Ventilation & Gas Exchange (Ch. 31)-- Term First Flashcards
Exam 2
Traumatic Pneumothorax
Chest Injury (penetrating or non-penetrating)
- fractured or dislocated ribs
- CPR
- Central line insertion
- Intubation
- Positive pressure ventilation
Acquired Atelectasis
Adults
- Airway obstruction
- Lung compression– tumor, exudate, pneumothorax
risk factors– sedation, pain, narcotics, immobility
Atelectasis Clinical Manifestations
⇡ RR, ⇡ HR, dyspnea, cyanosis, hypoxemia, decreased chest expansion, absent breath sounds, intercostal retractions
Prevention– incentive spirometer, frequent position changes, ambulate, hydrate
Treatment– fix cause, supplemental O2
Shunt
Perfusion without ventilation (LOW V/Q)
- Hypoxemia
- Atelectasis
- PNA
- Asthma
- COPD
- Chronic bronchitis
- Emphysema
Hypercapnic/Ventilation Failure
PaCO2 > 50 mmHg AND pH <7.30
Causes– ⇣ RR or WOB
- Upper airway obstruction– infection, laryngospasm, tumors
- Weakness or paralysis of respiratory muscles– brain injury, sedation, drug overdose (opioids), Guillen-Barre syndrome, Muscular Dystrophy, spinal cord injury
- Chest wall injury– physiologic dead space
Leads to– Vasodilation (systemic circulation), Pulmonary blood vessel constriction
Diagnosis
- ABG– elevated CO2
Chronic Bronchitis Clinical Manifestations
- Cyanosis
- Fluid retention
- R-sided HF (cor pulmonale)
- Productive cough
- ⇣ RR
-
Crackles and wheezes
- d/t mucus in the lungs
Inflammatory Mediators
Histamine, leukotrienes, prostaglandins → Bronchoconstriction
Transudate
Clear, thin fluid (hydrothorax), specific gravity <1.020
d/t– CHF, renal failure, nephrosis, liver failure, malignancies (cancer)
Emphysema Clinical Manifestations
-
Accessory muscle & pursed-lip breathing
- ⇡ positive pressure
-
Barrel chest
- d/t air trapping
- ⇣ Breath sounds
- ⇡ RR
- Non-productive cough
- NO cyanosis
Asthma Attack Triggers
- RTIs
- Exercise (EIB)
-
Drugs
- ASA– ⇣ COX, ⇡ LOX → ⇡ Leukotrienes
- Morphine– Histamine release
- Emotional Upset
-
Bronchial irritants
- Smoke
- Toxins
Late Phase Response
Extrinsic/Allergic/Atopic Response
- 2-8 hrs. after exposure
- Mucosal edema, ⇡ secretion, ⇡ WBC, epithelial damage, bronchospasm
- Lasts several days
Treatment– Corticosteroids (ICS)
Cystic Fibrosis Pathogenesis
-
Cl- unable to move into epithelial lumen of airway
- Cl- remains w/i cell
- Na+ & H2O move from airway into blood
- Respiratory secretions thicken
-
⇣ H2O in mucous membranes
- Dehydration
-
Accumulation of mucus
- Airway obstruction
- Pancreatic & biliary duct dysfunction
- Pancreatic enzyme deficiency
- Vas deferens dysfunction
- Azoospermia
- Increased risk of pulmonary infection
High V/Q
High V, Low Q (100:1)
- Dead air space
- Low flow states
- Pulmonary embolism (PE)
Hyperventilation
⇣ CO2 in the arterial blood → Hypocapnia/Hypocarbia → Respiratory Alkalosis
d/t– Panic attack, pain, ⇡ RR, hypoxemia
Respiratory Failure Manifestations
- Inadequate gas exchange
- V/Q mismatch
- PaO2 < 60 mmHg or PaCO2 > 50 mmHg & pH <7.30 or BOTH
- Severe Hypoxemia + Hypercapnia + Respiratory Acidosis
- Post-Surgery
- Atelectasis
- PNA
- Pulmonary edema
- Pulmonary emboli → Respiratory failure
- Smoking + lung Disease
- Underlying disease/infection
- Renal, cardiac, neurologic, or hepatic
Asthma Treatment
Limit exposure to allergens
