NCLEX-RN: Medical–Surgical Nursing

Medical–Surgical Nursing: Anatomy and Physiology of the Nervous System

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Central Nervous System: Brain and Spinal Cord

Focus topic: Medical–Surgical Nursing

A. Brain.

  • Cerebrum or cortex is the largest part of the human brain. (Consists of two hemispheres—right and left—separated by a fissure. It is responsible for the integration of complex sensory and neural functions and the initiation and coordination of voluntary activity in the body.) Each hemisphere receives sensory information from the opposite side of the body and controls the skeletal muscle of the opposite side.
    a. Function.
    (1) Highest level of functioning.
    (2) Governs all sensory and motor activity, thought, and learning.
    (3) Analyzes, associates, integrates, and stores information.
    b. Cerebral cortex (outer gray layer)—divided into four major lobes.
    (1) Frontal.
    (a) Precentral gyrus—motor function.
    (b) Broca’s area—motor speech area.
    (c) Prefrontal—controls morals, values, emotions, and judgment.
    (2) Parietal.
    (a) Postcentral gyrus—integrates general sensation.
    (b) Interprets pain, touch, temperature, and pressure.
    (c) Governs discrimination.
    (3) Temporal.
    (a) Auditory center.
    (b) Wernicke’s area—sensory speech center.
    (4) Occipital—visual area.
    c. Basal ganglia.
    (1) Collections of cell bodies in white matter.
    (2) Controls motor movement.
    (3) Part of extrapyramidal tract.
  • Diencephalon.
    a. Thalamus.
    (1) Screens and relays sensory impulses to cortex.
    (2) Lowest level of crude conscious awareness.
    b. Hypothalamus—regulates autonomic nervous system, stress response, sleep, appetite, body temperature, fluid balance, and emotions.
  • Brain stem.
    a. Midbrain—motor coordination, conjugate eye movements.
    b. Pons.
    (1) Contains projection tracts between spinal cord, medulla, and brain.
    (2) Controls involuntary respiratory reflexes.
    c. Medulla oblongata.
    (1) Contains all afferent and efferent tracts.
    (2) Decussation (intersection) of most upper motor neurons (pyramidal tracts).
    (3) Contains cardiac, respiratory, vomiting, and vasomotor centers.
  • Cerebellum.
    a. Connected by afferent/efferent pathways to all other parts of central nervous system (CNS).
    b. Coordinates muscle movement, posture, equilibrium, and muscle tone.

B. Spinal cord.

  • Structure.
    a. Conveys messages between brain and the rest of the body.
    b. Extends from foramen magnum to second lumbar vertebra.
    c. Inner column of H-shaped gray matter that contains two anterior and two posterior horns.
    d. Posterior horns—contain cell bodies that connect with afferent (sensory) nerve fibers from posterior root ganglia.
    e. Anterior horns—contain cell bodies giving rise to efferent (motor) nerve fibers.
    f. Lateral horns—present in thoracic segments; origin of autonomic fibers of sympathetic nervous system.
    g. White matter of cord contains nerve tracts.

(1) Principal ascending tracts (sensory pathways).
(a) Lateral spinothalamic—governs pain, temperature (contralateral).
(b) Anterior spinothalamic—governs touch, pressure (contralateral).
(c) Posterior column to medial lemniscus—governs proprioception, vibration, touch, pressure (ipsilateral).
(d) Spinocerebellar—governs bilateral proprioception to posterior and anterior portions of the cerebellum.
(2) Principal descending tracts (motor pathways).
(a) Pyramidal, upper motor neuron, or corticospinal—from motor cortex to anterior horn cell. Tract crosses in medulla.
(b) Extrapyramidal tracts consist of corticorubrospinal, corticoreticulospinal and vestibulospinal. These tracts facilitate or inhibit flexor/extensor activity.

