Masui. The Japanese journal of anesthesiology
-
Oscillometric noninvasive arterial pressure monitoring devices frequently fail to measure pressure precisely in patients with arrhythmia, such as atrial fibrillation, because beat-by-beat changes in pulse pressure and mean pressure level distort the relation between cuff pressure and oscillometric wave amplitude. To overcome this problem, we developed a new algorithm for oscillometric measurement in which oscillometric wave amplitude is corrected according to changes in pulse pressure and mean arterial pressure level. In 7 patients with atrial fibrillation, we compared systolic pressure thus estimated with that simultaneously measured invasively in the radial artery and averaged during oscillometric measurement. ⋯ Correction based on plethysmographically estimated pulse pressure decreased unmeasurable cases to 6% (P < 0.01). Standard error of systolic pressure estimates was 6.44 +/- 1.83, 4.10 +/- 0.85, and 4.75 +/- 1.26 mmHg with no, invasive, and plethysmographical correction in this order (P < 0.01). We conclude that oscillometric wave amplitude correction based on beat-by-beat pulse pressure and mean arterial pressure level lessened the number of unmeasurable cases and improved measurement precision in patients with atrial fibrillation.
-
[The changes of bispectral index induced by administration of midazolam during propofol anesthesia].
The effect of the additional administration of midazolam or flumazenil on bispectral index (BIS) during propofol anesthesia was investigated in 22 scheduled surgical patients. Midazolam 10 or 30 micrograms.kg-1, or flumazenil 6 or 12 micrograms.kg-1 was injected to the patients to evaluate their effect on BIS after achieving steady state of hypnosis more than 1 hr of propofol anesthesia with 5 mg.kg-1.hr-1. The only midazolam 30 micrograms.kg-1 significantly reduced BIS value from 47.8 +/- 8.6 to 36.8 +/- 6.5. The synergistic interaction between midazolam and propofol assessed by BIS might be less clear than that assessed by hypnotic dose of propofol using psychopharmacological investigation.