Acute Circulatory Failure / Shock Flashcards
What is shock?
Shock is when the body’s CO does not meet the metabolic demands of the body
=> 2 main features:
- Decreased BP
- Decreased tissue perfusion
What are the different types of shock?
- Hypovolemic shock (also known as haemorrhagic shock)
- Cardiogenic shock
- Obstructive shock
- Distributive shock (encompasses septic shock, anaphylactic shock and neurogenic shock)
What is hypovolemic shock and what are the main causes?
- Decreased circulatory volume
- Four main classes (see notes)
- Class IV seen as worst
=> Main causes of circulatory shock:
- Haemorrhage
- Tension Pneumothorax
- Spinal cord injury
- Myocardial Contusion
- Cardiac Tamponade
What are the clinical features of hypovolemic shock?
- Anxiety
- Altered mental state
- Cold, clammy skin
- Hypotension
- Compensatory tachycardia and tachyponea
- Fatigue
- Thirst
- Slow cap refill
What is the management of hypovolemic shock?
=> Volume expanders:
- Whole blood
- Colloidal solutions
- Crystalloid solutions
Once bleeding is controlled and volume restored, Hb should be maintained:
- 7-8 Hb if no risk factors for tissue hypoxia
- 10 if there are risk factors
What is cardiogenic shock and what are the potential causes?
- Occurs when heart is not pumping well, decreasing CO
- Decreased CO leads to low BP and perfusion
=> Causes:
- Ischaemic heart disease (main)
- Myocardial trauma
- Contusion
- MI
- Arrhythmias
- CHF
What are the clinical features of cardiogenic shock?
- Raised JVP
- Pulsus Alternans
- Gallop rhythm
- Pulmonary oedema
- Basal crackles
What are the investigations in suspected cardiogenic shock?
=> ECG
=> Troponin T levels
To see for MI
What is the management of cardiogenic shock?
- Largely supportive
- Transthoracic echocardiography used to determine evidence of pericardial fluid accumulation
- Surgery to repair any defects of heart
What is septic shock?
A type of distributive shock caused by infection that triggers Systemic Inflammatory Response Syndrome
=> Systemic Inflammatory Response Syndrome is characterised by:
- Temp 36-38
- HR > 90bpm
- RR > 20 breaths per min
- WBC > 12,000 OR < 4000
Patients with 2 or more of the SIRS criteria are diagnosed with sepsis
What is the pathophysiology of sepsis?
=> Marked by:
- excessive inflammation
- coagulation
- fibronolytic supression
What are the clinical features of septic shock?
- Pyrexia with rigors
- Warm and sweaty
- Increased levels of neutrophils
What is the management of sepsis?
- Emperical antibiotics
- Haemodynamic stabilisation. Aim for CVP 8-12 cm and MAP > 6 5mmHg
- Tight glycemic control
How can CVP be interpreted?
High = Obstructive shock
Low - Hypovolemic or Distributive shock
What is the general management of shock?
=> Ensure adequate oxygenation and ventilation:
- Maintain airway
- Oxygen via simple facemask
- Non invasive or mechanical ventilation if necessary
- Monitor RR, ABG, CXR
=> Restore CO and BP
- Lay patient flat and head down
- Volume expanders via a large bore cannulae
- In selected cases - ionotropic support, vasodilators
- In all cases, monitor - skin, BP, pulse, urine output, ECG
