Bleeding Flashcards
Mechanism behind head injury -> low BP
- Bleeding
- Acute Brain Injury:
Catecholamine surge:
- alpha: increased pulmonary capillary pressure (through peripheral vasoconstriction/pulmonary venous constriction) -> NPO
- beta: myocardial necrosis: LV Function
- alpha and beta: platelet/micro-emboli -> damaged endothelium -> NPO
All leads to cardiorespiratory compromise
ECG changes in SAH?
Q-T prolongation, T wave abnormalities, ST elevation or depression
What happens in late haemorrhage?
Late, vasodilatory phase of hemorrhagic shock - attributed to acidotic conditions, adrenaline receptors do not work as well and those that are, are completely saturated.
Also inflame response to trauma -> vasoplegia
How to mimic blunt trauma in animals?
7cm liver laceration
How to mimic penetrating trauma in animals?
Cannula in femoral artery - bleed out
What works regardless of acidotic state?
vasopressin/ADH
splanchnic circulation - gut/fingers peripherally constrict
Difficulty with animal studies?
Homogeneity with animal models and anaesthetised/ventilated - this does not represent the period of hypoxia that hemorrhagic shock leads to in real life, i.e. not tissue damage/inflam response to trauma.
Also liver lac not blunt trauma really
What might give you a crunchy pelvis that is a confounding sign?
Iliac wing fracture
Typical on scene HEMS stuff?
(Ketamine) sedation Extrication Anaesthesia Blood transfusion Pleural drainage (thoracostomy) Splintage Reversal of warfarin Rapid scene times
REBOA zone 1
take-off of the left subclavian artery down to the celiac trunk
REBOA zone 2
celiac trunk to the most caudal renal artery.
REBOA zone 3
Most caudal renal artery to the bifurcation.
CODE red indications?
Systolic BP <90
Poor response to initial fluids
Suspected active haemorrhage
What is in pack a?
6 units RBC, 4 units FFP
Timing of tranexamic acid?
Optimal if 1g in 1hr
Beneficial if within 3 hours, potentially harmful if after
Maximal effect for SBP <75 mmHg