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Chapter 27, Part 1
Pathophysiology and Respiratory
Disorders
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Lecture Outline
Introduction Physiology review Pathophysiology Assessment Management Specific respiratory diseases
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Introduction
More than 20 000 people die each year due to respiratory complaints
Intrinsic factors Heredity
Extrinsic factors Smoking Environmental pollutants
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Physiologic Processes Gas exchange
The process by which oxygen is taken in and carbon dioxide is eliminated Ventilation Diffusion Perfusion
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Ventilation Mechanical process of moving air
in and out of the lungs Requires body structures to be
intact Inspiration
Air drawn into lungs
Expiration Air leaves the lungs
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Body Structures for Ventilation
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Inspiration
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Expiration
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Diffusion Process by which gases move
between alveoli and pulmonary capillaries
Gases flow from areas of high to low concentration
O2 and CO2 Move across the membrane according to
their concentration gradients
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Diffusion Respiratory membrane must remain
intact Affected by
Disease process that damage alveoli Fluid accumulation in interstitial space Diseases that cause thickening of the endothelial
lining Oxygen therapy
Improves concentration gradient Medications
Address inflammation and fluid accumulation
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Lung Perfusion Circulation of blood through the
pulmonary capillaries Effective perfusion
Adequate lung volume Adequate concentration of hemoglobin
Oxygen transport 2% in solution 98% bound to hemoglobin
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Hemoglobin
Four iron heme and one protein globin molecules
Oxygen binds to heme molecule As oxygen binds
More readily accepts additional oxygen molecules
Relationship described in oxygen dissociation curve
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Oxygen Dissociation Curve
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Oxygen Dissociation Curve
Alterations Temperature Blood pH Carbon dioxide partial pressure
Allows for oxygen to be released at tissues and bound at lungs
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Carbon Dioxide Majority transported as bicarbonate
ions Transported in red blood cells and released at
lungs
Rest transported Bound to hemoglobin Dissolved in plasma
Haldane effect As heme is saturated with O2, more CO2 is
released
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Disruption in Ventilation Upper and lower respiratory tracts
Obstruction due to trauma or infectious processes
Chest wall and diaphragm Trauma Neuromuscular disease
Nervous System Trauma Poisoning or overdose Disease
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Abnormal Respiratory Patterns
Cheyne-Stokes respirations Progressively increasing then declining
respiration, separated by period of apnea Terminal illness or brain injury
Kussmaul’s respirations Deep rapid breaths Corrective measure for metabolic acidosis
Central neurogenic hyperventilation Deep, rapid respirations Stroke or injury to brainstem
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Abnormal Respiratory Patterns
Ataxic (Biot’s) respirations Repeated episodes of gasping separated by
apnea Increased intracranial pressure
Apneustic respirations Long deep breaths, stopped during inspiratory
phase Separated by periods of apnea Stroke or severe central nervous system disease
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Abnormal Respiratory Patterns
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Pathophysiology
Disruption in diffusion Hypoxia Damaged alveoli
Disruption in perfusion Alteration in blood flow Alterations in hemoglobin Pulmonary shunting
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Assessment
Scene assessment Safety BSI Identify rescue environments having
decreased oxygen levels Gases and other chemical or biological agents
Clues to patient information
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General Impression of the Patient
Position Color Mental status Ability to speak Respiratory effort
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Signs of Respiratory Distress
Nasal flaring Intercostal retraction Use of accessory muscles Cyanosis Pursed lips Tracheal tugging
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Airway Noisy breathing means partial airway
obstruction Obstructed breathing is not always noisy Brain can only survive minutes in asphyxia Ventilation is useless if the airway is blocked A patent airway is useless if the patient is
apneic Act on airway obstruction
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Breathing Signs of life-threatening problems
Alterations in mental status Severe central cyanosis, pallor, or
diaphoresis Absent or abnormal breath sounds Speaking limited to 1–2 words Tachycardia Use of accessory muscles or presence of
retractions
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History SAMPLE History OPQRST History
Paroxysmal nocturnal dyspnea and orthopnea
Coughing and hemoptysis Associated chest pain Smoking history or exposure to
secondary smoke
Similar Past Episodes
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Physical Examination Neck
Swelling JVD
Inspection Symmetry/asymmetry Increased diameter Paradoxical motion Scars, lesions, wounds, deformities
Palpation Tenderness Subcutaneous emphysema Tracheal deviation Tactile fremitus
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Auscultation Normal breath sounds
Bronchial Bronchovesicular Vesicular
Abnormal breath sounds Snoring Stridor Wheezing Rhonchi Crackles Pleural friction rub
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Extremities Peripheral cyanosis Swelling and redness, indicative of a venous clot Finger clubbing, which indicates chronic
hypoxia.
