Monitoring methods: SNAP

The SNAP electroencephalogram (EEG) monitor, described as an interesting, innovative EEG tool that samples raw EEG signals and uses its own unique algorithm, analyses both high- (80–420 Hz) and low- (0–20 Hz) frequency components of the signal. This is termed the SNAP index, and it ranges from 100 (arbitrarily representing the fully awake state) to 0 to provide functional data points for patient management. The SNAP is the first commercial EEG-monitoring tool to use Personal Digital Assistant computer technology. The first version of SNAP index was introduced in 2002, and so far there has been little experience with the SNAP device reported in the literature. Compared with other EEG devices, there is no evidence that SNAP is superior to others in generating more specific information about ‘depth of sedation’. Moreover, the influence of high-frequency electromyographic activity on the SNAP needs to be clarified.