Shock Flashcards

1
Q

Types of shock

A
Hypovolemic
Cardiogenic
Mechanical
Septic
Anaphylactic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Definition of shock

A

Acute circulatory failure resulting in inadequate tissue perfusion and insufficient oxygen supply to the cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Causes of hypovolemic shock

A

External blood loss
Hidden blood loss (intrathoracic/intrabdominal)

Others:
Diarrhoea and Vomiting
Oedema
Cutaneous (burns)
Polyuria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Changes in the circulatiory system due to hypovolemic shock

A

Loss of circulating volume
Reduced venous return and cardiac fillinf

Therefore reduced SVand reduced CO

This reduces BP and oxygen delivery

Impaired cellular function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Neuroendocrine response to hypovolemic shock

A

Reduced blood volume and blood pressure reduces stretch of aortic and carotid baroreceptors, reduced blood flow to chemoreceptors.

Causes reflex increase in sympathetic tone and reduces parasympathetic input.

Results in increased heart rate (tachycardia)
Release of catecholamines from adrenals
Vasoconstriction (increased TPR to maintain bp, increased cardiac filling)

Activation of RAAS to incerase water retention

Produces increase in cardiac output and SVR. Blood flow re-distributed to vital organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Clinical features of hypovolemic shock

A

Skin: cold, clammy, pale, slow capillary refill

Circulation: tachycardia, initially reduced pulse pressure (systolic maintained, diastolic rises), collapsed veins (severe)

Brain: confusion, restlessness, loss of consciousness

Respiration: tachypnoea

Altered brain and kidney function most significant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the metabolic changes that occur in hypovolemic shock

A

Increased anaerobic metabolism: Lactate and H+ production causing metabolic acidosis

Hyperglycaemia - glucagon and cortisol released in stress response

Lack of O2 reduces ATP production, leads to failure of Na/K+ pump. Cell swelling, release of K+, activation of lysomal enzymes, Ca2+ entery and cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Management of hypovolemic shock

A

High flow oxygen
Replacement of circulating volume (until bp is restored to normal limits)
Diagnosis and treatment of cause

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Causes of cardiogenic shock

A
Acute MI
Heart failure (more common)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Clinical features of cardiogenic shock

A

Reduced contractility due to ischemia and infarction of the myocardium.

Low CO and high LVEDV

Results in pulmonary congestion - dyspnoea, crackles and wheeze, pulmonary oedema, pleural effusion

Eventually leads to RH failure - raised JVP, peripheral oedema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Management of cardiogenic shock

A

Diagnosis - from history (IHD, chest pain), ECG, troponin

Treat with thrombolytics, angiography (stenting), high flow oxygen, analgesia, diuretics, IV fluids if necessary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Causes of mechanical shock

A

Pulmonary embolism
Tension pneumothorax
Cardiac tamponade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Pulmonary embolism

A

A mass in the pulmonary vessels that travels from a distant site and causes obstruction of blood flow.

Causes acute overloading of the right ventricle and hypovolemia of the LA and LV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Diagnosis and treatment of PE

A

Pulmonary angiography
(V/Q scan, ECG)

Full resuscitation, anticoagulants, thrombolysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Clinical presentation of PE

A

Crushing central chest pain
Dyspnoea
High venous pressure
Increased SVR

(DVT may be present)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Tension pneumothorax

A

Abnormal collection of air in the pleural cavity that is markedly increased when a one-way valve is formed by an area of damaged tissue.

Increasing pressure collapses teh lung and pushes the mediastinum and heart to the other side.

Impairs respiration and circulation (raised intrathoracic pressure and deviated great vessels prevent cardiac filling)

17
Q

Presentation of pneumothorax

A

hypoxia, hypercarbia, respiratory distress, hypotension and tachycardia

Examination shows poor chest expansion, mediastinal shift away from the side of the pneumothorax (deviated trachea, displaced apex beat) and a hyperresonant thorax

18
Q

Treatment of tension pneumothorax

A

Immediate decompression and chest drain.

Tube inserted 2nd intercostal space, midclavicular line

19
Q

Cardiac tamponade

A

Compression of the heart due to fluid accumulation in the pericardium. Compresses the heart.

20
Q

Treatment of cardiac tamponade

A

Sub-xiphoid pericardiocentesis

21
Q

Physiology of septic shock

A

Inflammatory mediators released in severe sepsis cause vasodilation, intravascular coagulation and loss of circulating volume through leaky capillaries

Blood pools in dilated peripheries, reducing venous return and CO.

Blood pressure is reduced (diastolic pressure falls, wider pulse pressure)

22
Q

Clinical features of septic shock

A

Early: Vasodilation causes warm peripheries, low venous pressure (hypotension). bounding pulse, rapid capillary refill, (fever)

Late: cold peripheries, tachycardia, sweating

23
Q

Mangement of septic shock

A

Sepsis 6

Oxygenation, fluid resusctation, inotropic agent, vasoconstrictor support

Bacterial cultures
Antibiotics and surgical drainage

24
Q

Anaphylactic shock

A

Anaphylaxis is a serious allergic reaction that is rapid in onset (and may cause death)

Anaphylactic shock is associated with systemic vasodilation and increased capillary permeability that causes hypovolemia and low blood pressure

25
Q

Presentation of anaphylaxis

A

Within 30min exposure…

Erythema, urticaria, oedema, palloe/cyanosis

Tachcardia, hypotension

Rhinitis, bronchospasm, laryngeal obstruction, pulmonary oedema

Vomiting, diarrhoea, cramps

26
Q

Management of anaphylaxis

A

IM adrenaline asap
Fluid resuscitation
CPR
Steroids, antihistamines