Objective To assess the protective effects of a new type of leukocyte-depletion filter-1 (LD-1) on red blood cells during cardiopulmonary bypass(CPB). Methods Twelve Mongolian dogs, weight range 25-30kg, were divided into control group and leukocyte depletion group (LD group) with random number table, LD group (n=6) had our new type of leukocyte depletion filter-1 placed in venous line which was used within the first 5 minutes after onset of CPB. The control group (n=6) had no leukocyte depletion filter installed in the circuit. CPB was set up by cannulated with a venous cannula through the right atrium and with an aortic cannula after median sternotomy. Aorta was clamped at 10 minutes of CPB and released at 70 minutes of CPB. Dogs were observed for 2 hours after weaning from CPB. Blood samples were collected prior to, at 10, 40, 75 minutes, end of and 2 hours after CPB to determine circulating leukocytes, erythrocyte fragility and plasma levels of malondialdehyde(MDA), superoxide dismutase(SOD) and free hemoglobin(FHB). Results Leukocyte numbers were significantly reduced in LD group during CPB(Plt;0.01), and lower than those in control group (Plt;0.05). Plasma levels of SOD dropped after 75 minutes of CPB in control group, but those kept normal in LD group, and higher than those in control group at 2 hours after CPB (Plt;0.05, 0.01). Serum MDA and FHB levels increased sharply in two groups (Plt;0.01), but were lower in LD group than those in control group. The concentrations of NaCl when starting and complete hemolysis were also lower in LD group than those in control group at end of and 2 hours after CPB. Conclusion The new type of LD-1 used in venous line only 5 minutes after onset of CPB can decrease leukocyte counts, and reduce erythrocyte injury effectively.
The increased morbidity and mortality following cardiopulmonary bypass （CPB） may be due to the development of systemic inflammatory response syndrome （SIRS）. Leukocyte, especially neutrophil, plays a crucial role in SIRS during and after CPB, so the leukocyte removal by filtrations appears to be a logical anti-inflammatory strategy. Many articles reported that leukocyte depletion filter can decrease the potential adverse effects during CPB and reduce the morbidity and mortality following CPB. But the protective effects of the filter varied greatly from paper to paper. This may be due to the different design and biocompatibility of the filter at present, But, because the leukocyte plays a central role in SIRS, leukocyte depletion filter would be an important apparatus in therapy of noninfectious inflammation induced by CPB after it was improved.
Objective To summarize the probability of pulmonary embolism （PE） induced by lower extremity deep venous thrombosis （DVT） and investigate the role of vena cava filter （VCF） in preventing from PE. Methods The clinical data of 1 058 patients with lower extremity DVT from January 2005 to January 2012 were analyzed retrospectively. Results The PE rate was 3.21% （34/1 058） and the death rate was 1.42% （15/1 058） in 1 058 patients with lower extremity DVT. The VCF was implanted in 171 of 1 058 patients. The VCFs of 151 patients were implanted from femoral vein， 20 patients were implanted from jugular vein. The PE rates were 3.61% （32/887） and 1.17% （2/171） and the death rates were 1.69% （15/887） and 0 （0/171） in patients without VCF and with VCF， respectively. Both of them occurred in the first ten days. PE could keep as long as 35 d. The PE rate and death rate in the patients without VCF were significantly higher than those in the patients with VCF （P＜0.01）. The PE rates and death rates in both lower extremities DVT were higher than those in patients with the right and left ones （P＜0.05）， which in the right lower extremity were higher than those in the left one （P＜0.05）. The PE rate and death rate in the patients with lower extremity DVT combined with vena cava thrombosis were significantly higher than those in the patients with central type （P＜0.05）， which in the central type were significantly higher than those in the peripheral type （P＜0.05）， there were no significant differences between peripheral type and mixed pattern. The follow-up time was from 1 month to 7 years with （39±19） months， the patency rate of VCF was 98.7%. There were no filter migration， declination， and failure of expansion. Conclusions VCF can prevent from PE effectively， but the indications must be controlled.
Objective To explore the therapeutic effect of catheter-directed thrombolysis combined with vena cava filter on deep venous thrombosis (DVT) of lower extremity.Methods The clinical data of 65 patients with DVT of lower extremities from January 2008 to August 2009 were analyzed retrospectively, whose course of diseases were not more than 7 d and clinical type included central type and mixed type. Thirty-two cases were treated with catheter-directed thrombolysis combined with vena cava filter, while administrating treatment of anticoagulation and activating blood circulation to dissipate blood stasis, which were named as study group. Thirty-three cases were treated traditionally with thrombolysis, anticoagulation, and activating blood circulation to dissipate blood stasis, which were named as control group. The course of therapy was continued 10-14 d, then the efficacy in two groups patients was evaluated. Results It was (7.35±1.42) cm that circumference difference before treatment between affected extremties and unaffected extremties in study group, which of 3, 7, and 14 d after treatment was (4.21±1.12) cm， (2.87±0.98) cm, and (1.22±1.02) cm, respectively. Circumference difference between before and after treatment had significant difference in study group (Plt;0.01). It was (6.97±1.27) cm that circumference difference before treatment between affected extremties and unaffected extremties in control group, which of 3, 7, and 14 d after treatment was (5.72±1.31) cm, (4.58±0.88) cm, and (3.18±1.24) cm, respectively. Circumference difference between before treatment and 3, 7, and 14 d after treatment had significant difference in control group (Plt;0.05 or Plt;0.01). Circumference difference before treatment in two groups had no significant difference (Pgt;0.05). Circumference difference after treatment at different time points in two groups was significantly different, respectively (Plt;0.01). Circumference difference after treatment at different time points in study group was significantly less than that in control group, respectively (Plt;0.01). After 14 d, complete recanalization rate （71.88%, 23/32） and cure rate (71.88%, 23/32) of iliofemoral vein in study group were significant higher than that (36.36%, 12/33) in control group (Plt;0.01). No pulmonary embolism occurred. Conclusion In terms of ideal therapy targets of DVT of lower extremity, the catheterdirected thrombolysis combined with vena cava filter is obviously superior to traditional thrombolysis treatment.
