功能性消化不良诊断与生物电阻抗检测方法

功能性消化不良（FD）为常见、多发疾病,其病因和发病机制可能与多种因素有关,胃动力和胃肠运动功能障碍是FD发病的重要原因。目前临床上对FD的诊断主要依据患者的自述症状．还缺乏有效的胃动力学检查方法或手段。采用生物阻抗胃动力检测方法可从电一机复合系统的认识高度,同时提取胃电活动和机械运动信息,研究从胃电活动到机械收缩、蠕动的复杂胃动力过程。此方法具有诱人的临床应用效果和发展前景。     

Some remarks relating to the technique of interpretation of plethysmographic data

Summary The beneficial effect of Barbamyi induced sleep on the development of diphtheria intoxication was shown in rabbits and guinea-pigs. Applying interrupted medicated sleep during 5–6 days we succeeded in an experiment to double the longevity of animals; in a number of cases a complete recovery of the animals was observed.Microscopic analysis of the organs of the experimental animals showed that Barbamyl protects against drastic circulatory disturbances characteristic of diphtheria intoxication and decreases fatty degeneration in the parenchymatous organs.Barbamyl induced sleep does not affect the development of pathological processes in the place of the diphtheria toxin injection.Submitted by Active Member of the Academy of Medical Sciences of the USSR. M. A. Skvortsov     

Continuous measurement of venous diameter by a combined photoelectric-photographic and plethysmographic technique

Summary The combined photoelectric-photographic and plethysmographic technique allows for the investigation of the distensibility characteristics and pharmacological influence on the capacitance vessels in an uniform vascular bed (skin veins of the isolated rabbit ear). Diameter changes of a vein segment are recorded continuously by means of a photoresistor and are photographed for calibration. Volume changes of the tissue are measured by a water filled plethysmograph and can be compared with diameter changes of the selected vein segment. The method allows for better interpretation of the results obtained by the plethysmographic technique. In particular, it is possible to distinguish between outward filtration and stress-relaxation.This research was supported by Contract, F 44620-71-C-0117 of the USAF School of Aerospace Medicine, European Office of Aerospace Research (OAR) United States Air Force and Deutsche Forschungsgemeinschaft     

Estimating pulmonary congestion in elderly patients using bio-impedance technique: Correlation with clinical examination and X-ray results

The bio-impedance technique provides a safe, low-cost and non-invasive alternative for lung fluid level monitoring. Here we have investigated the feasibility of a novel bio-impedance system in measuring pulmonary congestion in elderly patients suffering from congestive heart failure (CHF). The system employed a parametric reconstruction algorithm to assess mean lung resistivity. Fourteen patients were studied before and following treatment to reduce lung congestion. Significant correlation was found between the changes of radiographic scores and resistivity values following treatment (R = 0.57, p < 0.04). A significant difference in resistivity values between patients having low and high congestion degrees was also demonstrated (p < 0.01). Moreover, the bio-impedance technique successfully diagnosed an improvement of congestion level in 10 out of 14 patients, while the radiographic score indicated such an improvement in only 5 out of the 14 patients. These results, along with our previous validation studies, suggest that the bio-impedance technique is a feasible bedside system for monitoring of pulmonary congested patients, thus facilitating effective treatment strategies.     

Measurement of electrical bio-impedance and its applications

This paper describes: 1) the measurement method of electrical bio-impedance; 2) presentations of models of bio-impedance and their applications to some impedance analyses; 3) the analyses of steady state and dynamical state of electrical properties of the skin; and 4) the applications of bio-impedance. The applications include: 1) the influence of skin impedance to biological potential measurement; 2) skin moisturization measurement using skin admittance; and 3) gait analysis using lower leg electrical impedance.     

