ABSTRACT
The purpose of this study was prospectively to research the relationship between EEG power spectrum and anesthesia depth. Twenty-four patients,aged 20 to 50 years , ASA grade ,scheduled for selected surgical operations, were randomly divided into two groups:enflurane and isoflurane groups. Anesthesia was induced by thiopental 5 mg/kg and atracurium 6-7 mg/kg intravenously and maintained by inhalation anesthetics. After intubation patients were ventilated mechanically to maintain the level of PETCO2 between 4. 27 and 4. 93 kpa. NIBP,HR,SpO2 , ECG and EEG were recorded during anesthesia. According to TOF stimulation test intravenous atracurium 10-15 mg was given intermittently to maintain the ratio of T4/T1 less than 25%. Two channels EEG monitor was applied with the filtration range from 0 to 30 Hz Anesthesia level, adjusted at 0. 5,0. 8, 1. 0, 1. 3, 1. 5, 1. 3, 1. 0, 0.8 or 0. 5 MAC in sequence ,was maintained for 10 to 15 minutes before SEF (spectral edge frequency)and MPF (median power frequency) were recorded. NIBP decreased and HR increased with the inhaled agent concentration (IAC) level rising. The lowest BPs were 13. 1 /9. 33 kPa and 12. 9/8. 1kpa in both groups. There were negative remarkable correlations between either SEF or MPF and IAC in both groups (=- 0. 94 and -0. 82,P
ABSTRACT
A study was conducted to investigate muscle fatigue during isometric contraction of the indicis proprius using EMG analysis (BIMUTAS Ver. 2. 1) .<BR>The subjects were 8 healthy men (ranging in age from 19 to 42 years) .<BR>Plummets (ranging from 300g to 600g) were placed on the distal knuckle of the index finger to create loads on the indicis proprius muscle. EMG was recorded until the plummet dropped, and the total time required was divided into 10 equal parts. In each part, the EMG record for the first 1000 ms was picked out. Then the mean power frequency (MePF) and median power frequency (MdPF) of the power spectrum were calculated.<BR>The results were as follows:<BR>1) Both MePF and MdPF showed shits to lower frequency bands.<BR>2) Integrated values of the EMG power spectrum increased with time.<BR>3) The time courses of the MePF and MdPF in each EMG sample for the 8 subjects were determined by the 3-point moving average method.<BR>A break-point was observed in each MePF and MdPF diagram.<BR>It was considered that two-break points observed in the time courses of the EMG record were valid as an objective index of local muscle fatigue.