NCLEX-RN: Medical–Surgical Nursing

Medical–Surgical Nursing: Genitourinary System

Focus topic: Medical–Surgical Nursing

The genitourinary (GU) system—the kidneys and their drainage channels—is essential for the maintenance of life. This system is responsible for excreting the end products of metabolism as well as regulating water and electrolyte concentrations of body fluids. The genitalia are the organs of reproduction.

Medical–Surgical Nursing: Anatomy and Physiology

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Kidney Structure

Focus topic: Medical–Surgical Nursing

A. Paired organs located to the right and left of midline lateral to lower thoracic vertebrae.
B. Kidneys perform two major functions.

  • Excrete most of the end products of body metabolism.
  • Control the concentrations of most of the constituents of body fluids.

C. Composed of structural units, each of which functions the same as the total kidney and is capable of forming urine by itself.
D. T he functional renal unit is called the nephron.

Each nephron is composed of

  • A glomerulus (a network of many capillaries) that filters fluid out of the blood. It is encased by Bowman’s capsule.
  • Tubules (proximal, Henle’s loop, distal) in which fluid is converted to urine as it goes to the pelvis of the kidneys.

E. Fluid from Bowman’s capsule moves through the proximal tubule located in the cortex.
F. Fluid then flows through Henle’s loop and collecting duct located in medulla of the kidney.
G. Fluid flows from the loop to the collecting tubule.
H. After flowing through many convolutions, the fluid goes into a collecting sac called the pelvis of the kidney.
I. From the pelvis, fluid flows through the ureter and empties into the bladder.

Medical–Surgical Nursing

Medical–Surgical Nursing: Kidney Function

A. Urine production.

  • As the fluid filtrate flows through the proximal tubules, 80% of the water and solutes are reabsorbed into tubular capillaries.
  • The water and solutes that are not reabsorbed become urine.
  • The amount of fluid and solutes excreted is determined through selective reabsorption.

B. Nephron function.

  • The basic function is to rid the body of unwanted substances, the end products of metabolism (fluid and electrolytes).
  • The nephron filters much of the plasma through the glomerular membrane into the tubules.
  • The tubules filter the wanted elements of the blood (e.g., water and electrolytes) from the unwanted elements and reabsorb them into the plasma through the peritubular capillaries.
  • Reabsorption and secretion take place by both active and passive transport.

C. Tubular reabsorption and secretion.

  • Tubular secretion—passage of a substance by capillary action through tubular cells into tubular lumen.
  • Three substances filtered at glomerulus.
    a. Electrolytes: Na+, K+, Ca++, Mg++, HCO3–, Cl–, and HPO4– –.
    b. Nonelectrolytes: glucose, amino acids, urea, uric acid, creatinine.
    c. Water.
  • Proximal tubule reabsorption.
    a. Eighty percent of filtrate reabsorbed actively through obligatory reabsorption.
    b. H2O, Na+, and Cl– continue through loop of Henle, where Cl– is actively transported out of ascending loop, followed passively by Na+.

D . Glomerular filtration.

  • Glomerular membrane is semipermeable (proteins and glucose do not cross the membrane).
  • Amount of filtration is determined by hydrostatic pressure. Normal glomerular filtration rate is 120–125 mL/min in adults.
  • A decrease in blood pressure leads to a decrease in glomerular filtration rate (GFR) and, therefore, a decrease in urine output.
  • Approximately 1000–2000 mL blood flows through kidneys each minute to produce 60 mL urine output per hour.