Sharing in-office otoendoscopy recordings may improve patient satisfaction: A prospective cohort study

ObjectiveEvaluate the impact of sharing otoendoscopy exams on patient satisfaction in the outpatient clinical setting.MethodsRandomized, prospective cohort study. Consecutive adults presenting to otology clinic at one tertiary referral center were randomized into two groups: standard microscopy (SM) and video otoendoscopy (VO). The SM group had ears examined using a standard, otomicroscope; the VO group had ears examined using a 0° rigid endoscope connected to a video tower. All subjects were counseled on their exam findings in a routine manner; the VO group was concurrently shown a recording of their ear exam. All subjects completed the 18-item Patient Satisfaction Questionnaire (PSQ-18) at the conclusion of their clinic visit.ResultsThe SM group consisted of 27 patients and VO group consisted of 23 patients. VO subjects reported higher PSQ-18 scores compared to SM subjects within the domains of communication (p = 0.04) and technical quality (p = 0.005). On linear regression models, demographic factors and positive exam findings were not predictive of patient satisfaction.ConclusionsSharing otoendoscopy recordings may be a valuable tool that can improve patient satisfaction.Practice ImplicationsClinicians should consider sharing recordings of otoscopic exams with patients, particularly when faced with the possibility of surgery.     

Consistency of unitary shapes in dual lead recordings from myelinated fibres in human peripheral nerves: evidence for extracellular single-unit recordings in microneurography

Percutaneous microneurography is a powerful technique allowing studies of activity in single nerve fibres of conscious humans. However, the mechanisms by which single-unit recordings are achieved with this technique are not fully understood. To further elucidate these mechanisms, dual-lead recordings, using a modified concentric needle electrode with two separate recording surfaces at the tip, were performed in normal subjects. Sixty-two single units supplied by large myelinated afferents were studied. The majority (90%) of the units were recorded simultaneously on both surfaces but with different action potential amplitudes. Four types of unitary waveforms were encountered. The potentials recorded on the two channels were of the same type, although occasionally some details differed. Parallel waveform changes of the same units occurred simultaneously on the two surfaces. A displacement of a single fibre from one recording surface to the other with or without concomitant waveform-type transitions was observed when the electrode was slightly repositioned intraneurally. The results provided direct evidence to confirm that concentric needle electrodes record single-unit activity extracellularly from myelinated nerve fibres, probably at or close to a node of Ranvier. All the types of action potentials encountered with conventional tungsten electrodes were also identified in dual-channel recordings with concentric electrodes, which casts doubt on the previous explanation that single-unit activity recorded with tungsten electrodes is derived from intracellular sources. Some biological and technical aspects of the findings are discussed, especially concerning the applicability of in vivo measurements of the time course of the action potentials in humans and ways to improve microneurography towards multichannel recordings. Received: 8 September 1997 / Accepted: 15 December 1997     

Digital audio recordings improve the outcomes of patient consultations: A randomised cluster trial

ObjectivesTo investigate the effects on patients’ outcome of the consultations when provided with: a Digital Audio Recording (DAR) of the consultation and a Question Prompt List (QPL).MethodsThis is a three-armed randomised controlled cluster trial. One group of patients received standard care, while the other two groups received either the QPL in combination with a recording of their consultation or only the recording. Patients from four outpatient clinics participated: Paediatric, Orthopaedic, Internal Medicine, and Urology. The effects were evaluated by patient-administered questionnaires.ResultsA total of 4349 patients participated in the study. DAR significantly increased the probability of fulfilling the participants’ self-perceived information needs by 4.1% to 6.3%, particularly with regard to test results (OR = 1.41, 95%CI: 1.14-1.74, p = 0.001) and treatment options (OR = 1.39, 95%CI: 1.13-1.71, p = 0.002). Additionally, the interventions positively influenced the participants’ satisfaction with the treatment, their relationship with the health professional, and their experience of being involved in the decision-making.ConclusionProviding outpatients with a QPL and DAR of their consultation positively influences the patients’ perception of having adequate information after the consultation.Practice implicationsThe implementation of a QPL and audio recording of consultations should be considered in routine practice.     

