WEEK 1 - I’m feeling short of breath Flashcards
branches of the pulmonary ______ participate in gas exchange at the ________ _______ membrane
- arteries
- alveolar capillary membrane
an obstruction in the pulmonary artery would cause an immediate increase in blood pressure in which region?
right ventricle
When an obstruction causes a restriction of flow, increased pressure will occur upstream of the blockage. Should a blockage occur in the pulmonary artery, blood will pool behind the blockage (upstream) in the right ventricle, increasing the pressure in this chamber. This is called pulmonary hypertension.
what is gas exchange reduced by?
- obstruction of the pulmonary artery — reduces perfusion therefore reduces gas exchange
- fibrosis of the alveolar tissue
For gas exchange to occur, our respiratory and circulatory systems work together via 3 systematic mechanisms:
- _________, movement of air into and out of the lungs.
- __________, movement of gases between air spaces in the lungs and the bloodstream.
- __________, movement of blood in and out of the capillary beds of the lungs.
fibrosis of the alveolar tissue _______ diffusion as the alveolar surface is scarred.
For gas exchange to occur, our respiratory and circulatory systems work together via 3 systematic mechanisms:
- Ventilation, movement of air into and out of the lungs.
- Diffusion, movement of gases between air spaces in the lungs and the bloodstream.
- Perfusion, movement of blood in and out of the capillary beds of the lungs.
Fibrosis of the alveolar tissue reduces diffusion as the alveolar surface is scarred.
what covers the internal surface of the thoracic cavity?
pleura
what is the name of the physical space between the lungs and ribcage?
pleural cavity
what is the function of the serous fluid in the pleural cavity?
support lung expansion when you breathe in
what are the 2 layers of the pleural cavity?
the parietal pleura that covers the rib cage and the visceral pleura that covers the lung
which pleura is sensitive to pain, pressure and temperature and is innervated by the phrenic and intercostal nerves?
parietal
what 4 things can cause sudden onset of pleuritic chest pain and SOB?
- pulmonary embolism
- musculoskeletal chest pain
- pneumothorax
- pleurisy
what is the most common cause of chest pain in primary care?
musculoskeletal conditions
what does musculoskeletal chest pain arise from?
bones, ligaments, muscles or the costochondral junctions in the ribcage
what is a key diagnostic feature for isolated musculoskeletal chest pain?
reproducing the patient’s pain by palpation or by movement
what is usually sufficient for musculoskeletal chest pain treatment?
explanation, reassurance and treatment with NSAIDs
what is pleurisy?
inflammation of the parietal pleura
when a patient presents with pleuritic chest pain, what are some potentially life-threatening disorders that physicians should consider first?
pulmonary embolism, myocardial infarction, pneumothorax
Pericarditis and pneumonia are two other significant causes of pleuritic chest pain that should be considered before pleurisy is diagnosed.
what is one of the most common causes of pleurisy?
Viruses that have been linked as causative agents include influenza, parainfluenza, coxsackieviruses, respiratory syncytial virus, mumps, cytomegalovirus, adenovirus, Epstein-Barr and now of course corona virus.
what is a pneumothorax?
a collection of gas in the pleural space that results in a variable amount of lung collapse on the affected side
what are the types of pneumothoraxes?
SPONTANEOUS
- primary = no underlying lung disease
- secondary = lung disease present/or smoking history at least 20 PYs
TRAUMA
- iatrogenic = procedure related/barotrauma in ICU
- non-iatrogenic = RTC, trauma, fall
what are risk factors for a primary pneumothorax?
- tall
- thin
- male (5:1)
- 20-40
what are risk factors for a secondary pneumothorax?
- COPD 60% cases
- cigarette or cannabis smoker 20PYs
- marfans/homocystinuria
- familial — Birt-Hogg-Dube syndrome (Auto Dom) mutation in folliculin gene
- asthma
what is the classic presentation of a primary spontaneous pneumothorax?
pleuritic chest pain and dyspnoea at rest — the symptoms do not correlate closely with the size of the pneumothorax — in many cases the symptoms are mild and approximately half of patients will present after more than 2 days of symptoms
why are symptoms of a secondary spontaneous pneumothorax more severe?
because lung function may already have been compromised by the underlying pathological process
secondary spontaneous pneumothorax symptoms vary depending on what? what is the primary complaint?
symptoms will vary depending on the cause e.g. fever, weight loss, night sweats but the primary complaint is that of breathlessness which is often out of proportion to the size of the pneumothorax radiologically.
in a secondary spontaneous pneumothorax, unlike symptoms, what are the examination findings affected by?
the size of the pneumothorax — therefore a small pneumothorax can be impossible to identify on clinical examination
the lungs tend to ________ and the chest wall tends to _______
- collapse
- expand
the tendency for elastic recoil to ______ lungs and chest wall to ______ means pleural pressure will be _____ compared to alveolar pressure
- collapse
- expand
- negative
when no muscles act on the chest wall, “equilibrium” will be achieved when the force generated by the pressure gradient across the _______ wall (_________ pressure) is equal and opposite to __________ _______
what is this point?
- alveolar (trans-pleural pressure: Ppl — Palv)
- elastic recoil
this point is functional residual capacity
when do the lungs sit at functional residual capacity?
at the end of every normal expiration, when respiratory muscles are relaxed
at FRC, what does alveolar pressure equal?
atm pressure therefore no airflow
for inspiration, what must alveolar pressure be less than?
atm pressure
for expiration , what must alveolar pressure be greater than?
atm pressure
what happens in a simple pneumothorax? what does a chest drain do?
- pleural pressure equals atm pressure
- no force to counter elastic recoil
- lung collapses
- normal lung expansion cannot take place
- the lung will stay collapsed until the puncture is sealed
- a chest drain, acting as a one way valve allows air to escape from the pleural space, during expiration, and the lung will reinflate
what happens in a tension pneumothorax?
- injury creates a tear in the tissue that acts as a one way valves
- on inspiration, air is drawn into the pleural space
- on expiration the air in the pleural space is trapped and compressed
- pleural pressure can quickly exceed central venous pressure and obstruction cardiac filling leading to a life-threatening fall in cardiac output
NEEDLE ASPIRATION is a life saver
what is an embolism?
obstruction of a blood vessel by a blood clot or foreign substance
what % of leg thrombi embolise?
20% — more above the knee than below
where may a large clot get stuck in the lungs?
bifurcation of the main pulmonary arteries —> haemodynamic compromise
where might smaller clots get stuck? result?
more distally in the lungs —> infarction —> pleuritic pain
what are more uncommon or rare causes of pulmonary embolisms?
- fat (fracture of long bones)
- amniotic fluid (post-partum)
- air (from disconnected CVL)
- tumour embolus
- infected vegetations (tricuspid endocarditis)
- foreign materials (iv drug users)
mainly blood clots