Pharmacologic Agents
Immediate
-
Bronchodilator
- Albuterol (SABA)
-
Anti-Inflammatory
- Corticosteroid (ICS)
Long-Term
- Mometasone (ICS)
- Salmeterol (LABA)
- Symbicort– Combination (LABA + ICS)
Pleural Effusion
Collection of fluid in the pleural cavity
Acute Lung Injury (ALI)
Sudden inflammation that starts at the lungs → Disruption of gas exchange at alveolar-capillary membrane
-
Hypoxemia
- Less severe form
Exudate
Purulent, thick fluid, specific gravity >1.020
d/t– elevated LDH & protein, inflammatory cells
Hypoxemic/Oxygenation Failure
PaO2 < 60 mmHG d/t problem with O2 uptake
Causes– COPD, severe PNA, Atelectasis, ARDS, Pulmonary edema, V/Q mismatch (d/t shunt, dead air space…)
- Decreased O2 to alveoli (d/t high altitude or hypoventilation)
-
Impaired diffusion of O2 from alveoli to blood (d/t V/Q mismatch or alveolar-capillary impairment)
- Vasodilation (Systemic circulation)
-
Inadequate circulation through pulmonary capillaries (d/t pulmonary embolus or arteriovenous malformation)
- Pulmonary blood vessels constrict
Tension Pneumothorax
Air stuck in pleural space (intrapleural pressure > atmospheric pressure)
Leads to–
- compression atelectasis
- trachea and sternum shift L
- L lung shift
- Vena cava compression
- ⇣ venous return
- ⇣ cardiac output
Dead Air Space
Ventilation without perfusion (HIGH V/Q)
- Hypoxemia
Pneumothorax
Air in pleural space → ⇡ Pressure → Partial or complete lung collapse
Bronchial Asthma Types
Chronic inflammation of airway → airflow obstruction & airway hyperresponsiveness
-
Extrinsic/Allergic/Atopic
- Type I IgE-mediated hypersensitivity reaction
- Genetic component
-
Intrinsic/Non-allergic/Non-Atopic
- no allergy component
Pulmonary Embolism Risk Factors
Virchow Triad
-
Venous stasis (slowing) & Venous endothelial injury
- Bed rest, hip or femur fracture, surgery, childbirth, MI, HF, spinal cord injury
-
Hypercoagulability states
- Cancer
- Pregnancy
- HRT
- Oral contraceptives
Types of Respiratory Failure
- Hypoxemic– Oxygenation Failure
- (PaO2 < 60 mmHg)
- COPD
- PNA
- Atelectasis
- Impaired diffusion
- Pulmonary edema
- ALI/ARDS
- Hypercapnic/Hypoxemic– Ventilation & Oxygenation Failure
- (PaO2 < 60 mmHg, PaCO2 > 50 mmHg & pH <7.30)
- Upper airway obstruction
- Infection
- Laryngospams
- Weakness or paralysis of respiratory muscles
- Brain injury
- Overdose
- Guillain-Barre
- Muscular Dystrophy
- Spinal Cord Injury
- Chest wall injury
- Upper airway obstruction
Diagnosis– ABGs (determine if hypoxemic, hypercapnia or BOTH)
Pneumothorax Clinical Manifestations
Hypoxemia, ⇡ RR, absent breath sounds, dyspnea, chest asymmetry
Treatment– Fix cause, supplement O2, thoracentesis (large needle aspiration)
Tension– ⇡ HR, ⇣ cardiac output, shock, tracheal deviation (treat w/ chest tube)
Hypoxemia
Reduced oxygenation of arterial blood
- Always leads to reduced oxygenation of cells in tissues
Pulmonary Embolism Clinical Manifestations
-
Small emboli
-
Asymptomatic
- Not usually
-
Asymptomatic
-
Moderately-sized emboli
- Rapid, shallow respirations
- Pleuritic pain
- Cough
- Blood-streaked sputum
-
Massive emboli
- Sudden collapse
-
Crushing substernal chest pain
- Can be confused w/ MI
- Shock
- LOC
- Rapid, weak pulse
- Hypotension
- Distended neck veins (JVD)
- Cyanosis
- Fatal
Sympathetic Stimulation
