.g., 0.9% sodium chloride (normal saline), Lactated Ringer's (LR), D5W).
• Hypotonic: Less concentrated than blood, moves into cells. (e.g., 0.45% sodium chloride (half normal saline), D5W).
• Hypertonic: More concentrated than blood, pulls fluid from cells. (e.g., 3% sodium chloride (hypertonic saline), 5% dextrose in 0.9% sodium chloride, D5.9, D10).

IV Vascular Access

• Peripheral Intravenous (IV): Inserted by RN. Location and size based on fluid type and treatment length/client condition. Sites: Hand, forearm, antecubital space, upper arm.
• Central Venous Access Devices (CVADs): Inserted by MD. Advantages: Accommodate irritating fluids, remain longer, less phlebitis/infiltration. Disadvantages: Consent needed, X-ray required, strict sterile technique; Risks: Sepsis, air embolism, pneumothorax.

Blood Banking:

• Blood typing: Inherited and determined by self-antigen and antibodies. Types: A, B, AB, O. RH factor (either positive + or negative -) is additional antigen. Type O- is universal donor and type AB+ is universal recipient.
• Blood typing & cross-matching: Procedure to screen blood for any infection, and confirming recipient and donor compatibility.
• Blood products: Whole Blood, Packed Red Blood Cells (PRBCs), Fresh Frozen Plasma (FFP), Platelets, White blood Cells, and Plasma Derivatives (clotting factors, immunoglobins, albumin).
• Types of Blood Donatian: Standard, directed, autologous, intraoperative blood salvage.
• Initiating Blood Transfusions: Procedures detailed regarding consent, prescribed rates, appropriate IV catheter size, infusion pumps, and saline prep. Assess for symptoms during and after transfusion (includes allergic, hemolytic, circulatory overload, and febrile reactions)
• Transfusion Reactions: Allergic reaction (itching, wheezing, flushing), Hemolytic reaction (chills, fever, lower back pain, tachycardia/tachypnea, chest pain/tightening), Circulatory overload (respiratory distress, crackles, edema, distended neck veins, cough, anxiety, hypertension, tachycardia), Febrile reaction (temperature elevation, chills, full degree, warm flushed skin, aches), Bacterial reaction (fever, warm flushed skin, chills, vomiting).
• Addressing Transfusion Reactions: Stop the transfusion immediately, remove the blood tubing, and start normal saline infusion, monitor vital signs, notify physician. Include the procedures associated with the different types of reactions.

Acid-Base Balance

• Basic principles: Body's cellular activities require an alkaline medium. Normal pH of ECF is 7.35-7.45, and ratio of carbonic acid to bicarbonate is 1:20.
• Respiratory Regulation: Lungs regulate acid-base balance by eliminating CO2. Hyperventilation (rapid deep breathing) removes CO2, making blood more alkaline. Hypoventilation (shallow breathing) conserves CO2 to make blood more acidic. Normal CO2 range is 35-45 mmHg.
• Renal Regulation: Kidneys maintain acid-base balance by regulating bicarbonate. If serum pH is too acidic, kidneys conserve it. If too alkaline, kidneys excrete bicarbonate. Normal HCO3 range 22-26 mEq/L.
• Metabolic Acidosis: Caused by acid retention or increased acid production. Symptoms: headache, confusion, weakness, nausea, vomiting and Kussmaul respirations. Treatment: identify and address underlying cause and potentially administer bicarbonate.
• Metabolic Alkalosis: Caused by excessive acid loss (e.g., vomiting, gastric suction), and bicarbonate intake. Symptoms: dizziness, tingling, decreased respiratory rate and depth. Treatment: replace lost fluids using saline, identify and treat underlying cause,
• Interpreting ABGs: Evaluate pH, PCO2, and HCO3 (including interpretation of compensation and abnormal findings).

Electrolyte Imbalances & Nursing Care (Specifics):

• Hypokalemia: (< 3.5 mEq/L). Causes: GI losses, medications, alterations to acid-base balance, hyperaldosteronism, poor dietary intake, eating disorders (anorexia/bulimia). Symptoms: fatigue, anorexia, nausea, vomiting, cardiac dysrhythmias, muscle weakness, cramps, paresthesia, and ECG changes. Interventions include increased dietary potassium intake, oral potassium replacement, and IV potassium for severe deficits.

• Hyperkalemia: (> 5 mEq/L). Causes: impaired renal function, hypoaldosteronism, tissue trauma, acidosis, or treatment related. Symptoms: Cardiac dysrhythmias, muscle weakness, respiratory impairment, paresthesia, anxiety, and ECG changes. Interventions include dietary potassium restriction, cation-exchange resin, IV calcium, insulin, or dialysis.

• Hypocalcemia: (< 8.5 mg/dL). Causes: Hypoparathyroidism, malabsorption, pancreatitis, alkalosis, multiple transfusions of citrated blood, renal failure, medications. Symptoms: Tetany, circumoral numbness, hyperactive DTRs, seizures, respiratory symptoms (dyspnea/laryngospasm), abnormal clotting, anxiety. Interventions: IV calcium gluconate, calcium and vitamin D supplements, and diet.

• Hypercalcemia: (> 10.5 mg/dL). Causes: Malignancy, hyperparathyroidism, immobility, bone loss. Symptoms: muscle weakness, incoordination, anorexia, constipation, nausea/vomiting, abdominal/bone pain, polyuria, thirst, kidney stones, and ECG changes. Interventions: large volumes of IV fluids, diuretics to flush excess calcium, phosphates, calcitonin, bisphosphonates.

Electrolyte and Fluid Value Ranges and Function (Review)

• Sodium (Na+): 135-145 mEq/L (ECF, nerve conduction, fluid volume)
• Potassium (K+): 3.5-5.0 mEq/L (ICF, muscle contraction, neural conduction)
• Calcium (Ca++): 8.5-10.5 mg/dL (bone health, muscle function, blood clotting)
• Magnesium (Mg++): 1.5-2.5 mEq/L (nerves and muscles, cardiac conduction)