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Atelectasis
- Lack of gas exchange in the alveoli
- "collapse of lung tissue"
- Due to:
- Compression-tumor, fluid, abdominal distention
- Absorption: In obstucted or hypo-ventilated alveoli
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Hypoxemia
Decrease in PaO2 in arterial blood
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Hypercapnia
- Too much CO2 in the blood:
- Caused by hypoventilation or lung disease
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Bronchiolitis
- Inflammation of the bronchioles, the smallest air passages of the lungs.
- Most common in children
- Decrease V/Q
- May have delayed respiratory distress
- Usually caused by viruses/ toxic gases.
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Bronchiectasis
- Causes: cystic fibrosis, obstructions, infection, bronchial wall weakness, autoimmune/AIDS
- Abnormal dilation of bronchi = more weakened & more prone to collapse = causing local obstructions
- Focal more common = due to infection
- Diffuse = due to systemic illness (autoimmune)
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Pulmonary Disease S&S
- Dyspnea
- Abnormal Breathing
- Cough
- Clubbing
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Conditions caused by Pulmonary Disease
- -Hypercapnia, hypoxemia
- -Acute Respiratory failure
- -Pulmonary Edema
- -Aspiration
- -Atelectasis, Bronchiectasis, Bronchiolitis
- -Pleural Abnormalities
- -Abscesses, fibrosis, restriction
- -Inhalation disorders
- -Systemic disorders
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Types o f Pulmonary Disease
Acute vs chronic: bacteria vs COPD
Obstructive vs. Restrictive: Cancer vs. Fibrous of Lung
Infectious vs. noninfectious
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Overall lung Function
- Gas exchange
- Acid/base
- Prevent infection
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Lung Anatomy
- Surface Area
- Compliance
- Humidity
- Blood flow change in lung and heart
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Physiology modifications of lungs
- Modified by change in surface area (SA) and distance for diffusion
- Obstructions modifiy SA
- Changes in compliance and expandabilty and reduce filling capacity
- -asthm
- -COPD
- -musculoskeletal defects: broken ribs, RA
- -collapsed lung
- -fibrosis
- Fluids & inflammation in the lung can decrease both area and diffusion
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If pulmonary vascular resistance goes up, what happens to the right heart
Right heart failure
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When lungs are injured or stressed, what happens?
- -Hypoxia
- -Acid-base abnormalities
- -Infections
- -Altered hemodynamics
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When can damage to other organs cause secondary damage to lungs?
- Renal disease-metabolites damage lungs
- Immune disorders
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Dyspnea
- Subjective sense of uncomfortable breathing
- Can't get enough air
- Breathlessness, air hunger, SOB
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Causes of Dyspnea
- -Diffuse & extensive pulmonary involvment
- -Disturbances of ventilation &gas exchange
- 1. Stimulation of receptors in respiratory muscles
- -Increased airway resistance
- -Decreased compliance
- 2. Central & Peripheral chemoreceptors
- -low pH
- -hypercapnia
- -hypoxemia
- 3. Stimulation of afferent (vagal) receptors in lung
- -Stretch R's (smooth muscles): decrease volume & vent. rate
- -Irritant R's(epithelium esp. proximal airways): cause cough, bronchoconstriction, increased resp rate
- -J-R's (juxtapulmonary capillary): stimulates rapid , shallow breathing, hypotension, and bradycardia
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Dyspnea signs
- -Flaring of nostrils
- -Use of accessory muscles of respiration
- -Retraction of intercostal spaces
- -Position: worse when lying down
- -Paroxysmal nocturnal dyspnea (PND): problems with ventricular heart failure
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Eupnea
- Normal breathing pattern
- Tidal volume 400-800 ml
- Breathing rate 8-16/min
- Sigh breaths occuring ~ 10-12 hr
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Kussmaul respiration (hyperpnea)
- Triggered by strenuous excercise or acidosis
- Increased rate
- Big increase tidal volume
- No expiratory pause
- All go up
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Labored/Obstructed respiration
- COPD
- Decrease rate
- Increase tidal volume
- Increase effort
- Wheezing
- Stridor (high-pitch)
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Restricted breathing pattern
- Pulmonary fibrosis
- Stiff lungs or chest wall & decreased compliance
- Increase rate (tachypnea)
- Decrease tidal volume
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Gasping
- Seen in shock & severe cerebral hypoxia
- Irregular
- Quick inspirations
- Expiratory pause