Beta-adrenergic receptors → Bronchodilation
Pulmonary Embolism
Bloodborne substances lodged in pulmonary artery → Bloodflow obstructed (High V/Q)
d/t– Thrombus (DVT) → Pulmonary circulation, Injected air (IV), Fat mobilization after long bone fracture (femur, humerus, pelvis), Amniotic fluid entering maternal circulation during childbirth
Hemothorax
Blood in pleural cavity d/t lung puncture (trauma)
- Chest injury, chest surgery complications, malignancies, rupture of great vessel (aortic aneurysm)
Treatment– Chest tube
Cystic Fibrosis Clinical Manifestations
- Respiratory
- Accumulation of thick mucus in bronchi
- Impaired mucociliary clearance
-
Lung infections
-
Bronchiectasis
- Mucus buildup in the lungs
-
Bronchiectasis
- Chronic bronchitis/bronchiolitis
- Abnormal pancreatic function
-
Steatorrhea
- Fatty stool
- Diarrhea
- Abdominal pain
- Malabsorption
- Malnutrition
-
Steatorrhea
Spontaneous Pneumothorax
Bleb/Blister ruptures → Air flows from alveoli into pleural space
Primary
- Bleb @ top of lungs
- Tall, thin people
- Smokers
Secondary
-
Lung disease
- Asthma, TB, CF, COPD, lung CA
- Potentially life threatening
Diffusion
Movement of O2 and CO2 across the alveolar-capillary membrane
Gas Exchange
O2 from air in alveoli diffuses into blood in pulmonary capillaries
CO2 moves from blood in pulmonary capillaries into alveoli
Location– Alveolar-capillary membrane
Asthma Clinical Manifestations
-
Airways narrow d/t
- Bronchospasm
- Bronchial mucosal edema
- Mucus plugging
-
Prolonged expiration → Air trapping
- Lung hyperinflation
-
⇡ WOB → ⇡ O2 demands
- Dyspnea
- Fatigue
- ⇣ Alveolar ventilation → Low V/Q
- Hypoxemia
- Hypercapnia
Early Phase Response
Extrinsic/Allergic/Atopic Response
- 5-30 mins. after exposure
- ⇡ Release of inflammatory mediators
- Vasodilation, vascular damage, bronchospasm
Treatment– Albuterol (SABA)
Parasympathetic Stimulation
Cholinergic receptors → Bronchoconstriction
Atelectasis
Incomplete expansion of lung/alveoli
d/t– Pleural effusion, Pneumothorax, loss of surfactant
Pulmonary Embolism Treatment
Prevention is key
-
DVT Prevention
-
Hospital
- Sequential Compression Devices (SCDs)
-
Heparin (SC)
- 2X/day
-
Outpatient
- Warfarin (PO)
-
Lovenox (SC)
- Low molecular wt. heparin
-
Hospital
-
Multiple or large pulmonary emboli
- Thrombolytic therapy
- Streptokinase
- Anistreplace
- Recombinant tissue plasminogen activators (tPA)
- “clot buster”
- MI/Stroke
- “clot buster”
- Thrombolytic therapy
Ventilation
Movement of air into the lungs
Emphysema Etiology
⇣ Lung elasticity & abnormal enlargement of air spaces → Alveolar wall & capillary bed destruction
- ⇡ Serine elastase (Protease) release from neutrophils → Digestion of elastic fibers → ⇣ Alveolar recoil
- Lung hyperinflation → ⇡ Total lung capacity
d/t– Genetics, Smoking, Alpha 1 antitrypsin (AAT) (antiprotease enzyme) deficiency
Cor Pulmonale
Right Sided Heart Failure
d/t– Primary Lung Disease, Pulmonary Hypertension, Chronic Bronchitis
- ⇡ Pulmonary circulation pressures
- Fluid retention
- ⇡ Work of RV
- Hypertrophy → R sided HF
- Fluid retention
Hypoxemia Clinical Manifestations
Acute:
Mild– SANS activation
- ⇡ HR,
- ⇡ RR
- ⇣ mental acuity
- Vasoconstriction
- Pale skin
- Diaphoresis
Moderate/Severe– Altered mental status
- Confusion
- Stupor
- Coma
Chronic:
- ⇡ RR
