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Biomedical subjects

R J Pethybridge

Publications and source records attributed to R J Pethybridge.

17 recordsLinked to original sources
PubMed1992

DERMIS: a computer system for assisting primary-care physicians with dermatological diagnosis.

DERMIS is a computerized skin disease diagnostic prompting system which has been derived from the prospective study of 5203 cases. It has been designed for use by non-dermatologists such as general practitioners. The program produces a list of reasonable diagnoses based on probabilities calculated using Bayes' theorem. Out of 221 precise diagnoses made by the dermatologist in the clinic, 42 groupings were created to encompass the most common or important diseases encountered in general practice. Four 'remainder' or 'send to specialist' groups were included for the 13% of uncommon conditions. The program, when tested by 'one out' analysis on the original cases, placed the correct diagnosis first on 76% of occasions, and within the first three on 95% of occasions. In 76 of 125 cases randomly selected from the data base, a request for diagnostic assistance had been made by the referring general practitioner. It has been estimated that in 54 of these 76 cases the DERMIS system could have provided differential advice with the correct diagnosis appearing at the top of the list. The system has been written in MUMPS and runs on an IBM-compatible desk-top computer. The software allows real time data entry. Arrangements are in hand for performing clinical trials of the system in general practice. If current performance is maintained, and the response to the system's output is favourable, then DERMIS might well enhance performance in medical decision making for the benefit of patients, medical services and budget holders.

Diagnosis, Computer-Assisted↗
PubMed1992

An audit of resuscitation and anaesthesia during Operation 'Safe Haven'.

The Royal Navy combined Surgical Support Team deployed for six weeks to Northern Iraq. Eighteen casualties of civilian and military trauma required active resuscitation, 10 of whom were under the age of 16. Three died. Triage of multiple casualties was necessary on three occasions. The principles of Advanced Trauma Life Support (ATLS) were adopted and the experience is described under the ABCDE headings of the primary survey. Deficiencies of training and equipment are identified. Seventy one anaesthetics, administered to 52 patients, were audited prospectively in detail. Systolic blood pressure was significantly higher with isoflurane and controlled ventilation (ICV), compared with halothane and trichloroethylene (HTCV) (P < 0.05). ICV patients recovered more quickly than with HTCV (P < 0.05), but were significantly older and heavier (P < 0.05). Isoflurane should replace the standard halothane/trichloroethylene combination. Controlled ventilation or ketamine anaesthesia allowed satisfactory SpO2 on air alone. With controlled ventilation, anaesthesia was entirely satisfactory for children down to 6.5 kg. Local anaesthetic procedures were useful. The entire anaesthetic drug cost was only 127 pounds. Three patients received a degree of intensive care. Recommendations are made to improve future outcome, but sophisticated resuscitation, anaesthesia and monitoring is now possible in the front line.

Adolescent↗
PubMed1991

Minimum oxygen requirements during anaesthesia with the Triservice anaesthetic apparatus. A study of drawover anaesthesia in the young adult.

Thirty-six servicemen were anaesthetised using the Triservice anaesthetic apparatus. They were allocated randomly into one of two groups, to breathe spontaneously or to receive artificial ventilation, and into subgroups who were given air alone, or air supplemented with 1 or 4 litres/minute of oxygen. A further 12 subjects were studied subsequently using 0.5 litres/minute of added oxygen. Intra-operative blood gases were compared with those of awake premedicated controls. Artificial ventilation was associated with an unchanged arterial oxygen tension with air alone; in the other subgroups arterial oxygen tension was higher than with spontaneous respiration when related to inspired oxygen fraction (p less than 0.05). Air anaesthesia caused significant hypoxaemia with spontaneous ventilation (p less than 0.05), and 50% of the subjects required assisted ventilation. There was also a significant respiratory acidosis (p less than 0.05). Intermittent positive pressure ventilation is the method of choice for field anaesthesia when oxygen is unavailable. Spontaneous respiration must be supplemented with at least 0.5 litres minute of oxygen.

Adolescent↗
PubMed1991

Ventilation with isoflurane in the Triservice anaesthetic apparatus: a comparison with halothane and trichlorethylene.

Recovery from anaesthesia using the Triservice anaesthetic apparatus with either isoflurane alone or halothane and trichlorethylene, was assessed by measurement of reaction time. There was no statistically significant improvement in recovery between patients who received low concentrations of isoflurane and those who received halothane and trichlorethylene. The mean profiles of systolic pressure and heart rate were significantly greater in the isoflurane group (P less than 0.05) than in the halothane/trichlorethylene group. Cardiovascular stability was maintained into the recovery period. The benefits of low concentrations of isoflurane as sole agent in the Triservice anaesthetic apparatus and their extrapolation to a shocked casualty in a military setting are discussed.

Adult↗
PubMed1990

Acupressure and motion sickness.

