Respiratory Emergencies Flashcards
What is a pneumothroax
- Air in the pleural space
What are the causes of spontaneous pneumothorax
- Primary - normal lung
- Secondary - underlying lung disease
Who does a spontaneous peneumothorax commonly occur in
- tall, thin men
- male: female 5:1
- cigarettes 22x more common
- cannabis
- rarely familial
- biomodal - more commonly in 15-34 and then over 55s
What is the pathophysiology of a pneumothorax
Air leak from Apical bulla in visceral pleura leading to a right spontaneous pneumothorax
What is the cause of secondary pneumothorax
- COPD (60%)
- Asthma
- Connective tissue disease – Marfan’s
- Interstitial lung disease : fibrosis
- Lung infection = Tuberculosis
- Cystic Fibrosis
What are the clinical symptoms of pneumothorax
- Sudden onset/acute
- Pleuritic chest pain
- +/-SOB
What are the differential diagnosis for pneumothorax
Respiratory
- pulmonary embolus
- pneumonia
- acute exacerbation of respiratory disease
Cardiovascular
- acute coronary syndrome/MI
- pericarditis
- aortic dissection/aneurysm rupture
- cardiac tamponade
Other
- musculoskeletal pain
- GORD
- Panic attack
What are the clinical signs of pneumothorax
- reduced expansion
- hyper-resonant percussion
- quiet breath sounds
- tachycardia
What is a cause of subcutaneous emphysema
- spontaneous pneumothorax
-
How do you investigate a pneumothorax
- CXR
- ECG
- bloods
- CT chest
what do you see in a chest X ray of someone with a pneumothorax
CXR
- Lung edge
- No peripheral lung markings
- Small <2cm
- Large ≥ 2cm (50%)
What is the difference between a small and large pneumothorax
- Small <2cm
- Large ≥ 2cm (50%)
How do you manage pneumothorax
Conservative
- observation
- high flow oxygen
Medical - pleural aspiration - chest drain - suction - medical pleurodesis - can use Tetracycline/doxycycline / Talc to stick the pleural together
Surgical - stick visceral and parietal pleura together
- open thoractomy
- video assisted thoracic surgery (VATS)
what makes up the safe triangle
- lateral edge of pec major
- base of axilla
- 5th intercostal space (go in above a rib)
- lateral edge of lat doors
describe the management of a primary pneumothorax
- Primary pneumothorax and less than 2cm discharge and review in OPD in 2-4 weeks
- if primary pneumothorax and greater than 2cm then aspirate with 16-18G cannula, aspirate <2.5L
- if success (rib less than 2cm and breathing improved) then consider discharge
- if not a success chest drain and admit
Describe the management of a secondary pneumothorax
- secondary pneumothorax and less than 2cm, check if the size is 1-2cm
- if no - admit to high flow oxygen and observed for 24 hours
- if yes aspirate with a 16-18G cannula, and aspirate at less than 2.5L
- if this is a success admit, high flow oxygen and observe for 24 hours
- if this isn’t a success, chest drain and admit
Secondary pneumothorax and greater than 2cm and/or breathless
- chest drain and admit
describe how you manage a chest drain
- Underwater seal drainage
- Don’t lift bottle above waist
Retrograde entry of fluid/air into pleural space - Never clamp a bubbling chest drain = TENSION PNEUMOTHORAX
What are the symptoms of a tension pneumothorax
- Severe breathlessness
- Tachycardia
- Pulsus paradoxus
- Distended jugular veins
- Tracheal deviation
- Ipsilateral reduced/absent
breath sounds
describe the pathophysiology of a tension pneumothorax
On inspiration air goes out of the lung into the pleural space (-ve intrathoracic pressure)
- then on expiration air cannot get back into the lung resulting in positive intrathoracic pressure
What are the symptoms of a tension pneumothorax
- One-way valve
- Shift in mediastinum
- Reduced venous return
- Hypotension
- Cardiac arrest
How do you treat a tension pneumothorax
- Don’t wait for CXR
- Needle decompression
- Large bore cannula (14 G)
- Mid clavicular line, 2nd intercostal space
- Hiss of air as you release the tension
where do you put the needle in a tension pneumothorax
- Large bore cannula (14 G)
- Mid clavicular line, 2nd intercostal space
What advice should you give someone who has a pneumothorax
- no diving
- stop smoking
- no aeroplane travel for at least 2-6 weeks
- pregnancy can increase risk of recurrence - monitor closely
- return immediately if any shortness of breath or chest pain recurs
What is the risk of recurrence in a primary pneumothorax
Primary pneumothorax
- 33% to 40% risk of recurrence after first pneumothorax
What is the risk of a recurrence in a secondary pneumothorax
Recurrence 39-47%
what is the mortality for pneumothorax
