Hemostasis and Blood Replacement

Blood

The life-maintaining fluid pumped by the heart through all the vessels of the body, which accounts for approximately $7\%$ of total body weight.

Hematopoiesis

Blood cell formation

Originating in the bone marrow, where cells mature into five types: erythroblasts, myeloblasts, monoblasts, megakaryoblasts, and lymphoblasts.

Composition of blood

•Plasma – clear extracellular fluid
•Formed elements –blood cells and platelets
Formed elements are:
•erythrocytes (RBC);
•Leukocytes (WBC);
granulocytes and agranulocytes
•Platelets

Hemostasis

The arrest of blood flow or hemorrhage, achieved primarily through the physiological mechanism of coagulation.

• When a blood vessel is severed:
– Vessel constricts and the end contracts.
– Platelets clump and adhere to connective tissue

• Adenosine diphosphate (ADP), epinephrine and
serotonin are liberated by the platelet/collagen
interaction.

• ADP causes other platelets to clump to the initial layer
and to each other causing a platelet plug.

Platelet Plug

An aggregation of platelets formed at a severed vessel when platelets adhere to connective tissue and release adenosine diphosphate (ADP), epinephrine, and serotonin, causing additional platelets to clump together.

Topical Thrombin- Chemical Topical Hemostatic Agents

– Bovine origin
– Mixed with NaCl to encourage the formation of
fibrin on oozing surfaces
– Small pieces of gelatin sponges (Gelfoam) or
sponge patties (cottonoids) are soaked in
thrombin and placed over delicate bleeding
capillaries such as those in the brain, ear or spinal
cord

Fibrin- Chemical Hemostatic Agents

• Fibrin sealants – taking pure human fibrinogen and combining it with human or bovine thrombin.
– May have another an antifibrinolytic agent and
aprotinin to make this product more effective.

• Absorbs in 10-14 days and requires a
relatively dry field in order to work

• Also called fibrin glue

Tisseel, Floseal, Coseal

Hypotensive Anesthesia

Anesthesia can help reduce blood loss by creating and maintaining a hypotensive state for the patient through medication

Absorbable Gelatin (Gelfoam)- Chemical
Hemostatic Agent

A porcine-derived absorbable hemostatic agent available as powder or compressed foam pads

Absorbs approximately $45$ times its weight in blood

Expands to $200\%$ of its original volume

Absorbs within $20\text{ to }40\,\text{days}$, and liquefies on nasal mucosa within $2\text{ to }5\,\text{days}$.

It can be applied dry directly to the bleeding surface and
hold pressure over it or you can wet it in saline

Microfibrillar Collagen (Avitene, Instat) - Chemical
Hemostatic Agent

collagen, derived from bovine skin.
– Most commonly used in a loose fibrous form.
– Also comes in a non-woven web form.
– Absorbs in 3 months
– Needs to be applied DRY

– Collagen sponges

• Similar to Avitene, derived from bovine Achilles
tendon or skin
• Absorbs in 8-10 weeks

Oxidized Cellulose (Surgicel, Oxycel)- Chemical Topical Hemostatic Agents

A plant-derived alpha-cellulose topical hemostatic agent

Adheres to bleeding tissue

Promotes coagulation

Always applied dry

Absorbs within $$4\text{

Chemical – Injectable Hemostatic Agents

Injectables
– Vasoconstrictors
– Local anesthetic combined with epinephrine
– Oxytocin (Pitocin) commonly used to stimulate the
uterus to contract

Fibrin Sealants

Topical biological adhesives (such as Tisseel, Floseal, and Coseal) combining human fibrinogen with thrombin via a double-syringe system that absorb in $10\text{ to }14\,\text{days}$ and require a relatively dry operative field.

Platelet Concentrates- Chemical Topical Hemostatic Agents

– Hemostatic agents made from autologous plasma (from the pt.)
– Platelet concentrates are acceptable for use in
surgery on individuals whose faith does not
permit the use of transfused blood

Bone Wax

Beeswax used to stop bleeding from bone

Pneumatic Tourniquet

• A surgical device used to control venous and arterial
circulation to create a bloodless surgical site in limb
surgery
– Arm
– Wrist
– Leg
– Ankle
– Foot

• Pressure applied circumferentially
– Walls of the vessels are temporarily occluded

• Tourniquet may remain inflated up to 2 hours
• Circulation must be reestablished for at least 15-20 min.
to prevent necrosis and tissue damage

Thermal –Argon Plasma Coagulation

Argon gas and monopolar electrical energy are combined to deliver radiofrequency energy tissue in a noncontact, white light beam for
the purpose of rapid hemostasis

Autologous Blood

Blood recovered from the patient and reinfused

• Donating your own blood before an elective procedure
• Reduces demand on blood banks
• Safest blood you can receive
• Other autologous option is intraoperative autotransfusion – aka – Cell Saver
• May be an acceptable means of reinfusing blood for
those who for religious, cultural, or other reasons,
decline transfusion of blood from another person

Allogenic Blood

Blood drawn from one individual and transfused to another

Apheresis

– A procedure where whole blood is removed
– A desired component is retained, while the remainder of blood is returned to the donor

Hematocrit

Measures of the amount of red blood cells in your body

Whole Blood

• Use of allogenous whole blood continues to diminish
worldwide because:
– More likely to carry transfusion transmitted disease(s)
– Most pts. require only 1 component of whole blood so
their needs are better served by getting only what they
need
– Blood products have a longer shelf life than does whole
blood

Many blood products can be infused to any blood type

By separating whole blood into component products and using them as needed, one unit of whole blood can treat several patients

Whole blood is a volume expander as well as a source
of RBC’s, platelets and clotting factors.

