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Biomedical subjects

G Burt

Publications and source records attributed to G Burt.

10 recordsLinked to original sources
PubMed2005

Epidural steroid injection for nerve root compression. A randomised, controlled trial.

We have assessed whether an epidural steroid injection is effective in the treatment of symptoms due to compression of a nerve root in the lumbar spine by carrying out a prospective, randomised, controlled trial in which patients received either an epidural steroid injection or an intramuscular injection of local anaesthetic and steroid. We assessed a total of 93 patients according to the Oxford pain chart and the Oswestry disability index and followed up for a minimum of two years. All the patients had been categorised as potential candidates for surgery. There was a significant reduction in pain early on in those having an epidural steroid injection but no difference in the long term between the two groups. The rate of subsequent operation in the groups was similar.

Adult↗
PubMed2004

Use of three-dimensional animation for regional anaesthesia teaching: application to interscalene brachial plexus blockade.

BACKGROUND: Using commercial computer graphics software (TrueSpace), we constructed a virtual-reality model for teaching interscalene brachial plexus block. This tool combines the clarity of schematic drawings and the clinical relevance of video clips and live demonstrations. The aim is to accelerate learning and aid retention of relevant information. METHOD: We made a series of continuous short virtual-reality animations demonstrating the steps to perform an interscalene block. Superficial structures were made transparent to show the anatomical relevance of landmarking and needle manipulation. The clips were presented to delegates at a training course in Oxford. Delegates were surveyed to ascertain whether or not the presentation enhanced their understanding of anatomy and regional block technique. Before and after the presentation, delegates indicated surface landmarking, needle angulation, and movement on photographs of the lateral and anterolateral neck views of two volunteers. The markings were analysed by two independent assessors and rated as 'good', 'bad', or 'ungradeable'. The percentage improvement for each skill group was calculated and McNemar's test applied. RESULTS: Of 24 respondents, the majority thought that the presentation enhanced their understanding of the anatomical (87.5%) and technical principles (79.2%) of interscalene blocks. Analysis of the marked photographs showed an overall 24.1% improvement in landmarking skills after the teaching presentation (P<0.001). Changes were significant in moderately experienced skill groups (P<0.001) but not for the very experienced (P>0.5) and the inexperienced skill groups (P<0.1). There was 76.3% concordance in scoring between the two assessors. CONCLUSION: Three-dimensional animation is a promising new tool to accelerate the learning of regional anaesthetic techniques.

Anesthesiology↗
PubMed2004

Dispersion of helically corrugated waveguides: analytical, numerical, and experimental study.

Helically corrugated waveguides have recently been studied for use in various applications such as interaction regions in gyrotron traveling-wave tubes and gyrotron backward-wave oscillators and as a dispersive medium for passive microwave pulse compression. The paper presents a summary of various methods that can be used for analysis of the wave dispersion of such waveguides. The results obtained from an analytical approach, simulations with the three-dimensional numerical code MAGIC, and cold microwave measurements are analyzed and compared.

Journal Article↗
PubMed2004

Compression of frequency-modulated pulses using helically corrugated waveguides and its potential for generating multigigawatt rf radiation.

A new method to generate ultrahigh-power microwave pulses compatible with mildly relativistic electron sources is proposed. This method involves a novel microwave compressor in the form of a metal helically corrugated waveguide, which can enhance the power of frequency-modulated nanosecond pulses up to the multigigawatt level. The results of the proof-of-principle experiments at kilowatt power levels are in good agreement with theory.

Journal Article↗
PubMed1979

Continuous measurement of blood gases in vivo by mass spectrometry.

Continuous analysis of oxygen and carbon dioxide tension in the blood phase, over periods of 4-5 h, was carried out in the pulmonary artery (93 determinations in six anesthetized dogs) and in the aorta (29 determinations in four anaesthetized dogs). Silastic-covered stainless steel catheters attached to a mass spectrometer were used. The mass spectrometer signals were linearly related to the blood-gas tensions measured by conventional analysis. The mass spectrometer signals were calibrated in vivo by exposing the animals to high and low oxygen and carbon dioxide tension. With such in vivo calibration the slopes of the straight line regressions for mass spectrometer PO2 or PCO2 on PO2 or PCO2 by conventional analysis were comprised between 0.944 and 1.031 while the standard error of the slopes were between 0.019 and 0.031. Deliberate reductions of cardiac output had little effect on the mass spectrometer readings.

Animals↗
PubMed1979

Effects of metoprolol on systemic haemodynamics, myocardial performance and the coronary circulation during halothane anaesthesia.

The effects of metoprolol 1 mg kg-1 i.v. on the systemic and coronary circulations and on myocardial performance were studied in nine open-chested dogs ventilated with halothane 0.8% in oxygen at normocarbia. In terms of the chronotropic effect, this dose of metoprolol produced a substantial shift to the right of the dose-response curve to isoprenaline; substantial reductions of arterial pressure (10%), cardiac output (21%), aortic blood acceleration (13%), left ventricular dP/dt max (13%) and left ventricular power (25%) were observed. Both preload, represented by left ventricular end diastolic pressure, and afterload, represented by systemic vascular resistance, increased. Left circumflex coronary blood flow and myocardial oxygen consumption decreased by approximately the same amount as peak ventricular power.

Anesthesia, Inhalation↗
PubMed1978

Vascular surgery in an anephric patient.

A 33-year-old man with chronic renal failure underwent repair of an expanding aortic aneurysm. The management of the case is described and the anaesthetic problems discussed.

Adult↗