- 0.62/million per year for women
- 1.26/million per year for men
What is the definition of a pulmonary embolism
Obstruction of pulmonary arterial system due to Thrombi from distant vein
what are the two types of PE
- provoked
- unprovoked
What is a provoked PE
- due to a transient risk factor
- within the last 3 months
- removing this will reduce risk of recurrence
what is an unprovoked PE
- no transient risk factor
- persistent risk factor which is not correctable
- increased risk of recurrence
What is the difference between provoked and unprovoked PE
Provoked
- due to a transient risk factor
- within the last 3 months
- removing this will reduce risk of recurrence
Unprovoked PE
- no transient risk factor
- persistent risk factor which is not correctable
- increased risk of recurrence
describe the pathophysiology of a PE
- 75% thrombi formed in deep venous system of lower limbs and pelvis
- Other sites – upper limbs, cerebral veins, splanchnic veins
- Platelet aggregation around venous valve sinuses
- Clotting cascade activated
What happens to the lung tissue in an PE
- Lung tissue is ventilated but not perfused
- Intra-pulmonary dead space
- Impaired gas exchange - reduced oxygenation
- Lung tissue can infarct
- reduces cross section of pulmonary arterial bed
- increases PA pressure
- decrease in cardiac output as RV tries to overcome the increase in after load
what are non thrombotic emboli
Tumours
- esp prostate & breast
Fat
- long-bone fracture
Amniotic fluid in pregnancy
Sepsis
- tricuspid valve endocarditis : illicit IV drug use
- infected indwelling catheters
- pacemaker wires
Foreign bodies
- Illicit IV drug use
- Vena cava filters
- Endovascular stent components
- Air (during surgery/ trauma)
What are the major risk factors for a VTE
DVT
- >30% have PE
Previous VTE
Significant immobility
- Inpatient/ bedrest
Surgery (within 2 months)
- Orthopaedic highest
Malignancy
- 4x higher risk
- highest - brain cancer
Pregnancy
- especially 6 weeks post party
Lower limb trauma/fracture
What are some other risk factors
- > 60 years old
Oral contraception/ HRT
- Within last 6 weeks – 3 months
Significant comorbidity
- Including acute infection/ inflammation
Long distance sedentary
travel
Varicose veins
Superficial venous thrombosis
Known thrombophilias
describe THROMBOSIS risk factor analogy
- Travel
- Hypercoaguable/HRT
- Recreational drugs
- Old (>60)
- Malignancy
- Birth control pill
- Obesity/obstetrics
- Surgery/smoking
- Immobilization
- Sickness (CHF/MI, IBD, nephrotic syndrome, vasculitis
What is the clinical symptoms of a PE (non massive)
- May be asymptomatic
- SOB
- pleuritic chest pain
- Haemoptysis = may be delayed by 3 days or more
What are the clinical signs of a PE (non massive)
- Tachypnoea (85%)
- Low grade fever (40%)
- Sinus tachycardia (30%)/new AF
- Hypoxia
- Localised pleural rub
- DVT
- hypotension
- raised JVP
- pleural effusion
what is the clinical presentation of a massive PE
Hypotension, collapse, cardiac arrest, sudden death
Hypoxia
Acute right heart strain
- loud P2, splitting of 2nd heart sounds, gallop rhythm, tricuspid regurgitation
Right heart failure
- Low cardiac output, raised JVP, low blood pressure
How do you diagnose a PE
- History and examination
- Pre-test probability scoring
- CXR (usually normal)
- ECG (usually sinus tachy)
- Bloods (+/- D dimer)
- Arterial blood gases (20% of PE normal PaO2)
- Computed tomographic pulmonary angiography
- Ventilation:Perfusion scan
- Echo
what is the gold standard for diagnosis for a PE
- Computed tomographic pulmonary angiography
- greater than 95% sensitivity
What is the differential diagnosis for PE
Respiratory
- Pneumothorax
- Pneumonia
- Acute exacerbation of respiratory disease
Cardiovascular
- Acute coronary syndrome/ MI
- Pericarditis
- Aortic dissection/aneurysm rupture
- Cardiac tamponade
Other causes of collapse
- arrhythmia
- seizures
- syncope
Others
- musculoskeletal pain - chest wall tenderness in 20% of people with PE
- GORD
- panic attack
Who should you admit immediately if suspected PE
Admit immediately if suspected PE and:
Haemodynamically unstable
+/-
Pregnant
- Fatal in almost 15%
- 66% of these will die within 30 minutes of the embolic event
- No evidence for using Well’s score in pregnancy
- D-dimer – false positive
what makes up the wells score
- Clinical DVT = 3
- PE is number 1 diagnosis of equally likely = 3
- heart rate is greater than 100 = 1.5
- immobilisation for 3 days or surgery in the last 4 weeks = 1.5
- previous PE/DVT = 1.5
- haemopytsis = 1
