Download 15_Gas Exchange and Oxygenation_Upper Respiratory System

The Respiratory System
Respiratory systems is divided into two
functional Systems:
1. Upper Respiratory Tract
nares, nasal cavity, pharynx and
larynx
2. Lower Respiratory Tract
trachea, bronchi, bronchioles, alveoli,
and alveolar-capillary membrane
Oxygenation
 Ventilation – movement of air to the alveoli.
 A mechanical action
 Respiration – gas exchange at the alveolarcapillary membrane
 Perfusion – blood flow at the alveoli-capillary
bed. Affected by lung pressure and resistance,
edema, secretions and bronchospasm.
 Diffusion – movement of oxygen into capillaries
and carbon dioxide out of the blood.
Gas Exchange
Gas exchange is the process by which oxygen
is transported to cells and carbon dioxide is
transported from cells.
Impairment of gas exchange occurs when the
diffusion of gases (oxygen and carbon
dioxide) are affected by:
 Ineffective ventilation
 Reduced capacity for gas transportation
(reduced hemoglobin and/or red blood
cells), e.g. blood loss or anemia
 Inadequate perfusion
Risk Factors for Impaired Gas
Exchange
 Presence of chronic
medical conditions,
such as:
 chronic obstructive
pulmonary disease
(COPD),
 emphysema
 cystic fibrosis (CF),
 heart Failure (HF)
 Age
 Smoking
 Immunosuppression
 Reduced state of
cognition
 Brain injury
 Prolonged immobility
Pathophysiology: Upper Respiratory System
 Common cold is a viral
infection that starts in the
upper respiratory tract,
sometimes spreading to the
lower structures.
 Pharyngitis is an
inflammation or infection of
the pharynx.
 Laryngitis is an inflammation
of the larynx.
 Allergic or seasonal rhinitis
occurs when the upper airways
respond to a specific allergen.
 Sinusitis occurs when the
epithelial lining of the sinus
cavities becomes inflamed. It
can be caused by bacteria or
viruses.
 Influenza is an infection
caused by any of several strains
of myxo-viruses.
Upper Respiratory System
Drug Classifications for Upper
Respiratory Disease
 Antitussives
 Antihistamines
 Decongestants
 Expectorants
 Mucolytics
 Anti-inflammatories
Antitussive Drugs
 Antitussives are drugs that suppress the cough reflex.
 Many disorders of the upper and lower respiratory tracts
are accompanied by an uncomfortable, nonproductive
cough.
 Coughing normally is a protective mechanism that forces
foreign irritants out of the respiratory system, opening it
for more efficient flow of air.
Prototype drug:
dextromethorphan
(Robitussin DM)
Dextromethorphan: Core Drug
Knowledge
 Pharmacotherapeutics
 Chronic nonproductive cough
 Pharmacokinetics
 Administered: oral. Metabolism: liver. Excreted: kidneys.
 Pharmacodynamics
 Directly affects the cough center in the medulla in the
brain (CNS effect)
 Chemically related to the opiate agonists and can
suppress coughing as effectively as narcotics.
Dextromethorphan: Core Drug
Knowledge (cont.)
 Contraindications and precautions
 Chronic coughs resulting from emphysema and asthma
 Side effects
 Nausea, vomiting, drowsiness, dizziness, irritability, and
restlessness
 Adverse effects
 Poor respiratory clearance due to cough suppression effect
Dextromethorphan: Teaching,
Assessment, and Evaluation
 Patient and family education
 Emphasize that sedation, drowsiness, and impaired
orientation can occur.
 Advise not to drive or operate heavy equipment.
 Caution patients who are taking certain antidepressants.
 Ongoing assessment and evaluation
 Monitor the effect of dextromethorphan on the patient’s
motor control, sedation, and respiratory status.
Discussion Question
 Would an antitussive be a good idea for
a patient with severe lower respiratory
disease, such as emphysema?
 Why or why not?
