[A] 1.19 Hemostasis, shock Flashcards
1
Q
Haemostasis
A
Arrest of bleeding
- Finely regulated physiological response
2
Q
Purpose of physiological haemostasis
A
- Respond to vascular damage → Prevent blood loss
- Without affecting fluidity and flow of blood in normal, undamaged vasculature
3
Q
Disruption of the balance of:
- Endothelium
- Platelets
- Coagulation factors
A
- Haemorrhage
- Thrombosis
4
Q
Give the steps of haemostasis
A
- Primary stage
- Secondary stage
- Thrombus dissolution
- Tissue repair at the damaged site
5
Q
Haemostasis: Primary stage
A
- Transient vasoconstriction
- Platelet aggregation to form platelet plug
6
Q
Haemostasis: Secondary stage
A
- Coagulation to form a meshwork of fibrin
- Intrinsic (XII activation)
- Extrinsic (TF - VII activation)
- Common pathway activation of X
- Fibrin activation
7
Q
Haemostasis: Thrombus dissolution
A
- Thrombus retraction by plasmin
- Fibrinolysis
8
Q
List the disturbances of microcirculation
A
- Prehaemostasis
- Haemostasis
- Posthaemostasis
- Peristasis
9
Q
Praehaemostasis
A
Blood flow slows down
10
Q
Haemostasis of microcirculation
A
- In terminal bed
- Leakage
- Reversible
11
Q
Posthemostasis
A
Start of the blood flow
12
Q
Peristasis
A
Slow bloodflow
13
Q
What can induce haemostasis?
A
- Cellular changes
- Viscosity
- Chemical factor
- Rheological factors
14
Q
Cellular changes inducing haemostasis
A
- Stabile suspension - labile suspension
- Thrombocytes, RBCs, WBCs
15
Q
Viscosity changes inducing haemostasis
A
- Plasma leakage
- Higher density
16
Q
Chemical factors inducing haemostasis
A
- Intercellular bridges
- Hypercoagulability
17
Q
Shock
A
- General circulatory disturbance
- Peripheral circulatory failure
- Clinical term
- Blood is in the terminal circulatory bed
18
Q
Mild shock
A
Can lead to collapse
- Mild disorder for a short time
19
Q
Define shock
A
Cardiovascular collapse
- The syndrome resulting from a disproportion between blood volume and volume of the circulatory system (1:6)
- Profound circulatory failure resulting in life-threatening hypoperfusion of vital organs
20
Q
Give the types of shock
A
- Cardiogenic
- Hypovolaemic
- Blood maldistribution
21
Q
Cardiogenic shock
A
Acute/chronic heart failure
22
Q
Hypovolaemic shock
A
- Blood loss
- Reduced circulating blood volume
- Fluid loss
- Secondary to vomiting, diarrhoea, burn
23
Q
Blood maldistribution shock
A
- Neurogenic
- Vasodilation - paralysis of the vasomotor centre
- Anaphylactic - Type I hypersensitivity reaction
- Septic (endotoxin)
24
Q
Septic shock: Causes
A
- Gr- lipopolysaccharide
- Gr+ fungi
- Cytokines
- Vasoactive mediators
25
Give the steps of septic shock cause
1. LPS blocks production of anticoagulant substances
2. Activation of the complement cascade
3. Activation of the intrinsic coagulation
4. TNFα & IL-1 production by activated macrophages
5. Promotion of extrinsic coagulation by TF expression
6. PAF - Thrombocyte aggregation
26
Give the phases of shock
1. **Non-progressive**
2. **Progressive**
3. **Irreversible**
27
Non-progressive phase of shock
* Compensation
* Baroreceptors
* Sympathetic effect, epinephrine
* ↑ Cardiac output, ↑ peripheral resistance (vasoconstriction)
* ADH
* Renin-angiotensin-aldosterone system
* ACE-blockers
28
Progressive phase of shock
* Inadequate compensation
* Anaerobic glycolysis in the cells (lack of O2)
* Lactate, local hypoxia, ↑ CO2 → Arteriolar relaxation & dilation
29
Irreversible phase of shock
* Severe metabolic acidosis
* Insufficient blood supply of the vital organs, DIC
30
Shock: Pathological signs
* Haemorrhages:
* Under the serosal membranes
* On mucous membranes
* In some organs
* Congestion in the abdominal organs
* Acute dilation of the heart
* Ischemia in the kidney
