EM - Shock Flashcards
Define shock
Global tissue hypoperfusion resulting in inadequate oxygen delivery to meet metabolic demands and metabolic acidosis
Describe the autonomic response to maintain oxygen delivery and cardiac output during shock/ inadequate systemic oxygen delivery
- Vasoconstriction to cutaneous, muscle and visceral circulation protects the heart, kidneys and brain
- Pre-load is increased by venous vasoconstriction, this utilises starlings law to increase stroke volume
- Increased HR, water and sodium retention and increases in blood volume and pressure
What happens to pulse pressure and BP?
Pulse pressure will initially decrease due to this autonomic activation increasing peripheral vascular resistance
Hypotension will follow when the compensatory mechanisms begin to fail
What happens at the cellular level during shock?
ATP depletion (when oxygen supply is removed) which leads to a loss of ion pump activity and resultant cellular oedema that can lead to hydrolysis
The endothelial inflammation and disruption from hypoxia results in lactic acidosis, cardiovascular insufficiency and increased metabolic demands
What is the common physiological progression in shock?
Cardiac depression, respiratory distress, renal failure, DIC and organ failure
What are they types of shock?
Inadequate cardiac output:
- Hypovolaemia (through blood or fluid loss)
- Cardiogenic shock (pump failure or obstruction)
Peripheral circulation failure (leading to loss of systemic vascular resistance):
- Sepsis
- Anaphylaxis
- Neurogenic
Can you multiple causes of shock co-exist in the same patient?
Yes
What should be asked in the history in a case of shock?
- Recent illness or fever
- CP, abdo pain, SOB
- Comorbidities and medications
- Ingestion of any toxins
- Recent hospitalisation or surgery
What would BP and urine output be in shock?
Hypotension (less than 90 systolic or less than 65 MAP in severe cases)
Reduced urine output (to less than 0.5ml/kg/hr)
At what level of systolic BP does the post tibial pulse disappear?
less than 90
At what level of systolic BP does the radial pulse disappear?
less than 80
At what level of systolic BP does the femoral pulse disappear?
less than 70
At what level of systolic BP does the carotid pulse disappear?
less than 60
What does low diastolic pressure suggest the cause of shock is?
It suggests arterial vasodilation e.g. septic or anaphylactic shock
What does narrowed pulse pressure suggest the cause of shock is?
It suggests arterial vasoconstriction e.g. cardiogenic or hypovolaemic
How would you manage A and B (of an A to E assessment) in shock?
Ensure the airway is patent
shocked patients will be SOB
- give O2 through non- rebreathe
- Monitor SpO2
- Perform breathing assessment as normal, correcting as required e.g. tension pneumothorax causing cardiogenic shock
- Perform ABG (lactate will usually be more than 2)
How would you manage C (of an A to E assessment) in shock?
- Assess HR, CRT and BP
- Lie patient flat and elevate their legs
- Gain IV access using two large bore cannulae
Take bloods: FBC, U&Es, LFTs, coagulation studies, G&S, crossmatch, cultures
Give IV fluids (500ml bolus then high rate infusion when BP improves)
- ECG
- Catheter to monitor urine output
When BP improves after initial IV boluses how do you give fluid?
Switch from boluses to a high rate infusion
titrated to keep HR more than 100, SBP more than 90
If 2 fluid boluses fail to improve BP what do you do?
Refer to ITU
What do you specifically look for in shock during D (of an A to E assessment)?
That the patient is sufficiently able to maintain their airway
Spinal shock
What do you specifically look for in shock during E (of an A to E assessment)?
Look for further signs of infection and haemorrhage
Assess fluid balance
Name the type of shock:
Patient is warm and well perfused with a bounding pulse
Septic shock
Name the type of shock:
Patient has a raised JVP, pulmonary and peripheral oedema
Cardiogenic shock
Name the type of shock:
Patient is flushed and warm, with additional signs including urticaria, stridor, wheeze and swelling
Anaphylactic shock
Name the type of shock:
Patient is pale and cool to touch
Hypovolaemic shock
What may be required before ventilation in a patient with shock?
Volume resuscitation
As propofol will further decrease BP
What other treatments can you give to help with oxygen consumption?
Analgesia and anxiolytics
to relax muscles and avoid shivering