Pathophysiology of hemorrhagic shock Flashcards
What is the percentage of delivered O2 used by the body?
20-30%.
Under normal conditions, delivery of O2 far exceeds
O2 consumption. Reserve of 60-70%
Which tissues have a smaller reserve of O2 and are more susceptible to reduction of O2 delivery? And which ones have a bigger reserve?
- The heart (40%)
- Skeletal muscles, liver kidneys (60%)
In a dog model, how much blood can be removed before reaching the critical point of delivery of O2?
50% of the total estimated blood volume.
Once DO2crit is reached what happens at the level of the cells?
Cellular hypoxia –> mitochondrial respiratory dysfunction and transition from aerobic to anaerobic metabolism with lactate formation and development of acidosis.
Then cellular ATP becomes depleted, cells are not able to maintain the electric gradient across its cell membrane, which allows an influx of sodium, calcium and water into the cells, causing cell swelling, cellular lysis and necrosis. Cellular acidosis, oxygen-free radical generation,
and loss of cellular adenine nucleotides also
contribute to irreversible injury and cell
death.
Which tissues are particularly sensitive to hypoxia?
Brain and GIT
How much splenic contraction during anemia can increase the RBC mass circulating?
Up to 20%
Define massive haemorrhage
Massive hemorrhage is defined as a loss of TBV within a 24-hour period, or
loss of half of the TBV in a 3-hour period.
What is the estimated TBV of cats and dogs?
The estimated TBV is 80–90 mL/kg in dogs and 55–65 mL/kg in cats.
Where are located baroreceptors?
Left atrium, aortic arch, and carotid sinus.
Where are located chemoreceptors?
Carotid artery and aorta
What is referred as the “lethal triad”?
The combination of coagulopathy, acidosis
(pH < 7.2), and hypothermia (<33-
34°C) is referred to as the “lethal triad”
or “trauma triad of death” that, together,
foster a vicious cycle of continued blood
loss and hypoperfusion.
