Data processing and analysis of data

For the validation of CIC and the evaluation of ICP management, the CIC entries were related to automatically collected ICP data. High frequency physiological patient monitoring data are routinely collected from the bedside monitors, by the ODIN data monitoring and collection system, developed in Edinburgh and Uppsala by Tim Howells and colleagues [7]. Invasive physiological data, e.g. arterial blood pressure and ICP, is stored in the ODIN database. The clocks of CIC and ODIN systems are both synchronized with a time service to avoid discrepancies. Collected registrations from CIC were merged with 1 Hz (the 1 s mean value) ODIN data of intracranial pressure to combine the time-stamped treatment information from CIC with the collected physiological monitoring data. The study period was 3 days or longer if there were ongoing ICP problems.

The start of a potential ICP insult was defined as when ICP is above 20 mmHg for 5 min. The timespan of the ICP insult stretches from the start of such episode until the start of when ICP is below 20 mmHg for 5 min (Fig. 2). The NIC staff were not informed about the definition and were expected to treat according to the management protocol, i.e. when ICP was above 20 mmHg for a few minutes.

Definition of a potential ICP insult with start and end of episode marked with yellow arrows