舒利迭加无创通气治疗稳定期慢性阻塞性肺疾病的临床研究

目的探讨舒利迭(吸入型肾上腺皮质激素与长效β2-受体激动剂的预混制剂)联合双水平气道正压通气(B iPAP)对稳定期慢性阻塞性肺疾病(COPD)的治疗作用。方法稳定期COPD病人52例,舒利迭TM50/250,1吸/次,2次/d;B iPAP,吸气压力(IPAP)10~20cm H2O,呼气压力(EPAP,也称PEEP)3~6cm H2O,吸氧浓度(FiO2)3L/m in,每天夜间通气6~8h。观察治疗前、治疗后12周病人临床症状、生活质量、健康状态和肺功能。结果治疗前、治疗后12周病人的临床症状、急性加重次数及严重程度、健康状态和生活质量、肺功能等指标比较差异有统计学意义(P<0.05)。结论舒利迭联合B iPAP治疗稳定期COPD病人能够明显改善其症状,提高生活质量,有一定的临床应用价值,对减缓COPD病人肺功能下降有积极意义。     

术前无创正压通气治疗对脊柱侧凸患者围手术期肺功能的影响

目的:研究术前使用呼吸机无创正压通气治疗对脊柱侧凸患者围手术期肺功能的影响。方法:将40例Cobb角≥60°、肺功能存在中度以上限制性通气功能障碍、行脊柱侧凸矫形术的脊柱侧凸患者,随机分成A组和B组,每组20例。A组在术前采用BiPAP呼吸机,经用面罩无创正压通气(NIPPV)治疗1个月;B组常规术前准备。观察A组患者治疗前后肺功能的改善及两组患者围手术期肺功能的差异。结果:两组患者性别、年龄、身高、体重、Cobb角度、手术时间、手术径路、融合椎体数等基本情况比较无统计学差异(P>0.05);A组患者经NIPPV治疗后肺活量(VC)、肺活量占预计值的百分比(VC%)、用力肺活量(FVC)、第一秒最大呼气量(FEV1.0)、最大通气量(MVV)和最大通气量占预计值的百分比(MVV%)较治疗前明显改善(P<0.01);两组患者术中氧合指数、术后拔管时间、拔管后15min动脉血气PO2、PCO2比较有显著性差异(P<0.05)。结论:术前无创正压通气治疗可改善脊柱侧凸患者围手术期的肺功能,可缩短手术后气管插管的拔管时间,改善术后通气功能,有助于脊柱侧凸患者手术后早期恢复。     

介入法和无创法评价急性心肌梗死溶栓后心肌再灌注的一致性研究

目的 探讨急性心肌梗死（AMI）溶栓治疗后无创法评价心肌再灌注的可行性。方法选择AMI溶栓治疗后行冠状动脉造影的患者，溶栓后90min血浆肌红蛋白（Mb）浓度与溶栓前血浆Mb浓度比值≥2．4或心电图ST段回落≥50％定义为成功再灌注（阳性）。上述两项指标均阳性为完全再灌注，仅一项阳性为部分再灌注，两项均阴性为无再灌注。再根据冠状动脉造影结果将患者分为完全再灌注（TIMI3级）、部分再灌注（TIMI2级）、无再灌注（TIMI0～1级）。对无创法和介入法进行一致性检验。共入选45例患者。结果无创法和介入法评价心肌再灌注经一致性检验，符合率为84．4％，Kappa=0．75（P〈0．01）。结论．心电图ST段回落和血浆Mb浓度变化两项指标合用可提高评价心肌再灌注准确性，和介入法有很高的符合率，简便易行，且结果可靠。     

Noninvasive Electrocardiographic Imaging (ECGI): Application of the Generalized Minimal Residual (GMRes) Method

Electrocardiographic imaging (ECGI) is a developing imaging modality for cardiac electrophysiology and arrhythmias. It reconstructs epicardial potentials, electrograms, and isochrones from electrocardiographic body-surface potentials noninvasively. Current ECGI methodology employs Tikhonov regularization, which imposes constraints on the reconstructed potentials or their derivatives. This approach can sometimes reduce spatial resolution by smoothing the solution. Accuracy depends on a priori knowledge of solution characteristics and determination of an optimal regularization parameter. These properties led us to implement an independent, iterative approach for ECGI—the generalized minimal residual (GMRes) method—which does not apply constraints. GMRes was applied to experimental data during activation/repolarization of normal and infarcted hearts. GMRes reconstructions were compared to Tikhonov reconstructions and to measured gold standards in isolated hearts. Overall, the accuracy of GMRes solutions was similar to Tikhonov regularization. However, in certain cases GMRes recovered localized potential features (e.g., multiple potential minima), which were lost in the Tikhonov solution. Simultaneous use of these two complementary methods in clinical ECGI will ensure reliability and maximal extraction of diagnostic information in the absence of a priori information about a patient's condition.© 2003 Biomedical Engineering Society. PAC2003: 8719Hh, 8757Gg     

Simple,noninvasive system for measuring the heart rate of avian embryos and hatchlings by means of a piezoelectric film

Using a flexible piezoelectric film, the authors developed a simple system to determine noninvasively the heart rate of chicken embryos and hatchlings. The film was piezoelectric polyvinylidene fluoride (PVDF), which is sensitive enough to detect cardiogenic ballistic movements of the egg (ballistocardiogram (BCG)) and precordial movements of the hatchling attributable to cardiac contractions (apexcardiogram (ACG)). The BCG could be detected, during the second half of incubation, by placing the egg on the PVDF film on a soft substrate. The detected signal was found to be a measure of movement velocity. The ACG could be measured when the hatchling's chest wall made contact with the PVDF film installed in a box in which the hatchling was confined. The heart rate was counted from the lag time of autocorrelation calculated for a certain time segment (e.g. 2s) of the BCG and ACG recordings.     

