TRAUMA, ICP, VENTRICULOSTOMIES,

AND LICOX® MONITORS

Marie Taylor, PA-CRobert Lieberson, MD

ANMC Department of Neurosurgery

Monro-Kellie Doctrine

Herniation(s)Supratentorial herniation

1. Uncal 2. Central (transtentorial) 3. Cingulate (subfalcine) 4. Transcalvarial

Infratentorial herniation

5. Upward (transtentorial) 6. Tonsillar

Watershed Stroke

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

Papilledema

Papilledema is diagnostic but is a late finding.

“Guidelines” for ICP Monitoring Traumatic Brain Injury

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 yearsSystolic blood pressure ≤ 90 mm HgUnilateral or bilateral posturing

“Guidelines” for ICP Monitoring Traumatic Brain Injury

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

ICP Monitoring Technology

A ventricular catheter and external strain gauge are the most accurate, reliable, and method of monitoring

… and … ventriculostomies allow CSF drainage.

Other ICP Monitors

Convenient, fast, accurate.

… BUT …

Cannot be recalibrated after insertion, and are expensive ($6,000 to $10,000).

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

ICP Treatment

Cerebral Perfusion Pressure

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.

CPP = MAP - ICP

Brain Oxygen Monitoring

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.

Monitor Setup 1

Cranial Access kit. In Pyxis “A” side. Door 23.

Licox catheterIn 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 MachineIn 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 MachineIn clean utility on poles. Cords on pole.

Monitor Setup 2

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.

Monitor Setup 3

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.

Monitor Setup 4

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.

Other Treatments

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

Other Treatments

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