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41 Cards in this Set
- Front
- Back
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Aspiration
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upright:
lower part of R inf lobe supine: superior part of R inf lobe |
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Muscles of respiration
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Quiet:
inspiration: diaphragm expiration: passive exercise: inSp: external intercostals, scalenes, SCMs exp: internal intercostals, rectus abd, int/ext obliques, transversus abd (internal intercostals push air OUT) |
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Laplace Law
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tendency to collapse on expiration as radius decreases
P (collapsing pressure) = 2(surface tension)/r |
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Moment of lowest pulmonary vasc resistance
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at FRC (after expiration of TV)
*inward pull of lung is balanced by outward pull of chest wall; system pressure is atmospheric *airway and alveolar pressure are 0 and intrapleural pressure is negative (to prevent PTX) |
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Vital capacity
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TV + IRV + ERV (all but RV)
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Functional residual capacity
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RV + ERV
vol in lungs after nl expiration |
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Inspiratory capacity
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TV + IRV
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Physiologic dead space
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Vd = Vt (tidal vol) * (PaCO2 - PeCO2)/PaCO2
tidal volume * the difference in PCO2 between arterial and expired air / arterial PCO2 |
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Methemoglobin
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oxidized form of Hb (ferric, Fe3+); does not bind O2 as readily; increased affinity for CN-
cause: chloraquine/primaquine, dapsone, sulfonamides, local anesthetics, nitrates, metoclopramide Tx: METHylene blue & vit C CN- poisoning: give nitrites to oxidie hgb to methemoglobin, which binds CN-; then give thiosulfate to bind CN forming thiocyanate, which is renally excreted *hydroxycobalamin increases affinity for CN- |
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Perfusion limited
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O2 (in healthy), CO2, N2O
gas equilibrates early along length of capillary; diffusion increases only if blood flow increases |
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Diffusion limited
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O2 (emphysema, fibrosis), CO
gas does not equilibrate by the time blood reaches the end of the capillary |
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Diffusion eqn
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Vgas = Area/Thickness * Dx(P1-Pe)
difference in partial pressures A decreased in emphysema T increased in pulm fibrosis |
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Pulm HTN
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primary:
inactivating mutation in the BMPR2 gene: normally inhibits vasc SMC prolif women in 30s Secondary: COPD mitral stenosis recurrent thromboemboli autoimmune disease (sclerosis, fibrosis) L-R shunt Sleep apnea, high altitude * causes dilation of coronary sinus 2/2/ RA dilation |
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Alveolar gas equation
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PAO2 = PIO2 - PaCO2/R
R = resp quotient = CO2 produced/O2 consumed = 0.8 PAO2 = 150 - PaCO2/0.8 |
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Increased A-a gradient
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normal: 10-15
VQ mismatch diffusion limitation R-L shunt |
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Hypoxemia
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High altitude
Hypoventilation Increased A-a gradient: VQ mismatch diffusion limitation R-L shunt |
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V/Q mismatch
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Apex: V/Q = 3
PA > Pa > Pv Zone 2: Pa > PA > Pv Base: V/Q = 0.6 Pa > Pv > PA V/Q approaches 1 during exercise (becomes more uniform from apex to base |
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Haldane effect
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in lungs, oxygenation of Hb --> dissoc of H+ --> equalibrium shifted toward CO2 formation and CO2 is released from RBCs
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Bohr effect
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In periph tissue, increased H+ from tissue metabolism shifts curve to right, unloading O2
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High altitude
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get respiratory alkalosis
to compensate, kidney excretes more bicarb **can give acetazolamide for altitude sickness (CA inhib --> excrete more bicarb) |
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Chronic bronchitis
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Reid index: gland depth/total thickness of bronchial wall
>50% in COPD productive cough for >3mo a year for 2 consec years blue bloater: get cyanosis early hypoxemia (shunting) late dyspnea |
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Emphysema
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increased compliance
centriacinar: smoking panacinar: alpha1-antitrypsin def; cirrhosis paraseptal: assoc with bullae that rupture -->> spontaneous PTX (young, healthy males) *exhale thru pursed lips to increase airway pressure and prevent airway collapse early dyspnea late hypoxemia |
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Curschmann's spirals
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shed epithelium from mucous plugs seen in asthma
charcot-leiden crystals: eosinophilic |
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Bronchiectasis
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chronic necrotizing infxn of bronchi --> permanently dilated airways, purulent sputum, recurrent infxn, hemoptysis
can get aspergillosis, pseudomonas assoc with bronchial obstruction, CF, Kartagener's |
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Drugs that cause pulm fibrosis
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bleomycin
busulfan amiodarone |
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Neonatal resp distress syndrome
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surfactant made by type II pneum after 35th week
L:S < 1.5 RFs: prematurity, maternal DM, C section Tx: maternal steroids before birth (not after 34 wks gestation); artificial surfactant, thyroxine *O2 can cause retinopathy of prematurity |
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ARDS
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damage due to pmn substances; coag cascade, O2 free radicals
leads to edema and poor compliance |
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Lung Ca complications
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SPHERE:
SVC syndrome Pancoast Horner's Endocrine: paraneoplastic Recurrent laryngeal sxs Effusions (pleural or pericardial) |
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Squamous cell carcinoma
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Sentral, Smoking
hilar mass from bronchus **assoc with PTHrP *heratin pearls and intercellular bridges |
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Small cell (oat cell) carcinoma
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Sentral
undifferentiated, aggressive **ACTH, ADH, Lambert-Eaton *responsve to chemo, INOPERABLE neuroendocrine KULCHITSKY cells: small dark blue cells |
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Adenocarcinoma: bronchial
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Peripheral
develops in site of prior pulm inflammation or injury **MC lung CA in nonsmokers and females Clara cells -> type II pneum multiple densities on CXR |
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Adenocarcinoma: bronchioloalveolar
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Peripheral
not linked to smoking grows along airways; can present lik PNA can result in hypertrophic osteoarthropathy Clara cells -> type II pneum multiple densities on CXR |
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Large cell carcinoma
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peripheral
highly anaplastic undifferentiated tumor; poor prognosis *surgical *pleomorphic giant cells with leukocyte fragments in cytoplasm |
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Carcinoid tumor
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BFDR:
bronchospasm flushing diarrhea right heart lesions (fibrous deposits in valves --> TR, PS, RHF) secretes serotonin |
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Psammoma bodies
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PSaMM:
Papillary thyroid CA Serous cystadenocarcinoma of ovary Meningioma Mesothelioma |
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Bronchopneumonia
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Staph aureus
Group A Strep H flu Klebsiella acute inflammatory infiltrate from bronchioles into adjacent aveoli; patchy distribution |
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Theophylline
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for asthma; causes bronchodilation by inhib phosphodiesterase --> decrease cAMP hydrolysis
narrow TI (cardiotox, neurotox): abd pain, V/D, arrhythmias, seizures Tx of OD: activated charcoal, gastric lavage, cathartics; BB for the tachyarrhthmias metabolized by p450 blocks action of adenosine |
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Steroids
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inactivate NF-kB (transcription factor for TNF-alpha) --> inhibit synthesis of all cytokines
**1st line for chronic asthma |
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-lukasts
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kast for LAST step in pathway
block LT receptors good for ASA-induced asthma |
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Zileuton
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5-lipoxygenase pathway inhibitor
block conversion of arachidonic acid to LTs |
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Bosentan
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Tx; pulm HTN
competitively antagonized endothelin-1 receptors, decreasing pulm vascular resistance Other options: PG analog DHP CCB Sildenafil |