Decongestant Drugs
 Decongestants are drugs taken to decrease nasal congestion,
a condition that is caused by an inflammatory response in
the upper respiratory tract.
 Nasal decongestants work by constricting the nasal
arterioles, thereby decreasing the swelling of the nasal
membrane.
 These drugs can be administered orally
or topically.
Prototype drugs:
pseudoephedrine (Sudafed)
Phenylephrine (Neo-Synephrine)
Pseudoephedrine: Core Drug
Knowledge
 Pharmacotherapeutics
 Reduces the volume of nasal mucus and is recommended
for the temporary relief of nasal congestion
 Pharmacokinetics
 Administered: oral. Metabolism: liver. Excreted: kidneys.
Onset: 30 minutes.
 Pharmacodynamics
 Causes vasoconstriction in the nasal mucous membranes
Pseudoephedrine: Core Drug
Knowledge (cont.)
 Contraindications and precautions
 Caution with pregnancy and lactation
 Adverse effects
 Tension, anxiety, restlessness, tremor, insomnia, and weakness
 Maximizing therapeutic effects
 Encourage patients to use a humidifier, drink plenty of fluids, and
avoid smoke-filled rooms.
 Minimizing adverse effects
 Provide the patient with appropriate safety measures.
Pseudoephedrine: Teaching,
Assessment, and Evaluation
 Patient and family education
 Explain to patients that the purpose of the drug is to
promote breathing and relieve congestion.
 Caution patients to avoid using other OTC drugs.
 Ongoing assessment and evaluation
 Monitor patients receiving pseudoephedrine for rebound
congestion, sedation, dizziness, insomnia, weakness,
tremor, and urinary retention.
Discussion Questions
What else do you know about
pseudoephedrine (Sudafed)?
 It’s access is controlled as it is a main
ingredient in the illegal manufacture of
methamphetamine.
“Extra credit”: What herbal remedy is
related to pseudoephedrine?
 Ma Huang, which is now banned due to deaths
in athletes from cardiac arrest.
Decongestants: Phenylephrine
Phenylephrine (Neo-Synephrine) usually
used in nasal spray form to treat allergic or
nonallergic rhinities by relieving nasal
stuffiness and as a decongestant for sinusitis
and the common cold
 Pharmacodynamics
stimulates alpha-1 adrenergic receptors in
the sinuses causing reduction in
inflammation of the nasal membranes
Decongestants: Phenylephrine
 Contraindicated
Chronic rhinitis and caution in hypertension or coronary
artery disease
 Adverse Reactions
 CNS Stimulation – agitation, nervousness, unease
 Vasoconstriction
 Rebound nasal congestion develops very quickly
 Minimizing Adverse Effects
 Do not use nasal spray more than 3-5 days
 Taper use by alternating nostrils every other day
Nasal Glucocorticoids: Mometasone
Mometasone (Nasonex) are given by nasal spray
 Pharmacotherapeutics
 Used to decrease the inflammation associated with
allergic rhinitis by reducing: sneezing, nasal itching, and
runny nose.
 Adverse Effects
 Sore throat, nosebleed, headache, burning in the nose
 Minimizing Adverse Effects/Patient Education
 Administer daily – not PRN
 It may take up to 7 days to reach desired effects
Antihistamines
 Antihistamines are used to relieve symptoms of allergies.
 These drugs block the action of histamine as it is
released during the inflammatory response to an
antigen.
 Effective for allergic rhinitis.
 Their action restores normal airflow through the upper
respiratory system.
Prototype drug: Loratadine (Claritin)
or fexofenadine (Allegra)
Loratadine: Core Drug Knowledge
 Pharmacotherapeutics
 Relieves symptoms associated with seasonal and perennial
allergies
 Pharmacodynamics
 Selectively blocks the effects of histamine at H1-receptor sites
 Contraindications and precautions
 Hypersensitivity
 Adverse effects
 Nausea, drowsiness, dyspepsia, and fatigue
Loratadine : Nursing Diagnoses and
Outcomes
 Risk for Injury caused by drowsiness and
fatigue related to drug-induced CNS effects
 Patient and family education
 Caution patients to take the drug as prescribed.
