危重患者胸腔积液超声测量新方法的建立与应用

目的 探索危重患者胸腔积液超声精确测量的新方法 .方法 选择收住急诊ICU的危重患者46例,应用超声在平卧位、呼气末测定胸腔积液的高度(H)、中间层积液的面积(S)和在后背正中线、腋后线处的厚度(T1、T2),以H×S估算胸腔积液量(Vc),胸腔置管充分引流获取实际积液量.分析胸腔积液实际量与积液高度、厚度、面积及估算量的相关性,比较不同指标和方法 估算积液量的准确性.结果 在总组和各亚组中,胸腔积液实际量与S、(H和S)、Vc的相关性明显好于T1、T2和H.超声测量新方法 获取的估算量与实际积液量有较好的相关性(r=0.778,P＜0.001),而且非常接近实际积液量(平均相差56 ml),尤其在积液量＜500 ml时两者的差别无统计学意义[(417±94)ml对(402±95)ml,t=1.095,P=0.285].Logistic逐步回归分析和受试者工作特征曲线(ROC)分析均表明,以H、S、T1、T2预测实际积液量＞500 ml、400 ml和300 ml,其中以S最为可靠,其阈值分别为30.3 cm2、28.3 cm2和23.1cm2,相应的敏感性和特异性分别为0.77和0.88,0.72和1.0,0.95和1.0.结论 基于积液面积测定基础上建立的胸腔积液超声新测量方法 较传统方法 更可靠和精确,具有重要的临床价值,且测定技术简单,值得推广应用.

Abstract：

Objective To develop a new method to measure pleural effusion volume by ultrasound in critically ill patients. Methods Forty-six critically ill patients admitted to emergency ICU were involved.The height of effusion (H),area of effusion at the middle section (S), thickness of effusion at middle-back line (T1) and posterior axillary line (T2) were measured by ultrasound in supine position at the end of expiration. The measured volume of pleural effusion (Vc) was calculated by H×S,and the actual volume of drainage (V) within 2 hours was also recorded. The correlation of actual volume of pleural effusion (V)with effusion height (H) ,thickness (T1, T2), area (S) and the calculated volume (Vc) were analyzed to decide the most accurate index and method. Results There was much better correlation between actual volume of effusion and S, (H & S), Vc, than these between V and T1 ,T2, H in all patients and subgroup, Vc had good correlation with V and very close to V(the average difference was 56 ml) when the actual volume was less than 500 ml,there was no difference[(417 ± 94)ml vs (402±95)ml, t = 1.095, P = 0. 285]. Both Logistic regression analysis and receiver operating characteristic (ROC) curve showed S was the most reliable index to predict the actual volume to exceed 500 ml,400 ml,and 300 ml when compared with H,S,T1 and T2. The corresponding threshold was 30.3 cm2 , 28.3 cm2 and 23. 1 cm2 , with the sensitivity and specificity of 0. 77 and 0. 88,0.72 and 1.0,0.95 and 1.0, respectively. Conclusions This new method based on measuring the area of effusion by ultrasound is more efficient and reliable than those traditional ones to measure the volume of pleural effusion. It's clinically valuable and easy to perform, and deserves broad application.     

A drive system to add standing mobility to a manual standing wheelchair

Current manual standing wheelchairs are not mobile in the standing position. The addition of standing mobility may lead to improved health and function for the user and may increase utilization of standing wheelchairs. In this project, a chain drive system was fitted to a manual standing wheelchair, adding mobility in the standing position. The hand rims are accessible from both seated and standing positions. The prototype uses 16-inch drive wheels in front with casters in the rear. Additional anterior casters are elevated when seated for navigating obstacles and then descend when standing to create a six-wheeled base with extended anterior support. Stability testing shows the center of pressure remains within the base of support when leaning to the sides or front in both seated and standing positions. Four veterans with spinal cord injury provided feedback on the design and reported that mobility during standing was very important or extremely important to them. The veterans liked the perceived stability and mobility of the prototype and provided feedback for future refinements. For example, reducing the overall width (width from hand rim to hand rim) and weight could make this system more functional for users.     

