Pulmonary Flashcards
Alveolar O2 formula?
Normal A-a gradient?
PAO2 = 713*FiO2 - PaCO2/0.8
On room air (21% O2), this is:
PAO2 = 150 - PaCO2/0.8
Normal A-a gradient is <15 mm Hg.
Increases with aging but should always be <30 mm Hg
Light criteria for an exudative effusion
At least one of:
- Pleural fluid protein / serum protein ratio > 0.5
- Pleural fluid LDH / serum LDH ratio > 0.6
- Pleural fluid LDH > 2/3 the upper limit of normal for serum LDH
How can the severity of ARDS be graded?
PaO2 / FiO2 (P/F) ratio:
<100: Severe
<101-200: Moderate
<201-300: Mild
O2 saturation goal in ARDS
88-95% saturation (PaO2 55-80)
Extrapulmonary involvement of sarcoidosis (5)
- Skin lesions (e.g. erythema nodosum)
- Uveitis
- Arthralgias
- Hypercalcemia
- Heart disease
Hypoxia with a petechial rash and neurological signs after trauma
Fat embolism from long-bone fracture to lungs
Mechanism of secondary spontaneous pneumothorax
Rupture of alveolar blebs due to chronic destruction of alveolar sacks
(seen in chronic lung disease like COPD and CF)
Sensory complication of aspirin-induced respiratory disease
Anosmia (due to nasal polyps from chronic rhinosinusitis)
When is long-term suppelemntal oxygen started in COPD?
SaO2 < 89% (PaO2 55 mm Hg) ORA in patients with cor pulmonale, right heart failure, or hematocrit >55%
SaO2 <88% (PaO2 <59 mm Hg) ORA in anyone else
Treatment for all acute COPD exacerbations?
Moderate-to-severe? How is this defined?
- Oxygen (to SpO2 of 88-92%)
- Inhaled bronchodilators
- Systemic glucocorticoids
Moderate-to-severe: add antibiotics
Moderate-to-severe: at least 2 cardinal symptoms (increased dyspnea, increased sputum volume, incerased sputum purulence) or need for NPPV or intubation
Cardinal symptoms of COPD exacerbation
- Increased dyspnea
- Increased sputum volume
- Increased sputum purulence
Cause of panacinar emphysema in a young person?
Manifestation outside the lung
Alpha-1-antitrypsin (AAT) deficiency
Also leads to liver disease (e.g. hepatitis, cirrhosis, HCC)
Rare but specific signs of PE on CXR (3)
Westermark’s sign: area of hyperlucency distal to a visible pulmonary vessel
Hampton’s hump: peripheral wedge of lung opacity due to infarct
Fleischner sign: enlarged pulmonary artery
Rare but classic sign of PE on EKG
S1Q3T3:
- Deep S wave in I
- Q wave in III
- Inverted T wave in III
Rapidly progressing, necrotizing post-influenza pneumonia in a young person
Staph aureus
First-line treatment for community acquired pneumonia
No recent antibiotics or major comorbidities: macrolide (e.g. azithromycin) or doxycycline
With recent antibiotics or comorbidities: add a beta-lactam (e.g. ceftriaxone), or just use a respiratory fluoroquinolone (e.g. levofloxacin or moxifloxacin)
Tool for predicting community-acquired pneumonia severity and management:
CURB-65: one point for each of Confusion Urea >20 Respirations >30 BP low (systolic <90, diastolic <60) 65 years or older
0: low mortality, outpatient
1-2: Intermediate mortality, likely admission
3 or more: high mortality, urgent admission
Treatment options for pneumonia when aspiration suspected
- Amp/sulbactam (IV if inpatient) or amoxicillin/clavulanate (PO if outpatient)
- Clindamycin
- Metronidazole + amoxicillin or penicillin
Most common organisms for ventilator-associated pnuemonia
Gram-negative rods (Pseudomonis, E. coli, Klebsiella pneumonia) or gram positive cocci (Strep and Staph aureus)
Pneumonia associated with hyponatremia
Legionella (damage to JG cells that secrete renin)
Treatment for Legionella
Fluoroquinolones (levofloxacin) or macrolides (azithromycin)
Specific symptoms of Pancoast tumors
- Referred shoulder pain
- Horner symptom (sympathetic chain invasion)
- Brachial plexus invasion leading to arm motor and sensory symptoms
- Supraclavicular lymph node
Paraneoplastic syndrome(s) associated with lung SCC
Hypercalcemia (PTHrp)
Paraneoplastic syndrome(s) associated with small cell lung cancer
- Cushing syndrome (ACTH production)
- SIADH
- Lam`bert-Eaton myasthenic syndrome (antibodies against NMJ Ca2+ channels)
Lung cancer most associated with necrotizing and cavitation on CT
SCC