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Significant Lateralisation of Supratentorial ICP After Blunt Head Trauma. Th. Mindermann, H. ... Alter blunt head trauma simultaneous left and right hemispheric intracranial pressure .... multaneous pressure monitoring of the infratentorial and ...

Acta Neurochir (Wien.1 (1992) ll6: 60 6l

O Springer-Verlag


Printed in Austria

Significant Lateralisation of Supratentorial ICP After Blunt Head Trauma Th. Mindermann, H. Reinhardt, and O. Gratzl Neurochirurgische Universitetsklinik, Kantonsspital Base1, Switzerland


Case Report

Alter blunt head trauma simultaneous left and right hemispheric intracranial pressure (ICP) monitoring revealed a pressure gradient of about 3OmmHg persisting until the 5th day after the accident equilibrating thereafter. ICP was elevated over the radiologically more compressed hemisphere. The supratentorial space seems to allow considerable interhemispheric pressure gradients. As a consequence epidural ICP monitoring should be perlormed over the

Alter sulfering a blunt head injury and III' grade open leg fractures in a car accident a five year old girl arrives in the emergency room. At the accident site she has a GCS 7 with pupils equal and reactive to light, moving all extremities. At arrival in the hospital the child is intubated, relaxated and sedated, pupils are still equal and reactive to light. Chest X-ray and abdominal ultrasound in the emergency room are within normal limits. Emergency CT (Fig. 1) shows no intracranial bleeding, no contusion marks, a slight left hemispheric swelling with siight compression of the lelt ventricle anteriorly, no midline shift and a skull fracture olthe right parieto-


with signs ol greater compression.

Keywords; B1unt head trauma; ICP; supratentorial pressure gradient.

occipital region.

ICP after blunt head trauma is usually measured either intraventricularly or epidurally over the nondominant hemisphere. The assumption that there are no significant supratentorial pressure gradients lead to this policy. We report our observations with simultaneous left and right sided epidural ICP measurement in a five year old girl after a car accident.

In the operating room an ICP transducer (Gaeltec Type ICT/b, by Gaeltec Ltd., Dunvegan, Isle of Sky, Great Britain) is placed in between skull and dura precoronally and paramedian on the right side after routine checking for air tightness leaving the dura intact. After point zero calibration in situ the pressure curve shows physiological fluctuations with respiration and pulse rate. ICP moves around l4mmHg and operation for the left sided 1eg fracture is started. The left pupil dilates six hours after implantation of the transducer with monitored ICP showing normal values around l0mmHg with the above mentioned physiological fluctuations and

Fig. 1. Emergency CT

Fig.2. Control CT


Th. Mindermann etal.: Signifrcant Lateralisation of Supratentorial ICP Alter Blunt Head Trauma

ICP and mean arterial pressure


false high. Autopsy reveals massively raised ICP

altered brain, thronbosis

olboth transverse

with an autolytically

sinuses, no midline shift

and no iateral sublalcine herniation.

100 90


Experimental data suggest the presence of intracranial pressure gradients mostly intercompartmental


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referring to the supratentorial space as one compartment2. For this reason routine placement of epidural ICP transducers is performed over the non-dominant hemisphere. We report the clinical observation of a left

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to right hemispheric 30 10 0

terwards. ICP was elevated over the radiologically more compressed hemisphere. As far as we know this is the

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pressure gradient of about mmHg persisting for 6 days and equilibrating af-

first clinical report on a persistent supratentorial latim€ (days)

mean arterial pressure left sided


right sided ICP

Fig.3. ICP and mean arterial pressure

no problems with calibration. The immediate CT control (Fig.2) shows an increase of the left hemispheric swelling with the left ventricle slightly more compressed, no midline shift, contusion marks

bifrontaliy and compressed cisterna ambiens. A second ICP transducer (Gaeltec Type ICT/b) is placed accordingly on the left side creating the rare situation of simultaneous bilateral supratentorial ICP monitoring. Now both probes show fluctuations with respiration and pulserate, both can be zeroed without problems. The left probe

consistently indicates ICP values around 4OmmHg with the right indicating ICP around l0mmHg with congruent reaction of both to hyperventilation but 30 mmHg apart. Now both pupils are dilated and non-reactive. Switching of the electronic connection of the transducers does not alter the situation with left hemispheric ICP values 3OmmHg above right hemispheric values. Until the 5th day after the arcident left sided ICP is recorded persistently about 3OmmHg above right sided ICP equilibrating afterwards. The graph (Fig.3) shows average daily ICP and mean arterial pressure values as measured simultaneously with up to 65 recorded values/day. The arrow indicates the day of the accident. Cerebral perfusion pressure mirros this pattern with left sided values 20-40 mmHg below the right side. Treatment consists olmanual hyperventilation and barbiturates. The child dies on the 9th day alter the accident, never regaining consciousness with pupils always dilated and non-reactive to light. Continuous bilateral ICP monitoring has been perlormed for 9 days. Post mortem both ICP probes are removed and tested. Both transducers are still air tight. The left probe indicates given test pressures correctly from 0-100mmHg, the right indicates given test pressures above their value: 25mmHg are indicated as 29mmHg, 50 mmHg as 59 mmHg and 100 mmHg as 121 mmHg. In the clinically relevant range right hemispheric pressure is recorded as a slightly

teralized pressure difference. An intercompartmental pressure gradient has been reported clinically when simultaneous pressure monitoring of the infratentorial and supratentorial space revealed a diflerence of 50o in the first l2 hours after posterior fossa surgery equilibrating after 48 hoursl. We initially monitored dght sided ICP representing the radiologically less compressed hemisphere missing the experimentally proven point of focal exhaustion ol tissue compliance in the presence of a fast expanding intracranial mass which in our case was the post-traumatic oedema of the left side2. The question arises whether the supratentorial space should rather be feferred to as two compartments than one subdividing the intracranial space into three

compartments allowing considerable pressure gradients between each compartment. Intraventricular ICP measurement can only lead to average supratentorial ICP values and is likely to miss peak pressures in the presence of a gradient. We therefore will abandon our policy of routine placement of epidural ICP transducers on the right side in favour of the radiologically mofe compressed side.




RH, Kleiner LI, Krzeminski JP, Buchheit WA

(1989) Intracranial pressure monitoring in the posterior fossa: a preliminary report. J Neurosurg 71: 503 505

2. Symon L, Dorsch NWC (1975) The distribution of pressures within the intracranial cavity. In: Lundberg N e/ai (eds) Intracranial pressure


Springer, Berlin Heidelberg New York, pp

203-208 Correspondence and Reprints: Dr. Th. Mindermann, Neurochirurgische Universitiitsklinik, Kantonsspital Basel, CH-4031 Basel, Switzerland.