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151 Cards in this Set
- Front
- Back
What are the four primary physical signs used to evaluate respiratory distress in the newborn?
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Cyanosis, Grunting, Retraction, Tachypnea
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What scoring method is used to evaluate respiratory distress in the newborn?
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ACoRN (Acute care of at-risk newborns)
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What are the three most common causes of respiratory distress in the newborn?
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Idiopathic/Infant respiratory distress syndrome (IRDS); Transient tachypnea of the newborn (TTN); Aspiration syndromes
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What are the five embryological phases of lung development?
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Embryonic; Pseudoglandular; Canalicular; Terminal Sac; Alveolar phase
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During what embryological phase in bronchial branching completed? Is respiration possible during this phase?
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Pseudoglandular phase (7-16 weeks); Respiration is not possible due to lack of alveoli and respiratory bronchioles
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During which embryological phase is respiration possible?
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Canalicular phase (16-25 weeks)
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What cells are responsible for surfactant production?
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Type 2 cells
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When does surfactant production start?
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Terminal sac phase (25-40 weeks)
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What is the most common neonatal respiratory problem in newborns delivered via cesarean section?
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Transient tachypnea of the newborn
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What is the pathophysiology of transient tachypnea of the newborn?
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Delay in clearance of residual lung fluid after birth
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Is meconium aspiration syndrome more common in pre-term or post-term babies?
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Post-term, as a term or pre-term baby will typically not have a bowel movement before birth
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What is the primary deficiency in infant respiratory distress syndrome?
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Surfactant production is insufficient
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Why does peripheral edema occur in infant respiratory distress syndrome?
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IRDS babies are holding onto fluid, they don't pee much in the first 24 hours
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What drug can be used antenatally to increase lung maturity in a preterm fetus?
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Maternal betamethasone (steroid)
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What is required for a clinical diagnosis of bronchopulmonary dysplasia?
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Continuing requirement for oxygen at 28 days of age, or 36 weeks gestation (corrected)
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What is the pathophysiology of bronchopulmonary dysplasia?
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Abnormal/arrested lung development; Abnormal surfactant production or turnover; Inflammation; Barotrauma; Volutrauma; Oxygen toxicity
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A term baby is delivered without complications, is pink, screaming and crying as normal. However, when crying stops the baby turns blue. What might be the cause?
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Choanal atresia - Babies are obligate nose breathers and these C.A. babies have an obstruction in the nose
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Aspiration pneumonia, choking and cyanosis with feeding and an inability to insert a catheter into the stomach may be indicative of what congenital condition?
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Tracheo-esophageal fistula
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A lack of lung fluid during lung development can cause what condition?
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Pulmonary hypoplasia
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Where is efferent motor information sent from the inspiratory center?
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The phrenic nerve, which innervates the diaphragm
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Peripheral chemoreceptors which provide information to the inspiratory center are responsive to concentrations of which three substances?
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O2; CO2; H+ (pH)
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What are the four primary sources of afferent information to the inspiratory center in the brainstem?
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Peripheral chemoreceptors; Central chemoreceptors; Lung stretch receptors; Muscle and joint receptors
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How does responsiveness to changes in O2 and CO2 change during sleep?
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Respiratory centers in the brain are less responsive to changes in these substances
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What are the two general ways which we can manipulate pressure differentials to treat a pneumothorax?
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Increase air pressure inside lungs/alveoli (eg CPAP); Decrease pressure inside pleural space (eg thoracentesis)
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What is the primary action of surfactant?
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Reduces surface tension to prevent airway collapse
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Is lung compliance higher during inspiration or expiration?
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Expiration (i.e. it takes more energy to inspire than to expire)
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Total lung capacity - Vital capacity = ?
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Residual volume
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What is the difference between inspiratory reserve volume and inspiratory capacity?
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IC includes tidal volume, IRV does not
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What is a normal FEV1:FVC ratio?
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75-85%
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In obstructive lung disease, what happens to the FEV1:FVC ratio?
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It decreases (takes longer to exhale all the air)
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In restrictive lung disease, what happens to the FEV1:FVC ratio?