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Vital Signs Heart Rate
Tachycardia
Blood pressure Pulsus paradoxus
Respiratory rate Observe for trends Assume as elevated rate is caused by hypoxia Assume a slow rate is impending respiratory
arrest
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Pulse Oximetry
Offers rapid and accurate measure of oxygen saturation
Difficult or inaccurate Peripheral vasoconstriction
Hypothermia Sepsis
Carbon monoxide Hypovolemia
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Sensing unit for pulse oximetry
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Peak Flow Handheld device for
determining patient peak expiratory flow rate
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Capnometry Continuous waveform or colorimetric Detect carbon dioxide at end of expiration Roughly equal to partial pressure in blood Reflects adequacy of ventilations
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Management Principles Maintain the airway
Protect the cervical spine if trauma is suspected
Any patient with respiratory distress should receive oxygen
Any patient suspected of being hypoxic should receive oxygen
Oxygen should never be withheld from a patient suspected of suffering from hypoxia.
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Upper-Airway Obstruction Common Causes
Tongue, foreign matter, trauma, burns Allergic reaction, infection
Assessment Differentiate cause
Conscious patient If the patient is able to speak, encourage
coughing If the patient is unable to speak, perform
abdominal thrusts
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Upper-Airway Obstruction Unconscious Patient
Open the airway Attempt to give two ventilations
If they fail, reposition the head and reattempt Administer abdominal thrusts Attempt finger sweeps if foreign body is
visualized If foreign body is removed, resume ventilation If unsuccessful, continue abdominal thrusts and
sweeps Visualize the airway with the laryngoscope
Remove foreign body with Magill forceps and resume ventilations
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Adult Respiratory Distress Syndrome
Disorder of lung diffusion Inability to maintain proper fluid
balance in interstitial space Disruption of alveolar-capillary
membrane Non-cardiogenic pulmonary edema High mortality
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Adult Respiratory Distress Syndrome
Sepsis Aspiration Pneumonia Pulmonary Injury Burns/Inhalation Injury Oxygen Toxicity Drugs High Altitude Hypothermia
Near-Drowning Syndrome Head Injury Pulmonary Emboli Tumor Destruction Pancreatitis Invasive Procedures
Bypass, hemodialysis Hypoxia, Hypotension, or
Cardiac Arrest
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Adult Respiratory Distress Syndrome
Manage the underlying condition Provide supplemental oxygen Support respiratory effort
Provide positive pressure ventilation if respiratory failure is imminent
Monitor cardiac rhythm and vital signs Consider medications
Corticosteroids
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Obstructive Lung Diseases Widespread in society
Abnormal ventilation Some elements may be reversible
Asthma Chronic Obstructive Pulmonary
Disease Chronic bronchitis Emphysema
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Emphysema
Destruction of alveolar walls distal to the terminal bronchioles
Contributing factors Heredity Cigarette smoking Environmental factors
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Pathophysiology Destruction of alveolar surfaces
Decreased area for gas exchange Hypoxia
Cor pulmonale Decreased number of pulmonary capillaries Hypoxia constricts pulmonary vessels Increased resistance to right cardiac output Right heart failure
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Cor Pulmonale
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Pathophysiology Weakening of alveolar walls
Loss of elastic recoil Air trapping Pursed lipped breathing Barrel chest
Unable to expel carbon dioxide Chronic increased respiratory rate and accessory
muscle use SOBOE Polycythemia
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Assessment History
Recent weight loss, dyspnea with exertion Cigarette and tobacco usage Lack of cough
Physical Exam Barrel chest Prolonged expiration and rapid rest phase Thin Pink skin due to extra red cell production Hypertrophy of accessory muscles “Pink Puffers
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Chronic Bronchitis
Increased number of goblet cells in the respiratory tree
Production of large quantity of sputum
Often occurs after prolonged exposure to cigarette smoke
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Pathophysiology
Alveoli not severely affected Gas exchange is compromised
Decreased alveolar ventilation
Hypoxia Pulmonary vasoconstriction Cor pulmonale
Vital capacity is decreased
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Chronic mucous production and plugging of the airways
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Assessment History
Frequent respiratory infections Productive cough
Physical Assessment Often overweight Rhonchi present on auscultation Jugular vein distention Ankle edema Hepatic congestion “Blue Bloater.”
