TBI 2 Flashcards
Ancillary Therapies
Glycemic control
-hyperglycemia is associated with:
-ongoing debate as to whether ____ reflects brain injury
or a cause of worsened secondary injury
- reflects SNS activation vs
- potentiating injury MoA:
A study of hyperglycemia in naturally occurring TBI in dogs and cats suggested that the degree of hyperglycemia after TBI is associated with _____
not associated with _____
control of blood glucose concentrations with insulin was not investigated
THM:
increased mortality rates/worsened neurologic outcomes
hyperglycemia
SNS response
-.:. degree of hyperglycemia may simply be a reflection of the severity of the injury sustained
- studies = hyperglyc ALSO potentiates neurologic injury:
- hyperglycemia increases free radical production
- excitatory amino acid release (glutamate?)
- cerebral edema
- cerebral acidosis
severity of head trauma
outcome
prevent iatrogenic hyperglyc. but don’t supp. insulin
Hypothermia has been employed as a treatment strategy in human TBI patients and recently reported in a canine patient
MoA: hypothermia limits secondary brain injury unclear:
A human clinical trial demonstrated improvement in treatment time and neurologic outcome in patients with severe TBI treated for 24 hours with moderate hypothermia (32–34°C) when compared with normothermic controls
temp.:
Conversely, a National Acute Brain Injury Study in adult patients with TBI could not demonstrate a beneficial effect of iatrogenic hypothermia
more complications but no difference in mortality
Potential disadvantages to induced hypothermia include:
THM:
- trad. decrease brain metabolic demands
- curr. reduction in the release of excitatory neurotransmitters such as glutamate
- may also reduce inflammatory CK and preserv. BBB
A human clinical trial demonstrated improvement in treatment time and neurologic outcome in patients with severe TBI treated for 24 hours with moderate hypothermia (32–34°C) when compared with
89-93 (32-34)
coagulation disorders
increased susceptibility to infections
hypotension
bradycardia, and arrhythmias
current literature has failed to consistently support the positive influence of prophylactic hypothermia on mortality and morbidity its use cannot be recommended as standard therapy for TBI patients at this time
Pain Management
analgesia is critical to prevent of further ICP elevation:
-ve respiratory depression and hypotension, hw.
titrated to achieve adequate analgesia opioids:
presence of BBB damage opioid dose requirements:
fentanyl CRI:
shown to be safe
lower
avoid peaks and troughs
Anticonvulsant therapy
It has been reported that seizures complicate between:
Risk factors:
anticonvulsants administered prophylactically reduce the incidence of seizures within ____ following trauma, but do not reduce the incidence after the first ___
Have not shown that prevention of posttraumatic seizures improves
role in vet med following TBI remains:
for active seizures:
-ve
Recent veterinary studies have documented seizure rates of 6.8% in dogs and 0% in cats
Unfortunately, prophylactic anticonvulsant therapy has not been shown to reduce development of delayed seizures after TBI in people. However, aggressive treatment of seizures while animals are hospitalized is recommended
4% and 42% of cases of severe TBI in humans
depressed skull fractures, epidural, subdural, and intracerebral hematomas, penetrating head wounds, and a seizure within the first 24 hours following injury
first week
after first week
outcome
unclear
diaz/midaz
PB - load
phenobarbital - respiratory depression, carbon dioxide levels should be monitored
Barbiturates have the ability to decrease:
use of pentobarbital for induction of a barbiturate coma: pros and cons
energy of cerebral tissue
=decrease oxygen demand
=vasoconstriction and decreased blood flow
=decreased ICP
used to decrease metabolic demands of the brain —therapy instituted only when other therapies have failed
- limited evidence for the efficacy for barbiturate use, and induction of a barbiturate coma may be detrimental to survival
- not yet been reported in the veterinary literature
- human prophylactic barbiturate use does not prevent an increase in ICP and may worsen outcome
- initial IV bolus dose of 2–15mg/kg
- CRI at a dose of 0.2–1.0mg/kg/h is administered to maintain the barbiturate coma
Corticosteroids - clinical trials in humans shown use of corticosteroids: - now contraindicated in human medicine - also associated w.: hyperglycemia, immunos
increases mortality
hyperglycemia immunosuppression delayed wound healing gastric ulceration exacerbation of a catabolic state
GI protectants
Single‐system injuries of the CNS have been found to be independently predictive of bleeding
-therefore, routine stress ulcer prophylaxis in TBI:
- reduction of gastric acidity to a pH >4 is effective in:
- pH >6 is required to control:
is recommended
preventing stress ulceration
actively bleeding ulcers
Omeprazole may have an added benefit:
MoA unclear, omeprazole has been shown to decrease CSF production in dogs by 26%
Nutrition
TBI results in:
study comparing early (within 36h) versus delayed enteral nutrition demonstrated a:
authors recommend placement of a nasogastric tube with as little manipulation and stimulation as possible
hypermetabolic and catabolic state
55% reduction in the risk of infection in human traumatic head injury patients receiving early enteral nutrition.