• Whole blood has a shelf life of 35 days
• Whole blood must be matched for ABO compatibility (blood types) as well as Rh compatibility
• If whole blood is indicated but not available, one unit of RBC’s plus one unit of FFP equals one unit of whole blood

Fresh Frozen Plasma (FFP)

• FFP should be used to correct multiple coagulation factor
deficiencies in bleeding patients or patients at risk of bleeding
requiring an invasive procedure

• While frozen, shelf life is 1 year

• Common causes of coagulating deficiencies are hemorrhagic shock, burns, congenital deficiencies, liver disease, anticoagulation due
to blood thinning medications, massive transfusion with RBC’s and thrombotic thrombocytopenic purpura (TTP)

Rh (Rhesus) Factor

• Persons who have the D antigen are designated Rh positive and those who do not are designated as Rh negative
• Rh antibodies develop after exposure to one or more of the Rh antigens
• Approx. 50-75% of Rh negative persons develop the antibody to D antigen if they are exposed to Rh positive blood
• Rh negative patients can only receive Rh negative blood, but Rh positive patients can receive either one

Type and Screen

A pretransfusion laboratory analysis that identifies a patient's ABO blood group, Rh status, and screens for atypical antibodies, typically completed within $20\text{ to }30\,\text{minutes}$.

Type and Crossmatch

A thorough laboratory testing process combining patient serum with donor red blood cells to detect incompatibility prior to transfusion, usually requiring $30\text{ to }45\,\text{minutes}$.

Function of blood

• Transportation
• Protection
• Regulation

Transportation

Blood transports the following substances:
– Gases
• oxygen (O2) and carbon dioxide (CO2); between lungs and body

– Nutrients
• from digestive tract and storage sites to the rest of the body

– Waste products
• to be detoxified or removed by the liver and kidneys

– Hormones
• from the glands in which they are produced to their target cells

– Heat
• to the skin so as to help regulate body temperature

Protection

Blood has several roles in inflammation:
– Leukocytes - white blood cells
• destroy invading microorganisms and cancer cells

– Antibodies and other proteins
• destroy pathogenic substances

– Platelet factors
• initiate blood clotting and help minimize blood loss

Regulation

– pH by interacting with acids and bases
– Water balance by transferring water to and from
tissues

Make up of Blood

Plasma
– 54% of total Blood Volume
– Water, sugar, fat, hormones, protein, potassium, and calcium salts
– Approx 92% of plasma is water

• White Blood Cells and platelets
– 1% of Total Blood Volume

• Red Blood Cells
– 99% of cells
– Denser-pack at the bottom of tube
– Approx 45%

Homeostasis Physiology

– The injury activates clotting factors and other
reactions.

– Prothrombin reacts with thromboplastin and
with calcium to form thrombin.

– Thrombin unites with fibrinogen to form fibrin
(basic material for clot)

– The fibrin strands reinforce the platelet plug to
form a hemostatic plug that can withstand the
arterial pressure.

During surgery, we see two types of
bleeding:

– Pulsating arterial bleeding
– Oozing venous bleeding

Uncontrolled surgical blood loss

Can lead to:
– Decreased visualization of surgical site
– Hemorrhage
– DIC
– hematoma
– Increased cardiac strain
– Shock
– Death

Methods for Obtaining Hemostasis

• Chemical
• Hemostatic Adjuncts
• Mechanical
• Thermal

Ablation- Hemostatic Adjuncts

Ablation- Use of heat or cold delivered to destroy blood flow

Hypothermia
– External
– Internal

Mechanical Methods

• External
– Direct pressure
– Tourniquets
– Pressure Dressings

• Internal
– Digital pressure
– Bone wax
– Hemostatic clamps
– Ligatures
– Ligating clips

Direct pressure

– Allows body to take care of itself by coagulation, delays bleeding allowing clot to form

Mechanical –Preventive devices

• Antiembolic stockings
• Sequential Compression Devices
• MAST Pneumatic Counter pressure Device
• Tourniquets

Thermal Methods

• Minor bleeding
– Bovie
– ABC
– Laser

Laser Coagulation

• Light
• Amplification by
• Stimulated
• Emission of
• Radiation

Thermal Coagulation instruments

Tissue sealing device - Ligasure
Ultrasonic scalpel – Harmonic Scalpel

Who estimates blood loss

• Anesthesia typically estimates blood loss
• Checks suction canister
– Before irrigation, let anesthesia know you are
about to irrigate.

– Keep a running tally of how much irrigation you
have used.
• Looks at sponges

– Raytecs ~ 10-20 mL blood
Lap sponges ~ 100 mL blood

Blood loss

• Average adult has about 5-6 liters of blood.
• A loss of less than 500cc does not require transfusion.
• It may depend on the individual situation.

Red Blood Cells

• In the event of allogeninc transfusion, RBC’s must be cross matched.

• RBC’s increase the oxygen carrying capacity of the blood

Platelets and their substitutes

• Collected by apheresis or by centrifuging whole blood
• Platelet products also contain plasma (clotting factors), some RBC’s and some WBC’s so this needs to be ABO compatible with the patient
• Platelets collected by apheresis contain less leukocytes (wbc’s) than those obtained through centrifuge and are usually labeled as leukoreduced

• Platelet transfusions are indicated for patients with thrombocytopenia, thrombocytopathia or both conditions
• Shelf life for platelets is 5 days at room temperature
• One unit should increase patient platelet count by 6,000

4 major ABO blood groups

– Type O – has neither A or B antigens
– Type A – has A antigens
– Type B – has B antigens
– Type AB – has both A
and B antigens

ABO/Rh Compatibility

• In transfusing whole blood or RBC’s the patient can only receive a type his/her blood has no serum antibodies against.
• A simplistic way of thinking of it –
– A patient can only receive a blood type his or her
blood has “seen” before