Contrast-enhanced ultrasound: a new method for TIPS follow-up

Purpose  

To determine the diagnostic value of contrast-enhanced ultrasound (CEUS) for the detection of TIPS (transjugular intrahepatic portosystemic shunt) complications.     

A new polysaccharidic gel matrix for drug delivery: preparation and mechanical properties.

A new type of hydrogel was prepared, under controlled conditions, by diffusion of Ca(II) ions into a solution of the carboxylated derivative of Scleroglucan (Sclerox). The obtained hydrogel was loaded with Theophylline (TPH) and Myoglobin (MGB), two model drugs of remarkably different steric hindrance, and also used, after freeze drying, for the preparation of tablets. Release studies were carried out on both the freshly prepared gel and on the tablets. As far as the gel systems experiments are concerned, the delivery profiles resulted to be deeply dependent on the molecular dimensions of the loaded molecules; TPH was easily released while the larger tested molecule (MGB) remained partially entrapped within the three-dimensional network. Furthermore, in the case of MGB, the release was dependent also on polymer concentration (c(p)): at the highest investigated c(p) value a corresponding lowest delivery of the guest molecule was observed. This effect of polymer concentration on the rate of delivery was studied applying three different mathematical approaches: the one that better fitted the experimental release profile allowed to support the explanation of the mechanism involved in the observed two-step delivery that has been related to the drug trapping inside the clusters of the gel network. The delivery profiles from the tablets showed how the release, in this case, could be related, essentially, to the molecular dimensions of the guest molecules, independently on the c(p) used to prepare the starting hydrogel. TPH was completely delivered in a few hours while the MGB was almost unable to diffuse out of the matrix and more than 80% resulted entrapped in the network for at least 24 h. The novel hydrogel, at different c(p), was also characterized by means of a texture analyzer to inspect its mechanical properties. According to the compression data, the hardness, the work of cohesion and the work of adhesion of the networks were estimated. Furthermore, by means of relaxation experiments, analysed applying the generalized Maxwell model, the gels can be classified as solid viscoelastic materials and the mechanical spectra indicated a predominance of the viscous behaviour, while the Young modulus, E0, as expected, was found to increase with polymer concentration.     

A new ultrasound method for determining the acoustic phase shifts caused by the skull bone

A potential noninvasive means for obtaining the value of ultrasound (US) phase shifts caused by the skull is examined. Knowledge of these shifts could be used in new methods that restore the focus from an US array after transcranial propagation. In the present study, a pulsed signal was emitted from a single element of a therapeutic US transducer. The reflected signal was then recorded. The data were examined over the band width of the transducer, producing amplitude data as a function of frequency. A periodic appearance of local maxima and minima was observed in the data as a function of frequency. We hypothesize that the amplitude is primarily determined by the superposition of the reflections between the interfaces at the inner and outer surfaces of the skull and between the interior interfaces of trabecular and cortical bone. A homogeneous-layer model was used to predict the forward-propagated phase using the reflection data. Good correlation was found between the numeric calculation and phases measured after propagation through single-layer plastic plates. The method was used on curved three-layer plastic phantoms and four excised human skulls. The procedure could eventually be applied toward phasing multielement arrays. Such an application could have implications in both therapeutic and diagnostic brain procedures.     

Diagnosis of fetal lung maturity by ultrasound: a new method and first results.

The first results are presented of a method to determine the maturity of fetal lung by sonography. By comparing the frequency characteristics of lung echoes to those from the fetal liver as a reference organ, we avoid the known pitfalls which previously made it impossible to standardize fetal lung changes with gestation.We examined 222 patients between 27 and 39 completed weeks of gestation. In one ultrasound section we depicted fetal lung and liver simultaneously. Switching to A-mode we registered the frequencies contained in the video envelope in both organs.The registered frequencies were entered digitally in to a computer and checked for mean frequency, maximum frequency and minimum frequency. Afterwards, the ratio of the frequencies of the lung and liver were obtained. For all weeks of gestation, the mean value and standard deviation were calculated.We found the liver to be an adequate reference organ, since there is no change of the reflection pattern between the different weeks of gestation, while significant changes were registered in the fetal lungs. A quotient of Q(mean) lower than 1.1 suggests lung maturity, while values over 1.1 point to immaturity.This appeared to be confirmed in 13 patients who had agreement between amniotic fluid lecithin values and Q(mean). Further comparisons with amniotic fluid results will have to validate these findings.     