E. Concentrating and diluting mechanisms.

  • Countercurrent flow of blood and tubular fluid increase concentration of NaCl and, therefore, H2O reabsorption.
  • ADH (antidiuretic hormone) released by posterior pituitary gland controls H2O reabsorption at distal tubule.
    a. Concentrated urine leads to increased ADH secretion.
    b. Dilute urine leads to decreased ADH secretion.
  • Distal tubule and collecting duct.
    a. Secretion and reabsorption completed— reabsorption of Na+ and H2O takes place.
    b. Distal tubule—final regulation of H2O and acid–base balance.
    c. Uric acid and K+ secreted into distal tubules and excreted in urine.
  • Hormonal regulation.
    a. H2O reabsorption depends on ADH.
    b. Na+ and K+ reabsorption influenced by aldosterone.
    (1) Increased aldosterone causes increased Na+ reabsorption and increased K+ secretion.
    (2) Decreased aldosterone exhibits opposite effect.
    c. Ca++ and HPO4– – reabsorption regulated by parathyroid hormone. (1) Increased parathyroid hormone leads to increased Ca++ reabsorption and increased HPO4– – excretion.
    (2) Decreased parathyroid hormone exhibits opposite effect.
  • Water balance maintained through homeostasis—all functions of kidney must be maintained.
  • Acid–base regulation.
    a. Distal tubule maintains pH of extracellular fluid (ECF) within 7.35–7.45.
    b. Other actions: reabsorption, conservation of most of the bicarbonate and secretion of excess H+ ions.

F. Blood pressure regulation.

  • Regulation occurs through release of renin from juxtaglomerular cells in response to low blood volume or ischemia.
  • Renin stimulates conversion of angiotensinogen to angiotensin I in liver.
  • Angiotensin I changed to angiotensin II in pulmonary capillary bed.
  • Angiotensin II increases blood pressure by vasoconstriction of peripheral arterioles and secretion of aldosterone.
  • Increased aldosterone stimulates Na+ reabsorption.
  • Increased Na+ reabsorption causes increased H2O retention and plasma volume, which leads to increased blood pressure.

G. Additional functions.

  • Production of erythropoietin in response to hypoxia and decreased blood flow; stimulates production of red blood cells (RBCs) in bone marrow.
  • Renal failure leads to vitamin D deficiency, which leads to altered calcium and phosphate balance.

Characteristics of Urine
A. Components of urine include organic and inorganic materials in urine solution.
B. Cloudy urine is of little significance and is usually the result of urates or phosphates that precipitate out.
C. Red blood cells in the urine or hematuria are significant and indicate the presence of some disease or disorder in the body.

  • Acute nephritis or exacerbation of chronic nephritis.
  • Neoplasms, vascular accidents, or infections.
  • Renal stones.
  • Renal tuberculosis.
  • Trauma to the urinary tract.
  • A manifestation of thrombocytopenia.
  • May be the result of problems along the genitourinary tract, such as the ureter, the bladder, or the prostate gland.

D. The source of blood cells in urine must be determined.

  • Blood during the initial period of voiding may be from the anterior urethra or prostate.
  • Blood mixed with the total volume of urine may be from kidneys, ureters, or bladder.

Medical–Surgical Nursing: Renal Regulation of Fluid and Electrolytes

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Composition of the Body

Focus topic: Medical–Surgical Nursing

Body Fluids
Definition: Total body water represents the largest constituent (45–80%) of the total body weight, depending on the amount of fat present.
A. Intracellular—represents 40% of total body fluid; contained inside the cell; includes the red blood cells.
B. Extracellular—represents 20% of total body fluid; includes remaining fluid not contained within the cell.

  • Intravascular (plasma)—liquid in which the blood cells are suspended (5%).
  • Interstitial—liquid surrounding tissue cells (15%).
  • Percent varies with age and amount of fat.
    a. Infant—70–80% of baby’s weight is water.
    b. Elderly clients—45–55% of body weight is water.
    c. Thin person has more water.
    d. Men—greater percentage of body weight is water, more lean body mass than women.

Definition: Electrolytes are compounds that dissolve in a solution to form ions; each particle then carries either a positive or negative electrical charge.
A. Types.

  • Cations—positive charge (Na+, K+, Ca++, Mg++).
  • Anions—negative charge (Cl–, HCO3–, HPO4– –, SO4– –).
  • Equal number of cations and anions (154 each).

B. Concentration in solution is expressed in mEq/L. Total number of cations (mEq) plus total number of anions (mEq) will be the same in both intracellular fluid and extracellular fluid, thereby rendering the body’s fluid composition electrically neutral.
C. Compartment composition.