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Cheyne-Stokes breathing pattern
Seen in brain stem damage or decreased blood flow to it
- Alternating periods of deep & shallow breathing
- Apnea 15-60 sec followed by ventilations that increase in volume until a peak is reached then decreasing to apnea again
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Hypoventilation
Due to pulmonary or neurologic problems
Causes hypercapnea (paco2 > 44mmHg)
Respiratory acidosis b/c decrease in pH more H+ in blood
Decreases minute volume
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Hyperventilation
Causes hypocapnea
Respiratory alkalosis b/c increase in pH
- Due to:
- -severe anxiety
- -pain
- -head injury
- -conditions causing insufficient O2
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Hemoptysis
Coughing up blood or bloody secretions
Caused by bronchiectasis, lung cancer, bronchitis, pne, TB
Red, alkaline pH, frothy
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Hematemesis
Vomiting up blood
Darker, acidic pH
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Cyanosis & clubbbing
Bluish skin
- Desaturated Hb ~ 5 g/dL (~1/3 of Hb total)
- -If total Hb conc is 15 g/dl then to cause cyanosis
- Due to low PaO2 due to:
- -pulmonary or cardiac R-L shunts
- -decreased CO
- -cold, anxiety
*Adult cyanosis may be difficult to detect until severe
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Pulmonary Pain
- Plural pain is most common source
- -sharp, stabbing
- -pain when stretched (laugh,cough)
- Audible pleural friction rub over painful area
- -infection & inflammation
- -pulmonary infarction from PE
- -pulmonary hypertension during exercise
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Hypercapnea Causes
- -decrease resp from drugs
- -damage to medulla or spinal cord
- -neuromuscular disease
- -thoracic cage damage/deformity
- -large airway obstuction
- -increased work to breathe
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Hypercapnea problems
- -acidosis = dyshythmias
- -increased intracranial pressure due to CO2 vasodilation
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Hypoxia
Decreased PaCO2 in tissues
*Not always due to hypoxemia could be cyanide, low CO
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Hypoxemia causes
- -Decreased O2 in air (high altitude, suffocation)
- -Hypoventilation (COPD)
- -Diffusion abnormalities (thickened aveolar membrane - edema, inflammation, fibrosis)
- -Decrease in SA (emphysema)
- -Abnormal ventilation perfersion ratios (V/Q normal 0.8 to 0.9)
- -R-L shunts
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Low V/Q
Due to asthma, PE, obstruction, ARDS, hyaline membrane disease
Pco2 not affected
Supplemental O2 doesn't help much
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High V/Q
Pulmonary embolus, congenital heart disease, arterio-venous malformations, R-L shunts
Adequate ventilation
Poor perfusion of the lung
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Spirometry
- -May be measured @ rest & exercise
- -measures forced expiration
- -detects restrictive (decrease in lung volume) or obstructive condition (decrease in gas flow)
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FVC
Forced vital capacity
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FEV1
Aka IRV, ERV, RV
Forces expiratory volume in 1 second
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Arterial blood gases
Measures acidemia (arterial blood) vs acidosis (mixed venous blood)
Painful via pulmonary artery catheter
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Oximetry
- Measures O2 once PaO2 has been measured
- Not PaCO2 or pH
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Chest X-ray (CXR)
- Sees:
- -air trapping
- -consolidation
- -inflammation
- -sturctures (tumors, calcification, TB cavitation)
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Normal lungs kept dry by:
- -capillary hydrostatic & oncotic pressure
- -lymphatic drainage
- -surfactant
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Predisposing factors for pulmonary edema
- -heart disease
- -injury to pulmonary capillaries (toxic gases, ARDS)
- -lympthatic obstruction (rare)
- -plasma proteins leaking into lung = decreased oncotic pressure = edema
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Pulmonary Edema S&S
- -dyspnea
- -orthopnea (worse lying down)
- -hypoxemia
- -crackles & rales
- -dullenss to percussion over the lung bases
- -evidence of ventricular dilation
- -pink frothy sputum
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Pulmonary Edema TX
- -Remove from irritants
- -Improve volume status
- -Reduce volume overload (diuretics)
- -CHF: try to improve cardiac fx (vasodilators)
- -Mechanical ventilation
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Wedge pressure where pulmonary edema begins
> 20 mm Hg
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Aspiration risks
- -advanced age
- -difficulty swallowing
