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Biomedical subjects

R G Thomson

Publications and source records attributed to R G Thomson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Influence of the bipolar electrode transfer function on the electromyogram power spectrum.

This study demonstrates the impact of the bipolar electrode transfer function on the canine diaphragm electromyogram (EMG) power spectrum, as evaluated with a new electrode design and implantation technique. The results show that: (a) changes in interelectrode distance transformed single-peaked power spectrums into double-peaked spectrums; (b) the mean action potential conduction velocity (APCV), and power spectrum center frequency (CF) and median frequency (MF), are related for interelectrode distances of 5 and 10 mm, but not for 15 and 20 mm; and (C) CF, MF, -3-dB, and -6-dB bandwith values depend on interelectrode distance. We conclude that bipolar electrodes, with a nonfixed interelectrode distance, cannot be used for physiological interpretations of the EMG power spectrum. Nonetheless, power spectrums obtained with fixed and appropriate interelectrode distances can be trusted, if the electrodes are positioned in the direction of the muscle fibers and in regions with low densities of motor endplates.

Action Potentials↗
PubMed1996

Do performance indicators make a difference?

BACKGROUND: The Maryland Hospital Association, Inc (MHA) Quality Indicator (QI) Project, a program of indicator development and application, includes more than 1,100 participating hospitals. Access to data is limited to participants to promote improvement through comparison across hospitals. Participating hospitals have identified and acted on opportunities for improvement in information systems, communication across departments and functions, processes of care, identification of appropriateness of practice, and improvement ¿beyond the hospital door¿. CASE STUDY 1: Two teams were formed to address waiting time in the emergency department and failure of patients to find treatment. Improvements, including rapid notification of available inpatient beds, additional staffing during high-census periods, and streamlined processes for lab work and imaging turnaround times, were followed by better indicator performance. CASE STUDY 2: A hospital discovered three causes for a high rate of unscheduled admissions following ambulatory surgery. Interventions included extending the hours of the Same Day Surgery Unit (to solve a urination problem) and changing the anesthesia used (to reduce nausea and vomiting). CASE STUDY 4: To successfully bring its cesarean section (C-section) rate down closer to the statewide rate, one hospital had physicians encourage patients with previous C-sections to undergo a trial of labor, promoted the use of epidural anesthesia, and took advantage of new packaging to facilitate the use of prostaglandin gel to induce cervical dilation. CONCLUSIONS: The QI Project continues to deal with issues concerning quality of data versus quality of care, the correlation between indicator rates and care processes, and the usefulness of severity adjustment.

Adult↗
PubMed1995

Service provision and use of anticoagulants in atrial fibrillation.

Several large trials have shown that the risk of stroke in patients with non-valvar atrial fibrillation is reduced by treatment with warfarin. Implementing this research evidence requires not only an understanding of the trials' results and of the changes that they imply for clinicians' treatment decisions but also an appreciation of the organisation, quantity, and quality of services required to support these changes. Understanding of these implications is crucial for developing services that allow changes in practice to produce reductions in stroke incidence while minimising the risks of treatment. This article considers the developments in service provision that will probably be required to support the changes in clinical practice suggested by the trials' results. These services will be provided largely by doctors, and their development has implications for doctors in both primary and secondary care.

Atrial Fibrillation↗
PubMed1995

Validation of a population screening questionnaire to assess prevalence of stroke.

BACKGROUND AND PURPOSE: A cross-sectional survey is the best method for determining the prevalence of a chronic condition such as stroke. Before embarking on a large population study, a valid screening instrument is necessary. This study aimed to validate a self-completion postal screening questionnaire for assessing lifetime history of stroke. METHODS: A random sample of 2000 people aged 45 years and over was selected from the Family Health Services Authority register. A brief self-completion questionnaire requesting self-reported history of stroke was mailed to each individual. Responders reporting a history of stroke received a request for a standardized home assessment visit. Confirmation of the diagnosis of stroke was made based on information from the home visit together with multiple sources of case ascertainment. False-negative responses and assessment of nonresponse bias were documented. RESULTS: The response rate for the questionnaire was 88%. Of the sample, 120 (6%) who were wrongly registered were excluded; 173 (10%) of the 1663 responders reported a history of stroke. The question "Have you ever had a stroke?" had a sensitivity of 95% and a specificity of 96%. CONCLUSIONS: This simple self-completion questionnaire is a valid means of screening for cases of stroke in the community and could form the basis for subsequent studies of prevalence and health needs.

Aged↗
PubMed1993

An audit of distribution and use of guidelines for management of head injury.

