Trauma and head injury Flashcards
What is the golden hour concept?
-Critical period of 1 hour after injury, accident or trauma
-Mortality rates increase significantly if efficient care is not established within this window
What is acute coagulopathy of trauma (ACoT)?
-Impaired coagulation after significant injury / trauma
-Develops due to acidosis, hypothermia, loss and haemodilution of coagulation factors as a consequence of shock and aggressive fluid resuscitation
-Increases mortality, morbidity and transfusion requirements
How is ACoT recognised?
-Lack of well-defined diagnostic criteria
-Prolonged PT and APTT are useful indicators
How should ACoT be managed?
Damage control resuscitation (DCR):
-Early control of bleeding through interventional and surgical procedures
-Administration of blood products and coagulation factors
-Early correction of hypothermia, acidosis and hypocalcaemia and controlled administration of crystalloids
How are massive haemorrhage and massive transfusion defined?
-Massive haemorrhage = loss of more than one entire blood volume within 24h (or loss of >50% total blood volume in <3h)
-Massive transfusion = transfusion of 10+ units of RBC within 24h
What product is given to help limit blood loss?
-Tranexamic acid
-It is a synthetic analogue of lysine (amino acid)
-Helps to limit blood loss by promoting clotting
What is the Monro-Kellie doctrine?
-Rule describing the relationship between contents of the cranium and intracranial pressure
-Cranium is a fixed structure so volume that can be contained within it is fixed
-Intracranial volume is made up of 80% brain parenchyma, 10% blood volume, 10% CSF - if one increased in volume, another must decrease
What is a normal ICP?
-5-15 mmHg
-If >20 mmHg, signifies need for intervention to avoid significant consequences
What are the main compensatory mechanisms for raised ICP?
-Drainage of blood / CSF from cranial cavity
-If SOL continues to grow, patient becomes decompensated once fluid drainage is no longer possible and intracranial components are no longer in equilibrium
-Volume-pressure curve shows that once patient is in a decompensated state, small increases in ICV results in large increases in ICP
When does herniation happen and what are the two most serious forms?
-Herniation occurs when brain parenchyma is displaced due to significantly raised ICP
-Uncal herniation = displacement of medial part of temporal lobe below tentorium cerebelli
-Tonsillar herniation = occurs when cerebellar tonsils are forced downwards through foramen magnum –> compression of brainstem
What is cerebral perfusion pressure (CPP)?
-Pressure of blood flowing to the brain (a constant)
-CPP = MAP - ICP
-Raised ICP –> decreased CPP –> ischaemia
-Once ICP and MAP are matched, CPP falls
What is a late sign of increasing ICP?
-Cushing’s triad = 1. Hypertension 2. Bradycardia 3. Irregular RR
-CNS ischaemic response is initiated when MAP is less than ICP to improve CPP
-Sympathetic nervous system causes vasoconstriction –> high BP –> baroreceptors slow HR
-Irregular respiration occurs due to hypo perfusion of the brainstem due to swelling
What are signs of head injury?
-GCS <13 on initial assessment / <15 at 2h after injury
-Suspected open or depressed skull fracture
-Basal skull fracture
-Post-traumatic seizure
-Focal neurological deficit
->1 episode of vomiting since trauma
*If any of the following, or any RFs are present –> CT head
How do you manage raised ICP?
-POSITIONING = head+trunk elevation
-ETT ties
-AIRWAY+BREATHING = controlled hyperventilation to avoid hypoxia and hypercapnia as causes increased ICP
-OSMOTHERAPY = increases oxygen delivery to the brain due to decreased blood velocity
-SEDATION = decreases cerebral blood flow so decreases o2 consumption
-OPIATES = ICP increases in response to pain, also decreases cough reflex
What is the Canadian C-Spine rule?
- High-risk factors (>65, paraesthesia) –> SCAN
- Unable to safely assess rang of motion –> SCAN
- Unable to actively rotate neck –> SCAN
