title: Use of ICM+ software for on-line analysis of intracranial and arterial pressures in head-injured patients.
abstract: OBJECTIVE
  To summarize our experience from the first 2 years of use of the ICM+ software in our Neurocritical Care Unit (NCCU).
  
  
  METHODS
  Ninety-five head-injured patients (74 males, 21 females), average age 36 years, were managed in the NCCU. Intracranial pressure (ICP) was monitored using Codman intraparenchymal probes and arterial blood pressure (ABP) was measured from the radial artery. Signals were monitored by ICM+ software calculating mean values of ICP, ABP, cerebral perfusion pressure (CPP) and various indices describing pressure reactivity, compensation and vascular waveforms of ICP (pulse amplitude, respiratory, and slow waves), etc.
  
  
  RESULTS
  Mean ICP was 17 mmHg, mean CPP was 73 mmHg. Seven patients showed permanent disturbance of cerebral autoregulation (mean pressure reactivity index above 0.3). Pressure reactivity index demonstrated significant U-shape relationship with CPP, suggesting loss of pressure reactivity at too low (CPP < 55 mmHg) and too high CPPs (CPP > 95 mmHg). Mean ICP was inversely correlated with respiratory rate (R = 0.46; p < 0.0001; reciprocal model).
  
  
  CONCLUSIONS
  The new version of ICM+ software proved to be useful clinically in the NCCU. It allows continuous monitoring of pressure reactivity and exploratory analysis of factors implicating intracranial hypertension.
authors: Academic Department of Clinical Neuroscience, Addenbrooke's Hospital, Cambridge, UK.
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