Low V/Q (shunt) means
area of unventilated lung/ good blood flow
causes of low V/Q (5)
chronic bronchitis asthma pneumonia pulmonary edema atelectasis
high V/Q (dead space) means
area of ventilated lung/ no blood flow
cause of high V/Q mismatch
pulmonary embolus
matched defect (decreased V and Q) cause
emphysema
decreased respiratory drive is seen
paralysis, Gullain-Barre, Opioid overdose
a patient comes with shortness of breath, what is the initial test?
CXR w/ AP & lateral views
Light’s criteria
-Pleural fluid protein/serum protein > 0.5
• Pleural fluid LDH/serum LDH > 0.6
• Pleural fluid LDH > 2/3 upper limit of normal serum LDH
how to differentiate transudative or exudative from light criteria
1 criterion needs to be met; it must not meet any of the criterion
transudative etiologies (5)
CHF, nephrotic syndrome, hepatic hydrothorax, low albumin, peritoneal dialysis
exudative etiologies (6)
parapneumonic, other infections, cancer,inflammatory disease, connective tissue disease, lymphatic abnormalities (chylothorax)
exudative + increase lymphocytes
TB
exudative + bloody
malignancy, embolus
exudative + decrease glucose
rheumatoid arthritis
Progressive dyspnea, hypoxemia and bilateral alveolar infiltrates (not explained by fluid overload/ CHF) w/in 6-72 hrs of an inciting event
ARDS
Mild ARDS severity in terms of PaO2/FiO2
200-300mmHg
Moderate ARDS in terms of PaO2/FiO2
100- 200 mmHg
Severe ARDS in terms of PaO2/FiO2
<100 mmHg
Complications of ARDS
Barotrauma, nosocomial infections, delirium, stress ulcer