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Management For both emphysema and chronic
bronchitis Relieve hypoxia
Maintain airway Support breathing
Find position of comfort Monitor oxygen saturation Be prepared to ventilate or intubate
Reverse bronchoconstriction Bronchodilators
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Asthma
Chronic inflammatory disorder of the airways
Approximately 20 children and 500 adults die each year
50% die before reaching hospital Most deaths could be prevented
with education
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Pathophysiology Inflammation causes widespread
variable airflow obstruction Airways become hyperresponsive
Induced by a trigger (varies by individual) Release of histamine Bronchoconstriction and bronchial edema 6–8 hours later, immune system cells
invade the bronchial mucosa Additional edema.
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Assessment Identify immediate threats History
SAMPLE & OPQRST History History of asthma-related hospitalization History of respiratory failure/ventilator use
Physical Exam Presenting signs may include dyspnea, wheezing, cough
Wheezing is not present in all asthmatics Speech may be limited to 1–2 consecutive words
Hyperinflation of the chest and accessory muscle use Carefully auscultate breath sounds and measure peak
expiratory flow rate.
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Management Treatment goals:
Correct hypoxia Reverse bronchospasm Reduce inflammation
Maintain the airway Support breathing
High-flow oxygen or assisted ventilations as indicated Monitor cardiac rhythm Establish IV access Administer medications
Beta-agonists Ipratropium bromide Corticosteroids
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Special Cases of Asthma Status Asthmaticus
A severe, prolonged attack that cannot be broken by bronchodilators
Greatly diminished breath sounds Recognize imminent respiratory arrest
Aggressively manage airway and breathing Transport immediately
Asthma in Children Pathophysiology and management similar Adjust medication dosages as needed
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Upper Respiratory Infection Upper Respiratory Infections (URIs)
Frequent patient complaint Common pediatric complaint Rarely life threatening
Pathophysiology Frequently caused by viral and bacterial
infections Affect multiple parts of the upper airway Typically resolve after several days of symptoms
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Upper Respiratory Infection
Assessment Look for underlying illness Evaluate pediatrics for epiglottitis
Management Maintain the airway Support breathing Treat signs and symptoms
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Pneumonia
Infection of the lungs Particularly dangerous in immune-
suppressed patients
Usually a bacterial or viral infection Spreads to other parts of lung Fluid and inflammatory cells collect Disorder of ventilation May spread to entire lung
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Assessment
Focused history and physical exam SAMPLE & OPQRST
Recent fever, chills, weakness, and malaise Deep, productive cough with associated pain
Tachypnea and tachycardia may be present Breath sounds
Presence of rales/crackles in affected lung segments
Decreased air movement in the affected lung
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Management Maintain the airway Support breathing
High-flow oxygen or assisted ventilation as indicated
Monitor vital signs Establish IV access
Avoid fluid overload
Medications Antibiotics, antipyretics, beta-agonists
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Lung Cancer
Leading cause of cancer death among men and women
Linked to cigarette smoking and environmental pollutants
Causes: Spread from somewhere else in the body Carcinogen
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Lung Cancer Types
Adenocarcinoma Epidermoid Small-cell, and large-cell carcinomas
Assessment Focused history and physical exam
SAMPLE & OPQRST History• Cancer-related treatments and hospitalizations
Physical Exam• Evaluate for severe respiratory distress
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Lung Cancer
Management Administer oxygen Support ventilation Be aware of any DNR order Provide emotional support
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Toxic Inhalation Pathophysiology
Includes inhalation of heated air, chemical irritants, and steam
Airway obstruction due to edema Laryngospasm due to thermal and chemical
burns
Assessment Focused history and physical exam
SAMPLE & OPQRST History• Determine nature of substance.• Length of exposure and loss of consciousness
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Toxic Inhalation Ensure scene safety
Enter a scene only if properly trained and equipped
Remove the patient from the toxic environment
Maintain the airway Early, aggressive management may be indicated
Support breathing Establish IV access Transport promptly.