  • Extracellular—large quantities of sodium, chloride, and bicarbonate ions.
  • Intracellular—large quantities of potassium, phosphate, and proteins.

Medical–Surgical Nursing: Dynamics of Intercompartmental Fluid Transfer

Focus topic: Medical–Surgical Nursing

Transport of Fluids and Electrolytes
A. Diffusion—movement of solutes (substances that are dissolved in a solution) or gases from an area of higher concentration to an area of lower concentration; a passive transport system.
B. Filtration—passage of fluids through a semipermeable membrane as a result of a difference in hydrostatic pressures (pressure exerted by a fluid within a closed system). The semipermeable membrane prevents movement of solute particles.
C. Osmosis—passage of water or solvent through a semipermeable membrane from an area of lesser concentration to an area of greater concentration of solute; a passive transport system.
D. Facilitated diffusion—transport of molecules that are too large or insoluble across the membrane by means of a carrier molecule, creating a complex that is soluble in the membrane.
E. Active transport—transport (requiring external energy—adenosine triphosphate [ATP]) of substances across a membrane from an area of low concentration to an area of high concentration.

  • Molecules move from an area of high concentration to one of low concentration. Glucose transport into cell is an example.
  • Active transport is used for sodium moving out of the cell and potassium moving into the cell.

F. Oncotic pressure—osmotic pressure that results from dispersed colloid particles (the largest being proteins) in the blood capillaries; the pressure draws water back into the vascular system, thereby maintaining blood volume.
G. Lymphatics—vessels responsible for returning the large molecules that have escaped from the blood capillaries (including protein molecules) to the bloodstream, returning them from the interstitial fluid and the gastrointestinal (GI) tract.

Balance of Body Fluid
A. Intake.

  • Ingestion of foodstuff and water. Usual intake of fluid is 2000–3000 mL/day.
  • Oxidation of foodstuff.

B. Output.

  • Skin and lungs.
    a. Water is lost through vaporization from the skin surface and through expired air from the lungs.
    b. The amount lost increases as metabolism increases.
    c. About 900 mL loss/day.
  • Gastrointestinal tract.
    a. Routes include saliva, gastric secretions, bile, pancreatic juices, and intestinal mucosa.
    b. A volume in excess of 7 L is transferred from the ECF into the gastrointestinal tract, only to be reabsorbed, excepting some 200 mL that is passed with feces.
  • Kidneys.
    a. Carry the heaviest load.
    b. Through glomerular filtration and tubular reabsorption, the kidneys maintain homeostasis.
    c. Hormones influence the kidneys in terms of fluid balance.
    (1) Antidiuretic.
    (2) Aldosterone.

Medical–Surgical Nursing: Fluid Imbalances

Focus topic: Medical–Surgical Nursing

A. Assess for dehydration (extracellular fluid volume deficit).

  • Evaluate possible causes.
    a. Vomiting, diarrhea.
    b. Increased urine output.
    c. Diuretics.
    d. Excessive loss through respiration.
    e. Insufficient IV replacement.
    f. GI loss.
    g. Hemorrhage.
    h. Excessive perspiration.
  • Assess skin.
    a. Loss of skin turgor (after being pinched and lightly pulled upward, skin returns to normal very slowly).
    b. Dry, warm skin.
  • Assess febrile state (usually means there is fluid loss through perspiration).
  • Observe cracked lips, dry mucous membranes.
  • Assess decreased urinary output (normal output is > 30 mL/hr).
  • Concentrated urine—dark amber color and odorous.
  • Weight loss.
  • Low central venous pressure.
  • Increased respiration.

B. Assess for circulatory overload (extracellular fluid volume excess).

  • Evaluate possible causes.
    a. Excessive intravenous (IV) fluids.
    b. Inadequate kidney function.
    c. Cushing’s syndrome.
    d. Chronic liver disease.
  • Assess for headache.
  • Observe flushed skin.
  • Assess tachycardia.
  • Assess for venous distention, particularly neck veins.
  • Evaluate increased blood pressure and central venous pressure (CVP).
  • Assess tachypnea (increased respiratory rate), coughing, dyspnea (shortness of breath), cyanosis, and pulmonary edema.