The effectiveness of the "Sea Band" acupressure band compared with placebo and hyoscine (0.6 mg), also known as scopolamine, to increase tolerance to a laboratory nauseogenic cross-coupled motion challenge was assessed using 18 subjects. The results showed that the subjects had a significant increase in tolerance with hyoscine but had no increase in tolerance with the "Sea Band" or placebo. Possible reasons for the failure to show any significant protection from the use of these acupressure bands are insufficient movement of the wrist to provide continuous stimulation, and/or the likelihood that only a minority of the population would show non-negligible benefit as experience with medical acupressure would suggest. The application of transcutaneous electrical nerve stimulation may be worthy of study.

Acupuncture Therapy↗
PubMed1990

Excretion of a toxic dose of thallium.

We report a successfully treated case of severe thallium intoxication that required 95 days of assisted ventilation and 224 days of hospitalization. Monitoring of the patient for 500 days by measuring thallium in whole blood, serum, and urine is documented, and the role of the laboratory and utility of the measurements are considered.

Adult↗
PubMed1989

Changing trends in dental restorative treatment needs of naval recruits 1987-89--disease or diagnosis?

The restorative treatment needs of 9960 young men and women who entered the Naval Service at HMS Raleigh between January 1987 and April 1989 are summarised. A marked increase in the numbers of fillings required and a decrease in the proportion considered to be dentally fit occurred in May 1988 and has continued as a trend thereafter. Weighted non-orthogonal analysis of variances have been conducted to assess the significance of clinical and period variables upon the changes.

Dental Caries↗
PubMed1987

A comparison of halothane and trichloroethylene with isoflurane. A study of drawover air anaesthesia with the Triservice anaesthetic apparatus.

Induction and recovery times were not significantly different between two groups that received halothane with trichloroethylene and isoflurane, respectively. Maintenance of anaesthesia and analgesia was also satisfactory. Isoflurane resulted in a higher heart rate (p less than 0.01), a lower respiratory rate (p less than 0.01) and a higher inspired oxygen concentration (p less than 0.05). Respiration may be more efficient. Other potential advantages of isoflurane for anaesthesia in the field are discussed. Despite the fact that it is 15 times more expensive, the use of isoflurane as sole agent is recommended.

Adolescent↗
PubMed1975

Chest symptoms in farming communities with special reference to farmer's lung.

Surveys were carried out on random samples of the farming population in Devon and Wales in order to estimate the prevalence of respiratory symptoms and of positive precipitin reactions to thermophilic fungi. Bronchitis, as defined, was common among the Welsh hill farmers, and the proportion of positive serological tests was higher in both the areas surveyed in Wales as compared with Devon. All three surveys confirmed a previous finding that the proportion of positive precipitin tests was higher among non-smokers than smokers. Although the numbers were small there was some indication that measurement of peak expiratory flow showed different relationships with age in non-smokers according to the presence or absence of positive precipitin tests. The difficulty of determining prevalence rates for farmer's lung is discussed, but the results suggest a rate not dissimilar to those found in two areas of Scotland which were more than 20 times higher than any figure previously reported in Britain.

Adolescent↗
PubMed1975

A local maternity care system in South West England under review.

Since the Cranbrook Report in 1959 there has been a steady increase in the proportion of institutional confinements in England and Wales and a steady decrease in perinatal mortality. This association should not be regarded as evidence of cause and effect nor as justification for continuing the Cranbrook policies for the provision of maternity care throughout the 1970s. Due weight must be given to other factors, including improvements in the general health and education of the population and advances in standards of medical care affecting all parts of the maternity services. The present study examines current performance of a local maternity care system and analyzes some 3700 confinements which took place in a Health Care District (formerly a Hospital Management Committee area) in South West England during 1970. The local resources consisted of a consultant obstetric unit, a Special Care Baby Unit, five general practitioner units and the associated medical and nursing staff, and two Local Authority domiciliary midwife services. An expectant mother may call upon a variety of resources in pregnancy, during delivery, and in the puerperium. The concept is developed of the "stream" of care received by the mother and the case histories are analyzed in these terms. The deliveries are classified in terms of nonintervention and intervention at delivery. Perinatal mortality is not in itself an adequate measure of the overall performance of a local maternity care system so other performance indices are used. These are based upon the extent to which the resources available diverge between booking and actual usage. Results obtained indicate that existing policies may be less than optimal and alternatives ought to be considered.

Delivery of Health Care↗
PubMed1975

Maximum likelihood estimation for a special type of grouped data with an application to a dose-response problem.

A short-cut method is given for calculating grouped maximum likelihood (ML) estimates when the data are relatively coarsely grouped in some directions, but more finely grouped in others. The algebraic details are then worked out for a dose-response problem that generates data of this kind. The situation envisaged is a variation on the usual quantal response problem in that dosage levels are taken to be random but grouped. Finally, the method is applied both to real and simulated response data conforming to this pattern and shown to work well in practice.

Birth Weight↗