- Pulmonary vasoconstriction
- Polycythemia (⇡ RBC)
- Cyanosis
- Clubbing
Cystic Fibrosis
- Genetic
- Autosomal recessive
- Chronic respiratory disease
- Exocrine glands in epithelium of respiratory, GI, & reproductive tracts
- Pancreatic exocrine deficiency
- ⇡ NaCl in sweat
-
Mutation in cystic fibrosis transmembrane regulator (CFTR)
- Chloride channel in airway epithelium
- Impermeable to chloride
- Chloride channel in airway epithelium
- Exocrine glands in epithelium of respiratory, GI, & reproductive tracts
Hypoventilation
⇡ CO2 in the arterial blood → Hypercapnia/Hypercarbia → Respiratory Acidosis
d/t– ⇣ RR
Hypoxemia Etiology
Brain, lungs, and heart need O2 → Compensatory mechanisms activate
⇣ O2 → Anaerobic Metabolism → ⇡ Lactic Acid → Metabolic Acidosis
Empyema
Infection in pleural cavity d/t exudate
COPD Types
Chronic and recurrent obstruction of expiratory airflow
- Chronic Bronchitis
- Chronic Emphysema
ALI/ARDS Causes
-
Aspiration
- Near drowning
- Gastric contents
- Drugs & Toxins
- Heroin
- Free-base cocaine smoking
- Inhaled gases
- Smoke, ammonia
- High O2 Concentrations
- Radiation
- Infections
- Sepsis
- Trauma & Shock
- Burns
- Fat embolism
- Chest trauma
- Disseminated Intravascular Coagulation (DIC)
- Multiple blood transfusions
Types of Pneumothorax
- Traumatic
- Tension
- Spontaneous
Pulmonary Artery
Deoxygenated Blood
Acute Respiratory Distress Syndrome (ARDS) Clinical Manifestations
Sudden inflammation that starts at the lungs → Disruption of gas exchange at alveolar-capillary membrane
- Life-threatening Hypoxemia
- Refractory to supplemental O2 Therapy
- Diffuse crackles
-
Dyspnea
- Severe, sudden onset
- w/i 12-18 hrs. of insult
- Hypoxia
- Cyanosis
-
Tachypnea
- ⇡ RR
- Tachycardia
- Diaphoresis
- Sweating
-
Pulmonary infiltrates
- White on x-ray
-
Systemic response
- Multiple organ failure dysfunction syndrome (MODS)
- Renal, GI, CV, CNS
- Multiple organ failure dysfunction syndrome (MODS)
Disorders of Lung Inflation
Loss of negative pressure in pleural cavity → Collapsed lung
- Pleural effusion
- Pneumothorax
- Atelectasis
Hypoxia
Reduced oxygenation of cells in tissues
- Does not always indicate reduced oxygenation of arterial blood
Pulmonary Hypertension Clinical Manifestations
⇡ Pulmonary artery pressure with normal LV pressure
d/t– Genetics, Venous HTN, Hypoxemia, Thrombotic/Embolic Disease, Pulmonary Fibrosis
- SOB
- ⇣ Exercise tolerance
- R HF
-
Peripheral edema
- Legs/ankles
-
Functional limitations
- ⇣ ability to perform ADLs
⇡ Pulmonary artery pressure AND HF or Lung Disease
d/t– COPD, HF, Sleep Apnea, PE, Interstitial Lung Disease
-
Chronic Hypoxemia
- Pulmonary blood vessels constrict
-
Resistance to pulmonary venous drainage
- Diastolic dysfunction of LV
- Mitral/Aortic valve disorders
- Chronic thromboembolism
Low V/Q
Low V, High Q (1:100)
- Shunt
- Chronic bronchitis
- Asthma
Cystic Fibrosis Diagnosis & Treatment
Diagnosis–
- Respiratory & GI manifestations
- Family history
-
Newborn screening
- + = ⇡ immunoreactive trypsinogen
-
Sweat chloride test
- 2X normal NaCl in sweat
- CFTR functional testing & genetic analysis
Treatment–
- Goal: Slow progression of secondary organ dysfunction
-
Chronic lung infection
- Antibiotics
- Bronchodilators
- Chest percussion
- Postural draining
-
Pancreatic insufficiency
