Kaskinoro K.,Intensive Care |
Kaskinoro K.,University of Turku |
Maksimow A.,Intensive Care |
Maksimow A.,University of Turku |
And 6 more authors.
British Journal of Anaesthesia | Year: 2011
Background The bispectral index (BIS) and the spectral entropy (state entropy, SE, and response entropy, RE) are depth-of-anaesthesia monitors derived from EEG and have been developed to measure the effects of anaesthetics on the cerebral cortex. We studied whether they can differentiate consciousness from unconsciousness during increasing doses of three different anaesthetic agents. Methods Thirty healthy male volunteers aged 1930 yr were recruited and divided into three 10-volunteer groups to receive either dexmedetomidine, propofol, or sevoflurane in escalating concentrations at 10 min intervals until loss of consciousness (LOC) was reached. Consciousness was tested at 5 min intervals and after drug discontinuation at 1 min intervals by requesting the subjects to open their eyes. LOC was defined as unresponsiveness to the request and pre-LOC as the last meaningful response. The first meaningful response to the request after drug discontinuation was defined as regaining of consciousness (ROC). For the statistical analysis, pre-LOC and ROC values were pooled to represent the responsive state while LOC values represented the unresponsive state. Prediction probability (PK) was estimated with the jack-knife method. Results The lowest mean values for BIS, SE, and RE were recorded at LOC with all three drugs. The PK values were low for dexmedetomidine (BIS 0.62, SE 0.58, RE 0.59), propofol (BIS 0.73, SE 0.72, RE 0.72), and sevoflurane (BIS 0.70, SE 0.52, RE 0.62). Conclusions Because of wide inter-individual variability, BIS and entropy were not able to reliably differentiate consciousness from unconsciousness during and after stepwise increasing concentrations of dexmedetomidine, propofol, and sevoflurane. © 2011 The Author.
Ge Healthcare Finland Oy | Date: 2013-03-25
A sensor for measuring a concentration of a respiratory gas component is disclosed herein. The sensor comprises at least one radiation source configured to emit radiation and at least one radiation sensing detector configured to receive radiation and provide a signal indicative of the concentration of the gas component. The sensor further comprises an electronics board configured to receive and process the signal to determine the concentration, and an energy storage device configured to supply energy to the radiation source. The electronics board is configured to choose from among at least two different modes, one being an operation mode allowing sufficient energy supply to the radiation source, and another being a rest mode allowing reduced energy supply compared to the operation mode to limit radiation for saving energy within the breathing cycle. A gas analyzer and method for measuring a concentration of a respiratory gas component are also provided.
Ge Healthcare Finland Oy | Date: 2013-02-15
Lapinlampi T.P.,GE Healthcare Finland Oy |
Viertio-Oja H.E.,GE Healthcare Finland Oy |
Helin M.,GE Healthcare Finland Oy |
Uutela K.H.,GE Healthcare Finland Oy |
And 4 more authors.
Canadian Journal of Neurological Sciences | Year: 2014
Introduction: 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 ÂV 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. Conclusion: 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. © 2014 The Canadian Journal of Neurological Sciences Inc.
Tanner A.E.J.,GE Healthcare Finland Oy |
Sarkela M.O.K.,GE Healthcare Finland Oy |
Virtanen J.,GE Healthcare Finland Oy |
Viertio-Oja H.E.,GE Healthcare Finland Oy |
And 3 more authors.
Journal of Clinical Neurophysiology | Year: 2014
PURPOSE:: Problems with the availability of standard EEG monitoring in the intensive care unit have led to the use of recordings that have limited spatial coverage. We studied the performance of limited coverage EEG compared with more traditional full-montage EEG. METHODS:: Continuous EEG recordings were performed on 170 patients using the full-montage 10-20 placement of electrodes as a reference recording and an abbreviated montage of electrodes applied below the hairline (subhairline). Recordings were reviewed independently, with the identity of the patients concealed. RESULTS:: Seizures were found in 8% of patients. Sensitivity for detecting patients with seizures using the subhairline system was 0.54 [95% confidence interval (95% CI), 0.29-0.77] with specificity of 1.00 (95% CI, 0.97-1.00) and positive predictive value of 1.00 (95% CI, 0.65-1.00). For detecting interictal epileptiform activity, we found sensitivity to be 0.60 (95% CI, 0.46-0.74), specificity to be 0.94 (95% CI, 0.88-0.97), and positive predictive value to be 0.81 (95% CI, 0.65-0.91). Performance was poor for triphasic waves, alpha/theta/spindle coma, and suppression. CONCLUSIONS:: The subhairline montage shows excellent specificity for detecting patients with seizure activity but has limited sensitivity. It has relatively poor performance for other EEG phenomena, but further applications in trending and assessing reactivity should be assessed in further studies. Copyright © 2014 by the American Clinical Neurophysiology Society.