Ensuring effective distribution of guidelines is an important step towards their implementation. To examine the effectiveness of dissemination of a guidelines card on management of head injury and determine its usefulness to senior house officers (SHOs), a questionnaire survey was performed in May 1990, after distribution of the cards in induction packs for new doctors and at postgraduate lectures and displaying the guidelines in accident and emergency departments and wards. A further survey, in March 1992, assessed the impact of modifying the distribution. All (175) SHOs working in general surgery, accident and emergency medicine, orthopaedics, and neurosciences on 1 February 1990 in 19 hospitals including two neurosurgical units in Northern region were sent self completion questionnaires about awareness, receipt, use, and perceived usefulness of the guidelines. 131 of 163(80%) SHOs in post responded (median response from hospitals 83% (range 50%-100%)). Over three quarters (103, 79%) of SHOs were aware of the guidelines and 82(63%) had ever possessed a guidelines card. Only 36(44%) acquired the card in the induction pack. 92%(98/107) found them useful and 81% (89/110) referred to them to some extent. Owning and carrying the card and referring to guidelines were associated with departmental encouragement to use the guidelines. Increasing the displays of guidelines in wards and departments and the supply of cards to consultants in accident and emergency medicine as a result of this survey did not increase the number of SHOs who received cards (52/83, 63%), but more (71/83, 86%) were aware of the guidelines. The guidelines were welcomed by SHOs and used in treating patients with head injury, but their distribution requires improvement. Increased use of the guidelines may be achieved by introducing other distribution methods and as a result of encouragement by senior staff.

Craniocerebral Trauma↗
PubMed1993

Audit of public health medicine: the northern region's approach.

Public health doctors are required to audit their work, a principle endorsed by the Faculty of Public Health Medicine. Although general concepts of audit in clinical medicine are likely to apply to public health medicine, the practical problems are likely to be different. Public health medicine, therefore, needs to experiment with approaches to audit until general principles are established. The implementation of public health medicine audit in the Northern Region is reviewed here, highlighting the establishment of structures (e.g. a public health medicine audit promotion group and audit link-persons), processes (e.g. study days, exchange of information) and outcomes (e.g. audits undertaken and standards devised). The foundations for audit of public health medicine have been built upon wide debate and consultation, locally written documents detailing the arguments and making practical suggestions for change, ownership of policy-making decisions by a regional forum of public health doctors, day-to-day responsibility resting in an audit group, a heavy emphasis on communication including the gauging of opinions, attitudes and behaviour by survey, a perception that public health medicine has the same rights and obligations towards audit as other medical specialties, and the view that audit in our specialty will require time and patience to implement. The challenge remains of ensuring the implementation of cost-effective audit in the routine practice of public health medicine.

Data Collection↗
PubMed1992

Eight years' experience of clinical activity in an outpatient fracture clinic.

Major changes to the method of planning and provision of health care in Britain have led to the introduction of contracts as the main means through which services are procured. Never before has the need for accurate and comprehensive clinical information been greater. Yet comprehensive outpatient information, though planned, is not yet available, and there is relatively little experience of such systems which have been introduced in individual localities. Fracture clinic patients are an important group of outpatient, not least because interventions are often undertaken as an integral part of the outpatient episode. This is relevant for estimating resource use and for pricing, but until now has been 'hidden' work as far as conventional information systems are concerned. This study describes the establishment and manifestation of a clinical information system based on a fracture clinic serving the majority of a population of 850,000. Information was gathered over 8 years on 61,635 patients, who had 72,984 diagnoses and received 93,878 treatments. An information system of the type described in this study can be of great value as part of the contracting process (for both purchasers and providers of orthopaedic services), as a basis for clinical audit and research, and to facilitate undergraduate and postgraduate teaching.

Adolescent↗
PubMed1991

Severe hepatocellular dysfunction following cyproterone acetate therapy.

Cyproterone acetate (CPA) is a widely used drug in the treatment of advanced prostatic carcinoma. Although it is generally well tolerated, liver toxicity has been recognised as a complication of long-term use. We report 3 patients with severe hepatocellular damage due to CPA therapy, 2 with fatal fulminant hepatitis.

Aged↗
PubMed1990

Incidence of fractures in a geographically defined population.

STUDY OBJECTIVE: The aim was to describe the population based age and sex specific incidence of fractures at different sites in a large English health district. DESIGN: Recording of fractures was accomplished by a specially constructed outpatient index and by record linkage to hospital inpatient information, for the three years surrounding the 1981 census. SETTING: The fracture index was held by the Department of Community Health in Leicester using data from the fracture clinic at the central large district general hospital, supplemented by hospital inpatient data from Trent Region and the two adjoining regions. PARTICIPANTS: The denominator population was the Leicestershire Health Authority resident population. In the three years, 12,711 fractures amongst males and 10,565 amongst females were recorded. MEASUREMENTS AND MAIN RESULTS: The overall estimated annual incidence of fractures was 100 per 10,000 population for males and 81 per 10,000 population for females. Below the age of 55 years all fractures showed a higher incidence amongst males but amongst the over 55s, there was a consistent fall in the male:female incidence ratio with some sites showing a striking female preponderance. The results also show an apparent age specific temporal increase in incidence at certain fracture sites compared with earlier British data, but fracture incidence figures still suggest lower rates in this country than in North America and some Scandinavian countries. CONCLUSIONS: These findings provide population based incidence data on a major public health problem and are consistent with the major determinants of osteoporosis and increase in falls in postmenopausal women. The temporal and geographical variation in fracture incidence remain to be explained.

