Cardiorespiratory Flashcards
If you suspect pulmonary embolism, what treatment should be initiated before the results of investigations come through?
Low molecular weight heparin
OR
DOACs: Apixaban/ Rivaroxaban
What forms of anticoagulation are available in the UK for immediate coagulation?
LMWH
DOACs
Fondaparinux (related to LMWH)
Unfractionated heparin (less commonly used)
What factors influence your choice with different anticoagulants?
Patient preference
Side effects
Ease of use (SC/ IV/ PO)
What blood tests should you take before giving LMWH?
COAG
FBC
You want a baseline coagulation status and to ensure that platelet count is normal.
Why should you check that platelet count is normal before starting heparin?
Risk of heparin induced thrombocytopenia
Why do you need to continue LMWH for at least 5 days after starting a patient on warfarin?
Risk of a further embolism
To ensure that the patient reaches an appropriate therapeutic level of anticoagulation from warfarin which takes longer to start acting.
When is it safe to stop LMWH?
After 5 days, assuming INR has been above 2 for at least 48 hours
Which drugs affect the actions of warfarin?
Simvastatin
What should you tell a patient before they take warfarin?
What the drug is for
Bleeding risk - avoid sports/ actions that would increase chances of this
They should have bloods checked by doctor regularly
If they notice any side effects, see doctor asap.
What treatment would you give to a patient with a high INR?
Oral vitamin K
What advantages do NOACs/DOACs have over warfarin?
More predictable so no monitoring is needed (offsets drug costs)
What advantage does warfarin have over NOACs/DOACs?
More expensive drug cost
It has a reversal agent
(Dabigatran only just got one)
How long should patients with resolved PE be anti coagulated for?
3 months of warfarin
How do simvastatin and clarithromycin interact?
CYP3A4 - clarithromycin is a strong inhibitor
What are common causes of inappropriate ADH syndrome (SIADH?)
Pneumonia
Diuretics (indapamide & spironolactone)
How do you manage hyponatraemia in patients on diuretics?
Stop indamamide
Give IV fluids to correct hypovolemia
What IV fluids are most appropriate to give to patients?
0.9% NaCl
Hartmann’s solution (primarily sodium lactate)
Why are beta-blockers and verapamil contraindicated in combination with each other?
Interaction can cause serious bradycardia
How do you monitor indapamide?
Blood pressure
What alternatives can you provide for verapamil?
Dihydropyridine calcium channel blockers:
Felodipine
Amlodipine
What must you be careful of when swapping verapamil to a dihydropyridine calcium channel blocker?
Watch the dose of simvastatin
What medication would you consider first starting a patient with angina on?
Short acting nitrate
How do beta blockers work?
Stop norepinephrine binding to beta-adrenoreceptors, ultimately reduces PK-A mediated Ca2+ entry into the cell and smooth muscle contraction.
What are the types of nitrodilators?
Two types:
- Release NO spontaneously
- Require an enzymatic process to form NO
How do nitrates work in angina?
Nitric oxide activates guanylyl cyclase (GC) which forms cGMP.
The increased cGMP inhibits Ca2+ entry into the cell -> smooth muscle relaxation.
What are the adverse features of beta-blockers?
Dizziness, fatigue Cold hands Impotence Bronchoconstriction Bradycardia, heart block Masking hypoglycaemia Raynaud's phenomenon
How do calcium channel blockers work?
Bind to L-type calcium channels which would ordinarily facilitate calcium influx into muscle cells and allow for smooth muscle contraction. Blocking them therefore causes relaxation.
What are the adverse features of calcium channel blockers?
Peripheral oedema
Constipation
Headache & flushing
Tachycardia
What are the adverse features of nitrates?
Tolerance - need nitrate free intervals
Postural hypotension
Headache & flushing
Tachycardia