Pathophys Exam 2

• 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

Decrease in PaO₂ in arterial blood

• Too much CO₂ in the blood:
• Caused by hypoventilation or lung disease

• 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.

• 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)

• Dyspnea
• Abnormal Breathing
• Cough
• Clubbing

• -Hypercapnia, hypoxemia
• -Acute Respiratory failure
• -Pulmonary Edema
• -Aspiration
• -Atelectasis, Bronchiectasis, Bronchiolitis
• -Pleural Abnormalities
• -Abscesses, fibrosis, restriction
• -Inhalation disorders
• -Systemic disorders

Acute vs chronic: bacteria vs COPD

Obstructive vs. Restrictive: Cancer vs. Fibrous of Lung

Infectious vs. noninfectious

• Gas exchange
• Acid/base
• Prevent infection

• Surface Area
• Compliance
• Humidity
• Blood flow change in lung and heart

• 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

Right heart failure

• -Hypoxia
• -Acid-base abnormalities
• -Infections
• -Altered hemodynamics

• Renal disease-metabolites damage lungs
• Immune disorders

• Subjective sense of uncomfortable breathing
• Can't get enough air
• Breathlessness, air hunger, SOB

• -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

• -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

• Normal breathing pattern
• Tidal volume 400-800 ml
• Breathing rate 8-16/min
• Sigh breaths occuring ~ 10-12 hr

• Triggered by strenuous excercise or acidosis
• Increased rate
• Big increase tidal volume
• No expiratory pause
• All go up

• COPD
• Decrease rate
• Increase tidal volume
• Increase effort
• Wheezing
• Stridor (high-pitch)

• Pulmonary fibrosis
• Stiff lungs or chest wall & decreased compliance
• Increase rate (tachypnea)
• Decrease tidal volume

• Seen in shock & severe cerebral hypoxia
• Irregular
• Quick inspirations
• Expiratory pause

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

Due to pulmonary or neurologic problems

Causes hypercapnea (pa_co2 > 44mmHg)

Respiratory acidosis b/c decrease in pH more H+ in blood

Decreases minute volume

Causes hypocapnea

Respiratory alkalosis b/c increase in pH

• Due to:
• -severe anxiety
• -pain
• -head injury
• -conditions causing insufficient O₂

Coughing up blood or bloody secretions

Caused by bronchiectasis, lung cancer, bronchitis, pne, TB

Red, alkaline pH, frothy

Vomiting up blood

Darker, acidic pH

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

• 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

• -decrease resp from drugs
• -damage to medulla or spinal cord
• -neuromuscular disease
• -thoracic cage damage/deformity
• -large airway obstuction
• -increased work to breathe

• -acidosis = dyshythmias
• -increased intracranial pressure due to CO₂ vasodilation

Decreased PaCO₂ in tissues

*Not always due to hypoxemia could be cyanide, low CO

• -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

Due to asthma, PE, obstruction, ARDS, hyaline membrane disease

P_co2 not affected

Supplemental O₂ doesn't help much

Pulmonary embolus, congenital heart disease, arterio-venous malformations, R-L shunts

Adequate ventilation

Poor perfusion of the lung

• -May be measured @ rest & exercise
• -measures forced expiration
• -detects restrictive (decrease in lung volume) or obstructive condition (decrease in gas flow)

Forced vital capacity

Forces expiratory volume in 1 second

Measures acidemia (arterial blood) vs acidosis (mixed venous blood)

Painful via pulmonary artery catheter

• Measures O₂ once Pa_O2 has been measured
• Not PaCO2 or pH

• Sees:
• -air trapping
• -consolidation
• -inflammation
• -sturctures (tumors, calcification, TB cavitation)

• -capillary hydrostatic & oncotic pressure
• -lymphatic drainage
• -surfactant

• -heart disease
• -injury to pulmonary capillaries (toxic gases, ARDS)
• -lympthatic obstruction (rare)
• -plasma proteins leaking into lung = decreased oncotic pressure = edema

• -dyspnea
• -orthopnea (worse lying down)
• -hypoxemia
• -crackles & rales
• -dullenss to percussion over the lung bases
• -evidence of ventricular dilation
• -pink frothy sputum

• -Remove from irritants
• -Improve volume status
• -Reduce volume overload (diuretics)
• -CHF: try to improve cardiac fx (vasodilators)
• -Mechanical ventilation

> 20 mm Hg

• -advanced age
• -difficulty swallowing
• -altered consciousness
• -repeated vomiting
• -smoking
• -NG tube or intubation
• -seizures

• -GI contents
• -Large food particles
• -Oral or pharyngeal secretions- risk of infection
• -GERD & Asthma

• -Cylindrical: reversible & seen in PNA
• -Saccular & varicose: bronchial division plugged
• -Anastamoses may cause hemoptysis

• Air or gas in pleural space due to rupture of visceral pleura
• Lungs recoil & collapse

• -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

• Small: aspiration with small catheter
• Large: chest tube with water-seal drainage tube
• Persistent: pleurodesis- caustic into pleural space to scare it shut

Fluid leads into pleural space due to CHF or hypoproteinemia

• Fluid extended out of tissue or capillary
• Due to inflammation, infection, malignancy

• 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

Hemorrhage into pleura space

Solidification into a firm, dense mass

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

• -Musculoskeletal deformity
• -Neuromuscular disease
• -Immobilization
• -Obesity
• -Ankylosing spondylitis

• Increase work of breathing and decrease tidal volume (hypoventilation & hypercapnia)
• Increase risk PNA

• Toxic gases:
• -Smoke
• -Ammonia
• -Hydrogen Chloride
• -Sulfur Dioxide
• -Chlorine
• -Phosgene
• -Oxygen
• -Severe inflammatory response

• -Silcosis
• -Coal
• -Asbestosis

• -Inhaled free silica
• -Causes chronic fibrosis
• -Long-term onset - may be asymptomatic
• -S&S:
• cough, dyspnea, risk for PNA, bronchospasms & wheezing
• -TX: nothing specific

• -Inhaled coal, silica, & quartz
• -Advanced = severe pulmonary fibrosis with productive cough

• -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

Inhalation of organic dusts

S&S: cough, dyspnea, chills a few hours resolving in 1-3 days if acute

• -granulomatous (sarcoidosis)
• -connective tissue diseases (RA, SLE, cystic fibrosis, polyarteritis nodosa)

• -Asthma
• -COPD
• -Chronic bronchitis
• -emphysema

• 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

• -Sepsis = common
• -multiple trauma
• -shock
• -burns
• -pancreatitis
• -O2 toxicity
• -radiation
• -drowning
• -altitude
• -bypas surgery
• -disseminated intravascular coagulation (DIC)
• -PNA
• -aspiration
• -drugs/overdose