Circulation Part 1 Flashcards
Define ‘shock’.
Shock is an acute circulatory failure with inadequate tissue perfusion leading to cellular hypoxia, dysfunction and failure of major organ systems.
Explain the pathophysiology of cardiogenic shock.
Heart failure to contract and pump blood
effectively, leading to decreased CO, afterload
and MAP – leading to reduced perfusion
Explain the pathophysiology of hypovolaemic shock.
Reduction in blood volume leads to a
decrease in MAP that causing a lack of perfusion to tissues
Explain the pathophysiology of distributive shock.
Systemic vasodilation causes a decrease in
MAP (after initial decompensation from increased CO) leading to a lack of perfusion to tissues
Explain the pathophysiology of obstructive shock.
Cardiac function impaired by non-cardiac factors, leading to decreased CO, afterload and MAP – leading to reduced perfusion
List causes of cardiogenic shock.
MI
Myocardial contusion
Heart failure
Arrhythmias
List causes of hypovolaemic shock.
Haemorrhage
Vomiting
Diarrhoea
Burns
Pancreatitis
List causes of distributive shock.
Anaphylaxis
Sepsis
Neurogenic
List causes of obstructive shock.
PE
Cardiac tamponade
Tension pneumothorax
Explain management of cardiogenic shock.
ABCDE followed by:
Echocardiology + serum BNP, troponins
If acute STEMI: Perform Primary PCI if it can be delivered within 120 minutes of the time when fibrinolysis could have been given; otherwise, fibrinolysis e.g. 50mg alteplase
Explain management of hypovolaemic shock.
ABCDE + group & cross-match
Fluid replacement (If hemorrhage, try to stem and elevate legs – consider O- blood transfusion ) Find source of fluid loss and treat
Explain management of distributive shock.
ABCDE followed by:
Sepsis 6:
3 in: O2 therapy, IV fluids, ABx (After culture)
3 out: Blood culture, ABG (for lactate), Urine (via catheter)
Then assess procalcitonin level
Neurogenic: Dopamine, Vasopressin, ephedrine, atropine (increase damaged sympathetic system activity)
Anaphylaxis: O2 therapy, IV Fluids (20 mL/kg in a child or 500-1000 mL in an adult), 0.5mg IM (1:1000) adrenaline (in those >12 years), repeat dose at 5-minute intervals according to response; if airway compromised called anesthetics.
After initial resus: chlorphenamine 10mg IM, Hydrocortisone 200mg IM (Both in >12 years)
Explain management of obstructive shock.
ABCDE followed by:
PE: Anticoagulation with LMWH e.g enoxaparin at 1.5mg/kg/24h by s/c inj then oral warfarin (10mg) aiming for INR of
2-3 for 3 months after PE and lifelong if recurrent
o Caval Filter if anticoag contraindicated/recurrent PE
o Major embolism may require: ICU, Pulmonary thrombectomy, Thrombolysis (50mg alteplase)
Cardiac Tamponade: Emergency subxiphoid pericardiocentesis performed under guidance by ECHO (eeserve sample for culture)
Tension pneumothorax: If suspected, attempt to aspirate before CXR, use a large bore needle with syringe,
filled with saline, to act as a water seal – followed by thoracostomy with chest drain
Explain briefly the management of acute MI.
ABCDE
- Diamorphine 5-10 mg IV / Metoclopramide 10 mg IV
- Low flow O2 if SpO2 <94% (evidence worsens myocardial ischaemia if SpO2 within normal limits)
- GTN - 2 puffs
- Aspirin 300 mg PO
- Ticagrelor 180 mg (or clopidogrel depending on Trust local policy)
- Primary PCI if available within 120 mins
- If not, candidate for fibrinolysis
Briefly explain the management of anaphylaxis (>12 years old).
ABCDE followed by:
- Lie flat and raise legs (physiological fluid bolus)
- 0.5 mg IM 1:1000 adrenaline; repeat after 5 minutes
- O2 therapy/IV fluids 500-1000 mL bolus
- After initial resus: chlorphenamine 10 mg IM + hydrocortisone 200 mg IV