Single channel recordings of reconstituted ion channel proteins: an improved technique

Single channel recording of reconstituted ion channels is possible by patch clamp measurements of giant liposomes formed by dehydration-rehydration of lipid films. This hydration technique consists of carefully controlled dehydration of a suspension of small vesicles followed by rehydration of the residue resulting in formation of large liposomes. Patch pipettes can be attached to the liposome surface, yielding stable, high resistance seals between membranes and glass pipettes. This method allows the study of the properties of reconstituted ion channels from different tissues. The hydration technique was used to characterize the reconstituted K⁺-channel of sarcoplasmic reticulum from rabbit skeletal muscle. In a solution of 100 mM KCl, the sarcoplasmic reticulum K⁺-channel studied displays a conductance _K ⁺ of 145 pS. The single channel conductance in 100 mM Rb⁺ and Na⁺ is _Rb ⁺ = 98 pS and _Na ⁺ = 65 pS respectively. A concentration of 0.5 mM decamethonium causes a flickering channel block. These properties are in good agreement with the ones found in sarcoplasmic reticulum K⁺-channels characterized by other methods. Other ion channels have also been reconstituted and studied by this technique. This improved method is compared with previous approaches and its applicability for the characterization of reconstituted ion channel proteins is discussed.     

Physiological correlates of impedance plethysmographic waveform

A review of investigations into the origin of impedance plethysmographic waveform is presented in this article. Attempts made by several investigators in the comparison of impedance plethysmographic estimations of peripheral blood flow with that obtained by standard methods are briefly described. Investigations indicating the negligible contribution from contact impedance at body electrode interface are highlighted. Temporal correlation of impedance plethysmographic waveform recorded from thorax with various important events of the cardiac cycle is summarised and various hypotheses on the genesis of this waveform are presented.     

An automated technique for analysis of current transitions in multilevel single-channel recordings

Detailed kinetic studies of ion channel gating are best carried out using the patch-clamp technique which permits the measurement of the ionic current through individual channels. Typical patch-clamp recordings show the current signal, in the form of a sequence of rectangular pulses (analogous to a random telegraph signal), riding on slow baseline drift, partially obscured by high-frequency noise and distorted by filtering. In order to analyze such recordings, we have developed a set of interactive Pascal programs based on a feature-detection algorithm capable of identifying current transitions in multiple-channel recordings in the presence of substantial levels of noise and drift. Software operation is largely automated but includes provisions for examination and correction of the output. The software was optimized and systematically evaluated using simulated data with variable amounts of noise and drift. Results indicate that satisfactory performance is obtained for signal-to-noise ratio as low as four even with uncommonly large baseline drift. Steady-state processing speeds varied from 1000 to 4000 samples per second depending on data complexity.     

Use of short-term bio-impedance for gastric motility assessment

Gastric motility (GM) has been assessed using bio-impedance (BI) techniques in the time domain using short term recordings and analyzing mainly the median of the area under the fast Fourier transform (FFT) spectra. The BI technique has been applied to the gastric system mainly for gastric emptying (GE) studies. However, gastric motility evaluation using BI has not been fully implemented. In this study, we propose the use of the BI technique for the evaluation of gastric motility considering global features of the fast FFT spectra. The study was performed in eleven healthy subjects who were evaluated in fasting and postprandial conditions. The results indicate that the use of the median of the area under the FFT spectra is equivalent to the use of the main peak of the spectra to determine the changes in gastric motility from the fasting to the postprandial state. This demonstrates that BI is a valid technique for gastric motility evaluation in short time recordings.     

