Shock Flashcards
What is shock?
An imbalance between oxygen delivery to the tissues and the oxygen consumption by the tissue,
Types of circulatory shock.
Define hypoperfusion/circulatory shock
Hypovolaemic
cardiogenic
Obstructive
Distributive
A critical condition that is brought on by a sudden and global deficit in tissue perfusion, resulting in inadequate delivery of oxygen and nutrients to vital organs.
What does a reduced blood pressure result in?
How is BP calculated?
How is CO calculated?
What is SV determined by?
Reduced perfusion
Cardiac output (CO) X systemic vascular resistance (SVR)
HR x SV
Pre-load, afterload and the heart’s contractility.
What is hypovolaemic shock?
Shock resulting in decreased blood volume.
Very common.
May be the result of fluid losses or decreased fluid intake.
Fluid losses may be haemorrhagic (int or ext) or non-haemorrhagic (int or ext).
Decreased fluid intake may be due to restricted water access or conditions where animals are unable to swallow/keep water down.
What is cardiogenic shock?
Give examples.
‘Forward or ‘pump’ failure i.e. reduced cardiac output.
- Conditions with decreased systolic function e.g. dilate cardiomyopathy.
- Conditions with diastolic dysfunction e.g. Hypertrophic cardiomyopathy or pericardial tamponade.
- Bradyarrhythmias e.g. AV block
- Tachyarrhythmias e.g. ventricular tachycardia.
Obstructive shock.
Causes.
Due to physical obstructions in blood flow to or from the heart or through the great vessels.
Overlaps with cardiogenic shock.
Causes
- GDV
- Pericardial tamponade
- Tension pneumothorax
- Pulmonary or aortic thromboembolism.
Distributive shock.
Causes.
Shock due to maldistribution of blood flow, usually due to inappropriate and widespread vasodilation.
Causes:
- Histamine release i.e. anaphylaxis.
- Generalised uncontrolled inflammatory responses due to bacterial infection (sepsis) or non-infectious insults e.g. pancreatitis, trauma, burns etc.
How is hypovolaemic shock further classified?
Give defs.
Compensated = the homeostatic mechs are successfully maintaining tissue perfusion.
Decompensated = Compensatory physiological mechs are are failing and the patient is in danger of dying.
Give canine HR ranges for…
1. Normal
2. Mild shock (comp)
3. Moderate shock
4. Severe shock (decomp)
- 60-120
- 130-150
- 150-170
- 170-220
Give canine MM colour ranges for….
1. Normal
2. Mild
3. Moderate
4. Severe
- Pink
- Normal to pinker
- Pale pink
- Pale pink to white
Give canine CRT ranges for……
1. Normal
2. Mild
3. Moderate
4. Severe
- <2
- <1
- 2
- > 2
Give canine pulse quality ranges for….
1. Normal
2. Mild
3. Moderate
4 Severe
- Normal
- Bounding
- Weak
- Very weak
Give canine sys BP ranges for……
1. Normal
2. Mild
3. Moderate
4. Severe
- > 90
- > 90
- > 90
- <90
Give canine mentation for….
1. Normal
2. Mild
3. Moderate
4. Severe
- Normal
- Normal
- Normal-obtunded
4 Obtunded
Give canine lactate conc ranges for…
1. Norm
2. Mild
3. Moderate
4. Severe
- 0.5-2.5
- 3-5
- 5-8
4 >8