  • Protection for CNS.
    a. Skull—rigid chamber with opening at the base (foramen magnum).
    b. Meninges—three layers of protective membranes.
    (1) Dura mater—tough, fibrous membrane—forms falx, tentorium.
    (2) Arachnoid membrane—delicate membrane that contains subarachnoid fluid.
    (3) Pia mater—vascular membrane.
    c. Ventricles are a communicating network of cavities filled with cerebrospinal fluid (CSF) located within the brain parenchyma.
    (1) Four ventricles—two lateral, the cerebral aqueduct, and the fourth ventricle.
    (2) Communication between subarachnoid space.
    (3) Subarachnoid space—formed by the arachnoid membrane and the pia mater.
    (4) Produce and circulate cerebrospinal fluid.
    d. CSF
    (1) Secreted from choroid plexuses in lateral ventricles, third ventricle, and fourth ventricle.
    (2) Circulates within interconnecting ventricles and subarachnoid space.
    (3) Protective cushion; aids exchange of nutrients and wastes.
    (4) Normal pressure: 60 to 180 mm H2O.
    (5) Volume: 80 to 200 mL, average 130 mL.
    (6) Allows fluid shifts from cranial cavity to the spinal cavity.
    e. Blood–brain barrier.
    (1) CSF.
    (2) Brain parenchyma.
    (3) Structure of brain capillaries differs from other capillaries. Some substances that normally pass into most tissue are prevented from entering brain tissue. This barrier protects the brain from certain harmful agents and limits penetration of some drugs.
    f. Blood supply—conductor of oxygen vitally needed by nervous system.
    (1) Internal carotids branch to form anterior and middle cerebral arteries.
    (2) Vertebral arteries arise from the subclavian arteries and merge to form the basilar arteries, which then subdivide into the two posterior cerebral arteries.
    (3) Circle of Willis—formed as the anterior communicating artery bridges the anterior cerebral arteries, and as the posterior communicating artery bridges each posterior and middle cerebral artery.

Medical–Surgical Nursing: Neuron Structure and Function

Focus topic: Medical–Surgical Nursing

A. Structure.

  • Cell body (gray matter).
  • Processes (nerve fibers).
    a. Axon conducts impulses from cell body.
    b. Dendrites receive stimuli from the body and transmit them to the axon.
  • Synapse—chemical transmission of impulses from one neuron to another.

B. Myelin sheath (white matter).

  • Surrounds axon.
  • Insulates; correlates with function and speed of conduction.
  • Produced by neurilemma cells in peripheral nerve fibers (sheath of Schwann).
  • Produced by neuroglial cells in CNS fibers.

C. Classification by function.

  • Sensory (afferent)—conducts impulses from end of the organ to CNS.
  • Motor (efferent)—conducts impulses from CNS to muscles and glands.
  • Internuncial (connector)—conducts impulses from sensory to motor neurons.
  • Somatic—innervates body wall.
  • Visceral—innervates the viscera.

D. Reflex arc (basic unit of function).

  • Receptor—receives stimulus.
  • Afferent pathway—transmits impulses to spinal cord.
  • CNS—integration takes place at synapse between sensory and motor neurons.
  • Efferent pathway—motor neurons transmit impulses from CNS to effector.
  • Effector—the organ or muscle that responds to the stimulus.

E. Regeneration of destroyed nerve fibers.

  • Peripheral nerve—can regenerate, possibly due to neurilemma.
  • CNS—cannot regenerate; lacks neurilemma.

Medical–Surgical Nursing: Peripheral Nervous System

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Nerves (Cranial and Spinal)

A. Cranial nerves—12 pairs of parasympathetic nerves with their nuclei along the brain stem.
B. Spinal nerves (31 pairs).

  • All mixed nerve fibers formed by joining the anterior motor and posterior sensory roots.
  • Anterior root—efferent nerve fibers to glands and voluntary and involuntary muscles.
  • Posterior root—afferent nerve fibers from sensory receptors. Contains posterior ganglion—the cell body of sensory neuron.

Medical–Surgical Nursing: Dysfunction of Cranial Nerves

A. Eye deviation from midline or unusual movements.

  • Unilateral pupil dilation: compression of the third cranial nerve (controls pupillary constriction).
  • Fixed pupils, often unequal: midbrain injury.
  • Pinpoint, fixed pupils, often unequal: pontine damage.

B. Reflexes present with dysfunction.

  • Plantar (called Babinski): dorsiflexion ankle and great toe with fanning of other toes; indicates disruption of pyramidal tract.
    a. Paralyzed side in cerebrovascular accident (CVA).
    b. Bilateral presence with spinal cord injury.
  • Corneal (blink): Loss of blink reflex indicates dysfunction of fifth cranial nerve (danger of corneal injuries).
  • Gag: Loss of gag reflex indicates dysfunction on the ninth and tenth cranial nerves (danger of aspiration).
Medical–Surgical Nursing

Medical–Surgical Nursing: Autonomic Nervous System

Focus topic: Medical–Surgical Nursing

A. Structure and function.

  • The term “autonomic” means that this system operates independently of desires and intentions.
  • Part of the peripheral nervous system controlling smooth muscle, cardiac muscle, and glands.
  • The autonomic nervous system (ANS) is divided into two components.
    a. Sympathetic.
    b. Parasympathetic.
    c. Two divisions make involuntary adjustments for integrated balance (homeostasis).

