The intensive care multimodality monitoring system adopted in the Cambridge Neurosurgical Unit is based on software for the standard IBM compatible personal computer, equipped with a digital to analogue converter and RS232 serial interface. The first version of the software was introduced into clinical practice in Poland, Denmark and the UK in the middle 1980s and has subsequently been extended into a system for multimodal neuro-intensive care monitoring (ICM) and waveform analysis of intracranial pressure used in Cambridge UK and other centres in Europe (Copenhagen, Goteborg, Toulouse) and United States (Detroit).
In a clinical neuroscience department huge amounts of data can be taken from each patient regarding, for example, cerebral processes, oxygenation, and metabolite production and function. Monitoring changes in data requires time-consuming analysis of a variety of complex signal processing, which can generate overwhelming amounts of data configurations, with the resulting need in choosing parameters and making decisions on how data should be interpreted. This information then requires processing to make it understandable and easily presentable to medical staff.
Most data has been derived from head injured and hydrocephalus patients. However, the same or similar techniques are being increasingly applied to those suffering from severe stroke, subarachnoid haemorrhage, cerebral infections, encephalopathy, liver failure, benign intracranial hypertension, and so on.
Apart from monitoring of multiple variables, describing dynamics of the studied pathology, some secondary indices have proved to be useful in clinical neurosciences. The best known example is the cerebral perfusion pressure, calculated as a difference between mean arterial pressure and ICP. More sophisticated indices describing cerebrospinal compensatory reserve, pressure autoregulation and vascular reactivity were introduced to clinical practice recently and proved to be useful in head injury or poor grade subarachnoid haemorrhage.
Carbon-dioxide or acetozolamide reactivity indices are good descriptors of haemodynamic reserve in patients with carotid artery stenotic disease. Transient-hyperaemic response is a simple test of cerebral autoregulation used in patients after subarachnoid haemorrghage. Analysis of cerebrospinal fluid circulatory and compensatory reserves was used in hydrocephalic patients for at least few decades. It aids decision abut shunting and also helps in objective detection of shunt failure, needing revision. This method has been refined in form of so-called computerized infusion test with built in data-base derived from the UK Shunt Evaluation Laboratory, valuable in shunt testing in-vivo.
Overnight ICP monitoring to detect abnormal CSF dynamics (hydrocephalus, pseudotumor cerebri, cranistenosis) has been supplemented by automatic analysis of B waves of ICP, waveform assessment of pulse wave and respiratory wave.
All these, already documented methodologies, are incorporated in the new software as pre-defined set up configurations. On top of this, performance of the software may be programmed and new form of analysis may be added by the user. Flexibility of the software is therefore virtually unlimited.