Introduction ICM+ software encapsulates our 20 years' experience
in brain monitoring. It collects data from a variety of bedside monitors
and produces time trends of parameters defi ned using confi gurable
mathematical formulae. To date it is being used in nearly 40 clinical
research centres worldwide. We present its application for continuous
monitoring of cerebral autoregulation using near-infrared spectroscopy
(NIRS).
Methods Data from multiple bedside monitors are processed by ICM+
in real time using a large selection of signal processing methods. These
include various time and frequency domain analysis functions as well as
fully customisable digital fi lters. The fi nal results are displayed in a variety
of ways including simple time trends, as well as time window based
histograms, cross histograms, correlations, and so forth. All this allows
complex information from bedside monitors to be summarized in a
concise fashion and presented to medical and nursing staff in a simple way
that alerts them to the development of various pathological processes.
Results One hundred and fi fty patients monitored continuously with
NIRS, arterial blood pressure (ABP) and intracranial pressure (ICP), where
available, were included in this study. There were 40 severely headinjured
adult patients, 27 SAH patients (NCCU, Cambridge); 60 patients
undergoing cardiopulmonary bypass (John Hopkins Hospital, Baltimore)
and 23 patients with sepsis (University Hospital, Basel). In addition,
MCA fl ow velocity (FV) was monitored intermittently using transcranial
Doppler. FV-derived and ICP-derived pressure reactivity indices (PRx, Mx),
as well as NIRS-derived reactivity indices (Cox, Tox, Thx) were calculated
and showed signifi cant correlation with each other in all cohorts. Errorbar
charts showing reactivity index PRx versus CPP (optimal CPP chart)
as well as similar curves for NIRS indices versus CPP and ABP were also
demonstrated.
Conclusions ICM+ software is proving to be a very useful tool for enhancing
the battery of available means for monitoring cerebral vasoreactivity and
potentially facilitating autoregulation guided therapy. Complexity of data
analysis is also hidden inside loadable profi les, thus allowing investigators
to take full advantage of validated protocols including advanced
processing formulas.