A. Take central venous pressure to determine fluid balance if CVP catheter is in place. The CVP reflects the competency of the heart (particularly the right side) to handle the volume of blood returning to it.

  • CVP indicates the comparison of the pumping capacity of the heart and the volume of the circulating blood.
  • Normal CVP reading: 5–10 cm H2O.
  • Increased CVP (above 15 cm H2O) can be indicative of congestive heart failure or circulatory overload.
  • Decreased CVP (below 5 cm H2O) is indicative of hypovolemia (decreased fluid volume) whether from blood loss or other fluid losses.

B. Monitor client’s condition.

  • Check condition of skin.
    a. Dry, warm, cracked lips.
    b. Elasticity.
  • Check body temperature—fever suggests loss of body fluids.
  • Check for venous distention, increased pulse rate, and increasing blood pressure.
  • Ask client about unusual related symptoms, if possible, such as headache, shortness of breath.
  • Monitor fluid intake.
  • Check urine output at least every 8 hours for maintenance IV therapy, or as often as every hour for replacement fluid administration.
  • Check specific gravity (over 1.025 indicates dehydration; less than 1.010 indicates overhydration).
  • Check for symptoms of electrolyte disturbances at least every 4 hours.
  • Weigh client daily and watch for weight gain.

Medical–Surgical Nursing: Electrolyte Imbalances

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Potassium Imbalance

Focus topic: Medical–Surgical Nursing

A. Normal serum level is 3.5–5.0 mEq/L.
B. Potassium deficiency and excess is a common problem in fluid and electrolyte imbalance.
C. Major cell cation.
D. General nursing management related to potassium imbalances.

  • Observe electrocardiogram (ECG) tracings for change in T wave, ST segment, or QRS complex.
  • Measure intake and output (I&O) accurately.
  • Draw frequent blood specimens for potassium level.
  • Observe for signs of metabolic acidosis and alkalosis.

Definition: Hypokalemia is a very low concentration of potassium ions in extracellular fluid (serum level below 3.5 mEq/L).

A. Signs and symptoms of hypokalemia.

  • Muscle weakness, muscle pain, leg cramps, hyporeflexia, fatigue.
  • Hypotension, shallow respiration.
  • Arrhythmias—premature ventricular contractions (PVCs) particularly.
  • Nausea, vomiting, diarrhea.
  • Apathy, drowsiness leading to coma.
  • ECG changes include peaked P wave, flat T wave, depressed ST segment, and elevated U waves.
  • Paralytic ileus.

B. Causes of hypokalemia.

  • Renal loss most common (usually caused by use of diuretics).
  • Insufficient potassium intake.
  • Loss from gastrointestinal tract via nasogastric (NG) tube placement without replacement electrolyte solution, or from vomiting or diarrhea.

C. Nursing management of hypokalemia.

  • Maintain IVs with potassium chloride (KCl) added.
  • Replace K+ when excess loss occurs (NG tubes, diarrhea, etc.).
  • Replace no more than 20 mEq of KCl in 1 hour; observe ECG monitor if possible.
  • Dilute KCl in 30–50 mL IV fluid and administer with an IV pump.
  • Observe for adequate urine output.

Definition: Hyperkalemia is an excess of potassium in extracellular fluid (serum level greater than 5.0 mEq/L).

A. Signs and symptoms of hyperkalemia.

  • Weakness, muscle cramp, flaccid paralysis, irritability.
  • Hyperreflexia proceeding to paralysis.
  • Bradycardia, arrhythmias.
  • Ventricular fibrillation.
  • ECG changes depict elevated or tented T wave, widened QRS complex, prolonged P-R interval, and flattened P wave with depressed ST segment.
  • Oliguria.
  • Diarrhea, nausea.

B. Causes of hyperkalemia.

  • Usually renal disease (cannot excrete potassium).
  • Burns (due to cellular destruction releasing potassium from cells into extracellular space).
  • Crushing injuries (due to cellular breakage releasing potassium from cells).
  • Adrenal insufficiency.
  • Respiratory or metabolic acidosis.
  • Excess potassium administration.

