Respiratory Flashcards

1
Q

SMART-COP criteria

A
  • Systolic BP (less than 90 mmHg) - 2 pt
  • Multilobar CXR involvement - 1 pt
  • Albumin (less than 35 g/L) - 1 pt
  • Respiratory rate (≥30) - 1 pt
  • Tachycardia (≥125) - 1 pt
  • Confusion - 1 pt
  • Oxygenation (PaO2 ≤59 mmHg, SaO2 ≤90%, PaO2/FiO2 ≤249) - 1 pt
  • pH arterial (less than 7.35) - 2 pt

Severe CAP = score ≥5

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2
Q

CURB65 score

A
  • Confusion, AMT ≤8
  • Urea >7mmol/L
  • Respiratory rate ≥30/min
  • Blood pressure less than 90/60 mmHg
  • Age 65 or more

Severe CAP = score ≥3

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3
Q

Long term O2 therapy indications

A
PaO2 ≤55 mmHg or SaO2 ≤88%
OR
PaO2 ≤59 mmHg or SaO2 ≤89%, with:
 - ECG evidence of P pulmonale 
- Hematocrit >55 percent 
- Clinical evidence of right heart failure
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4
Q

Hb-oxygen dissociation curve left shift

A

Carbon monoxide
Foetal haemoglobin

Decrease in:
Temperature
Acidity
2,3-DPG
pCO2
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5
Q

Hb-oxygen dissociation curve right shift

A
Increase in:
Temperature
Acidity
2,3-DPG
pCO2
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6
Q

Alveolar-arterial gradient (A-a gradient) calculation

A

=FiO2(Patm - PH2O) - PaCO2/0.8 - PaO2

=0.21 (760 - 47) - 1.25(PaCO2) - PaO2

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7
Q

Normal A-a gradient

A

Less than 15mmHg:

  • Hypoventilation (high PaCO2) - CNS depression, neuromuscular disease, kyphoscoliosis, obesity hypoventilation
  • Low PiO2 (low PaCO2) - altitude, aircraft cabin
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8
Q

Widened A-a gradient

A

Equal or greater than 15mmHg:

  • Diffusion defect (normal PaCO2) - ILD, elite athlete during exercise
  • V/Q mismatch (normal PaCO2, overcome by high flow O2) - pneumonia, APO, ARDS, atelectasis, ILD
  • Right-left shunt (normal/low PaCO2, true shunt not overcome by high flow O2) - PFO, ASD, pulmonary AVM
  • Increased O2 extraction
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9
Q

Blood gas - Methaemoglobinaemia

A
  • Chocolate brown blood
  • Normal PaO2
  • SaO2 usually 85-90%
  • Saturation gap (Oximetry SaO2 5% lower than ABG SpO2)
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10
Q

Blood gas - Carboxyhaemoglobinaemia

A
  • Cherry red skin and lips
  • Normal PaO2
  • Decreased ABG SpO2
  • Normal oximetry SaO2
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11
Q

Methacholine provacation test

A

Specific for asthma diagnosis.

Reduction in FEV1 of 15% or more, using 4mg/ml or less.

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12
Q

Bronchodilator reversibility

A

Increase in FEV1 by at least 12% and 200ml.

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13
Q

Best predictor of mortality in COPD

A

Acute exacerbation with hospital admission

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14
Q

Spirometry - asthma

A
FEV1 ≤80%
FER ≤70%
DLCO ≥75% (normal or high)
TLC ≥80%
Bronchodilator response - more than 12% and 200ml
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15
Q

Major form of carbon dioxide in the blood

A

Bicarbonate ion - 80%
Carbamino compound bound to Hb - 10%
Dissolved in plasma - 10%

(Diffuses to RBC then rapidly anhydrated by intracellular carbonic anhydrase to carbonic acid, then dissociates to bicarbonate)

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16
Q

Obstructive sleep apnoea - cardiac physiology

A
Increased LV afterload
Decreased LV preload
Increased RV venous return
Increased sympathetic outflow
Decreased stroke volume (during apnoea) - increased with relief from obstruction
17
Q

Obstructive sleep apnoea - definition

A

Polysomnography with more than 5 obstructive events per hour with symptoms/comorbidities, or more than 15 obstructive events per hour regardless

18
Q

Central sleep apnoea - definition

A

Polysomnography with more than 5 central events per hour with symptoms/comorbidities, and no Cheyne-Stokes breathing

19
Q

Obesity hypoventilation syndrome - definition

A

Obesity - BMI more than 30
Alveolar hypoventilation - PaCO2 more than 45mmHg (while awake, with no other cause)
Nocturnal hypoventilation - increase in PaCO2 more than 55mmHg or rise of 10mmHg exceeding 50mmHg for 10 min or more

20
Q

Narcolepsy - definition

A

EDS - more than 3 months
Mean sleep latency - 8 minutes or less
SOREM - 2 or more naps with sleep onset to REM within 15 minutes

Type 1 - CSF hypocretin-1 less than 110 picograms/ml, cataplexy present
Type 2 - normal CSF hypocretin-1, cataplexy absent

21
Q

Chronic obstructive pulmonary disease (COPD) - criteria for long-term azithromycin prophylaxis

A

COPD with 2 or more exacerbations per year
HR less than 100, QTc less than 450
Sputum culture mycobacterium negative
No baseline high cardiac risk

22
Q

Idiopathic pulmonary fibrosis (IPF) - treatment

aka usual interstitial pneumonia (UIP)

A

Anti-fibrolytic - pirfenidone or nintedanib

Triple therapy - N-acetyl cysteine, prednisolone, azathioprine

23
Q

Well’s score for pulmonary embolism (PE)

A
Clinical symptoms of DVT (3)
No alternative diagnosis (3)
Previous DVT/PE (1.5)
Immobilisation/surgery past month (1.5)
Tachycardia more than 100 (1.5)
Malignancy (1)
Haemoptysis (1)

PE likely = score more than 4

24
Q

Spirometry - obstructive defect

A

FEV1/FRC (ie. FER) ≤70% or LLN

25
Q

Spirometry - restrictive defect

A

TLC less than 80% or LLN, with normal FER

26
Q

Alpha-1 antitrypsin deficiency (AAT) - lung pathophysiology

A

Toxic loss of function - AAT normally inhibits elastase, results in proteolytic degradation of elastin

27
Q

Lung transplant - contraindications

A
Uncontrolled infection
Malignancy last 2 years
Significant dysfunction in other organs
Significant coronary artery disease or HF
Chest wall / spine deformity
Active smoking
Drug / alcohol dependency
HIV infection / active hep B or C infection
Obese BMI ≥35