B. Diseases of sympathetic nerve trunks result in specific syndromes.

  • Dilation of pupils.
  • Bowel paralysis.
  • Variations in pulse rate and rhythm.

C. Structure of sympathetic nervous system—thoracolumbar division.

  • Long postganglionic (adrenergic) fibers.
  • Fibers arise in brain stem and descend to gray matter in spinal cord from C8 to L2.

D. Structure of parasympathetic nervous system— craniosacral division.

  • Short postganglionic (cholinergic) fibers.
  • Cells lie in brain stem and sacral region of spinal cord.

Medical–Surgical Nursing: System Assessment

Focus topic: Medical–Surgical Nursing

A. Evaluate client’s history regarding common signs, symptoms, and risk factors.

  • Signs and symptoms.
    a. Numbness, weakness.
    b. Dizziness, fainting, loss of consciousness.
    c. Headache, pain.
    d. Speech disturbances.
    e. Visual disturbances.
    f. Disturbances in memory, thinking, personality.
    g. Nausea, vomiting.
  • Risk factors.
    a. Trauma.
    b. Tumors.
    c. Hypoxia.
    d. Hemorrhage.
    e. Infections.
    f. Exposure to or ingestion of toxic substances.
    g. Metabolic and endocrine disorders.
    h. Hypertension.

B. Assess client’s level of consciousness.

  • Evaluate cerebral function (most sensitive and reliable index of consciousness).
  • Evaluate level of consciousness.
  • Assess behavior to determine level of consciousness: clouding, confusion, delirium, stupor, coma.

C. Evaluate pupillary signs.

  • Assess size: Measure in millimeters; compare each eye.
  • Assess equality: equal, unequal, fluctuations.
  • Assess reactions to light: brisk, slow, fixed.
    a. Light reflex is most important sign differentiating structural from metabolic coma.
    b. Early warning of deteriorating condition or elevated intracranial pressure (ICP).
  • Evaluate unusual eye movements or deviations from midline.

D. Evaluate motor function.

  • Assess face and upper and lower extremities for:
    a. Muscle tone, strength, equality; normal is equal bilaterally.
    b. Voluntary movement.
    c. Involuntary movements.
    d. Reflexes: Babinski, corneal, gag.
  • Evaluate patterns of motor function.
  • Inappropriate—nonpurposeful.
    a. Involuntary.
    (1) Choreiform (jerky, quick).
    (2) Athetoid (twisting, slow).
    (3) Tremors.
    (4) Spasms.
    (5) Convulsions.

E. Assess reflexes.

  • Evaluate for presence of reflexes.
  • Identify reflex response.
    a. Scale is 0 to 4.
    b. Absence of reflex is rated 0.
    c. Weak response is rated 1.
    d. Normal response is rated 2.
    e. Exaggerated response is rated 3.
    f. Hyperreflexia is rated 4.

F. Evaluate sensory function.
G. Evaluate vital signs.

  • Increasing blood pressure (BP) with reflex slowing of pulse—compensatory stage with increasing intracranial pressure.
  • Fall in blood pressure with increasing or irregular pulse—decompensation.
  • Assess respiratory rate and rhythm.

H. Evaluate intracranial pressure.

I. Evaluate autonomic nervous system.

  • Assess for sympathetic function.
    a. Fight, flight, or freeze; diffuse response.
    b. Increases heart rate, blood pressure.
    c. Dilates pupils, bronchi.
    d. Decreases peristalsis.
    e. Increases perspiration.
    f. Increases blood sugar.
  • Assess for parasympathetic function.
    a. Repair, repose; discrete response.
    b. Decreases heart rate, blood pressure.
    c. Constricts pupils, bronchi.
    d. Increases salivation and peristalsis.
    e. Dilates blood vessels.
    f. Bladder contraction.

J. Assess for pain.

  • Assess for nonverbal signs of pain (e.g., facial grimaces, retracting from painful stimuli).
  • Evaluate onset, location, intensity, duration, and aggravating factor.
  • Observe for precipitating factors, associated manifestations, and alleviating factors.
  • Assess ability to distinguish between sharp and dull sensation; use cotton-tip applicator and wooden end.