C. Nursing management of hyperkalemia.

  • Administer diuretics if kidney function is adequate.
  • Administer hypertonic IV glucose with insulin.
  • Provide exchange resins through NG or enema (Kayexalate [sodium polystyrene sulfonate]).
  • Provide calcium IV to stimulate heart if depressed action.
  • Administer sodium bicarbonate if client is acidotic.
  • Withhold food and medications with high potassium levels.

Medical–Surgical Nursing: Sodium Imbalance

Focus topic: Medical–Surgical Nursing

A. Normal serum level is 135–145 mEq/L.
B. Sodium deficiency and excess are common problems in fluid and electrolyte imbalance.
C. General nursing management.

  • Observe skin condition.
  • Measure intake and output.
  • Auscultate lung sounds.
  • Observe urine for specific gravity and color.

Definition: Hyponatremia is caused by a very low concentration of sodium in extracellular fluid (serum level below 135 mEq/L).
A. Signs and symptoms of hyponatremia.

  • Signs and symptoms are the same as those for extracellular fluid deficiency.
    a. Weakness.
    b. Restlessness.
    c. Delirium, irritability, confusion.
    d. Hyperpnea.
    e. Oliguria.
    f. Increased temperature and pulse.
    g. Flushed skin, dry mucous membranes.
    h. Abdominal cramps.
    i. Convulsions.
    j. Nausea, anorexia.
  • If sodium is lost but fluid is not, the following signs and symptoms will be present (similar to those of water excess):
    a. Mental confusion, restlessness.
    b. Headache.
    c. Muscle twitching and weakness.
    d. Coma.
    e. Convulsions.
    f. Oliguria.

B. Causes of hyponatremia.

  • Excessive perspiration.
  • Use of diuretics.
  • Gastrointestinal losses—severe diarrhea, vomiting, pancreatic and biliary fistulas.
  • Lack of sodium in diet.
  • Burns, fibrocystic disease.
  • Excessive IV administration without sodium chloride (NaCl).
  • Diabetic acidosis.
  • Adrenal insufficiency.

C. Nursing management of hyponatremia.

  • Administer IV fluids with sodium.
  • Maintain accurate intake and output.

Definition: Hypernatremia is caused by a very high concentration of sodium in extracellular fluid (serum level above 145 mEq/L).

A. Signs and symptoms of hypernatremia.

  • Signs and symptoms are the same as for extracellular fluid excesses.
    a. Pitting edema.
    b. Excessive weight gain.
    c. Increased blood pressure.
    d. Dyspnea.
  • If hypernatremia is due to dehydration, in which a loss of fluid increases the number of ions, the signs and symptoms include
    a. Concentrated urine and oliguria.
    b. Dry mucous membranes, dry swollen tongue.
    c. Thirst.
    d. Flushed skin.
    e. Increased temperature.
    f. Tachycardia, hypertension.
    g. Seizures, coma.

B. Causes of hypernatremia.

  • Severe diarrhea.
  • Decreased water intake.
  • Febrile states.
  • Ingestion of sodium chloride.
  • Excessive loss of water through rapid and deep respiration.
  • Renal failure.
  • Diabetes insipidus.

C. Nursing management of hypernatremia.

  • Record intake and output.
  • Restrict sodium in diet.
  • Weigh daily.
  • Observe vital signs (VS).
  • Administer fluids orally or IV.

Medical–Surgical Nursing: Calcium Imbalance

Focus topic: Medical–Surgical Nursing

A. Normal serum level is 4.3–5.3 mEq/L; 9–11 mg/ dL.
B. Mineral plays major role in blood coagulation, cardiac muscle function, and muscle and nerve function.

Definition: Hypocalcemia results from a deficit of calcium in the extracellular fluid (serum level below 8.5 mg/dL).

