Comment to the article:

R. J. Firsching, B. Voellger. Evidence-Based Indications for ICP Recording After Head Injury. A Review. Cen Eur Neurosurg 2010; 71: 134–137

The statement of the authors of the article “The evidence based indication for ICP recording after head injury. A review” is correct, that up to now there is no definite proof showing that ICP monitoring improves outcome in traumatic brain injury. The statement, that ICP monitoring is a dangerous procedure, likewise is correct: In the literature the bleeding rate in general is about 5%.

However, the authors did not mention that there is a difference between detection of blood near the catheter and a space occupying bleeding, which is much rarer. Furthermore, to take a series in children instead of one in adults to underline the high complication rate is misleading.

In addition, the author forgot to mention that this is a procedure in severely ill patients with a high risk of deterioration and death. The absolute majority of procedures in intensive care medicine are accepted but unevaluated by EBM criteria. For good reasons nobody will ever try to proof the benefit of resuscitation in a double blind randomized study. Artificial ventilation, online invasive blood pressure measurement or even normalisation of coagulation disorders and so on, all have a high risk, but are used because the logic behind these procedures is self-evident.

The logic and our pathophysiological knowledge of certain diseases will lead to appreciation and judgement between the potential risk and the potential benefit for the patient. Until we will obtain new insights into brain pathology after trauma, our knowledge today is, that a primary brain injury will start a cascade of secondary brain injuries resulting in brain oedema. According to the Monroe-Kellie-doctrine an increase of volume inside the skull will be followed by an increase of the intracranial pressure, which will cause a decrease of the blood supply, aggravating the risk of secondary damage to the brain. From this point of view it makes sense to know the ICP values. Neurological examination is a quite unreliable monitoring, as it only can be performed in intervals and not online. Since the work of Frohwein we are well aware of the benefit of artificial ventilation in head injury patients. However, for ventilation, sedation is often required which hinders accurate neurological examination. Thus, the recommendation to monitor by clinical examination could sometimes equal to wait for a dilated pupil. However, it should be our goal to prevent that deterioration, and not to react after deterioration.

The authors favour the decompressive craniectomy which is an invasive procedure with a rate of complications higher than those of ICP monitoring. Furthermore, decompressive craniectomy is also a procedure which never has shown to improve outcome by EBM criteria. ICP monitoring is mandatory to identify the right moment in which craniectomy is lifesaving and not a needless operation.

In conclusion, it is correct that there is no proof of the effect of ICP monitoring. But it makes sense to obtain as many information as possible about factors which could endanger the life of the critically ill head-injured patient, among which ICP is the major one. Knowledge of ICP is essential for correct decision making, and to abandon deliberately to know the ICP is a step back.

Eckhard Rickels
Allgemeines Krankenhaus Celle
Abt. Neurotraumatologie
Celle, Germany