- -altered consciousness
- -repeated vomiting
- -smoking
- -NG tube or intubation
- -seizures
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Things that can be aspirated
- -GI contents
- -Large food particles
- -Oral or pharyngeal secretions- risk of infection
- -GERD & Asthma
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Bronchiectasis types
- -Cylindrical: reversible & seen in PNA
- -Saccular & varicose: bronchial division plugged
- -Anastamoses may cause hemoptysis
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Pneumothorax
- Air or gas in pleural space due to rupture of visceral pleura
- Lungs recoil & collapse
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Pneumothorax types
- -Open
- -Tension: opening acts like one-way valve, preventing air exit: life threatening
- S&S severe hypoxemia, dyspnea, hypotension
- -Spontaneous: in healthy males 20-40, ruptures of blebs
- S&S pleural pain, tachypnea, mild dyspnea
-Secondary: rib fracture, stab, bullet, COPD, ventilation with positive pressure
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Pneumothorax treatment
- Small: aspiration with small catheter
- Large: chest tube with water-seal drainage tube
- Persistent: pleurodesis- caustic into pleural space to scare it shut
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Transudate (hydrothorax)
Fluid leads into pleural space due to CHF or hypoproteinemia
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Exudate
- Fluid extended out of tissue or capillary
- Due to inflammation, infection, malignancy
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Empyema
- collection of pus in the space between the lung and the inside of the chest wall (pleural space).
- May be caused by blocked lymphatics adjacent to PNA
- S. aureus
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Hemothorax
Hemorrhage into pleura space
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Lung consolidation
Solidification into a firm, dense mass
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How abscess formation & cavitation formed
Lung consolidation > necrosis & death > fluid, pus, debris > abscess formation > empties into bronchus > coughed up
Caused by aspiration PNA due to staph & klebsiella
TX: Antibiotics, percussion, postural drainage
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Chest wall restriction
- -Musculoskeletal deformity
- -Neuromuscular disease
- -Immobilization
- -Obesity
- -Ankylosing spondylitis
- Increase work of breathing and decrease tidal volume (hypoventilation & hypercapnia)
- Increase risk PNA
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Inhalation Disorders
- Toxic gases:
- -Smoke
- -Ammonia
- -Hydrogen Chloride
- -Sulfur Dioxide
- -Chlorine
- -Phosgene
- -Oxygen
- -Severe inflammatory response
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Pneumoconiosis (inhalation disorders)
Causing inflammation and fibrosis
- -Silcosis
- -Coal
- -Asbestosis
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Silcosis
- -Inhaled free silica
- -Causes chronic fibrosis
- -Long-term onset - may be asymptomatic
- -S&S:
- cough, dyspnea, risk for PNA, bronchospasms & wheezing
- -TX: nothing specific
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Coal (black lung)
- -Inhaled coal, silica, & quartz
- -Advanced = severe pulmonary fibrosis with productive cough
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Abestos
- -Slow onset 15-30 years to see cancer
- -Smoking & houses near mines increases risk
- -Particles inhaled & permanently into lungs : body cant expel = scarring & fibrosis
- -Long thin fibers worse
- S&S
- Non-malignant changes- lung parenchyma, pleura
- Malignancies - lung cancers, mesothelioma
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Allergic Alveolitis
Inhalation of organic dusts
S&S: cough, dyspnea, chills a few hours resolving in 1-3 days if acute
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Systemic diseases affecting lungs
- -granulomatous (sarcoidosis)
- -connective tissue diseases (RA, SLE, cystic fibrosis, polyarteritis nodosa)
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Obstructive pulmonary diseases examples
- -Asthma
- -COPD
- -Chronic bronchitis
- -emphysema
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Acute Respiratory Distress Syndrome (ARDS)
- Acute lung inflammation and diffuse alveocapillary injury = alveolar epithelium
- Direct vs indirect (sepsis)
- Respiratory insuffiency leading to cyanosis, arterial hypoxemia
- Deadly and common
- Absence of increase L atrial pressure
- Pulmonary capillary wedge <18 mm Hg
- Resistant to O2 TX
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ARDS causes
- -Sepsis = common
- -multiple trauma
- -shock
- -burns
- -pancreatitis
- -O2 toxicity
- -radiation
- -drowning
- -altitude
- -bypas surgery
- -disseminated intravascular coagulation (DIC)
- -PNA
- -aspiration
- -drugs/overdose
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