- Pancreatic enzyme replacement
- Vitamin supplements
-
Chronic lung infection
Perfusion
Movement of blood through pulmonary circulation
Pleural Effusion Clinical Manifestations
Dyspnea, Hypoxemia
- ⇣ lung expansion on affected side
- Dull to percussion
- ⇣ breath sounds
Treatment– antibiotics, thoracentesis (large needle aspiration), chest tube
Primary Atelectasis
Newborns
- Lack of surfactant
- Aspiration of amniotic fluids
Pleural Cavity
Space between parietal pleura and visceral pleura
VQ Mismatch/Inadequate Gas Exchange
VQ ratio not 1:1
- Ventilation (V)
- Perfusion/Blood Flow (Q)
ARDS Treatment
Goals–
- Oxygenate lungs and vital organs
- Recognize & treat underlying medical condition
-
Prevent further injury and complications
- Venous thromboembolism
- Aspiration
- Infection
- Decrease risk for mortality
Treatment– Intubation & Mechanical ventilation
Pulmonary Hypertension
Abnormal elevation of pressure within pulmonary arterial circulation
-
⇣ Size of lumen in pulmonary arteries
- Vasoconstriction → Hypoxia
- ⇡ Inflow of blood to pulmonary arteries
-
Occlusion of outflow of blood from pulmonary circulation
- ⇡ Pressure in LV
Very Low V/Q
Low V, Very High Q (1:1000)
- Atelectasis
- ARDS
- Pneumonia
Atopic Asthma Etiology
Exaggerated Type I IgE-mediated hypersensitivity response to inflammatory mediators
Leads to–
- Bronchoconstriction
- Vascular permeability
- ⇡ Mucus production
-
Prolonged expiration → Air trapping
- Lung hyperinflation
- ⇡ Pulmonary artery pressure
COPD Treatment
- Smoking cessation
- Avoid bronchospasm triggers
-
Pulmonary rehab
- ⇡ efficiency
- ⇣ WOB
- Prevent RTIs
- Bronchodilators
- Albuterol (SABA)
-
Anticholinergics
- Ipratropium bromide
-
O2 therapy w/ significant hypoxemia (PaO2 < 55 mmHg)
- 1-2 L low-flow oxygen
- Limit to stimulate breathing
- Goal: PaO2 55-65 mmHg
- Goal: SpO2 88-92%
- 1-2 L low-flow oxygen
Obstructive Airway Disorders
Limited expiratory airflow →Trapped air → Flattened diaphragm
Low V/Q–
- Bronchial Asthma
- COPD
- Cystic Fibrosis (CF)
Cor Pulmonale Manifestations
- S/S Primary Chronic Lung Disease– Chronic Bronchitis
- Cyanosis
-
Polycythemia
- ⇡ RBCs
- ⇣ SpO2
- Drowsiness
- Altered Mental Status (AMS)
- ⇡ CO2
- S/S R Sided HF
- Venous congestion
- Peripheral edema
- SOB
- Productive cough
Management– Treatment of lung disease & HF, Low-flow O2 Therapy
ALI/ARDS Pathophysiology
Pulmonary insult → Inflammatory response (neutrophils secrete proteases, cytokines, & ROS)
⇡ Permeability of alveolar-capillary membrane → Fluid, plasma, proteins, and blood cells into interstitium & alveoli
Loss of surfactant & damage (Type I & Type II pneumocytes) → ⇣ Pulmonary compliance → Lung collapse
Injury to alveolar epithelium → Disorganized repair → Fibrosis → Lungs stiffen (difficult to inflate, ⇡ WOB)
⇣ Gas exchange at alveolar-capillary membrane → ⇡ Intrapulmonary shunting (find alveolus that has O2) → ⇣ V/Q Ratio
Hypoxemia refractory to supplemental O2 → Alveoli collapse
Measures of blood oxygenation
Pulse Oximetry
Arterial Blood Gas (ABG)
Chronic Bronchitis Etiology
Thick mucus hypersecretion → Mucus plugs → Gas trapped in distal portion of lungs
- Lung hyperinflation
- Chronic, productive cough
-
Smoking
- ⇡ mucus production
- ⇡ size and # of mucus glands
Pulmonary Veins
Oxygenated Blood