ICP Monitoring and Treatment Flashcards
What is the GCS indication for ICP monitoring of patients?
GCS
What are risk factors for IC-HTN despite a normal head CT? (3)
Age > 40
SBP
What is an indication for ICP monitoring in patients based on head CT?
If CT is abnormal (i.e. hematomas (SDH, EDH, ICH), contusions, swelling, compression of basal cisterns, herniation)
T/F
If a patient presents with altered consciousness in the face of multiple organ systems damaged (e.g. will be placed on PEEP and receive IV fluids) their ICP should be monitored.
True
Monitor ICP if multiple organ systems damaged and where therapies may have deleterious effects on ICP
Generally speaking, should awake patients and those with coagulopathies be monitored?
Generally, no. Those with coagulopathies should have it corrected and then measured with a bolt or epidural monitor.
When is the appropriate time to discontinue ICP monitoring?
48-72 hrs after withdrawal of last ICP therapy
What are the common complications of ICP monitoring devices?
Infection
Hemorrhage
Malfunction/Obstruction
Malposition
What are the four types of ICP monitoring devices?
Subdural
Subarachnoid (Bolt)
Intraparenchymal
Intraventricular (e.g. EVD)
What is the treatment of infection of an ICP colonization device?
If possible, remove the device (consider reapplication at another site if need continued ICP measurement) and start antibiotics after cultures.
What is the standard and most accurate device for ICP measurement?
EVD
1 mm Hg = __ cm H20
1 mm Hg = 1.36 cm H20
What is the commonly used reference point for an EVD? What anatomical structure does this roughly correlate to?
External auditory canal (EAC) which correlates to level of Foramen of Monro
What is a good way to check for patency of IVC system?
Open the system for drainage and lower the bag to see if a few drops of CSF drain off. Don’t let more drain off and then close and return back to its normal position.
A Licox probe may be used an adjunct to ICP monitoring. What does it measure?
Brain tissue oxygen tension
Brain tissue oxygen tension less than what value increases the likelihood of death?
What are common scenarios that Licox probes are used for brain tissue oxygen monitoring?
In TBI patients and in SAH patients (i.e. to assess impending risk of vasospasm in a particular vascular territory)
Generally, at what ICP should ICP lowering treatments be used?
ICP 20-25 mm Hg
At what CPP threshold may ischemia occur? What should be the goal CPP?
Ischemia may occur in the 50-60 mm Hg range for CPP
Goal should be 60-70 mm Hg
Avoid going far above 70 mmHg CPP with use of pressors and fluids bc of risk of ARDS in adult patients.
What are general measures for reduction of ICP (aka those which should be utilized routinely and early on)?
Elevate HOB to 30-45 degrees
Control BP to normotensive
Avoid hypoxia (keep PaO2 > 60mmHg)
Ventilate to normocarbia (PaCo2 35-40 mmHg)
Light sedation (e.g. codeine 30-60mg q4 PRN)
Prophylactic hypothermia (?)
Noncon head CT
Why is light sedation useful for preventing elevated ICPs?
It reduces sympathetic tone, BP, and contraction of musculature which may contribute to increasing ICP
(e.g. Codeine 30-60 mmHg q4 PRN)
If general measures for ICP control fail then what are the steps (in order) to follow (1-7)?
1) Heavy sedation and/or paralysis
2) Drain 3-5mL of CSF if IVC present
3) Hyperventilate to PaCo2 30-35 mmHg
4) Mannitol
5) Hypertonic saline (if there is ‘osmotic room’ aka Osm
Your patient has ICP issues and general measures have failed to keep ICP low. ICP is now 27 mmHg and you decide to heavily sedate and paralyze the patient. What are your drugs of choice?
Fentanyl 1-2mL IV q1 hr
Vecuronium 8-10mg IV
What dose of mannitol is used when initially attempting to lower ICPs after general ICP-lowering measures have failed?
What dose should be used after the initial dose?
What is the Osm limit you should be aware of?
- 25-1.0 g/kg initially
- 25 g/kg q6 thereafter
Caution increasing the dose if serum Osm > 320
You’ve given you’re patient mannitol but their ICP remains at 27 mmHg. You check their serum Osm and find it to be 285. What is the next step you are considering and at what dose?
Bolus with hypertonic saline (23.4%) about 10-20 mL
If all specific medical measures are failing to lower ICP then what diagnostic testing should be considered?
Head CT to evaluate for risk of herniation
EEG for possible clinically silent status epilepticus (may be helped by pentobarbitol or propofol)
How can lidocaine be an effective adjunct to controlling high ICPs?
If given immediately prior to intubation it can blunt the spike of ICP which comes with intubation
Should patients be chronically hyperventilated or prophylactically hyperventilated?
Should patients be hyperventilaed in the time period after head trauma?
No and No (patients should not be hyperventilated in the 24 hrs after head trauma and preferably not in the first 5 days after)
If you need to hyperventilate to 25-30 mmHg then what adjunctive measures should you take?
Consider measuring jugular venous oxygen saturation or CBF to rule out cerebral ischemia
How long after bolusing with mannitol will a patient start to show lowered ICP? When does the effect peak?
Should take effect in 1-5 minutes
Peak effect after 20-60 minutes
When discontinuing mannitol should it be tapered or just removed?
Tapered to prevent a rebound spike in ICP
One of the few level I recommendations of the Brain Trauma foundations concerns steroid use after head trauma. What is the recommendation?
Methylprednisolone should NOT be given after head trauma because of association with increased mortality.
Steroids are helpful in reducing vasogenic edema but not with cytogenic edema
*One situation it may be given is TBI patients with know lack of endogenous adrenal hormones
Via what mechanism do barbiturates reduce ICP?
Lower cerebral metabolic rate of oxygen Causes vasoconstriction in normal cerebral areas thus promoting shunting to more ischemic areas Lysosomal stabilization Reduction of intracellular calcium Free radical scavenging
What is often the limiting factor for barbiturate use in reducing refractory ICP?
Hypotension due to reduced sympathetic tone
What are commonly used agents for barbiturate coma in ICP refractory cases?
Pentobarbital
Thiopental
Propofol
