Resp Physiology + Star points

Question 1

What is the dual blood supply of the lung?

Answer 1

Pulmonary (venous) - DeO2 via pulmonary artery from RHS.
O2 inhaled- returned to heart by pulmonary veins
Systemic (arterial)

Question 2

What are some common causes of cough?

Answer 2

Acute: 3w
Postnasal drip-> rhinitis, sinusitis, acute nasopharyngitis.
Asthma + wheeze + breathlessness or only cough: worse 🌙✨, on waking and after exercise.
GORD*
Lung airway disease: COPD, bronchiectasis, tumour.
Foureign body
Lung parenchymal disease: interstitial lung disease, lung abscess

Drugs: ACE inhibitors

Cough: commonest LRTD.
Cough receptors: mechanically stimulated- touch and displacement
+ chemical- fumes. –> afferent nerves in medulla cough centre.
↪️generating efferent signals via phrenic nerve and efferent vagus branches. -> to expiratory musculature to generate a cough.

Smokers: cough and sputum production.

Question 3

Dyspnoea

Answer 3

SOB
Orthopnoea- SOB that occures when lying down- abdo conetnts into thorax + redistribution of blood from lower extremeties to the lungs.

Paroxysmal nocturnal dyspnoea- LHF- pt wakes up gasping for breath- relieved when sat upright. Sensory awarness depressed in sleep- severe interstitial pulmonary oedema can occur.

Question 4

What 2 epithelia are in the conduction system?

Answer 4

Ciliated columnar and mucus (goblet) cells

Question 5

What are the resp complications of asbestos?

Answer 5

Asbestos fibers cannot be cleared.

1. Pleural plaques/ thickeini g seen on CXR, restrictive lung cage , mesothelioma.
2. Fibrotic lung disease, pc like Idiopathic pulmonary fibrosis.
3. Malignanr mesothelioma pf pleura- 1 year median surviabal.

Sx pts- entitled to compensation- occupational most cases.

Question 6

How would u asses someones suitability for lung cancer surgery?

Answer 6

Non small cell lung cancer- best trated surgically at eaely stage:1-2.

Hpwever: might not benefit if high preop risk:
Age: >80 + large pneumectomy. 
CVs risk
Echo if murmur
Lung function: FEV

Question 7

This pt has O2 sats 90% air, how would u give them supplementary Oxygen?

Answer 7

If known to retain CO2- 90 is acceptable.

Consider nasal cannulae with low flow oxygen (1-4L/min) cz this is more comfortable. Allow talking and eating and dry the mouth less.

Dose titrated upwards with controlled rate(Venturi) face,ask- with target sats 94-98%.

Question 8

What causes bronchiectasis?

Answer 8

Pulmonary infection- esp recurren and chronic- TB, after rubella, measles. Risk fx: chronic lung disease, immunodeficiency.

Pulmonary inflammation: allergy, chemical pneumonitis.

Ciliary dysmobility. - CF,

Question 9

Whats the difference b/w AP and PA film? In CXR?

Answer 9

PA preferred: cz ❤️ near to radiographic plate- less lung fields- more cardiac size accuracy. Hands up- remove scapulae.
However- pys needs to be mobile.

Unwell pts: or portable films: taken lying down- AP.

Question 10

When should a pts be considered for oxygen therapy at home?

Answer 10

Stop smoking + COPD-
At least 15hrs a day.
Keep b/w 90-92% O2 sats.

1. PaO2 55%

Question 11

What are some causes of breathlessness??

Answer 11

1. Sudden onset: inhaled foreign body, pneumothorax, PE.
2. SOB developing over a few hours: Asthma/COPD, pneumonia, pulmonary oedema, resp muscle disease- Guillian Barree.

Intermittent breathlessness: asthma, pulm oedema, PE.

Breathlessness over a few days: pleural effusion, carcinoma of the bronchus, pneumonia including pulmonary tuberculosis.

SOB developing over a few M or years: Fibrosing alveolitis, COPD, Sarcoid, chest wall or neuromuscular disease.
Non resp causes: anaemia, hyperthyroidism.

Question 12

29Year old male, out drinking, home throwing up, difficulty breathing. He is in great distress. A friend calls an ambulance.
Is this an emergency?

Whats the Heimlich manoeuvre?

Answer 12

Yes!!
UPPER AIRWAY OBSTRUCTION ‼️
Stridor
Resp distress
Cyanosis +|- shock. 

Used to expel inhaled foreign object.
“Pounia sto upper part of abdomen”
Expelling air from lungs to force object out of trachea.

If obstruction beyong vocal cords: fibre optic or rigid bronchoscopy.

Question 13

What are some causes of upper airway obstruction?

Answer 13

Anaphylaxis: laryngeal oedema: 1. Adrenaline (epinephrine) 0.5mg IM, 2. antihistamine e.g. Chlorphenamine 10-20mg by slow IV injection, 3. Hydrocortisone IV 100 mg slowly.
4. O2.

Carcinoma of upper airway: Call ENT for laryngyoscopy

Tracheal compression: eg bleeding post thyroidectomy-> yracheal decompression, eg release skin sutures.

Inhaled foreign body: Heimlich manoeuvre

Question 14

67 year old male with MI,treated successfully and goes ho,e om enalapril, atrovastatin and antiplatelet therapy.
He has a cough keeping him awake at night. Whats happening?

Answer 14

Most prob cause: ACEi should be stopped and an ACE receptor antagonist eg vasartan should be started. ARBS do not affect bradykinin.