Noninvasive,automatic 24-h ambulatory blood pressure monitoring in normotensive subjects

Summary The reliability of noninvasive, automatic blood pressure monitoring is not yet clearly established. A 24-h ambulatory blood pressure profile was obtained in 9 healthy, normotensive subjects with an automatic, noninvasive device. The blood pressure profile showed the typical circadian pattern with lower systolic and diastolic values during sleep, although pulse pressure was fairly constant (about 40 mm Hg). The systolic blood pressure rose steeply in the early morning hours — before waking up. The results were compared with simultaneous hourly readings using the auscultatory method. There were no statistically significant differences between the automatic and auscultatory readings, 13 of the 18 mean values at. different time points being within 2 mm Hg of each other. All the auscultatory means fell within the 95% confidence limits of those measured hourly by the automatic method. Although the automatic method seemed to be reliable compared with the auscultatory method, its sensitivity to motion artifacts is a disadvantage in a truly ambulatory setting.     

Source Localization of P300 from Oddball, Single Stimulus, and Omitted-Stimulus Paradigms

Three different auditory stimulus paradigms were used to elicit P300 potentials. Normal subjects were tested on the classical rare target stimulus, single-stimulus and omitted-stimulus conditions. Noninvasive identification of the cerebral sources of the event-related potentials (ERPs) was performed using spatio-temporal multiple dipole modeling (BESA software) with individually sized spherical head models. The grand average data of each condition was first independently modeled and these models were used as starting values for modeling each individual subject's data. Models for the rare-stimulus condition and single-stimulus condition both consisted of 6 dipoles. Models for the omitted-stimulus condition consisted of 2 dipoles. The dipole locations of the final individual 6-dipole models for the rare and single-stimulus conditions did not differ significantly from each other or from one previous result obtained from a another group of subjects (Tarkka et al. 1995). Super-imposition of the dipole coordinates on the sterotaxic brain atlas suggests that bilateral deep medial temporal lobe structures are the major contributors to rare and single-stimulus P300s. Because both the wave form morphology and the source model of the P300 elicited by single stimulus were close to those of the rare-stimulus P300 it may be that the underlying neural mechanisms eliciting these P300 potentials are essentially the same.     

Long-term ambulatory monitoring of indirect arterial blood pressure using a volume-oscillometric method

A new portable instrument equipped with a microprocessor was designed for the long-term ambulatory monitoring of indirect arterial pressure in the human finger at desired intervals using a volume-oscillometric technique. All the necessary procedures such as (1) programmed control of cuff pressure, (2) detection of the systolic end-point and the point of maximum amplitude of arterial volume pulsations, (3) reading of the cuff pressures corresponding to these two points, (4) its processing and (5) recording of the systolic and mean pressure together with heart rate on a digital memory integrated circuit were performed automatically. After the monitoring, the data were reproduced and analysed by a conventional personal computer. Simultaneous comparison of the data with direct measurement, operation and evaluation of this instrument, and ambulatory monitoring were carried out. With this instrument noninvasive and accurate monitoring of arterial pressure could be made in unrestricted subjects during daily activities.     

人体组织中血液灌注率和动脉血温度的无损测量研究

由于人体组织中存在血液对流传热和代谢产热，当皮肤表面绝热后，皮肤表面的温度将上升，体表温升值是人体组织中血液灌注率和动脉血温度的函数，根据实际测量的体表温升与时间的关系就可以测出活体组织的血液灌注率和动脉血温度。根据一维Pennes生物传热方程，推导出了体表绝热后人体组织中及皮肤表面温度分布的解析解，并对人体组织中的血液灌注率及动脉血温度进行了实验测量。由于测量过程中利用的只是皮肤表面的温度信息，无须引入外加热源，对人体组织完全不会造成损伤，亦避免了干扰人体组织的正常生理状态，整个测量系统也比较简单。     

Continuous estimation of systolic blood pressure using the pulse arrival time and intermittent calibration

A continuous noninvasive method of systolic blood pressure estimation is described. Systolic blood pressure is estimated by combining two separately obtained components: a higher frequency component obtained by extracting a specific frequency band of pulse arrival time and a lower frequency component obtained from the intermittently acquired systolic blood pressure measurements with an auscultatory or oscillometric system. The pulse arrival time was determined by the time interval from QRS apex in electrocardiogram to the onset of photoplethysmogram in a fingertip beat-by-beat via an oximetric sensor. The method was examined in 20 patients during cardiovascular surgery. The estimated values of systolic blood pressure were compared with those measured invasively using a radial arterial catheter. The results showed that the correlation coefficients between estimated values and invasively obtained systolic blood pressure reached 0.97±0.02 (mean±SD), and the error remained within ±10% in 97.8% of the monitoring period. By using a system with automatic cuff inflation and deflation to acquire intermittent systolic blood pressure values, this method can be applicable for the continuous noninvasive monitoring of systolic blood pressure.