A. Signs and symptoms of hypocalcemia.

  • Abdominal cramps, muscle cramps, spasms of larynx and bronchus.
  • Tetany, carpopedal spasms.
  • Circumoral tingling, especially in fingers.
  • Convulsions.
  • Confusion, anxiety, and moodiness.
  • ECG changes, prolonged QT interval, ventricular tachycardia.

B. Causes of hypocalcemia.

  • Acute pancreatitis.
  • Chronic renal insufficiency.
  • Burns.
  • Removal of parathyroid glands.
  • Massive transfusion (over 2000 mL of blood) requires calcium supplement.
  • Malabsorption syndrome.
  • Vitamin D deficiency.

C. Nursing management of hypocalcemia.

  • Calcium gluconate IV, followed by oral calcium supplements.
  • Serum albumin if condition is due to low serum albumin concentration.
  • Monitor for hypocalcemia.
    a. Trousseau’s test positive.
    b. Chvostek’s test positive.
  • Monitor for signs of hypercalcemia and dysrhythmias.

Definition: Hypercalcemia results from an excess of calcium in the extracellular fluid (serum level above 5.3 mEq/L).

A. Signs and symptoms of hypercalcemia.

  • Anorexia, nausea, vomiting.
  • Lethargy, weight loss, polydipsia, polyuria, dehydration.
  • Flank pain, bone pain, decreased muscle tone, pathologic fractures.
  • Stupor, coma.
  • ECG changes, shortened QT segment, ventricular arrhythmia.

B. Causes of hypercalcemia.

  • Excessive intake of vitamin D (milk) or calcium supplements.
  • Hyperparathyroidism, neoplasm of parathyroids.
  • Thyrotoxicosis.
  • Immobilization.
  • Paget’s disease.

C. Nursing management of hypercalcemia.

  • Treat the underlying cause of the high serum calcium level.
  • Immediate reversal—sodium salts IV and diuretics (Lasix [furosemide]).

Medical–Surgical Nursing: Magnesium Imbalance

Focus topic: Medical–Surgical Nursing

A. Normal serum magnesium level is 1.3–2.1 mEq/L.
B. Fifty percent of magnesium is in the bones and remaining 45% in intracellular compartment.

Definition: Deficit of magnesium due to chronic alcoholism, starvation, malabsorption, or vigorous diuresis (serum level below 1.3 mEq/L).

A. Signs and symptoms of hypomagnesemia.

  • Neuromuscular irritability.
    a. Jerks, twitches.
    b. Hyperactive reflexes.
    c. Convulsions, hallucinations, coma.
    d. Tetany.
  • Cardiovascular changes.
    a. Tachycardia, ventricular dysrhythmias.
    b. Hypotension.
    c. ECG changes: prolonged PR and QT segments.

B. Causes of hypomagnesemia.

  • Low intake.
  • Abnormal loss—chronic diarrhea.
  • Chronic nephritis.
  • Diuretic phase of renal failure.
  • Alcoholism.
  • Pancreatitis.
  • Toxemia of pregnancy.
  • Cancer chemotherapy.

C. Nursing management of hypomagnesemia.

  • Magnesium sulfate.
    a. Administer IV or intramuscular (IM) slowly.
    b. Observe for adequate urine output.
    c. Antidote: calcium gluconate.
  • Monitor cardiac rhythm.
  • Institute seizure precautions.

Definition: An excess of magnesium as a result of renal insufficiency or inability to excrete magnesium absorbed from food (serum level above 2.1 mEq/L).

A. Causes of hypermagnesemia.

  • Renal insufficiency.
  • Overdose of magnesium.
  • Severe dehydration, oliguria.
  • Overuse of antacids with magnesium (Gelusil).

B. Signs and symptoms of hypermagnesemia.

  • Hypotension, decreased respirations.
  • Curare-like paralysis.
  • Sedation.
  • Hypoactive deep tendon reflex.
  • Cardiac arrhythmias, bradycardia.
  • Warm sensation in body.

C. Nursing management of hypermagnesemia.

  • Administer calcium gluconate IV slowly.
  • Give in peripheral veins (not CVP line).
  • Monitor vital signs and neurological status.




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