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Typically, the ratio is normal (though FVC is decreased)
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What are the two main zones of the lungs?
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Conducting zone & Respiratory zone
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What is the difference between anatomical and physiological dead space?
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Anatomical dead space is only the conducting zone; Physiological dead space also includes diseased areas in lungs which are not functioning properly in gas exchange
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What two components comprise tidal volume?
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Alveolar volume + Dead space volume
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What is the formula for alveolar ventilation?
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Respiratory rate * (Tidal volume - Dead space volume)
Also: (Tidal volume - Dead space volume) = Alveolar volume |
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What are the 6 steps to allow use of oxygen by tissues?
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Control (brain); Ventilation; Diffusion (alveolar); Circulation; Diffusion (tissue); Metabolism
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How does volume of a gas change with an increase in pressure? With an increase in temperature?
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Increased pressure: Volume decreases; Increased temperature: Volume increases
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What is the fraction of oxygen in room air?
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21%
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What is the formula for Fick's law of diffusion across a cell membrane?
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Vgas = (DA/t) * (P1-P2)
A (surface area) = 85 m2 per lung t (thickness) = 0.5 microns D (constant) = Solubility/MW P1, P2 = pressure of gas on each side of the membrane |
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Is diffusion-limited alveolar gas exchange considered normal or abnormal?
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It is considered abnormal, as the rate of diffusion, rather than the rate of perfusion (i.e. resp/heart rate) is the limiting factor in diseased states
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What is the active carrier of oxygen in the blood?
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Hemoglobin
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1 gram of hemoglobin can hold how much O2?
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1.39 mL O2
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What is the formula for A-a gradient? What is a normal A-a gradient?
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A-a = PAO2 - PaO2
PA = alveolar pressure Pa = arterial pressure A normal A-a gradient should be less than 10 mm Hg for a healthy young adult, with age correction at A-a/4 + 4 |
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How do you calculate the alveolar oxygen pressure?
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PAO2 = FIO2*(PB - 47) - PaCO2/R
FIO2 = Fraction of inspired O2 (0.21) PB = Barometric pressure (760 mm Hg) 47 = Vapour pressure of water PaCO2 should be ~ 40 R (respiratory quotient) = VCO2/VO2 (0.8) Subbing the numbers in: Normal air sea level, PAO2 = 100 mm Hg |
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What three roles does airway surface liquid have?
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Airway hydration; Innate immunity; Antimicrobial defense
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Submucosal glands of the conducting zone secrete what?
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Airway surface liquid
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What is the primary active transport channel responsible for chloride content in airway mucus?
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CFTR
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What effect do pro-inflammatory signalling molecules released in an allergic reaction have on airway diameter?
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These molecules (histamine, cytokines, leukotrienes, etc) have a bronchoconstrictory effect
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What is the first step following IgE binding to an allergen and pro-inflammatory mediator release from mast cells?
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Mucus hypersecretion
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What two types of chronic inflammatory cells are found in patients with COPD?
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CD8+ lymphocytes; Neutrophils
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How do epithelial cells change in COPD?
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Replacement of epithelial cells by squamous cells
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What is the mechanism of action of inhaled corticosteroids?
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They diffuse into the cells to directly modulate gene expression and suppress inflammatory responses
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Put the following structures in order from proximal to distal: Alveolus, Bronchus, Respiratory bronchiole, Terminal bronchiole, Trachea
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Trachea; Bronchus; Terminal Bronchiole; Respiratory Bronchiole; Alveolus
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What two "old fashioned" terms were used to describe what is now known as COPD?
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Emphysema; Chronic bronchitis
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What are some examples of chest exam physical signs in COPD?
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Barrel chest; Hyperresonance to percussion; Diffusely diminished breath sounds; Scattered expiratory wheezes
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Is COPD preventable? Treatable? Reversible?
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COPD is preventable and treatable, but not fully reversible (though it is partially reversible)
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What is the most common cause of COPD in the Western world?
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Cigarette smoking
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What deficiency has been associated with COPD?
