Flashcards in Haemorrhage Deck (32)
What is haemorrhage?
Loss of blood from a circulatory system due to traumatic disruption of blood vessels
Why do many surgeons make huge effort to prevent and control haemorrhage?
Because the presence of blood in the operating field obscures the view of the surgical site and increases the difficulty of the surgery
What are the deleterious effects of haemorrhage
1. Obscures the surgical field and slows surgery
2. Increases chance of wound infection
- clotted blood is an ideal bacterial medium
3. Creates a barrier to healing
4. Compromises patient circulatory status
- can lead to shock
What does a haematoma do?
- Creates space and occupies it
- Prevents correct tissue approximation and healing
What is primary haemorrhage?
Occurs immediately after trauma to blood vessel
What are the body's initial local defense mechanisms against haemorrhage?
- Platelet plug formation, the fibrin clot via intrinsic coagulation cascade
- Changes in intra and extr luminal pressure
What are the body's initial systemic defense mechanisms against decreased blood volume?
- Vasoconstriction of skin
- Increased heart rate
- Interstitial fluid movement into vascular space
What are the clinical signs of the body's initial response to haemorrhage?
1. Pale mucous membranes and skin
2. Cold extremities
4. Deep, rapid respirations
5. Decreased pulse pressure as systolic pressure diminishes
6. Depressed and immobile patient
7. Swollen surgical site
What occurs in the body later after prolonged haemorrhage?
- Fluid conservation
-- The RAA system promotes Na+ conservation
- ADH is released from the posterior pituitary gland causing water resorption
- Thirst stimulus at medullary centres
How is haemorrhage classified?
1. Arterial, venous or capillary
2. External or internal
3. Primary, intermediate or secondary
How do you differentiate between arterial, venous and capillary haemorrhage?
Arterial: Bright red spurting blood
Venous: Darker, less vigorous and not spurting
How do you differentiate between internal and external haemorrhage?
External: bleeding through the surface of the body
Internal: blood which accumulates within the body
How do you differentiate between primary, secondary and intermediate haemorrhage?
Primary: occurs immediately after vessel is opened
Intermediate: Bleeding within 24 hours of trauma
Secondary: occurs at least 24 hours after the vascular injury
What are the signs of a post-op infection?
- Pale Mucous Membranes
- Cold extremities
- Deep respiration, tachypnoea
- Poor pulse pressure
- Depressed patient
What do you do if a blood vessel cannot be avoided in surgery?
Recognise it prior to transection
Ligate it and divide it between the ligatures
How can vision be restored to see where the bleed is coming from?
- Active suction
- Gauze swabs
- Apply pressure to the site
How do you increase exposure to the surgery field?
- Extend the incision
- Use retractors
In what order are combatting haemorrhage methods used from most to least used?
1. Application of pressure
3. Ligatures and Ligaclips
5. Electrosurgery (diathermy)
6. Rumel tourniquets/ bulldog vascular clamps
8. Topical vasoconstrictors
9. Haemostatic agents
Describe pressure application in haemorrhage...
It can be done in 3 ways:
2. Pack the wound
3. Pressure bandaging
Describe the use of haemostats in haemorrhage...
Most common haemostat forceps are "mosquitos"
- Crush the vascular wall thus activating the clotting mechanism
1. Can be applied to the end of small vessels and left in place
2. Can grasp the cut end of a vessel and twist it
3. Applied to either side of an intended cut before it is performed
Describe Ligatures and...
Most commonly used to stop bleeding from transected vessels
Reliable if they remain in place
But remain as a foreign object in the wound
- Simple ligatures are most commonly used
- Transfixation ligatures are more secure because they incorporate a bite through the vessel wall
- Made of stainless steel
- Used on small vessels <5mm diameter
- V-shaped metal pressed together around the vessel
Application of direct heat to tissue
High frequency radiowave current delivered via an electrode to the tip of small cut vessels
- The heat volatises tissue fluid and leads to vessel ends sealing
- Smaller vessels just need a brief touch with the electrode
- Larger vessels must first be grasped with haemostatic forceps and the electrode placed on the forceps itself
= Coagulation where the forceps grasp the tissue
Describe a Rumel Tourniquet...
A loop of suture or umbilical tape passed around a vessel and through a piece of rubber tubing
- tubing is slid down vessel to create a temporary pressure
Describe bulldog clamps...
- To prevent bleeding
- Usually applied to the major arteries supplying the area on which surgery is intended
- Don't cause damage to the vessel wall
Describe a Tourniquet...
Applying pressure on the vessels passing to the surgical site
- Particularly on limbs and tails
What can occur if a tourniquet is left on for too long?
Over 1.5 hours
- Nerve injury
- Damage to the skin and underlying tissue
What is an Esmarch's bandage?
A broad elastic compression bandage
- often wrapped from distal to proximal to "milk out" venous blood
- Then secured proximally to be used as a tourniquet for operations on horses limbs
- If used properly, limbs are emptied of blood and surgical site will be blood-free