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ENGLISH
Chapter 16 Monitoring CSM
The CSM function can be achieved through the External CSM unit, the Built-in CSM module, and the Plugin CSM module.
16.1 Introduction
The Cerebral State Monitoring (CSM) is intended for use in monitoring the hypnotic state of the brain by data acquisition
of EEG signals of the anaesthetized or sedated patient in all areas of the hospital. CSM is a non-invasive measurement tool
to be used by a trained professional to measure the level of consciousness during general anaesthesia and sedation by
use of variations in the frequency content of the spontaneous EEG. It analyses the frequency shifts that take place in the
EEG signal as the level of consciousness changes. Based on this principle, the device calculates the Cerebral State Index
(CSI), which is used to estimate the level of consciousness of the patient.
16.2 Safety Information
If used with High Frequency (HF) surgery please pay attention to the positioning of CSM electrodes. In order to
reduce the hazard of burns, the electrodes should not be located between the surgical site and the electro-surgical
unit return sensor.
The conductive parts of sensors and their connectors, including the neutral sensor, should not contact other
conductive parts including earth and ground.
The monitor will not render accurate reading when used on patients with severe neurological disorders and patients
under 2 years old.
The use of pacemakers might cause either long periods of artefacts or elevated CSI values.
If skin rash or other unusual symptoms are developed, remove sensors from patient.
Ethanol is not recommended as a skin cleanser, for it leaves a film layer that may cause high sensor impedance.
If used with High Frequency surgery during CSM monitoring, then artefacts or elevated CSI value may be caused.
16.3 Understanding CSM Parameters
CSI
The performance of the CSM is based on the analysis of the frequency content of the EEG signal.
The energy of the EEG is evaluated in specific frequency bands. These are used to define two energy ratios called
alpha (α) and beta (β). Both of these show a shift in energy content from a higher to the lower frequencies
during anaesthesia. The relationship between these quantities is also analysed as a separate parameter (β-α).
α
ratio
=ln(E
30-42.5Hz
/E
6-12Hz
)
β
r
atio
=ln(E
30-42.5Hz
/E
11-21Hz
)
The monitor also on-line evaluates the amount of instantaneous burst suppression (BS) in each thirty-second period
of the EEG. This measurement quantifies the amount of “silent” or “flat” EEG period characteristic of the deepest
levels of hypnosis.
These four parameters are used as input to a fuzzy logic classifier system that calculated the Cerebral State Index.
Summary of Contents for 35306
Page 2: ...2 ENGLISH Patient Monitor Operator s Manual ...
Page 21: ...21 ENGLISH Series III Front view Rear view Left view Right view 11 ...
Page 22: ...22 ENGLISH Series IV Front view Rear view Left view Right view 11 Extended Module ...
Page 171: ...2 ESPAÑOL Monitor de paciente Manual de operador ...
Page 343: ...2 FRANÇAIS Moniteur patient Manuel d utilisation ...
Page 362: ...21 FRANÇAIS Série III Vue de face Vue arrière Vue de gauche Vue de droite 11 ...
Page 519: ...2 ITALIANO Monitor Paziente Manuale d Uso ...
Page 538: ...21 ITALIANO Serie III Vista anteriore Vista posteriore Lato sinistro Lato destro 11 ...