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Alpha 1-antritrypsin deficiency
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What are the three main components of expiratory flow limitation in COPD?
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Increased resistance; Extrinsic airway factors; Reduced driving pressure
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How does increased airway resistance occur in COPD?
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Mucosal inflammation and edema; Airway remodelling and fibrosis; Mucus secretions
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How much sputum production is required for a diagnosis of chronic bronchitis?
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4 days/week; 3 months/year; 2 years in a row
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What 3 factors contribute to increased sputum production in chronic bronchitis/COPD?
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Increased number of mucous glands; Increased number of goblet cells; Reduced mucous clearance by damaged cilia
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What should PaCO2 and PaO2 arterial blood gases be relative to normal in COPD?
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PaCO2 increased (hypercapnea); PaO2 decreased (hypoxia)
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How can hematocrit change in COPD?
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It can increase in order to compensate for low oxygen (i.e. polycythemia)
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Is emphysema a clinical, radiological or pathological diagnosis?
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Pathological
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How do neutrophils worsen emphysema/COPD?
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Neutrophils release elastase which destroys the alveolar tissue and stimulates mucous production (Elastase damages elastin in lungs)
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What does alpha-1 antitrypsin do?
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It inhibits neutrophil elastase to prevent damage to healthy tissue
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The parenchyma distal to the terminal bronchiole is know as what region?
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Acinar region (Acinus) - Also, respiratory zone
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Is alpha 1-antitrypsin deficiency more associated with upper or lower-lobe emphysema?
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Lower lobe (i.e. distal instead of proximal)
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In which direction do cilia in the bronchus move?
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Distal to proximal (towards the mouth)
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Is cartilage present in bronchioles?
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No, only in the bronchus and trachea
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What is the smallest distinct functional unit in the lung visible on pathology specimens?
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Lobule (each containing ~30 acini, which cannot be definitively distinguished)
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What should you suspect if you see clubbing in a patient with COPD who smokes?
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Suspect another cause, such as lung cancer - COPD does not cause clubbing
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What test can be used to diagnose asthma?
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Methacholine challenge
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Unlike in chronic bronchitis, which type of leukocyte is typically prevalent in asthma?
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Eosinophils
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What is Sempter's triad?
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ASA sensitivity, Nasal polyps, Asthma
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In general, how is a wheeze formed?
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Narrowing of the airways causing a vibration when air passes through
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What are the three main categories of defense against pathogens in the upper conducting zone?
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Physical processes (Coughing, cilia, air flow); Chemical defense (Mucus, NO); Cellular mechanisms (phagocytosis by macrophages)
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What is the approximate flow rate of mucus?
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3 mm/min
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What are two examples of bactericidal molecules in the airway?
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Reactive oxygen species; Lysozyme
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What are four factors that may defeat mucosal defenses?
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Too many bacteria/viruses; Pathogenic evasion of defenses; Exposures which may incapacitate defenses; Host factors (genetic predisposition, systemic disease)
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What are three components to making a diagnosis of asthma in a preschooler?
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Typical pattern of symptoms; Response to therapy; Absence of any red flags. PFT's are not reliable in this age group.
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Is persistent wheezing in early childhood more or less indicative of allergic/atopic triggers than transient wheezing?
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More. Transient wheezing is typically related to viral triggers
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According to the modified asthma predictive index, what is considered a major risk factor for the development of asthma (there are 3)?
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Parental history of asthma; Physician-diagnosed atopic dermatitis; Allergic sensitization to at least one aeroallergen
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What are the two classes of "controller" medications for asthma?
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Inhaled corticosteroids; Leukotriene receptor antagonists
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What are the three classes of "reliever" medications for asthma?
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Fast-acting beta-2 agonists; Long-acting beta-2 agonists; Anticholinergic agents
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Ipratropium bromide and Tiotropium bromide are examples of what class of medication?
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Inhaled anticholinergic agents (for COPD & asthma)
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How long do inhaled corticosteroids need to be used before they achieve a maximal effect?
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2 to 4 weeks
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What is acceptable asthma control in relation to frequency of daytime symptoms? Nighttime symptoms?
