Objective To investigate different gases and hematocrits on cerebral injury during deep hypothermic circulatory arrest (DHCA) in a piglet model including monitoring by near-infrared spectroscopy (NIRS). Methods Twenty-four piglets were assigned to 4 groups with respect to different blood gas and hematocrit during DHCA. Group A: hematocrit was maintained between 0.25 to 0.30, pH-stat strategy during cooling phases and alpha stat strategy in other phases; group B: hematocrit was maintained between 0.25 to 0.30 and alpha stat strategy; group C: hematocrit was maintained between 0.20 to 0.25, pH-stat strategy during cooling phases and alpha stat strategy in other phases; group D: hematocrit was maintained between 0.20 to 0.25 and alpha stat strategy. Cerebral oxygenations of piglets were monitored continuously by NIRS. The brain was fixed in situ at 6 hours after operation and a histological score for neurological injury was assessed. Results Oxygenated hemoglobin (HbO2) and total hemoglobin (HbT) signals detected by NIRS were significantly lower in group D than those in group A and group B during cooling (Plt;0.05). Oxygenated hemoglobin nadir time was significantly shorter in group A(Plt;0.05). All piglets with oxygenated hemoglobin signal nadir time less than 25 minutes were free from histological evidence of brain injury. Conclusion Combination of pH-stat strategy and higher hematocrit reduces neurological injury after DHCA.
【Abstract】 Objective To compare the accuracy of color-doppler ultrasonography, mammography and near-infrared light scanning for diagnosing breast diseases. Methods The diagnostic accuracy of the above three imaging methods were analyzed and compared with each other on the basis of the postoperative pathological results. ResultsFive hundreds and sixty-five cases (breast cancer: 274 cases, benign diseases: 291 cases) were examined. The sensitivity of color-doppler ultrasonography, mammography and near-infrared light scanning for diagnosing breast cancer were 83.7%(200/239), 84.2%(64/76) and 76.9%(100/130), respectively. The specificity were 88.6%(226/255), 93.2%(69/74) and 82.6%(114/138), and the accuracy were 86.2%(426/494), 88.7%(133/150) and 79.9%(214/268), respectively. Color-doppler ultrasonography and mammography were superior to near-infrared light in the item of accuracy (P＜0.05), especially for lesions of breast cancers that were less than 2 cm. The false negative rate of near-infrared light was higher (48.8%, 21/43）than those of the other methods in detecting breast cancer at early stage. The sensitivity for detecting intraductal papilloma and inflammation of breast using color-doppler ultrasonography were 58.8%(10/17) and 69.2%(18/26), respectively, which were higher than that of near-infrared light scanning 〔0 and 23.5%(4/17)， P＜0.05 and P＜0.01〕. The sensitivity and the accuracy of near-infrared light without physical examination reduced significantly, in which the sensitivity reduced from 76.9%(100/130) to 56.9%(74/130), P＜0.01, and the accuracy reduced from 79.9%(214/298) to 61.9%(166/268), P＜0.01. Conclusion Color-doppler ultrasonography and mammography are accurate imaging methods for diagnosing breast diseases.
ObjectiveTo evaluate the possibility of monitoring regional tissue oxygen saturation by near-infrared spectroscopy (NIRS) for early predicting adverse events in patients with pulmonary atresia.MethodsTwenty-six patients aged under 3 months who were diagnosed with pulmonary atresia and admitted to cardiovascular intensive care unit in our hospital between January 2016 and May 2017, accepted regional tissue oxygenation (cerebral and splanchnic) by near-infrared spectroscopy. There were 19 males and 7 females at age of 2–89 days. A total of 625 times of heart rate, blood pressure, pulse saturation, regional tissue oxygenation, and 98 serum lactate were retrospectively analyzed. The relationship of the tissue oxygen saturation and clinical adverse events was explored.ResultsThe adverse event by routine monitoring was 69 (11.04%) person-time: isolated hypoxia in 27, hypoxia combined increased lactate in 16, hypotension in 6, hypotension combined increased lactate in 17, isolated increased lactate in 3. A reduction of 12.80% in cranial oxygen predicted the high probability of adverse events, with a sensitivity of 85.30% and a specificity of 87.00%. A reduction of 20.60% in splanchnic oxygen predicted the high probability of adverse event, with a sensitivity of 73.50% and a specificity of 91.2%. On average, the splanchnic oxygenation had fell 3 minutes before a reduction of blood pressure, or 45 minutes before an increase in lactate.ConclusionFor preoperative patients with pulmonary atresia, a fall of 12.80% in cranial oxygen saturations, or of 20.60% in splanchnic oxygen saturation, should attract clinician’s awareness.
Most of the existing near-infrared noninvasive blood glucose detection models focus on the relationship between near-infrared absorbance and blood glucose concentration, but do not consider the impact of human physiological state on blood glucose concentration. In order to improve the performance of prediction model, particle swarm optimization (PSO) algorithm was used to train the structure paramters of back propagation (BP) neural network. Moreover, systolic blood pressure, pulse rate, body temperature and 1 550 nm absorbance were introduced as input variables of blood glucose concentration prediction model, and BP neural network was used as prediction model. In order to solve the problem that traditional BP neural network is easy to fall into local optimization, a hybrid model based on PSO-BP was introduced in this paper. The results showed that the prediction effect of PSO-BP model was better than that of traditional BP neural network. The prediction root mean square error and correlation coefficient of ten-fold cross-validation were 0.95 mmol/L and 0.74, respectively. The Clarke error grid analysis results showed that the proportion of model prediction results falling into region A was 84.39%, and the proportion falling into region B was 15.61%, which met the clinical requirements. The model can quickly measure the blood glucose concentration of the subject, and has relatively high accuracy.
Near-infrared fluorescence imaging technology, which possesses superior advantages including real-time and fast imaging, high spatial and temporal resolution, and deep tissue penetration, shows great potential for tumor imaging in vivo and therapy. Ⅰ-Ⅲ-Ⅵ quantum dots exhibit high brightness, broad excitation, easily tunable emission wavelength and superior stability, and do not contain highly toxic heavy metal elements such as cadmium or lead. These advantages make Ⅰ-Ⅲ-Ⅵ quantum dots attract widespread attention in biomedical field. This review summarizes the recent advances in the controlled synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots and their applications in tumor imaging in vivo and therapy. Firstly, the organic-phase and aqueous-phase synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots as well as the strategies for regulating the near-infrared photoluminescence are briefly introduced; secondly, representative biomedical applications of near-infrared-emitting cadmium-free quantum dots including early diagnosis of tumor, lymphatic imaging, drug delivery, photothermal and photodynamic therapy are emphatically discussed; lastly, perspectives on the future directions of developing quantum dots for biomedical application and the faced challenges are discussed. This paper may provide guidance and reference for further research and clinical translation of cadmium-free quantum dots in tumor diagnosis and treatment.