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Carbon Monoxide Odorless, colourless gas
Results from the incomplete combustion Often builds up to dangerous levels in
confined spaces Hazardous to Rescuers
Pathophysiology Binds to hemoglobin Prevents oxygen from binding and
creates hypoxia at the cellular level.
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Carbon Monoxide
Assessment Determine source and length of exposure Headache Confusion Agitation Lack of coordination, Loss of consciousness Seizures
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Management Ensure the safety of rescue personnel Remove the patient from the exposure
site Maintain an open airway Provide high-concentration oxygen Consider transport to hyperbaric
chamber
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Pulmonary Embolism Pathophysiology
Obstruction of a pulmonary arteryEmboli may be of air, thrombus, fat, or amniotic fluidForeign bodies may also cause an embolus
Risk FactorsRecent surgery, long-bone fractures, pregnancyPregnant or postpartumOral contraceptive use, tobacco use
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Assessment Focused history and physical exam SAMPLE and OPQRST History
Presence of risk factors Sudden onset of severe dyspnea and pain Cough, often blood-tinged
Physical Exam Signs of heart failure, including JVD and
hypotension Warm, swollen extremities (DVT)
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Management Maintain the airway Support breathing
High-flow oxygen or assist ventilations as indicated
Intubation may be indicated
Establish IV access Monitor vital signs closely Transport to appropriate facility
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Spontaneous Pneumothorax
Occurs in absence of trauma Risk factors
Rare but high recurrence rate More males than females (5:1) Tall, thin stature Between 20 and 40 years COPD (ruptured bleb)
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Spontaneous Pneumothorax
Pathophysiology Disease of ventilation Pneumothorax occupying 15-20% of chest
cavity generally well tolerated
Assessment Presence of risk factors Rapid onset of symptoms Sharp, pleuritic chest or shoulder pain Often precipitated by coughing or lifting
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Management
Maintain the airway Support breathing Monitor for tension pneumothorax Pleural decompression JVD Tracheal deviation away from the
affected side.
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Hyperventilation Syndrome
Characterized by rapid breathing Chest pains Numbness Other symptoms associated with anxiety
Many serious diseases cause hyperventilation Consider it to be an indicator of a serious
medical condition
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Hyperventilation Syndrome
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Hyperventilation Syndrome
Assessment SAMPLE & OPQRST history
Fatigue, nervousness, dizziness, dyspnea, chest pain
Numbness and tingling in hands, mouth, and feet
Presence of tachypnea and tachycardia Spasms of the fingers and feet.
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Hyperventilation Syndrome
Management Maintain the airway Support breathing Provide high-flow oxygen or assist
ventilations as indicated Do not allow the patient to rebreathe
exhaled air Reassure the patient
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CNS Dysfunction Pathophysiology
Traumatic/atraumatic brain injury Tumours Drugs
Assessment Evaluate potentially treatable causes
Narcotic drug overdose CNS trauma.
Carefully evaluate breathing pattern.
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Pathophysiology PNS problems affecting respiratory function
Trauma Polio Myasthenia gravis Viral infections Tumours
Assessment Rule out traumatic injury, and assess for
numbness, pain, or signs of PNS dysfunction.
Dysfunction of the Spinal Cord, Nerves, or
Respiratory Muscles
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Management
Follow general management principles.
Maintain the airway and support breathing.
Use cervical spine precautions if indicated.
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Summary
Review of Respiratory Physiology Pathophysiology Assessment Management Specific Respiratory Diseases