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< 4 daytime symptoms/week; < 1 nighttime symptom/week
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What is the most common reason for poor asthma control? What are three other?
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Compliance issues are most common; Technique, Environment, Comorbidities (GERD, URTI)
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A severe exacerbation of asthma despite inhaled corticosteroid use may warrant a short course of what type of drug?
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Oral corticosteroids
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Are leukotriene receptor antagonists more useful in children older or younger than 5 years of age?
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LTRAs are typically used in children under 5 in combination with an ICS
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What are five ways which a virus-infected airway epithelium can stimulate compensatory changes?
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Mucus hypersecretion; Plasma leakage; Inflammatory cell recruitment; Airway hyperresponsiveness; Neural activation
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What is the strongest predictor of a patient receiving an antibiotic for a respiratory illness?
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If the doctor thinks that the patient is expecting an antibiotic
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What are the three ways in which bacteria can reach the lungs?
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Inhalation, aspriation, hematogenous spread
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Are larger bacteria typically seen in inhalation or aspiration routes of pneumonia?
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Typically aspiration - large inhaled bacteria cannot pass through the innate defenses of the lungs.
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What 4 clinical features (signs/symptoms) are typically required for the diagnosis of community acquired pneumonia?
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Cough, fever, sputum production, pleuritic chest pain
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What is the average mortality for hospitalized patients with community-acquired pneumonia?
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14%
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What is the most common bacterial cause of community-acquired pneumonia?
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Strep pneumoniae
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What is the most common "atypical" pathogen causing community-acquired pneumonia?
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Mycoplasma pneumoniae (23% of all cases)
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What is the most common viral cause of pneumonia?
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Influenza (A & B)
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What are some indicators that a pneumonia may have a viral instead of bacterial cause?
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Older, more frail patients with more cardiac disease; More likely normal white cell count; October - May
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What are three issues facing treatment of community-acquired pneumonia?
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Empiric therapy may be ineffective; Increases in antimicrobial resistance; Host factors
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What is a 4-step approach to patients with pneumonia in the ER?
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Severity of illness upon clinical presentation; Presence or absence of comorbid illness; Acquired in community or nursing home; Where will treatment be given?
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What are some example of diagnostic testing for pneumonia?
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CXR; Sputum aerobic culture; Blood culture; Pleural fluid culture
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What are two examples of nosocomial pneumonia?
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Hospital-acquired pneumonia & Ventilator-associated pneumonia (Also: Healthcare-associated pneumonia - nursing home; dialysis patient)
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Acid-fast bacillus staining is useful to identify which genus of organism?
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Mycobacterium (eg: tuberculosis, bovis)
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What is the gold standard for diagnosis of TB?
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Mycobacterial culture
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What is the most common human infection known?
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Tuberculosis
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What infection has been associated with a 100-fold increase in risk of progression from tubercle to active TB?
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HIV infection (immunosuppression; AIDS is 170x)
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What are the two cornerstone drugs for first-line treatment of TB?
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Isoniazid & Rifampin
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What is the most common cause of death in HIV infected individuals worldwide?
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Tuberculosis
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How have incidence rates of lung cancer changed in women in the last 30 years? In men?
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Women: Increased incidence; Men: Decreased incidence
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What percentage of lung cancer is attributable to smoking?
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85%
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When do peripheral nodules become symptomatic?
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Not until they touch the chest wall
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What are two common sites of metastases for lung cancer? What are two less common sites?
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Bone & Brain; Adrenal glands & Liver
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How are peripheral lung nodules most often diagnosed?
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Usually as an incidental finding on CXR or CT for some other reason
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What percentage of lung cancers are associated with a paraneoplastic syndrome?
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2%
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A tumour in the apex of the lung is known as what?
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Pancoast tumour
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What are the two primary classifications of lung cancer on histology?
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Small cell and non-small cell
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What percentage of lung cancers are small-cell?
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20%
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What is the typical treatment for early stage non-small cell lung cancer?
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Surgery
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What is the typical treatment for early stage small cell lung cancer?