Medical–Surgical Nursing: Diagnostic Procedures

Focus topic: Medical–Surgical Nursing

Medical–Surgical Nursing: Skull Series

Focus topic: Medical–Surgical Nursing

A. Procedure: x-rays of head from different angles.
B. Purpose: to visualize configuration, density, and vascular markings.
C. Tomograms: layered vertical or horizontal x-ray exposures.

Medical–Surgical Nursing: Myelography

Focus topic: Medical–Surgical Nursing

A. Injection of dye or air into lumbar or cisternal subarachnoid space followed by x-rays of the spinal column.
B. Purpose: to visualize spinal subarachnoid space for distortions caused by lesions or tumors.
C. Potential complications.

  • Same as for lumbar puncture.
  • Cerebral meningeal irritation from dye.

D. Nursing implementation.

  • If dye is used, elevate head and observe for meningeal irritation.
  • If air is used, keep head lower than trunk.
  • Frequently observe neurological signs and vital signs and compare to baseline.
  • Check for adequate voiding.

Medical–Surgical Nursing: Cerebral Angiography

Focus topic: Medical–Surgical Nursing

A. Injection of radiopaque dye into femoral, carotid, and/or vertebral arteries followed by serial x-rays.
B. Purpose: to visualize cerebral vessels and localize lesions such as aneurysms, occlusions, angiomas, hematomas, tumors, arteriovenous malformations, or abscesses.
C. Potential complications.

  • Anaphylactic reaction to dye.
  • Local hemorrhage.
  • Vasospasm.
  • Adverse intracranial pressure.

D . Nursing implementation.

  • Prior to procedure.
    a. Check for allergies.
    b. Take baseline assessment.
    c. Measure neck circumference.
  • During procedure and postprocedure.
    a. Have emergency equipment available.
    b. Monitor neurological and vital signs for shock, level of consciousness, hemiparesis, hemiplegia, and aphasia.
    c. Monitor puncture site for bleeding as well as swelling of neck and difficulty in swallowing or breathing.
    d. Apply ice collar for carotid punctures as ordered.

Medical–Surgical Nursing: Magnetic Resonance Imaging

Focus topic: Medical–Surgical Nursing

A. Visualization of distribution of hydrogen molecules in the body in three dimensions.
B. Purpose: to differentiate types of tissues, including those in normal and abnormal states (includes brain, both tumors and vascular abnormalities, as well as cardiac, respiratory, and renal conditions).
C. Magnetic resonance imaging (MRI) yields greater contrast in the images of soft-tissue structures than CT scan.
D. Requires longer time to complete. May not be appropriate when evaluating life-threatening situations.

Medical–Surgical Nursing

Medical–Surgical Nursing: Computerized Tomography Scan

Focus topic: Medical–Surgical Nursing

A. Procedure: a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce horizontally and vertically cross-sectional images of the body to analyze relative tissue density as an x-ray beam passes through. Done with or without contrast.
B. Purpose: Provides detailed three-dimensional images of any part of the body, including the bones, muscles, fat, and organs, to determine location and extent of tumors, infracted areas, vascular lesions/ abnormalities, or tissue atrophy.
C. Nursing implementation.

  • Explain procedure; advise client that he or she will have to lie still.
  • Obtain informed consent.
  • Assess for allergy to iodine, a component of the contrast material.
  • Withhold food for approximately 2 hours; contrast may cause nausea and vomiting.
  • Have client use the bathroom before the test.
  • Have client remove all hair pieces, pins, and clips prior to computerized tomography (CT) of head.
  • Instruct client to remove hearing aids and glasses before the test.

Medical–Surgical Nursing: Tomography

Focus topic: Medical–Surgical Nursing

A. Type of brain scan that relies on tissue density and  shadows to reflect internal state of brain tissue.
B. EMI scanner (CT scan).
C. Xenon computed tomography quantitative cerebral blood flow (Xe/CT/CBF).

  • Precisely measures blood flow to various areas of the brain.
  • Defines degree and extent of ischemia in an acute neurologic condition.
  • Enables clinicians to identify irreversibly damaged brain tissue hours to days before changes become evident on standard CT or MRI tests.
  • Most often used to select stroke clients for thrombolytic therapy.
  • Identifies and manages vasospasm after subarachnoid hemorrhage.
  • Diagnoses brain death by confirming the absence of cerebral blood flow.
  • Determines the effect of hyperventilation when used with head trauma clients with increased intracranial pressure (ICP).
  • Evaluates the effectiveness of interventions to increase cerebral perfusion (e.g., hypertensive therapies).
  • Provides both quantitative and qualitative measurement of blood flow.
  • Xenon gas eliminated from body within 20 minutes, test can be repeated quickly if needed.
  • Client prep as for normal noncontrast CT.

