1. This document discusses various types of supratentorial and infratentorial herniations that can occur, as well as the anterior, middle, and posterior cerebral blood vessel circulations and areas susceptible to infarction. 2. Guidelines are provided for intracranial pressure (ICP) monitoring in severe traumatic brain injury patients based on Glasgow Coma Scale score and computed tomography results. Objectives and targets for ICP monitoring and cerebral perfusion pressure are also outlined. 3. Information is given about equipment and procedures for ICP monitoring, including ventricular catheters, Licox brain oxygen tension monitors, Camino ICP monitors, and locations of supplies in the hospital.

3. Supratentorial
herniation
1. Uncal
2. Central
(transtentorial)
3. Cingulate
(subfalcine)
4. Transcalvarial
Infratentorial
herniation
5. Upward
(transtentorial)
6. Tonsillar

4. The area where the
distributions of two blood
vessels intersect is susceptible
to a low flow infarct.
The anterior, middle and
posterior circulations have two
borders roughly at the tips of
the ventricles.
Anterior
Cerebral
Middle
Cerebral
Posterior
Cerebral
Infarct
Infarct

5. Papilledema is
diagnostic but
is a late finding.

6. Monitor ICP in all “severe” head injury
patients (GCS ≤ 8) with an abnormal CT
Monitor ICP in all “severe” head injury and
a normal CT if two or more of the following:
 Age ≥ 40 years
 Systolic blood pressure ≤ 90 mm Hg
 Unilateral or bilateral posturing

7. Objectives of ICP monitoring:
 Maintain cerebral perfusion and oxygenation
 Avoid secondary injury
Cerebral perfusion pressure (CPP):
 ICP minus MAP
 Should be over 50 mm Hg

8. A ventricular catheter and
external strain gauge are the
most accurate, reliable, and
method of monitoring
… and …
ventriculostomies
allow CSF drainage.

9. Convenient, fast, accurate.
… BUT …
Cannot be recalibrated
after insertion, and are
expensive ($6,000 to
$10,000).

10.  The ICP threshold that was most predictive of 6 month outcome
was analyzed in 428 severely head injured patients.
 The proportion of hourly ICP reading greater than 20 mm Hg
was a significant independent determinant of outcome.
 CT data also determines need for treatment (the ICP may not be
uniform across the brain).
J. Neurosurg
75:S59-S66,
1991

11.  Cerebral Perfusion Pressure is MAP minus ICP
 If MAP is 90 and ICP is 20, CPP is 70.
 CPP should be over 70 mm Hg
 A CPP less than 50 is especially damaging.

12.  Licox (brain oxygen
tension) must be over 15
and should be over 20
mmHg.
 A jugular venous
saturation of less than 50%
is a similar but an older
and more difficult test.

13. Cranial Access kit.
In Pyxis “A” side. Door 23.
Licox catheter
In black refrigerator in Central Supply—phone #2542. If unable to reach
Central. House Supervisors can access. Enter in basement through door
labeled “Dress down to enter.” Dress in white “bunny suit” and cover hair
with hat. Fridge is located on counter, to left, between rows labeled “Dental”
and “GYN”
Licox Machine
In CCU Manager’s office on shelf. Slave cord is only to attach Licox
machine to CCU monitor.
Camino transducer tip catheter.
In Pyxis “A” side. Door 23.
Camino Machine
In clean utility on poles. Cords on pole.

14.  The cranial access kit
contains the supplies
necessary to open the skin
and make a twist drill hole.
 A double barrel “bolt” is part
of the Licox catheter kit.

15.  The Licox monitor is inserted into
one of the two ports on the “bolt.”
 The card that comes with the
monitor is inserted in the
machine.
 The cables are connected to the
front of the machine.
 The extra box and cable from the
back is used to connect to the ICU
monitor but is not required for the
Licox to operate.

16.  The Camino ICP monitor is
inserted into the other port on the
“bolt.”
 The card that comes with the
monitor is inserted in the
machine.
 The cables are connected to the
front of the machine.
 The extra box and cable from the
back is used to connect to the ICU
monitor but is not required for the
Licox to operate.

17.  Maintain systolic pressure over 90 mm Hg
 Avoid hypoxia (PaO2 < 60 mmHg or SaO2 <
90%)
 Mannatol can be used for emergencies or short
periods (usually 1 g/kg or 100 g total)
 Hypertonic saline (4%) as bolus or infusion
 Barbiturates can be used for ICP refractory to
all other interventions.
 Must monitor EEG (burst-suppression)
 Must support blood pressure

18.  Early tracheostomy should be considered
 Sequential compression stockings and TEDS in non-
ambulatory patients
 Use low dose heparin with caution (not with intracranial
hemorrhage, low molecular weight heparin
[LMWH/Lovenox] contraindicated in some spine patients)
 Antibiotics are indicated for intubation and before surgical
procedures surgery (one dose, 20 minutes before)
 Full caloric replacement should begin before day 7 post-
injury
 Hypothermia not indicated
 Steroids are not recommended and may increase mortality
 Seizure prophylaxis does not improve outcome and not
recommended