Algorithm for Quantifying Frontal EMG Responsiveness for Sedation Monitoring.
BACKGROUND
To study stimulation-related facial electromyographic (FEMG) activity in intensive care unit (ICU) patients, develop an algorithm for quantifying the FEMG activity, and to optimize the algorithm for monitoring the sedation state of ICU patients.


METHODS
First, the characteristics of FEMG response patterns related to vocal stimulation of 17 ICU patients were studied. Second, we collected continuous FEMG data from 30 ICU patients. Based on these data, we developed the Responsiveness Index (RI) algorithm that quantifies FEMG responses. Third, we compared the RI values with clinical sedation level assessments and adjusted algorithm parameters for best performance.


RESULTS
In patients who produced a clinically observed response to the vocal stimulus, the poststimulus FEMG power was 0.33 µV higher than the prestimulus power. In nonresponding patients, there was no difference. The sensitivity and specificity of the developed RI for detecting deep sedation in the subgroup with low probability of encephalopathy were 0.90 and 0.79, respectively.


CONCLUSIONS
Consistent FEMG patterns were found related to standard stimulation of ICU patients. A simple and robust algorithm was developed and good correlation with clinical sedation scores achieved in the development data.
1GE Healthcare Finland Oy,Helsinki,Finland.
Timo Petteri
TP
Lapinlampi
1GE Healthcare Finland Oy,Helsinki,Finland.
Hanna Elina
HE
Viertiö-Oja
1GE Healthcare Finland Oy,Helsinki,Finland.
Matti
M
Helin
1GE Healthcare Finland Oy,Helsinki,Finland.
Kimmo Henrik
KH
Uutela
1GE Healthcare Finland Oy,Helsinki,Finland.
Mika Olli Kristian
MO
Särkelä
2Department of Anesthesiology and Intensive Care Medicine,Helsinki University Hospital,Peijas Hospital,Vantaa,Finland.
Anne
A
Vakkuri
3Department of Clinical Neurological Sciences,London Health Sciences Centre,London,Ontario,Canada.
Gordon Bryan
GB
Young
4Anaesthetics,Critical Care and Pain Medicine,Edinburgh Royal Infirmary,Edinburgh,Scotland.
Timothy Simon
TS
Walsh
D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000465:Algorithms; D004576:Electromyography / Q000187:drug effects / Q000379:methods*; D005152:Facial Muscles / Q000502:physiology*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D064926:Neurophysiological Monitoring / Q000379:methods
D006993:Hypnotics and Sedatives