Define Shock
- Shock is a clinical syndrome characterised by inadequate supply of O2 meeting its demand.
- Inadequate blood supply to the organs and tissues will result in cellular dysfunction.
Classification of Shock
- Septic shock
- Cardiogenic shock
- Hypovalaemic shock
- Anaphylactic shock
- Neurogenic shock
- Distribution shock
- Obstructive shock
What is the cause of Neurogenic, Anaphylactic and Septic shock?
- Caused by decreased in peripheral resistance
a) Neurogenic shock:
- Inadequate autonomic nerve activity to arterioles.
b) Anaphylactic shock:
- Release of vasodilators by excessive immune responses.
c) Septic shock:
- Presence of vasodilatory bacterial toxins
What is the cause of Hypovalaemic and Cardiogenic shock?
- Caused my decreased cardiac output
a) Hypovalaemic shock: Reduction of blood volume
b) Cardiogenic shock: Failure of the cardiac pump
Simple pathology of Hypovalaemic shock
- Inadequate myocardial contractility
- Sympathetic overactivity causes vasoconstriction in order to maintain the blood pressure
- BP remains normal however organs are poorly perfused due to decreased blood volume.
Simple pathology of Cardiogenic shock
- Poor myocardial contractility
- Increased venous pressure results in fluid to shift out of the vascular compartment causing oedema.
- SNS overactivity causes vasoconstriction in order to maintain BP
- BP remains high or normal however organs are poorly perfused.
Simple pathology of Distributive shock
- With adequate fluid replacement, heart compensates by increasing HR.
- Vessels dilate resulting in SVR (systemic vascular resistance)
- Capillaries continue to leak fluid; worsens hypovalaemia causes oedema (pulmonary oedema)
- Changes in BP and organ perfusion
Simple pathology of Obstructive shock
- Myocardial contracts against high after-load
- Back pressure leads of venous congestion.
- SNS over activity causes vasoconstriction in order to maintain BP
- BP remains normal however organs are poorly perfused.
Factors that induce Triad of death in shock
- Hypovalaemia
- Coagulopathy
- Hyper-perfusion metabolic acidosis
Paediactic shock
- Acute illness demands increased CO(HRxSV)
- Infants have a fixed SV; dependant on increased (CO/HR)
- Myocardial compliance decreases affecting the preload to increase SV
- loss of >25% fluid circulation volume -> signs of shock
Signs/symptoms of Paediatric Shock
- Tachycardia
- Tachypnoea (rapid breathing)
- Vasoconstriction
- Decreased consciousness
- Pallor & mottled peripheries (delayed capillary refills)
- Hypotension
Signs/symptoms of shock in Elderly
- Shock progress is rapid
- Reduced compensatory mechanisms in place
- Predisposed hypothermia
- Co- morbidities present
What are principals of shock management?
- ABC
- Oxygenation
- Fluid resuscitation
- Medications
- Symptom support
- Surgery
What are your intra-collaborative care?
- FBE: Hb, Hemocrit, WCC
- ABGs: O2, CO2, PH: 7.4
- U&E: Renal function
- F&E: glucose, Na, K, lactate lvls: metabolic acidosis.
5 Cardiac enzymes: CK, troponin, LH, CKMB
What are your airway management care?
- Ensure, clear & patent
Simple -> Advanced measures
- High flow O2 Mask
- Intubation
- Circothyrotomy
What are your breathing management care?
- Maintain & assess breathing
- Remove the obstruction
- High- flow O2
- Intubated: CPAP;
SpO2: >93%
O2 >60
What are your circulation management care?
- Positioning
- 2 large bore IVC/ CVC
- Bloods; Lactate lvls
- 12 lead ECG
- ABGs
- Vitals
- Intubated: ETCO2
Assess/control: Bleeding
Assess/control: Internal bleeding
Altering cardiac output
Preload: Fluid-loading &resuscitation
Afterload: Vasoconstriction/vasodilation
Contractility: Medications
Fluid loading
- Recom. 2/3 Cystalloid- 1/3-1/5 Colloid (10-20mls/kgs x2)
2. Hb & haemocrit are decreased after fluid loading
What are the differences with crystalloids vs colloids?
- Crystalloids:
a) Synthetic (Hartmans, 4% Dextrose, NS)
b) Inexpensive
c) No allergic reactions - Colloids: Blood expanders
a) 20x more expensive
b) Improves CO, O2 consumption/delievery
c) Increases allergic reactions
Why are blood replacements used?
- RBC needed for O2 carrying capacity
2. Platelet for homeostatic & coagulation properties
What are your blood replacement considerations?
- Need to be typed and crossed matched
- Time limited use O negative
- > 2units of blood need to be warmed
- Lines should be primed with NS or blood
- Must be used 4hrs after removal from fridge
Guide to fluid replacement
- Volume replacement with crystalloids
- 3mls for every 1ml lost - Fluid challenges/options:
- Bolus 20mls/kg 4% & 1/5 NS in children
- IV bolus 200-300mls Hartmans/NS in adults (medical & surgical) - Volume replacement for measured losses; (GIT loss 1ml for each ml lost every 4hrs)
- Volume replacement with colloids:
1ml for every 1ml lost
How would you minimise O2 consumption?
- WOB/Shivering
- Reduce cardiac work
- Neural Stress Response
- Treatment of Sepsis