Cavitation threshold of microbubbles in gel tunnels by focused ultrasound

The investigation of inertial cavitation in micro-tunnels has significant implications for the development of therapeutic applications of ultrasound such as ultrasound-mediated drug and gene delivery. The threshold for inertial cavitation was investigated using a passive cavitation detector with a center frequency of 1 MHz. Micro-tunnels of various diameters (90 to 800 microm) embedded in gel were fabricated and injected with a solution of Optison(trade mark) contrast agent of concentrations 1.2% and 0.2% diluted in water. An ultrasound pulse of duration 500 ms and center frequency 1.736 MHz was used to insonate the microbubbles. The acoustic pressure was increased at 1-s intervals until broadband noise emission was detected. The pressure threshold at which broadband noise emission was observed was found to be dependent on the diameter of the micro-tunnels, with an average increase of 1.2 to 1.5 between the smallest and the largest tunnels, depending on the microbubble concentration. The evaluation of inertial cavitation in gel tunnels rather than tubes provides a novel opportunity to investigate microbubble collapse in a situation that simulates in vivo blood vessels better than tubes with solid walls do.     

A new technique utilizing ultrasound to aid in intrauterine transfusion

A new technique is described which utilizes ultrasound to diminish fetal exposure to x ray during intrauterine transfusion. In replacing x ray imagery, ultrasound better localizes the exact position of the intrauterine contents, including the vital fetal intraabdominal structures. Using an A mode needle aspiration transducer, it is possible to guide the tip of the transfusing needle into the center of the fetal intraperitoneal cavity.     

A method to estimate wall shear rate with a clinical ultrasound scanner

A simple technique to estimate the wall shear rate in healthy arteries using a clinical ultrasound scanner has been developed. This method uses the theory of fully developed oscillatory flow together with a spectral Doppler trace and an estimate of mean arterial diameter. A method using color flow imaging was compared with the spectral Doppler method in vascular phantoms and found to have errors that were on average 35% greater. Differences from the theoretic value for the time averaged wall shear rate using the spectral Doppler method varied by artery: brachial −9 (1) %; carotid −7 (1) %; femoral −22 (4) %; and fetal aorta −17 (10) %. Test measurements obtained from one healthy volunteer demonstrated the feasibility of the technique in vivo. E-mail: (james.blake@ed.ac.uk)     

Third-dimension sweep: new scanning method in diagnostic ultrasound

The inability to image the 3rd dimension has meant a loss of valuable information, e.g., examination of an IUD in the uterine cavity. Whatever plane is examined longitudinal, transverse, or oblique the image always is a 2-dimensional tomograph producing either bars or dots. Even when the transducer lies perpendicular to the long axis of the IUD, the IUD cannot be visualized as a whole because the 1st bar produces an acoustic shadow that covers all the other bars. A technique now exists for obtaining the 3rd dimension by moving a linear array transducer over the area to be examined, which produces an endless number of images on the screen. Since the commonly used real-time scanners are not equipped with storage capacity, these images immediately fade away. This problem can be resolved by using a Polaroid camera as a storage device. The shutter is opened for the longest exposure possible, i.e., 1 second, while the diaphragm is closed. During this 1 second of exposure, the linear array transducer is "swept" over the area for examination using the compound movement technique. A second is a relatively long time, but some training is necessary before the operator can easily perform the "sweep." If the whole movement cannot be carried out in 1 second, an additional second can be used. This will rusult in a slightly overexposed picture, but these are sometimes even easier to interpret. It is important that the area be well lubricated, and the patient stop breathing for the duration of the scan. The equipment used in the study included a Picker 2000 and a Unirad real-time scanner. Both scanners were handled in the same way, and the same technique was used. Different kinds of IUDs were visualized and recorded.     

