Hemorrhage and Haemodynamics Flashcards
What is haemodynamic?
- The physiology of blood flow and the forces involved in circulation
How is Haemodynamic measured?
- HR, BP, perfusion
What is the two-part process of perfusion?
- Oxygen and nutrients go in and waste comes out
What is oxygenation?
- Oxygen reaching a tissue or cell
What three components of the body need to be functional and working adequately for the body to perfuse?
- Lungs, heart and Vessels
Lung Perfusion
- Adequate O2 reaching alveoli
- Adequate oxygenation and ability to diffuse across the alveoli membrane
What are all vasculature lined with?
- Smooth endothelial cells
What mechanisms are a feature of vessels bigger than capillaries?
- They have elastic layers, tunicae, these regulate pressure
What determines the nature of flow through the body?
- The difference in pressure at two ends of a vessel.
Define Haemorrhage.
- Disruption or leakage from the circulatory system, it can be broken down into three subtypes. o External o Internal (concealed) Bleeding into tissue or organs, but not visible o Internal (revealed) Becomes visible through passage or orophas of the body.
What types of external haemorrhage may occur?
- Arterial
o Will be seen as pulses, and spurts of bright red blood, denoting that it is oxygenated - Venous
o Will be a steady flow from the wound and will present with a dark red colour, denoting that it is deoxygenated. - Capillary
o Small volume of blood and will ooze out
What determines how serious a haemorrhage is?
the amount of the vasculature is disrupted and the amount of blood loss.
What body cavity will an internal haemorrhage from illness, disease or rupture tend to occur in?
- Chest
- Abdomen
- Pelvis
- Retroperitoneal
- Skull
What is the natural control of bleeding?
- Haemostasis, the prevention of blood loss.
What are platelets function in the clotting mechanism?
- Forming a temporary plug that helps seal breaks or ruptures that have occurred in blood vessels.
What is the clotting process?
- A injury occurs, LAC, Blunt injury etc.
- Vascular spasm occurs
o This is to reduce the level of blood lost through the hole - Platelet plug formation
o Clotting cascade occurs - Blood coagulation
o The formation of scabs and scars
Platelet plug formation
- Platelets adhere to the collagen under the epithelium
- Platelets become enlarge and irregular
- Platelets become sticky and attracts other platelets forming a temporary plug
Blood coagulation
- Blood coagulation is a complex process, it not only involves platelets but also substances that secrete vessel walls and blood proteins that initiate clotting.
What pathways are involved in the clotting process?
- Extrinsic and intrinsic pathways
Explain the Extrinsic pathway
- The extrinsic pathway takes effect within seconds of damage occurring.
- It is initiated with liquid blood contacting damaged tissue.
- It starts with damage to the vessel wall and surrounding tissue
Explain the Intrinsic pathway
- The intrinsic process is initiated by liquid blood contacting a foreign surface, i.e. something that is not a part of the body, occurs minutes after the wound has occurred.
What are the stages of the common pathway?
- Stage one o Formation of prothrombin activator - Stage two o Conversion of prothrombin - Stage three o Conversion of soluble fibrinogen
How does the formation of Pro thrombin activator occur?
- The process occurs differently in the intrinsic and extrinsic pathways.
- Involves the activation of 4 other factors.
What is factor 1?
- Fibrinogen
What is factor 2>
- Prothrombin
What is Factor 3?
- Tissue thromboplastin
What is Factor 4?
- Calcium
What is Factor 5?
- Proaccelerin labile factor: AC-globulin
What is factor 8?
- Antihemophilic factor
- Antihemophilic Factor A
What is Factor 10?
- Stuart Factor, Stuart-power factor.
How does clot retraction and Dissolution work?
- As the cloth retracts, it pulls the edges of the broken blood vessel together, opening the blood vessel and increasing the blood flow.
What is Fibrinolysis?
- The break down of the clot so that the vessels don’t become blocked.
o Occurs through the breakdown of fibrin.
What forms of drugs have an effect on clotting?
- Platelet inhibitors
o Aspirin – Stops production of thromboxane A, required in platelet plug formation.
Prevents the clot growing larger. - Anticoagulants
o Warfarin – Interferes with Vitamin K dependent clotting factors, for example, prothrombin (factor 2). - Streptokinase – convert plasminogen into active plasmin
o Clot dissolving
What patient pathologies may affect the clotting process?
- Excessive bleeding.
- Liver disease
o Preventing the synthesis of clotting factors - Vitamin K deficiency
o Required for clotting factor synthesis - Haemophilia
o Commonly due to deficiency of factor VIII (Antihemophilic factor), Haemophilia A - Thrombocytopenia
o Abnormally low levels of circulating platelets - Von Willebrand’s disease
o Compound defect involving both platelet function and clotting factor deficiency. - Thromboembolic conditions
o Unwanted clots are formed - Disseminated intravascular coagulation DIC
o Spontaneous clots form as a failure of multiple systems.
These create blocked blood flow and may create severe bleeding.
What types of internal haemorrhage can be considered?
- Haematemesis
- Haemoptysis
o Associated with tuberculosis or cancer - Haematuria
o Related to trauma of urinary tract and kidney stones - Vaginal bleeds
o Spontaneous abortion, intrapartum haemorrhage - Rectal bleeds
o heemraads - Melaena
o Dark and highly offensive smell Stools. Indicative of ulcer/tumour. Small and upper GIT bleeds.
How might a patient with an internal haemorrhage present?
- Light headed
- Nausea or vomiting
- Rapid, weak, thready pulse
- Rapid respirations
- Pale, cold, and clammy
- Thirsty
What are exceptions of bad cavity bleeds?
- Menstruation
- Haemorrhoids
- Some epistaxis
What is the treatment of Epistaxis?
- Firm pressure to the soft part of the nose for 10 minutes
- Sit upright, head forward
- Don’t blow the nose
o This will disturb the clotting process - Cold compress on the back of the neck
- If bleed continues for > 10 minutes transport