Age Factors↗
PubMed1988

The acute and subchronic effects of ketoconazole on hepatic microsomal monooxygenases in the rat.

Female adult Wistar rats were treated with single or repeated doses of ketoconazole ranging from 10 mg/kg to 100 mg/kg. Single dose treatment produced inhibition of hepatic microsomal ethoxyresorufin O-deethylation (EROD) and aldrin epoxidation (AE) 2 hr after oral dosing. Twenty-four hours after a single dose, inhibition was still demonstrable after the low dose of 10 mg/kg, but at higher doses increased microsomal activity was apparent. After 7 days repeated dosing liver weight and microsomal protein content were increased in a dose-dependent fashion. EROD and AE were induced at all doses after repeated treatment when the increase in liver size was considered. These effects were seen at doses within the antimycotic therapeutic range and add support to the suggestion that reported drug interactions with ketoconazole in man are due to the effects of this drug on hepatic microsomal activity.

Animals↗
PubMed1986

Seventh-nerve palsy and hepatitis associated with nitrofurantoin.

Adverse hepatic reactions to nitrofurantoin therapy are well reported and range from acute cholestatic or hepatitic injury to chronic active hepatitis [R G. Penn & J.P. Griffin (1982) Br. Med. J., 284, 1440-1442]. Neurological side-effects, predominantly sensorimotor peripheral polyneuropathy, have also been documented [R.G. Penn & J.P. Griffin (1982)]. We report the first case of combined neurological and hepatic reaction to nitrofurantoin; this occurred during repeated treatment with the drug.

Adult↗
PubMed1986

Cellular inflammatory response in the lungs of calves exposed to bovine viral diarrhea virus, Mycoplasma bovis, and Pasteurella haemolytica.

Three, 5, or 7 days after inoculation with bovine viral diarrhea (BVD) virus (n = 12) or Mycoplasma bovis (n = 12), groups of calves were exposed to aerosols of Pasteurella haemolytica and were euthanatized 4 hours later. Histologic lesions in the lungs and the ratios of neutrophils to alveolar macrophages, collected by bronchoalveolar lavage, were compared with those of clinically healthy calves (n = 8) and calves inoculated with BVD virus only (n = 4), M bovis only (n = 4), or P haemolytica only (n = 2). Inoculation with BVD virus or M bovis did not have a significant (P greater than 0.05) effect on the neutrophil/macrophage ratio in the bronchoalveolar lavage. Aerosol exposure to P haemolytica induced a marked and significant (P less than 0.01) change in the neutrophil/macrophage ratio (from less than 1:9 to greater than 9:1). The reversed neutrophil/macrophage ratio in calves exposed to P haemolytica correlated well with the histologic changes in which small bronchi and bronchioles were plugged with purulent exudate. Inoculation with BVD virus did not induce gross or microscopic lesions in the lungs. Inoculation with M bovis resulted in a severe peribronchial lymphoid hyperplasia with mild exudation of neutrophils and macrophages into the cranioventral parts of the lungs.

Animals↗
PubMed1984

The possible role of stress in the induction of pneumonic pasteurellosis.

Five groups of range bred calves (four calves per group) were used to investigate the effect of stress on susceptibility to aerosol exposures with bovine herpesvirus-1 or Pasteurella haemolytica. Twelve calves were weaned, transported, processed at a commercial feedlot and transported to isolation facilities three days later. An aerosol challenge of either 10 colony forming units of P. haemolytica or 10 plaque forming units of bovine herpesvirus-1 virus was given to two groups of calves and the third group was not challenged. The fourth group was transported directly to the isolation facilities after weaning and aerosol challenged with P. haemolytica. The fifth group remained at the farm after weaning and was not challenged. All transported animals had elevated plasma cortisol levels which remained above normal for at least three days postchallenge. The blastogenic response of all calves was depressed after leaving the farm and remained depressed throughout the experiment. The suppression correlated well with elevated serum cortisol levels. Calves processed through the feedlot encountered bovine herpesvirus-1 because eight out of 12 animals seroconverted to this antigen. Most calves seroconverted to P. haemolytica whether they were experimentally challenged or not. Where the unchallenged calves encountered P. haemolytica is unknown. Calves challenged with bovine herpesvirus-1 but not with P. haemolytica, had significant clinical signs of pneumonia and two animals died due to bovine herpesvirus-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