Validation of a new method based on ultrasound velocity dilution to measure cardiac output in paediatric patients

Purpose

To validate a novel method of ultrasound dilution (COstatus^®; Transonic Systems, Ithaca, NY) for measuring cardiac output in paediatric patients after biventricular repair of congenital heart disease.

Methods

Children undergoing biventricular repair of congenital heart disease were prospectively identified. Patients with significant intracardiac shunts were excluded. Postoperative cardiac output was measured by ultrasound dilution (COud) and concurrently calculated by the Fick equation (COrms) using measured oxygen consumption by respiratory mass spectrometry.

Results

Thirty-five patients were studied generating 66 individual data sets. Subjects had a median (interquartile range) age of 147 days (11, 216), weight of 4.98 kg (3.78, 6.90) and body surface area of 0.28 m² (0.22, 0.34). Of the patients, 66 % had peripheral arterial catheters and 34 % had femoral cannulation; peripheral arterial lines accounted for 6/8 of unsuccessful studies due to inability to generate sufficient flow. The site of the central venous cannula did not impact the feasibility of completing the study. A mean bias of 0.00 L/min [2 standard deviation (SD) ± 0.76 L/min] between COud and COrms was found with a percentage error of 97 %. When comparing cardiac index, bias increased to 0.13 L/min/m² (2SD ± 2.16 L/min/m²).

Conclusions

Cardiac output by ultrasound dilution showed low bias with wide limits of agreement when compared to measurement derived by the Fick equation. Although measurements through central and peripheral arterial lines were completed with minimal difficulties in the majority of patients, the application of COstatus^® in neonates with low body surface area may be limited.     

Contrast agent bubble and erythrocyte behavior in a 1.5-MHz standing ultrasound wave

Human erythrocytes and Optison contrast agent have been exposed to ultrasound, both alone and in combination, in a single-half-wavelength chamber driven at its resonance frequency (fo) of 1.5 MHz. Cell movements were recorded by video microscopy at speeds up to 500 frames/s. The hypothesis that cells near a standing wave pressure node might be stressed by the microbubble products of sonicated contrast agent was examined. In the absence of contrast agent, cells moved rapidly to form an aggregate in the standing wave pressure node plane. First subharmonic and second harmonic emissions were detected from cell-contrast agent suspensions immediately on exposure to a threshold peak pressure amplitude of 0.98 MPa. Emissions at 3fo/2 occurred at 1.47 MPa, whereas white noise and lower-order subharmonic emissions coincided with the appearance of visible bubbles at a threshold of approximately 1.96 MPa. Cells exposed together with contrast agent at a pressure of 0.98 MPa precessed very rapidly about the pressure node plane. This behavior was discussed in the context of a recent analysis predicting that, in contrast to the situation for lower-pressure amplitudes, subresonant size bubbles translate about pressure node plane if the driving pressure amplitude is sufficiently high. Many precessing erythrocytes were clearly spiculated and this morphology persisted after the cells had left the area of precession. Hemoglobin release was significant under conditions inducing precession with first subharmonic and first harmonic emissions. Protein release increased discontinuously near the pressure thresholds, where more complex categories of frequency emission were detected. The potential of this system, which induces erythrocyte morphology changes and some protein release at the first emission threshold, to provide some control on the membrane-permeabilizing stress experienced by cells in a cavitation field is discussed.     

