12 - Hemostasis Flashcards
Hemostasis
- Hemostasis is an imperative component of the surgical decision making
- Better visualization of tissue planes and structures
- Minimizes surgical time
- Decreases complications
Anatomical dissection
- Is the identification of tissue planes and the use of atraumatic technique
- Dissect by layers to control blood flow to extremity
Pneumatic cuffs (tourniquets)
- Thigh cuff
- Ankle cuff
Thigh cuff
PREFERRED
o Preferred type of hemostasis because a lot of soft tissue around the area, so less injury to the area
o General or spinal anesthesia required because it will cause pain - Cannot use a thigh cuff with sedation because patient will be very uncomfortable
o Should not exceed 500mm Hg
Ankle cuff
o Generally used with all forms of anesthesia
o Higher incidence of complications (due to lack of soft tissue in this area)
o Should not exceed 250 mm Hg
Exsanguination
Definition
o Draining blood from extremity before applying pneumatic cuff
Elevation of extremity before you pump up the cuff
o 45 degrees (3min.)
o 60 degrees (2min.)
o This decreases the amount of blood present in the extremity
Esmarch or ace wrap
- Wrap all the way up to the cuff
- Esmarch is large elastic band which is much wider and has much more tension
Contraindications of cuff use
- Infection (when debriding, can’t see what tissue is bleeding/healthy)
- Malignancy (can possibly cause malignant particles to flow/spread through lymphatics)
- Thrombo-embolic disease (throw a clot)
- A prior endovascular procedure (stent will collapse if you use a cuff)
Cuff inflation
- Proper inflation based upon systolic BP.
- Approx. 100-200mmHg above systolic 100 mmHg for ankle, 200 mmHg for thigh
- Max. times: approx. 2-3 hours (preferably 2 hours)
o “Breathing times” 5-10 min. - stop surgery and let the tissues reperfuse
STUDY - tourniquet
Studies have shown a max. tourniquet time of 1 ½ hours with a 5-10min. reperfusion interval allowed complete cellular recovery – this is IDEAL
LOCAL physiologic changes associated with tourniquet use
o pH initially 7.4 to 7.19 o pH after 2 hrs 6.9 o Oxygen partial pressures (45-20mm Hg) o Carbon dioxide (38-62 mm Hg) o Results in loss of integrity of muscle cell membrane
SYSTEMIC physiologic changes associated with tourniquet use
o Volume overload
o Acid base disturbances
BIlateral thigh cuffs
o Do NOT pump them up at the same time
o Can cause MI, cardiovascular collapse, pulmonary edema, hypertension
Complications of cuff use
- Thrombosis
- Inflammation
- Paralysis
- Tissue necrosis
- Circulatory volume overload
Vasoconstrictors
o Mimics natural catecholamines that bind to alpha adrenergic receptors
Hemostasis with epinephrine
o Reduces vascularity locally
o Permits a higher allowable dose of local
o Increases the duration of the block (because it keeps drug in area for longer period)
o Permissible concentrations = 1:100,000 or 1:200,000
Homeostatic agents
- Topical thrombin (Evithrom)
- Gelfoam
- Avitene
- Surgicel
- Floseal
- Evicel (Fibrin)
- Bone wax
Topical thrombin (Evithrom)
o Protein substance of bovine origin - Reconstituted with saline 1,000-2,000units/ml
o Clots fibrinogen of blood – put on wound, hold pressure 1-2 min, check again
o 500units will clot 5ml
Gelfoam
o Purified animal protein – promotes clotting via proteins as well as physical barrier
– Mechanical matrix promotes clotting, and it’s a physical compression barrier
– Always apply pressure to the area and wait a couple minutes before rechecking
o Absorbs many times its own weight in blood
o Completely absorbed 4-6 weeks – don’t need to remove from the wound
Avitene
o Avitene is a microfibrillar collagen agent
o Agent that adheres to blood, works by attracting platelets
o Does not interfere w/ bone healing
o Applied with direct compression 1-5 min
o May be utilized in patients undergoing heparin and aspirin therapy
Surgicel
o Comes in many different forms, is also absorbable (can leave in wound)
o Oxyidized regenerated cellulose (absorbable, fibrillar absorbable, Nu-knit absorbable)
o Hemostasis is based upon physical properties rather than chemical
– Works by binding to bleeding areas to coagulate vessels
– It’s expansion aids in compression to the area
o Promotes vasoconstriction
o Bactericidal properties – there is a small collection of blood in the wound, so it prevents infection in this case
Floseal
o Newer agent – hemostatic matrix (combination of two independent hemostatic agents)
o Stops bleeding within 2 minutes, can stop a LOT of bleeding (oozing of blood, collection of blood) – you will need compression as well
o Can be utilized on abnormal surfaces
o Effective on soft tissue and bone
Evicel (Fibrin)
o Injected into the area
o Human thrombin, forms a fibrin clot
Bone wax
o Refined bees wax (hard to use)
o Physical barrier
o Inhibits bone healing
Dressings
- Used for maintaining correction
- Used for compression to control bleeding, limit the accumulation of fluids
o Use compression in an OPEN or a CLOSED wound when leaving the OR
o Also keeps tissues approximated so they can heal appropriately - Drain systems may also be incorporated within the closure/dressing when there is anticipated oozing expected