明胶-氧化铅血管造影术的优化

目的：在总结分析传统的血管解剖学研究技术基础上对全身性血管造影术进行重点探讨。方法：应用不同强度的明胶、不同的明胶-氧化铅配方及其多种不同组合方式的X线参数反复进行测试。结果：经测试，本实验得出明胶与氧化铅的最佳配方为：300Bloom的明胶5g，40℃温水100ml，氧化铅100g。灌注量为20～30ml／kg。结论：改良后的氧化铅-明胶灌注技术可提供高质量的血管显影效果，不失为研究皮动脉及设计穿支皮瓣的最好方法之一，而其他方法也能为血管解剖学提供补充信息。     

Integrated monitoring can detect critical events and improve alarm accuracy

A computer-based, integrated monitor system was designed and utilized to collect and interactively manage physiologic data (13 variables and 3 waveforms) from six routinely used operating room monitors. Various approaches were developed to reduce false alarms, classify waveforms, and recognize events. False alarms: false alarms in ECG heart rate detection were reduced from 37.3% to 2.6% (p=0.005) of total alarms using multi-variable analysis and rate-of-change limits. Waveform classification: using artificial neural networks (AN), CO2 waveforms were classified into (a) spontaneous, (b) mechanical, and (c) mechanical/with spontaneous breathing attempts. The system properly classified 47 of 71 spontaneous, 65 of 67 mechanical, and 37 of 44 mechanical breaths/with spontaneous breathing attempts. Another ANN was used for detection of elevated and depressed ST segments in the ECG signal. All ST segment elevations and depressions of 0.1 mV were correctly identified. Event recognition: an algorithm developed to identify endotracheal intubation correctly recognized 13 of 17 intubations. This resulted in a 42% reduction in low end-tidal-CO2 false alarms.     

Algorithm to improve accuracy of energy expended in a room calorimeter

The whole-room indirect calorimeter is considered as important equipment for human energy expenditure measurement, but noise reduction in the system remains a challenge. A selective filtering method (SFM) was designed to improve the accuracy of the computation of O₂ consumption rate (\( \dot{V}_{{{\text{O}}_{ 2} }} \)) and CO₂ production rate (\( \dot{V}_{{{\text{CO}}_{ 2} }} \)), based on two facts: (1) the rapid changes of \( \dot{V}_{{{\text{O}}_{ 2} }} \), \( \dot{V}_{{{\text{CO}}_{ 2} }} \) and respiratory quotient (RQ) in human should be accompanied by physical activity; (2) the oxygen consumption and the carbon dioxide production should not be negative because living humans do not generate oxygen, nor consume carbon dioxide. The performance of SFM was compared with the moving average method, the central difference method and the wavelet de-noising method. The range of \( \dot{V}_{{{\text{O}}_{ 2} }} \) and \( \dot{V}_{{{\text{CO}}_{ 2} }} \) in the empty room (the background noise) is reduced from ?130.00–146.00 ml/min to ?26.00–24.00 ml/min, and from ?20.50–12.50 ml/min to ?3.99–4.19 ml/min, by SFM. The background noise was added to simulated rectangular and sinusoidal signals that were used to evaluate the four methods over different time periods (64, 32, 16 and 8 min). The highest signal-to-noise ratio and the lowest deviation were achieved by SFM. Abnormal metabolic rates and RQs were corrected and compensated with measurement accuracy of 98.51 ± 0.3 % for 24-h alcohol burning tests. The results of the study showed that SFM can significantly improve \( \dot{V}_{{\text{O}_{2} }} \) and \( \dot{V}_{{{\text{CO}}_{ 2} }} \) measurements.     

Quantitative interpretation of arterial impedance plethysmographic signals

A discussion of the quantitative interpretation of impedance plethysmographic signals recorded on human limbs is presented. It is found that a short limb segment behaves, from an electrical point of view, as a system of two resistances in parallel the larger time-varying one corresponding to blood, and the smaller, approximately constant, corresponding to bones and tissues. Systolic dilation of arteries can be calculated from the signal amplitude and is found to correlate well with arterial distensibility determined from pulse velocity measurements. Signal reproducibility was found to be ±10%