- malignancy with treatment within 6 months or palliative = 1
What should you do once you have calculated the wells score
If the score is greater than 4
- CPTA – if there is a delay in getting CPTA then interim anticoagulation should be given
- Anticoagulation is given such as a DOAC if CPTA positive – either apixaban or rivaroxaban if these are not suitable then wither LMWH followed by dabigatran or edoxaban or LMWH followed by vitamin K antagonists
- If CPTA negative then consider a proximal leg vein ultrasound scan if DVT suspect
If the score is less than 4
- D dimer
- If D dimer is negative look for alterative diagnose s
- If D dimer positive – CPTA and anticoagulation
What does a CXR look like in a PE
- Usually normal
Possible signs of - pulmonary hypertension (enlarged pulmonary vessels)
- pleural effusions
Westermark’s sign
- focal peripheral hyper lucency secondary to oligaemia
- central pulmonary vessels may be dilated
- Wedge shaped infarcts
What is westermark’s sign
Left mid/upper zone regional lucency with truncation of normal left-sided pulmonary markings. Bilateral pleural effusions
What is Hamptons hump
Wedge-shaped infarct
Peripheral wedge of airspace opacity in the right middle zone
What does an ECG look like in PE
- Sinus tachycardia
- New AF
- RBBB
- Peaked T waves
- R ventricular strain – ant T wave inversion
- S1Q3T3 = but rare
- could be normal
when should you do imaging for PE
Imaging within 1 hour (massive), 24 hours (non-massive)
when should V/Q scanning be used for PE
Only used if :
- Normal CXR
- No concurrent symptomatic cardiovascular disease
- Used in renal impairment as this does not require the use of contrast unlike CTPA
What should you do if you suspect PE in pregnancy
- Well’s score and D-dimer unhelpful
- Start LMWH
- CXR (with lead protection for foetus)
- ECG
- Bilateral leg ultrasounds – if positive, treat
- VQ – lower risk for breast cancer(when pregnant, increased risk from radiation) BUT higher risk of childhood cancer (absolute risk minimal)
- But CTPA more definitive
- Warfarin contraindicated in pregnancy, but safe with breastfeeding
- Novel oral anticoagulants can be considered
- Continue antcoagulation for at least 6 weeks postnatally (at least 3 months total)
When should you use an echo to diagnose a PE
- In massive PEs - used when it is unsafe to proceed to CT
- Bedside Echo - right ventricular pressure raised
What is the medical management of PE
Anticoagulation
- Heparin
- Oral anticoagulant
Thrombolysis
- Massive PE, haemodynamic instability
what is the invasive treatment for a massive PE
- Embolectomy
- Mechanical fragmentation with R heart angiography
- Pulmonary thrombo-
endarterectomy
chronic PE’s unresolved after 3 months - Inferior vena cava filter
What should you do if you have a suspected non massive PE (management)
Low molecular weight heparin (LMWH) OR fondaparinux OR unfractionated heparin (UFH) - Incr bleeding risk - Regular blood tests - Rapid reversal possible - More rapid anticoagulation
What should you do if you have a confirmed non massive PE which is haemodynamically stable
UFH/LMWH/fondaparinux lead in + Warfarin - Target INR 2-3 - then stop heparin OR Direct oral anticoagulant with or without LMWH lead-in
How long should you use oral anticoagulation for
Provoked Reversible
- 3 months - orthopaedic surgery, trauma, CVC line
- 3-12 months - OCP, Flights, HRT, immobility, pregnancy
Provoked irreversible/unprovoked/recurrent
- indefinite
what is an inferior vena cava filter
- used if you cannot use anticoagulation in proximal PE/DVT
- recurrent VTE despite anticoagulation despite alternatives (LMWH or higher INR target)
- temporary
What should you consider with an unprovoked PE
CONSIDER CANCER
What investigations should you use to look for cancer after an unprovoked PE
- History and examination
- Bloods – incl calcium, FBC, - LFT
- CXR
- Urinalysis
- If > 40 ? abdo-pelvic CT + mammogram
- +/- antiphospholipid testing
- Thrombophilia testing (first-degree relative with VTE)
What is the prognosis of a massive PE
20% mortality following treatment (18-65% overall)
What is the prognosis of a non massive PE
Death rate <5% in first 3-6 months
30% of people with VTE have recurrence within 10 years
what do you use to thrombolyse a massive PE
- when haemodynamically unstable you should thrombolyse for massive PE
- alteplase 10mg IV over 1 minute then 90mg IV over 2 hours
When do you thrombolyse in PE
- Thrombolysis is now recommended as the first line treatment for massive PE when there is circulatory failure (e.g. hypotension)
