B a c k g r o u n d: Near Infrared Spectroscopy (NIRS) is considered a reliable assessment method of a balance between cerebral oxygen demand and supply. One of forms of anaesthesia applied during extensive abdominal surgical procedures is the epidural anaesthesia. Its application in addition to the general anaesthesia is a commonly accepted form of anaesthesia in patients undergoing abdominal surgery. The aim of this study was to verify the hypothesis that epidural blocks may have eff ects on cerebral saturation in patients undergoing abdominal surgery under general anaesthesia.
M e t h o d s: Cerebral saturation was monitored intrasurgically. Reduction of cerebral oxymetry by over 25% in relation to the baseline, or cerebral oxymetry value below 50% was considered clinically significant.
R e s u l t s: One hundred and one (101) subsequent and non-randomised patients, age between 35 and 84 years (mean 64 ± 10) qualifi ed for major abdominal surgeries were enrolled. In 14 (13.9%) patients of 101 enrolled a clinically signifi cant reduction of cerebral saturation was observed. In 50 (49.5%) of the enrolled patients, the epidural anaesthesia was applied along the general anaesthesia. A clinically signifi cant reduction of cerebral saturation was observed in 9 of them. No statistically significant association was found between the application of epidural anaesthesia and development of cerebral desaturation.
C o n c l u s i o n: The application of epidural anaesthesia caused no clinically significant reduction of cerebral saturation during the general anaesthesia in course of major abdominal surgical procedures.
Finger vein biometric systems become increasingly more popular because they offer higher security comparing to other authentication solutions with respect to positive persons experience. Those systems operate on near infrared light (NIR) in wavelength range from around 700 to 1000 nm, however dedicated research to determine impact of NIR lighting on biometric system effectiveness has not been conducted and presented in the literature ever before. In this paper the study of correlation between wavelengths in NIR spectra and effectiveness of person identification in a biometric system is presented. To achieve that goal, a new model of image acquisition system allowing change of light wavelengths has been created and NIR finger vein dataset containing 11 556 images was established. Furthermore, this model was used to perform experimental work and proof that some NIR wavelengths better suit for vein patterns acquisition, allowing to increase the recognition effectiveness of finger vein biometric systems.