A new method to measure necrotic core and calcium content in coronary plaques using intravascular ultrasound radiofrequency-based analysis

Although previous intravascular ultrasound (IVUS) radiofrequency-based analysis data showed acceptable reproducibility for plaque composition, measurements are not easily obtained, particularly that of lumen contour, because of the limited IVUS resolution. The purpose of this study was to compare a new measurement method (Shin’s method) and the conventional measurement method for necrotic core and calcium content in atherosclerotic lesions using Virtual Histology-intravascular ultrasound (VH-IVUS). Fifty-seven patients with unstable angina who underwent elective percutaneous coronary intervention were included. Shin’s method focuses on catheter contour, instead of lumen contour, and vessel contour. Patients ages ranged from 46 to 88 years, and 34 were men. A total of 1,401 frames from 59 culprit lesions were assessed. There were no significant differences in the mean area and volume of necrotic core and dense calcium between the two methods. Correlation coefficients (R) were ≥0.99 for all above mentioned parameters (P < 0.001). Between methods, the absolute differences in mean area and volume of necrotic core were 0.02 ± 0.02 mm2 and 0.34 ± 0.29 mm3, respectively, while for mean area and volume of dense calcium, the absolute differences were 0.04 ± 0.07 mm2 and 0.36 ± 0.52 mm3, respectively. The reproducibility of Shin’s method was excellent. For area of the necrotic core and dense calcium, the means of the differences between the two measurements were nearly zero, and the reproducibility coefficients were within 1% of the means of the two measurements. Mean analysis time for both measurements was 26.8 ± 6.7 min/segment in the conventional method and 3.3 ± 0.6 min/segment in Shin’s method. Shin’s method for measurement of necrotic core and dense calcium using VH-IVUS demonstrated a good correlation with the conventional method and excellent reproducibility. Also, Shin’s method required a significantly shorter analysis time than the conventional method. Therefore, Shin’s method could replace the conventional method for necrotic core and calcium measurement in atherosclerotic lesions, and it might be useful in the catheterization laboratory for online clinical decision.     

纤维蛋白凝胶基质材料用于组织工程修复兔关节软骨缺损与Ⅰ型胶原凝胶和混合凝胶性能特征的比较

目的:观察纤维蛋白凝胶、Ⅰ型胶原凝胶、混合凝胶3种不同生物型细胞外基质用于组织工程修复兔关节软骨缺损形态学及性能特征比较。方法:实验于2002-01/2003-12在哈尔滨医科大学附属二院实验中心进行。6月龄日本大耳白兔48只。①人工软骨制备:传代培养兔骨髓基质干细胞,与纤维蛋白原凝胶、Ⅰ型胶原凝胶、纤维蛋白-Ⅰ型胶原混合凝胶混合制成3种人工软骨。②模型制备与动物分组:兔麻醉后取膝关节外侧切口,显露髌股关节面,作直径4.5mm,深3mm转孔获得关节软骨缺损模型。48只兔分为4组,每组12只。纤维蛋白凝胶组,缺损区充填骨髓基质细胞纤维蛋白凝胶;Ⅰ型胶原凝胶组,充填骨髓基质细胞Ⅰ型胶原凝胶;混合凝胶组,充填骨髓基质细胞纤维蛋白-Ⅰ型胶原混合凝胶;空白对照组,不充填材料。术后各组动物膝关节不予外固定,自由活动。③标本观察:分别于4,8,12周每组取3只(6侧膝关节)麻醉后处死,行膝关节大体观察,选择损伤区股骨干切片作苯胺蓝、苏木精-伊红染色、Ⅱ型胶原免疫组织化学染色采用光学显微镜观察,并按改良的Seller评分(0分为正常关节,分数越高表示关节退行性变越严重)进行量化评分。结果:①各组兔膝关节4周及12周时大体形态学观察:4周时:纤维蛋白凝胶组、混合凝胶组为淡粉色半透明的软骨样结构,Ⅰ型胶原凝胶组、空白对照组多数缺损区仍呈暗红色,表面不规则。12周时:纤维蛋白凝胶组、混合凝胶组修复组织与周围软骨平滑过渡高度一致、光泽度较正常软骨略差;Ⅰ型胶原凝胶组、空白对照组修复区多数不平整,中央凹陷且存在龟裂。②各组兔股骨组织切片观察结果:纤维蛋白原凝胶、混合凝胶组各时间点组织化学染色均显著优于Ⅰ型胶原凝胶组和空白对照组;纤维蛋白原凝胶、混合凝胶组无显著差异。③组织切片的Seller评分结果:纤维蛋白凝胶组、混合凝胶组在8,12周均显著低于Ⅰ型胶原凝胶组与空白对照组犤8周:(19.7,20.5)分比(27.0,25.1)分,P<0.05;12周:(7.4,9.1)分比(18.2,20.0)分,P<0.05犦。结论:纤维蛋白凝胶作为支架材料修复缺损软骨,材料成分接近透明软骨,优于Ⅰ型胶原,与纤维蛋白Ⅰ型胶原混合物无显著差异,可作为理想的细胞外基质用于组织工程修复关节软骨缺损。     