 Tell patients to avoid the use of other OTC drugs.
Expectorant Drugs
 Expectorants are drugs that liquefy lower respiratory
tract secretions.
 This effect decreases the viscosity of the secretions and
improves airflow.
 Expectorants are available in many OTC preparations.
Prototype drug:
guaifenesin
Guaifenesin: Core Drug Knowledge
 Pharmacotherapeutics
 Relieves dry, nonproductive cough
 Pharmacodynamics
 Enhances the output of respiratory tract fluids by reducing
the adhesiveness and surface tension of the fluids
 Contraindications and precautions
 Known allergy to medication
 Adverse effects
 GI symptoms, headache, and dizziness
Guaifenesin: Patient Education
 Maximizing therapeutic effects
 Teach the patient about good pulmonary hygiene, which
includes coughing, using deep breathing, drinking
plenty of fluids, and using a humidifier.
 Minimizing adverse effects
 Suggest that the patient eats small, frequent meals to
alleviate GI upset.
 Guaifenesin should only be used for one week.
Mucolytic Drugs
 Mucolytics break down mucus.
 The drugs can be administered by a nebulizer or by
direct instillation into the trachea.
 Mucolytics usually are reserved for patients who have
major difficulty mobilizing and coughing up
secretions.
Prototype drug: acetylcysteine
(Mucomyst)
Acetylcysteine: Core Drug
Knowledge
 Pharmacotherapeutics
 Used to liquefy the thick, tenacious secretions.
 Pharmacodynamics
 It splits disulfide bonds that are responsible for holding the
mucous material together.
 Contraindications and precautions
 Hypersensitive
 Adverse effects
 Bronchospasm, bronchoconstriction, chest tightness, a
burning feeling in the upper airway, and rhinorrhea
 Unpleasant (sulfur, rotten egg) smell with
Acetylcysteine: Planning and
Interventions
 Maximizing therapeutic effects
 Administer an inhaled beta-agonist before administering
acetylcysteine.
 Minimizing adverse effects
 Inform the patient that nebulization may produce an
initially disagreeable odor, but that this odor is transient.
Drug + Effect Matching
Phenylephrine
Loosens/thins secretions
Acetylcysteine
Rebound nasal congestion
Mometasone
Suppresses mucous production due to
anticholinergic effects
Pseudoephedrine
Dextromethorphan
Loratadine
Central nervous system suppression of
cough reflex
Allergic rhinitis
Sympathetic nervous system
stimulation
NCLEX-Style Question #1
NCLEX-Style Question #2
NCLEX-Style Question #3
NCLEX-Style Question #4
Answers to NCLEX-Style Questions
1.
2.
3.
4.
B
B
C
A
Case Study: The Common Cold
Erika Adams, age 22, comes to the nurse-run clinic
at the university with complaints of a cold and flulike symptoms. She states that her cough is
keeping her up at night.
Data obtained from the nursing assessment
include the following:
 Complaints of fatigue, body aches, cough, nasal
congestion, and mild fever
 Vital signs: temperature, 99.1°F; pulse, 90;
respiration, 20; blood pressure, 98/68
 Harsh nonproductive cough noted.
Case Study: The Common Cold
 You suggest comfort measures, including rest
and increased fluids, a steam vaporizer.
 The patient’s recommended medications
include the use of pseudoephedrine, 30 to 60
mg PO every 4 to 6 hours PRN; and
dextromethorphan, 30 mg PO every 4 to 8
hours PRN.
Case Study: The Common Cold
1. How do these drugs work together to
address Erika’s underlying pathologic
conditions?
2. What other medications may have been
considered for treating Erika’s symptoms?
3. Which findings might demonstrate possible
adverse effects from drug therapy?
4. What teaching is required for Erika
regarding her drug therapy?