Depth of anesthesia monitoring in Norway-A web-based survey.

BACKGROUND: The bispectral index (BIS) monitor is the most frequently used electroencephalogram (EEG)-based depth of anesthesia (DoA) technology in Norwegian hospitals. However, there is limited knowledge regarding the extent and clinical impact of its use and how anesthesiologists and nurse anesthetists use the information provided by the DoA monitors in their clinical practice. METHODS: This cross-sectional survey on the use of DoA monitors in Norway used a web-based questionnaire distributed to anesthesia personnel in all hospitals in Norway. Participation was voluntary and anonymized, and the web form could not track IP sources or respondents' locations. RESULTS: Three hundred and ninety-one nurse anesthetists (n = 324) and anesthesiologists (n = 67) responded. Among the EEG-based DoA monitoring tools, BIS was most often used to observe and assess patients' DoA (98%). Raw EEG waveform analysis (10%), EEG-spectrogram (9%), and suppression rate (10%) were seldom used. Twenty-seven percent of the anesthesia personnel were able to recognize a burst suppression pattern on EEG and its significance. Fifty-eight percent of the respondents considered clinical observations more reliable than BIS. Almost all respondents reported adjusting anesthetic dosage based on the BIS index values (80%). However, the anesthetic dose was more often increased (90%) because of high BIS index values than lowered (55%) because of low BIS index values. CONCLUSION: Despite our respondents' extensive use of DoA monitoring, the anesthesia personnel in our survey did not use all the information and the potential to guide the titration of anesthetics the DoA monitors provide. Thus, anesthesia personnel could generally benefit from increased knowledge of how EEG-based DoA monitoring can be used to assess and determine individual patients' need for anesthetic medication.

Monitoring the Awake and Anesthetized Unconscious States Using Bispectral Index and Electroencephalographic Connectivity Measures.

Objective. Our objective was to compare three electroencephalography (EEG)-based methods with anesthesiologist clinical judgment of the awake and anesthetized unconscious states. Methods. EEG recorded from 25 channels and from four channel bilateral Bispectral index (BIS) electrodes were collected from 20 patients undergoing surgery with general anesthesia. To measure connectivity we applied Directed Transfer Function (DTF) in eight channels of the EEG, and extracted data from BIS over the same time segments. Shannon's entropy was applied to assess the complexity of the EEG signal. Discriminant analysis was used to evaluate the data in relation to clinical judgment. Results. Assessing anesthetic state relative clinical judgment, the bilateral BIS gave the highest accuracy (ACC) (95.4%) and lowest false positive discovery rate (FDR) (0.5%) . Equivalent DTF gave 94.5% for ACC and 2.6% for FDR. Combining all methods gave ACC = 94.9% and FDR = 1%. Generally, entropy scored lower on ACC and higher on FDR than the other methods (ACC 90.87% and FDR 4.6%). BIS showed at least a one minute delay in 18 of the 20 patients. Conclusions. Our results show that BIS and DTF both have a high ACC and low FDR. Because of time delays in BIS values, we recommend combining the two methods.

[Impaired glucose tolerance in patients with acute myocardial infarction]. / Nedsatt glukosetoleranse hos pasienter med akutt hjerteinfarkt.

BACKGROUND: Diabetes and impaired glucose tolerance are associated with increased mortality in patients with acute myocardial infarction. We have used standardised oral glucose tolerance tests shortly after a myocardial infarction. METHODS: 109 patients admitted with acute myocardial infarction were prospectively enrolled in the study. An oral glucose tolerance test was performed the first morning the patients were stable, without pain, nausea or hyperglycaemia. The patients were classified into normal glucose tolerance, impaired glucose tolerance or diabetes, according to the results of the oral glucose tolerance test and fasting plasma glucose levels. RESULTS: 109 patients (25 women) were included. Eight patients were previously diagnosed with diabetes type 2. Oral glucose tolerance was tested for 90 patients, usually the day after admission. The test was positive in 47 patients; 32 of them had 2-h plasma glucose levels between 7.8 and 11.0 mmol/L and were classified as having impaired glucose tolerance, and 15 had 2-h plasma glucose > or = 11.1 mmol/L and were classified as newly diagnosed diabetes patients. Similar body mass indexes and lipid values were found in patients with different glycometabolic states. Smoking was associated with a positive oral glucose tolerance test. INTERPRETATION: More than half of the patients with acute myocardial infarction had undiagnosed impaired glucose tolerance or diabetes type 2, as determined by an oral glucose tolerance test. The test could easily be performed shortly after a myocardial infarction in most of the patients. Oral glucose tolerance testing should be considered in all patients with coronary heart disease without a history of diagnosed diabetes.