19 Flashcards
vessels that can be permanently ligated
BOTH common carotid arteries (NOT IN CATS)BOTH jugular veins (NOT IN CATS)Brachiocephalic v.Brachial arteriesHepatic veinfemoral arteriesBoth external iliac arteriesBoth common iliac veinsabdominal vena cava caudal to liver
why can’t both common carotid arteries and jugular veins be ligated in cats
less collateral circulation vs Circle of Willis and vertebral artery
three main principles that can be used to augment hemostasis
- reduce blood flow to affected areas 2. topical hemostatic agents3. anti-fibrinolytics
list methods to reduce blood flow to affected areas
- digital P/tamponade2. topical vasoconstrictors3. induce hypotension/hypothermia4. distant occlusion of blood flow
length of time it takes to form a platelet plug and cross link fibrin for clot
platelet plug 30 scross link fibrin for clot 2-3 minutes
types of topical vasoconstrictors
- epinephrine2. ephedrine3. adrenaline
ways to control distal blood flow
- vascular clamps (bull dogs, statinsky)2. tourniquets (rumel, esmarch-limbs)3. fingers
times in normothermic patients to temporary ligatehepatic arterypringle maneuverthoracic aortaabdominal aortarenal artery/vein
hepatic artery 30 minutespringle maneuver 10-15 minutesthoracic aorta 5-10 minutesabdominal aorta 30 minutesrenal artery/ vein 30 minutes
what pressure applied to distal limb tourniquet can be associated with neurogenic degeneration
1000 mm Hgdegeneration of myelin of compressed nerveddeficit ~ 6 months
pneumatic tourniquets
used in human surgerydeliver controlled pressure–100 mm Hg above patients systolic pressuremay reduce complicationsocclusion time is measured
equation used for tourniquet pressure
pressure = T (bandage tension)/R(radius)Width(bandage)P = T/RWPressure is inversely proportional to bandage width
most recommendations for length of duration of bandage tourniquets
MAX 1.5-2 hours (corresponds with muscle depletion of ATP stores)release for 10-15 minutes before reapplication
complications of hemostatic agents
volumetric swellingexothermic reactionsimmunogenic reactionsFB reactionsinhibition of normal healing
types of mechanical hemostatic agents
- porcine gelatin (gelfoam)2. bovine collagen II (ultrafoam)3. cellulose (surgicel)4. wax (bone wax)
MOA of mechanical hemostatics
Absorb bloodprovide a mechanical barrier or tamponadecreate a matrix for clot formation/stabilization