Pulm Extras Flashcards
alveolar oxygen equation
PAO2=150-PCO2/.8
exhaled CO2 equation
Vt(PaCO2-PeCO2)=Vd(PaCO2)
complex alveolar oxygen equation
PAO2=FiO2(Patm-Ph20)-PCO2/R
Aa gradient equation
A/a=(150-PCO2/.8)-PaO2
A/a= PAO2-PaO2
> 10mm Aa gradient suggests
gas exchange problem
gas flow equation
Vgas=A/T*Dk(PA-Pc)
flow increases with area, decreased thickness, better diffusion and more pressure from alveolus to capillary
5 causes of hypoxia
decreased cardiac output hypoxemia anemia carbon monoxide cyanide
mec of hypoxia via hypoxemia
decreased PaO2, O2 sat of hemoglobin, O2 in blood
mec of hypoxia via anemia
decreased hemoglobin concentration, O2 in blood
mec of hypoxia via carbon monoxide poisoning
less O2 in blood, left-shift of hemoglobin curve
mec of hypoxia via cyanide
less O2 utilization by tissue
no cartilage or goblet cells
terminal and respiratory bronchioles, alveoli
no cilia or smooth muscle
respiratory bronchioles and alveolus
5 causes of hypoxemia
increased altitude hypoventilation diffusion defect v/q defect RL shunt
3 cause of hypoxemia with increased Aa gradient
diffusion defect, V/Q defect, RL shunt
cause of hypoxemia not helped by supplemental O2
RL shunt
squamous and thin
type 1 pneumocytes
cuboidal, secrete surfactant, precursor to I and II pneumocytes
type II pneumocytes
nonciliated, columnar, secrete component of surfactant
clara cells
muscles in exercise inspiration
external intercostals, scalenes, SCM
muscles in exercise expiration
abs, internal intercostals
shift curve right (less affinity) 5
increased PCO2, temp, 2,3PG
decreased pH,
exercise
shift curve left (more affinity) 5
decreased PCO2, temp, 2,3DPG
increased pH
fetal hemoglobin
High HR in modified wells
100 BPM (1.5)
wells points for DVT, PE
> 2, >4
PaO2, PaCO2 in exercise
stay the same
arterial pH in exercise
decrease (strenuous)
V/Q ratio in exercise
more evenly distributed
dead space in exercise
decreases
PAO2, PaO2 at high altitude
decreases
RR, pH, Hgb, 2,3DPG, PVR, PAP at high altitude
go up
top of lung
vent is lower, v/q high
bottom of lung
vent is higher, v/q is lower
decreased O2 delivery to tissues
hypoxia
PEEP benefits 4
prevent alveolar collapse, lower shunt fraction, improve LV function, decrease autoPEEP (usually 3-5)
PEEP harm 2
increase airway pressure, decrease cerebral perfusion
incomplete exhalation, leads to air trapping
autoPEEP
treat autoPEEP 4
lower TV/RR
increase inspiratory flow rate (makes exhale longer than inhale)
treat airflow obstruction
temporarily disconnect the vent
70% of CF mutations
deltaF508 (block in gene processing)
reabsorbs Cl from sweat
CFTR
positive sweat test
> 60 mEq/L
airflow obstruction definition
FEV1/FVC < .7
chronic bronchitis criteria
persistent cough/sputum for at least 3 months
for 2 consecutive years
may also cause liver disease?
AAT deficiency (basilar emphysema)
shunt or diffusion defects contribute to hypoxemia in COPD
no
pulmonary edema *always due to
osmosis of fluid from pulmonary capillaries
ARDS gas exchange criterion
PaO2/FiO2 <300
FiO2 in room air
.21
ARDS risk factors 5
fat, old, ill-fed, EtOH & cirrhosis
refractory hypoxemia, shunt, decreased compliance, hyaline membranes
exudative ARDS (2-3 days)
increased dead space and Ve, pulmonary HTN, type II pneumoncyte hyperplasia
ARDS proliferative stage
mostly likely thrombus to embolize
popliteal and proximal veins
inherited risk factors for VTE 5
V leiden, prothrombin mutation, S, C, antithrombin deficiency
d-dimers are elevated in nearly all cases of
DVT. sensitive, not specific
anatomic disposition to DVT
May-Thurner: squashed left iliac vein
untreated DVTs leading to PEs
50%
untreated PEs leading to death
30%
hypoxemia and respiratory alkalosis
PE?!
mec of hypoxemia in PE
VQ mismatch and shunt
do anticoagulants accelerate thrombus lysis?
no
recurrent PE frequency, mortality
3%, 79%
over 40, limited mobility for 3 or more days, or other risk factor
consider PE prophylaxis
empyema
pus in the pleural space
denser, infection inflammation malignancy
exudate
less dense, (<.5 protein, .6 LDH), heart failure, cirrhosis
transudate
rare, milky, lipid rich, exudative
chylothorax (50% trauma)
rare, unilateral, usually neoplasm or obstruction
urinothorax
very rare, pleural effusion with ascites and benign ovarian tumor
meig’s syndrome
rare fatal spontaneous pneumothorax/pleural effusion in young female
lymphangioleiomyomatosis
centrilobar nodules that aren’t TB or bacterial infection
hypersensitivity pneumonitis
opiods, trauma, stroke, increased ICP, bihemispheric infarc
cluster breathing
mean PAP over 25
PH
mean PAP over 25, PCPW less than 15
PAH
most frequent PAH symptom
exertion dyspnea
PAH risk factors 7
FHx, premature, CTD, congenital heart disease, portal HTN, environment/drugs, HIV
9-15% of adult asthma
occupational
requires desensitization period
immunological occupational asthma
alveolar filling (acute) & nodular opacities (chronic)
silicosis
parenchymal & pleural disease, malignancy, ferruginous bodies, plaques, BAPE and atelectasis (PE and collapsed lung)
asbestosis
noncaseating granulomas, looks like sarcoid, treat with steroids
berylliosis (T cell rxn to beryllium)