摘要:

Four 6 mm e-PTFE grafts were placed subcutaneously into four dogs between the carotid artery and jugular vein to model shunt flow through an access graft. Flow-rates were varied from 120 to 2000 ml/min (N = 42) by use of a cardiac stimulant (Aramine) and external constrictor. Measures of graft flow were made simultaneously by electromagnetic flowmeter (EMF) and Doppler ultrasound based on a known graft diameter, use of a flat-head probe providing a fixed beam-to-vessel angle and derivation of the mean Doppler-shift frequency from first moment computation of the frequency spectra.Correlation coefficients between the Doppler ultrasound and EMF recordings were 0–54, 0·96 and 0·92 at measurement sites just beyond the arterial/graft anastomosis, at the graft loop and just proximal to the graft/venous anastomosis, respectively. Availability of a simple and accurate, non-invasive flowmeter for superficially placed e-PTFE grafts may be valuable for evaluating the systemic effects of vascular shunts, for monitoring the patency of access grafts and for assessing the function of bypass grafts for limb ischaemia.

ISSN:0309-1902    

DOI:10.3109/03091908509018197

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

A radio-telemetry system using a microcomputer has been constructed to measure both the heart-rate (HR) and right atrial blood-temperature in dogs. The telemeter incorporates a thermistor temperature probe, which allows blood-temperature measurements in the range of 35°-42°C with an available resolution of±0·02°C. The output of the receiver is connected to active filters, a frequency counter and an HR meter, and finally to a microcomputer, through an appropriate interface circuit, for data linearization and storage.

ISSN:0309-1902    

DOI:10.3109/03091908509018198

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091908509018199

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

The performance of the Hitachi HME-20 pulse and blood-pressure (BP) monitor in comparison with direct intra-arterial BP recording and electrocardiographic monitoring is described. Highly significant (p<0·001) correlations were found between intra-arterial systolic and diastolic pressures and pressures recorded by the Hitachi monitor. Similarly, the electrocardiographically computed heart-rate, and that given by the Hitachi monitor were significantly correlated (p150 mmHg. These results are comparable to more expensive pulse and blood-pressure monitors. We conclude that the instrument can reproduce a satisfactory estimate of heart-rate and blood-pressure and may be of particular use when a change of blood-pressure is of prime importance, rather than an absolute measurement.

ISSN:0309-1902    

DOI:10.3109/03091908509018200

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

An instrument which locates blood vessels by means of Doppler ultrasound and directs a needle at the located vessel has been developed. The feature of this instrument is that the needle does not pass down the ultrasonic beam as in other techniques that have been tried. Two transducers, mounted on sliding bars, are used to pin-point the vessel. The needle is then guided towards the itersection point of the two beams. Both the angle of entry and the point of incision of the needle can be chosen arbitrarily, while the transducers are kept well away from the needle and at an optimum angle to the skin.

ISSN:0309-1902    

DOI:10.3109/03091908509018201

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

The need to investigate the elastic properties of arterial vessels‘in situ’for the early recognition of degenerative disorders in arteries has long been apparent. Volume pulses in defined segments of arteries can be evaluated for this purpose, and the present paper contains a survey of earlier attempts to quantify volume pulses by means of ultrasound. A presentation is given of a recently developed digital system, comprising a phase-locked echo tracker, capable of monitoring non-invasively the diameter and its pulsatile changes of a selected artery along two chosen image lines of a linear array ultrasound scanner. The physical limitations of tracking fastmoving ultrasound echoes by means of phase-locked range gating are reported and the advantage is emphasized of using a gate length of one full period. This system has been calibrated, tested and applied in measurements of pulse wave pattern and propagation velocity in the descending aorta of human foetuses in the last trimester of gestation. The present high-resolution echo-tracking method has yielded reproducible results in the foetus and appears suitable also for screening studies on adult vessels.

ISSN:0309-1902    

DOI:10.3109/03091908509018202

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

‘Health Equipment Information’No. 128 (October 1984) contains the results of the UK Health Departments’evaluation of ultrasonic humidifiers—the study was directed by Dr B. Hayes and Mr S. Tilling of Dudley Road Hospital, Birmingham, UK. The humidifiers involved were the DeVilbiss 35B and 65, the Intersugical Variosonic, the Medap Monsun 803 and the Mistogen EN145(E). A previous‘HEI’(No. 103) looked at single-use unheated humidifiers; a future report will include evaluations on heated vapourizing humidifiers: the Chemetron Midi, the Draeger Aquapor, the Fisher&Paykel 328 and 418, the Penlon Model H and the Puritan Bennett Cascade II.For full details of the evaluation findings, readers should consult‘HEI’128–the following contains extracts from the report.Enquiries about the evaluation of humidifiers should be directed to Gordon Judge, Scientific and Technical Branch, DHSS, 14 Russell Square, London WC1B 5EP.

ISSN:0309-1902    

DOI:10.3109/03091908509018203

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091908509018204

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

摘要:

A recent edition of‘Health Equipment Information’(‘HEI’), No. 129 published in October 1984, contains evaluation reports on a further three defibrillators. These are the Albury Instruments Life-Gard 80 and Life-Gard 86 and the Temtech Liteguard.Technical and user evaluation was carried out for the DHSS within the Sheffield and Rotherham Area Health Authorities, with the equipment being assessed against BS 5724 Part 1, supplemented by a particular defibrillator standard, IEC Publication 601-2-4. The protocols used for the hospital trials were devised jointly by the DHSS, the clinicians involved in the trial, and the assessors at the evaluation centre. Earlier evaluation reports have been published in this journal, the first containing a discussion on points to consider before deciding what to buy [1 and 2]. An extensive review of defibrillator design and development has also been published [3].For full details of the evaluation findings readers should consult‘HEI 129’—the following contains extracts from the report.

ISSN:0309-1902    

DOI:10.3109/03091908509018205

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor

ISSN:0309-1902    

DOI:10.3109/03091908509018206

出版商:Taylor&Francis    

年代:1985

数据来源: Taylor