Objective To discuss and evaluate the value of insertion of inferior vena cava filter in treating lower extremity deep venous thrombosis (DVT). Methods Inferior vena cava filters were placed in 46 patients with lower extremity DVT prior treatment, 20 in which were treated by therapy with anticoagulation and thrombolysis, and therapy with pressure gradient, and the other 26 patients by operation and thrombolysis therapy, and therapy with pressure gradient. Whether patients occurred pulmonary embolism was observed and the form and site of filters were monitored by periodic fluoroscopy. Results Inferior vena cava filters were placed successfully in all patients, 38 cases were implanted permanence inferior vena cava filter, 8 cases were implanted temporary inferior vena cava filter. Symptoms and signs of DVT disappeared or remitted in 44/46 patients after treatment. None of pulmonary embolism was occurred. Follow up 2-24 months (average 13 months) for 36 cases with permanence inferior vena cava filter, there was no complication of the filter and pulmonary embolism occurred. Conclusions The method of inserting inferior vena cava filter is simple and safe, which can prevent pulmonary embolism effectually to offer sufficient safeguard for the treatment of DVT.
Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.
In order to improve the speech quality and auditory perceptiveness of electronic cochlear implant under strong noise background, a speech enhancement system used for electronic cochlear implant front-end was constructed. Taking digital signal processing (DSP) as the core, the system combines its multi-channel buffered serial port (McBSP) data transmission channel with extended audio interface chip TLV320AIC10, so speech signal acquisition and output with high speed are realized. Meanwhile, due to the traditional speech enhancement method which has the problems as bad adaptability, slow convergence speed and big steady-state error, versiera function and de-correlation principle were used to improve the existing adaptive filtering algorithm, which effectively enhanced the quality of voice communications. Test results verified the stability of the system and the de-noising performance of the algorithm, and it also proved that they could provide clearer speech signals for the deaf or tinnitus patients.
The research of sleep staging is not only the basis of diagnosing sleep related diseases, but also the precondition of evaluating sleep quality, and has important clinical significance. In recent years, the research of automatic sleep staging based on computer has become a hotspot and made some achievements. Feature extraction and feature classification are two key technologies in automatic sleep staging system. In order to achieve effective automatic sleep staging, we proposed a new automatic sleep staging method which combines the energy features and least squares support vector machines (LS-SVM). Firstly, we used FIR band-pass filter to extract the energy features of Pz-Oz channel sleep electroencephalogram (EEG) signals, and compared them with those from wavelet packet transform method. Then we designed an LS-SVM classifier to realize the automatic sleep stage classification. The research showed that FIR band-pass filter (with the Kaiser window) performed better than wavelet packet transform (WPT) for energy feature extraction just in terms of the data from the Sleep-EDF Database and the LS-SVM classifier (with the RBF Kernel function) designed was good, and the automatic sleep staging method proposed in this paper was better than many similar methods from other studies with an average accuracy of 88.89% and had a very prosperous application future.
Cough recognition provides important clinical information for the treatment of many respiratory diseases. A new Mel frequency cepstrum coefficient (MFCC) extracting method has been proposed on the basis of the distributional characteristics of cough spectrum. The whole frequency band was divided into several sub-bands, and the energy coefficient for each band was obtained by method of principle component analysis. Then non-uniform filter-bank in Mel frequency is designed to improve the extracting process of MFCC by distributing filters according to the spectrum energy coefficients. Cough recognition experiment using hidden Markov model was carried out, and the results showed that the proposed method could effectively improve the performance of cough recognition.
The successful suppression of clutter arising from stationary or slowly moving tissue is one of the key issues in medical ultrasound color blood imaging. Remaining clutter may cause bias in the mean blood frequency estimation and results in a potentially misleading description of blood-flow. In this paper, based on the principle of general wall-filter, the design process of three classes of filters, infinitely impulse response with projection initialization (Prj-ⅡR), polynomials regression (Pol-Reg), and eigen-based filters are previewed and analyzed. The performance of the filters was assessed by calculating the bias and variance of a mean blood velocity using a standard autocorrelation estimator. Simulation results show that the performance of Pol-Reg filter is similar to Prj-ⅡR filters. Both of them can offer accurate estimation of mean blood flow speed under steady clutter conditions, and the clutter rejection ability can be enhanced by increasing the ensemble size of Doppler vector. Eigen-based filters can effectively remove the non-stationary clutter component, and further improve the estimation accuracy for low speed blood flow signals. There is also no significant increase in computation complexity for eigen-based filters when the ensemble size is less than 10.