A direct method for ultrasound prediction of day of delivery: a new, population-based approach.

OBJECTIVES: To introduce a direct population-based method for prediction of term based on ultrasound measurements of the biparietal diameter and femur length in the second trimester of pregnancy. METHODS: Our data consisted of 41 343 ultrasound scans from a non-selected population, prospectively collected during the years 1987-2004. Using measurements of biparietal diameter and femur length, we constructed prediction curves for term by computing median remaining time of pregnancy from the ultrasound measurement to birth. A local linear quantile regression method was used to smooth the median and quantile curves. RESULTS: The quality of term prediction was stable over the prediction range for both biparietal diameter (25-60 mm) and femur length (11-42 mm). The femur-based predictions were nearly as good as those of the biparietal diameter. For the biparietal diameter, the median of the prediction residual was -0.09 days; 87.2% of the births fell within +/- 14 days of the predicted day of delivery, 3.5% births were classified as preterm and 4.3% as post-term. The corresponding figures for femur length were - 0.04 days, 86.7%, 3.6% and 4.5%. The covariates maternal age, parity, mother's smoking habits, sex of the fetus and examination year generally affected the predicted term by less than 1 day. CONCLUSIONS: This direct ultrasound-based prediction of term using population-based data avoids selection biases possibly present in smaller prospective samples. The model obviates the dependence on last menstrual period found in standard methods for term prediction, and allows an immediate assessment of prediction quality in a population setting. The femur-based predictions had a quality similar to those based on the biparietal diameter. The model can be updated continuously as new data are collected.     

Quantitative response of volumetric variables measured by a new ultrasound dilution method in a juvenile model of hemorrhagic shock and resuscitation

ObjectiveNew volumetric variables of preload, such as total end-diastolic volume index (TEDVI) and active circulation volume index (ACVI) and central blood volume index (CBVI), may represent good indicators of preload and predictors of fluid responsiveness. During acute changes of intravascular volume these variables would allow a more accurate intervention.AimThe aim of the present study was to investigate the changes in TEDVI, ACVI, CBVI in a juvenile model of hemorrhagic shock and resuscitation.MethodsTwelve anaesthetized ponies (3–8 months of age) were studied at normovolaemia (BASE), after blood withdrawal to mean arterial pressure (MAP) of 40 mmHg (HEMO), after infusion of norepinephrine to reach a MAP of ±10% of baseline (HE-NE), and after retransfusion of shed blood (RESU). TEDVI, ACVI, CBVI were measured by Ultrasound Dilution (UD) technology with CoStatus device. Data were analyzed using 1-way (ANOVA) followed by Bonferroni's multiple pairwise comparisons. Evaluation of dependence between CoStatus volumetric variables and stroke volume index (SVI) were performed using the linear regression analysis and calculating the r² coefficient of determination.ResultsTEDVI and ACVI changed significantly during HEMO and RESU status. NE administration induced MAP and CVP significant changes, whereas TEDVI and ACVI remained unchanged. CBVI showed high variability and seemed to be inconsistent on the identification of the volume status. In the correlation analysis, only TEDVI consistently correlated with SVI and volume induced SVI changes.ConclusionsIn this animal model, TEDVI and ACVI were superior to CBVI in consistently reflecting hemorrhage. TEDVI but not ACVI and CBVI correlated with volume-induced changes in SVI. NE administration did not affect this correlation.