Medical–Surgical Nursing: Positron Emission Tomography

Focus topic: Medical–Surgical Nursing

A. Procedure: a computerized image of regional metabolic activity of the body tissues used to determine the presence of disease. The test involves injecting a very small dose of a radioactive glucose, called a radiotracer, into a vein. A scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is metabolized, blood flows, and oxygen is extracted.
B. Purpose: A positron emission tomography (PET) scan differs from other imaging tests such as CT scan or MRI in that it reveals cellular- level metabolic changes occurring in an organ or tissue where disease processes begin.

  • A PET scan can often detect these very early changes, whereas a CT or MRI detects changes a little later—as the disease causes changes in the structure of organs or tissues.
  • PET scans can detect cancer, brain disorders (including brain tumors, memory disorders, and seizures), and other CNS problems.

C. Nursing implementation.

  • Explain procedure. Advise client that he or she will have to lie still during procedure and may require sedation—if so, use carefully with head injury or surgery. Explain that the client will have two intravenous (IV) lines.
  • Obtain informed consent.
  • Withhold food for approximately 4–6 hours.
  • Have client use the bathroom before the test.

Medical–Surgical Nursing: Electroencephalography

A. Procedure: graphic recording of brain’s electrical activity by electrodes placed on the scalp.
B. Purpose: to detect intracranial lesion and characteristic abnormal electrical activity (seizures).
C. Nursing implementation.

  • Wash hair.
  • Withhold sedatives or stimulants.
  • Administer fluids as ordered.

Medical–Surgical Nursing: Electromyography

Focus topic: Medical–Surgical Nursing

A. Procedure: recording the potential of muscle action by surface or needle electrodes.
B. Purpose: to diagnose or localize neuromuscular disease.

Medical–Surgical Nursing: Lumbar Puncture

Focus topic: Medical–Surgical Nursing

A. Procedure: insertion of spinal needle through L3–4 or L4–5 interspace into lumbar subarachnoid space.
B. Purpose.

  • To obtain cerebrospinal fluid (CSF).
  • To measure intracranial pressure and spinal fluid dynamics.
  • To instill air, dye, or medications.

C. Potential complications: headache, backache, and herniation with brain stem compression (especially if intracranial pressure is high).
D. Nursing implementation.

  • Explain procedure. Advise client that he or she will have to lie or sit still during procedure.
  • Obtain informed consent.
  • Have client empty bowel and bladder before the test.
  • Monitor vital signs.
  • Position client in a position that will facilitate enlarging the opening of the vertebral space.
    a. Lying on side with feet drawn up, head to chest on edge of bed.
    b. Sitting on side of bed, leaning over bedside table, support feet on flat surface.
  • Assist with specimen collection and spinal fluid dynamics.
  • Post procedure.
    a. Maintain client in prone position for 2 hours or flat side-lying for 2–3 hours to avoid headache.
    b. Assess puncture site for CSF leakage—a complication of lumbar puncture (LP).
  • Label specimens, send to lab; note color and amount of fluid.
  • Assess for signs of shock.
  • Maintain asepsis and administer fluids unless contraindicated.

E. Spinal fluid dynamics—Queckenstedt–Stookey
test.

  • Normal pressure is 60–150 mm H2O when client is in lateral recumbent position. Pressure increases with jugular compression and drops to normal 10–30 seconds after release of compression.
  • Partial block: slow rise and return to normal.
  • Complete block: no rise.

Medical–Surgical Nursing: System Implementation

Focus topic: Medical–Surgical Nursing

A. Observe for and treat seizure activity.
B. Monitor vital signs for signs of hyperthermia, increased intracranial pressure, and infection.
C. Observe motor and sensory function.
D. Observe pupillary signs for metabolic or structural complications.
E. Prevent muscle weakness and atrophy through range-of-motion exercises.
F. Promote bowel and bladder function.
G. Maintain nutritional status.
H. Prevent complications of immobility (e.g., skin breakdown).
I. Provide emotional support for client and family during hospitalization and upon discharge.
J. Monitor cardiac and respiratory function for identification of potential complications.
K. Provide appropriate preoperative and postoperative nursing interventions.
L. Establish an individualized rehabilitative program.
M. Administer drug therapy and monitor side effects.
N. Institute nursing implementation to assist in decreasing intracranial pressure.
O. Establish appropriate measures for pain relief.

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