Respiratory Flashcards
What pCO2 is incompatible with life?
80 mmHg (normal 35-45 mmHg)
What is glycopyrrolate?
Antimuscarinic (bronchodilator)
Used for COPD
What are the stages of pneumonia?
- Congestion
- Red hepatisation
- Grey hepatisation
- Resolution
What are the 4 Ts of a mediastinal mass
Thymoma
Teratoma (and other germ cell tumors )
Thyroid neoplasm
Terrible lymphoma
What causes an increased residual volume in COPD?
Reduced alveoli recoil
How does hyperinflation help preserve maximal expiratory airflow in COPD?
Pressures generated by elastic recoil increase
At which oxygen saturation do patients become centrally cyanosed?
≤85 percent
Name a SAMA
Ipratropium
Name a LAMA
Tiotropium
What is theophylline?
A methylxanthine
Inhibits metabolism of cAMP by phosphodiesterases
cAMP stimulates B-adrenoceptors, causing bronchoconstriction
What FEV1/FVC is diagnostic for COPD?
< 0.7
How does CO diffusing capacity help differentiate emphysema and chronic bronchitis?
Decreased CO diffusing capacity suggests emphysema
What is alpha-1-antitrypsin?
Inhibitor of the proteolytic enzyme elastase
ATT protects against the proteolytic degradation of elastin
What is the most common cause of SVC syndrome?
Lung cancer
- Compression of the SVC reduces venous return to the right atrium*
- Feeling of fullness in the head, dyspnoea, oedema of the upper extremities and face*
How is acute pulmonary oedema managed?
LMNOP
Loop diuretic/lasix
Morphine
Nitroglycerin
Oxygen
Position/prop up the patient
What is the definition of pulmonary hypertension?
mPAP > 25 mmHg (normal 10-14 mmHg)
What is the definition of cor pulmonale?
Altered structure (hypertrophy/dilation) or function of the right ventricle due to pulmonary hypertension from a primary disorder of the respiratory or pulmonary artery system
How does COPD cause cor pulmonale?
Hypoxia → pulmonary vasoconstriction → increased pulmonary vascular resistance → cor pulmonale
(RV has to push against a higher resistance)
What does bronchial breathing suggest?
Consolidation
Sounds from the bronchi are able to be transmitted to the lung fields
What do bronchial breath sounds sound like?
Equal duration of inspiration and expiration (expiration usually 1/3 of the time)
Gap between the two phases
Tubular, hollow sound
Normally heard over the trachea
What are the two types of respiratory failure?
- Hypoxaemic (low PaO2)
* V/Q mismatch, high altitude, hypoventilation, poor diffusion* - Hypercapnic (high PaCO2 and low PaO2)
* Airway resistance, neuromuscular disorders, reduced respiratory effort*
What does a monophonic wheeze suggest?
Obstruction of large airways e.g. tumour, foreign body
What are the 5 mechanisms of hypoxaemia?
- Hypoventilation
- V/Q mismatch
- Right to left shunt
- Diffusion limiting
- Reduced inspired oxygen tension
What is V/Q mismatch?
An imbalance between blood flow and ventilation
What happens if you over-oxygenate someone with COPD?
Excess O2 inhibits peripheral chemoreceptors, decreasing their respiratory drive
Which 4 drugs can be used for TB?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
RIPE
How do you differentiate a stridor from a wheeze?
Wheezes are musical
Where is the obstruction in an inspiratory stridor?
Above the glottis
- Negative pressure with inspiration further narrows the airway, causing stridor*
- Expiratory = below the thoracic inlet*
Where is the obstruction in an expiratory stridor?
Lower airways below the thoracic inlet
Inspiratory = above the glottis
Where is the obstruction in a biphasic stridor?
Subglottal/glottic down to the tracheal ring

What does stony dullness on percussion of the lungs suggest?
Pleural effusion
Where is the obstruction in an inspiratory stridor?
Laryngeal/supraglottic
Where is the obstruction in an expiratory stridor?
Tracheobronchial - below the thoracic inlet
Which lung volume equates the volume of air that can still be breathed in after normal inspiration?
Inspiratory reserve volume (IRV)

Which lung volume equates the volume of air that moves into the lungs with each quiet inspiration?
Tidal volume (TV)

Which lung volume equates to the volume of air that can still be breathed out after normal expiration?
Expiratory reserve volume (ERV)
Which lung volume equates to the volume of air that remains in the lung after maximal expiration?
Residual volume (RV)
Which lung volume cannot be measured on spirometry?
Residual volume
What is functional vital capacity (FVC)?
The maximum volume of air that can be expired after a maximal inspiration

What does the A-a gradient reflect?
The integrity of oxygen diffusion across the alveolar and pulmonary arterial membranes
PAO2 - PaO2
Useful for determining the cause of hypoxemia. E.g. at high altitudes the A-a gradient will be normal because the alveolar oxygen concentration is low
A = alveolar
a = arterial
What is the PERC criteria?
Pulmonary Embolism Rule Out Criteria

What is this?

Westermark sign
Peripheral lucency due to a hypoperfused area secondary to PE
What is this?

Hampton hump
Secondary to PE/pulmonary infarction
What is the most specific sign of PE on ECG?
V1 + V3 T wave inversion
What is a massive PE?
PE with haemodynamic instability
What is a submassive PE?
Haemodynamically stable PE with right ventricular strain
Which tools can be used to decide whether a patient with pneumonia should be admitted to hospital?
CRB-65
CURB-65
Which tools can be used to identify patients with pneumonia who are at a higher risk of death or requiring intensive care support?
SMART-COP
CORB
How is a CURB-65 score calculated?

How is a CORB score calculated?

How is a SMART-COP score calculated?

How is mild CAP empirically treated?
Oral amoxycillin OR doxycycline
Outpatient
How is moderate CAP empirically treated?
IV benzylpenicillin PLUS oral doxycycline
Inpatient
How is severe CAP empirically treated?
IV benzylpenicillin + IV gentamicin + IV azithromycin (HNE)
OR
IV ceftriaxone/cefotaxime + IV azithromycin (eTG)
What is the difference between a transudative and an exudative pleural effusion?
Transudative
Permeation of fluid through walls of intact pulmonary vessels
Low protein (<50% of serum) and cell count
- Increased hydrostatic pressure (CHF)
- Decreased oncotic pressure
Exudative
Exudation of fluid through lesions in blood and lymph
Cloudy fluid with a high protein (> 50% of serum) and cell count
Pneumonia, tuberculosis
Malignancy
Pleural empyema
Pulmonary embolism
Vasculitis