Intracranial Pressure Monitoring
Treatment decisions based on ICP measurements rather
ICP monitoring is standard procedure for human TBI
high cost of the fiberoptic monitoring system as well as the technical expertise required for its placement limits its use in vet med to research & referral practices
future:
decreased morbidity and mortality in human TBI
ICP monitoring may become a more routine and integral part of TBI management in domestic pets
Diagnostic Imaging
indicated when:
human head trauma CT is standard of care
abnormalities noted on CT that are associated with increased ICP include:
patient fails to respond to aggressive medical therapy
or patient deteriorates
subdural hematomas subarachnoid hemorrhage intracerebral hematomas cerebral infarcts generalized cerebral edema w shift of midline structures and ventricular compression
Surgical Therapy
In human head trauma patients with elevated ICP refractory to optimal medical therapy consider:
no consensus as to if and when surgery should be pursued and the effect of surgical intervention on:
RESCUEicp:
determine whether decompressive craniectomy has a role in the management of human patients with TBI
decision in vet med should be based on CT or MRI of the brain and consultation with a neurosurgeon
Indications for surgery include:
barbiturate coma
decompressive surgical
i.e. decompressive craniectomy
outcome remains unclear
Decompressive craniectomy in patients with TBI and persistently raised intracranial pressure
- associated with lower mortality
- however, more survivors in the surgical group than in the medical group were dependent on others
- vegetative state
- likely to be concern that life saving surgery does not = good functional survival
open or depressed skull fractures ongoing hemorrhage foreign body hematoma removal declining neurologic status despite aggressive mx.
Prognosis
Potential complications associated with TBI:
delayed seizure disorders may develop:
as a result of:
human rate between:
incidence of seizures in veterinary TBI
Dogs and cats have a remarkable ability to compensate for the loss of cerebral tissue - important to not to make:
MGCS has recently been correlated with probability of survival in the first 48 hours after TBI in dogs
Platt SR, The prognostic value of the modified Glasgow coma scale in head trauma in dogs. J Vet Int Med 2001
MGCS predicted a ___% probability of survival in a patient with a score of:
This same study found presence of skull fractures did
This study, however, excluded patients with systemic abnormalities which are common in trauma
As such, the MGCS must be utilized with:
Prognosis coagulopathies pneumonia sepsis transient or permanent central diabetes insipidus seizures
months to years later
glial scar seizure focus
4% and 13%
6.8%
hasty prognostic conclusion
50%
8 out of a total of 18
not predict survival
caution as px. difficult to assess due to the multifactorial nature of traumatic injuries
A recent systematic review concluded that mild to moderate therapeutic hypothermia for 48 hours:
beneficial in human patients with severe TBI
ICH: (>12mmHg)
When ventricular pressure is elevated, the flow of fluid may be reversed, back into the brain parenchyma…
compensation:
CSF production falls, absorption increases, and a greater volume of CSF is displaced to spinal subarachnoid space
