Shock

Question 1

Shock

Answer 1

• Syndrome of decreased tissue perfusion and impaired cellular metabolism, switch to anaerobic
• Leads to O2 and nutrient demand that exceeds supply

Question 2

Types of shock

+ causes

Answer 2

Cardiogenic: cardiac dysfuntion decreases pumping & CO (MI, HTN, arrythmias)
Hypovolaemia: intravascular fluid loss, can be absolute (haem, diarrhoea), or relative (third spacing, burns, bowel obstruction, fracture)
Distributive: systemic peripheral vasodilation
* Neurogenic: spinal cord injury, severe pain
* Anaphylaxis
* Septic

Question 3

Pathophysiology

Answer 3

Cardiogenic: systolic dysfuntion, decreased SV and CO, increase pul pressure, oedema, reduced oxygenation, reduced tissue perfusion
Hypovolaemic: low blood volume, venous return, CO, SV, reduced O2 supply and tissue perfusion
Neurogenic - SC: loss of sympathetic tone & vasodilation, low venous return, SV, CO, HR
**Neurogenic - anaphylaxis: ** massive vasoD and increase in permeability, fluid leakage, respiratory distress due to oedema
Neurogenic - sepsis: microorganism triggers pro-inflammatory cytokines causing endothelial damage, peripheral vasoD, increased permeability, low BV, low O2, hypoperfusion

Question 4

Stages of shock

Answer 4

Compensatory: SNS attemp to restore homeostasis (increase in HR, peripheral vasoC, increase in CO, RAAS activation, ADH release)
* HoTN, tachy, tachypnoea, pale skin, low urine output

Progressive: above fails, and Na/K pumps fail, cells swell and rupture, decrease BV, SV and CO, lactic acidosis
* sev symptoms of above, oedema, MI, reduced consciousness, ARDS, GI bleeding, jaundice

Refractory : unresponsive to therapy, multiple organ dysfunction syndrome (MODS) that is irreversible, required critical care
* unconscious, severe HoTN, resp failure, anuria, hypothermia, cyanosis

Question 5

Diagnostic Tests

Answer 5

Cardiogenic: cardiac markers (troponin, CK-MB), ECG, XR, BUN & glucose
Hypovolaemic: low Hb and haematocrit, high lactate, high USG
Anaphylactic: sudden allergy onset
Septic: low WBC & platelets, positive blood culture, high lactate and glucose

Question 6

Emergency management

Answer 6

• ABC, patent airway, highflow supp O2
• Maintain sat above 90
• IV fluid resus
• Blood cultures, antibiotic therapy
• 12 lead ECG
• Assess LOC, vitals, resp, urine output

Question 7

Fluid therapy

Answer 7

Crystalloids: isotonic (0.9% saline, Hartmanns - primary initial volume replacement) & hypertonic (for expansion in hypovolaemic)
Blood: for blood loss, loss of O2 & coag factors
Colloids: serum albumin (osmotic expansion in all but cardiogenic & neurogenic), dextran (glucose osmotic expansion - limited)

Question 8

Medication therapy

Answer 8

• Sympathomimetic drugs that mimic SNS by binding to alpha and beta adrenergic receptors, & cause peripheral vasocontriction (vasopressors)
• Dobutamine, dopamine, adrenaline, noradrenaline, phenylephrine, glyceryl trinitrate, hydrocortisone, vassopressin

Question 9

Systemic inflammatory response syndrome (SIRS)

Answer 9

• Exagerrated systemic inflammatory response to noxious insult (infection, ischaemia, infarction, injury)
• Generalised inflammation in multiple organs

Question 10

Multiple organ dysfunction syndrome (MODS)

Answer 10

• Failure of two or more organ system that began with SIRS
• Homeostasis cannot be restored without intervention