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Combined chemotherapy and radiation (due to high likelihood of hematogenous spread)
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Are squamous cell tumours typically found peripherally or in the central airway? What about adenocarcinomas?
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SC: Central; AC: Peripheral
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Enlargement of what lymph node is likely indicative of lung cancer?
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Supraclavicular lymph node
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What information might you want when investigating a solitary pulmonary nodule?
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Smoking history; Old X-rays; TB history; Characteristics of nodule; Hx of pneumonia; Hx of cancer
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What are four X-ray characteristics of lung cancer?
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Growing nodule (sequential CXR); Rough edges; Solid; Solitary
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What is the approximate cure rate for all forms of lung cancer in Stage 1? Stage 3?
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1: 60-80%; 3: 10-15%
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What 5 facts are necessary to describe a cancer?
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1: Primary or secondary - cell type
2: Stage 3: Date of diagnosis 4: What treatment was given 5: Age of patient |
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Is there greater resistance to airflow in the bronchus or in the alveoli?
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Bronchus
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How does the diffusion coefficient of CO2 compare with that of O2?
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The diffusion coefficient, D, or CO2 is about 20 times higher than that of O2
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Which three parameters of gas diffusion change with breathing?
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Surface area, thickness, alveolar pressure
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At the end of inspiration, what is alveolar surface area and wall thickness in relation to that at the end of expiration?
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At the end of inspiration, surface area is largest and thickness is smallest to allow for easier O2 diffusion across the membrane
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What are some indications for doing a surgical airway?
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Edema of glottis; Fracture of larynx; Severe oropharyngeal hemorrhage
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What are the three (four) classifications of pneumothorax?
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Simple; tension; open; (major airway injury)
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Pneumothorax resulting from pressure rising in the chest is what type?
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Tension
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Why does decreased venous return occur in tension pneumothorax?
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The IVC is kinked in a tension pneumothorax due to increased pressure on the mediastinum pushing it to one side
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What is the best way to evaluate/visualize a major airway injury causing a pneumothorax?
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Bronchoscopy
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What are three sources of blood from a hemothorax?
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Bleeding chest wall vessels (intercostals, mammary); Torn lung; Major vascular injury (pulmonary, aorta)
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Is the presence of a meniscus on CXR more suggestive of a pnemothorax or hemothorax?
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Hemothorax (meniscus is top of fluid - could also be a pleural effusion)
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What is the most common chest wall injury?
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Rib fracture
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Why is a rib fracture in a kid more serious than in an adult?
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Pediatric ribs are more flexible, and thus much greater blunt force trauma is required to break them
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3 or more ribs fractured in 2 places, frequently associated with lung contusions is known as what?
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Flail chest
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Why do we always admit someone with flail chest?
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High risk of going into respiratory failure
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A patient comes into the ER following an MVC with a number of rib fractures including the first and second rib. Mediastinal structures are displaced and the AP window is reduced. What should you be worried about?
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Aortic injury
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What are four possible tests used to diagnose an injury to the aorta?
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CXR; CT Chest; Transesophageal echogram; Angiography
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A patient presents with a ruptured spleen and an injury to the aorta. What should you fix first?
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Fix the spleen first - the aortic injury will be contained for some time
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At sea level and at rest, what is the approximate distance along the pulmonary capillary that O2 is fully diffused and saturated? How might this change with fibrosis?
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About 1/3 of the way. With fibrosis, it takes longer to reach the equilibrium between air and blood, possibly never reaching equilibrium
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At higher altitudes, how does the speed of O2 diffusion from airway to bloodstream change?
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Due to reduced driving pressure (lower airway pressure), it takes longer for equilibrium to be reached
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What five factors contribute to lung diffusing capacity?
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Diffusion coefficient of the gase; Surface area of the membrane; Thickness of the membrane; Time required for the gas to combine with proteins in the lungs; Capillary blood (binding of hemoglobin to O2)
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The amount of O2 delivered to tissues is determined by which two factors?
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Cardiac output (blood flow); Oxygen content of blood (dissolved and bound to Hb)
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