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Biomedical subjects

T B Stretton

Publications and source records attributed to T B Stretton.

At least 19 recordsLinked to original sources
PubMed1991

Evaluation of 99Tcm Technegas ventilation scintigraphy in the diagnosis of pulmonary embolism.

In the diagnosis of pulmonary embolism, perfusion lung scintigraphy offers high sensitivity but low specificity. The specificity can be significantly increased by the use of combined ventilation and perfusion studies. Most aspects of perfusion lung scintigraphy are uniformly accepted but the technique of ventilation imaging varies from centre to centre. This study describes a new technique for the performance of ventilation scintigraphy using a suspension of ultrafine carbon particles labelled with 99Tcm ("Technegas"). The technique combines the ready availability of 99Tcm and its optimal imaging properties with an easily administered radiopharmaceutical of particle size sufficiently small to deposit in the alveoli. Of 63 patients studied by conventional perfusion scintigraphy plus Technegas ventilation scintigraphy, images of diagnostic quality were obtained in all. 31 of these patients also had a ventilation study using 81Krm gas and in only one instance did the two methods of ventilation imaging lead to differing interpretations. We conclude that high quality diagnostic images may be obtained using this new technique, which can be made available on both a routine and an emergency basis, thus improving the service provided for patients suspected of having pulmonary embolism.

Adult↗
PubMed1986

The effect of indomethacin on breathlessness in patients with diffuse parenchymal disease of the lung.

We have shown in a previous study that indomethacin reduced breathlessness in normal subjects during exercise. In a double-blind randomized study we have determined the effects of both acute (50 mg) and chronic (25 mg twice daily for 7 days) oral treatment with indomethacin on breathlessness induced by exercise in patients with diffuse parenchymal disease of the lung. The relationship of breathlessness, as measured on a visual analogue scale, to ventilation was not significantly altered by either acute or chronic treatment with indomethacin compared to placebo. There was no significant change in the distance walked in 6 minutes after any of the treatments. Possible explanations for the differing effects on breathlessness observed in normal subjects and in patients are discussed.

Adult↗
PubMed1985

Effects of small-particle aerosols of local anaesthetic on dyspnoea in patients with respiratory disease.

This study was devised to test the hypothesis that dyspnoea could be mediated by unmyelinated vagal sensory nerve endings (type J receptors) situated at alveolar level in the lung. A modified jet nebulizer was used to generate an aerosol of local anaesthetic in particles small enough to allow alveolar deposition. Lignocaine (2% and 5%) produced aerosols with an arithmetic mean diameter (+/- SD) of 1.5 +/- 0.3 and 1.2 +/- 0.6 micron respectively, the mass median diameters being 1.7 (geometric standard deviation = 1.2) and 2.5 (geometric standard deviation = 1.7) micron respectively. In experimental animal models a vagally mediated tachypnoea may be induced acutely by pulmonary microembolism. This response is known to be mediated by unmyelinated pulmonary afferent nerves in the vagus. Local anaesthetic agents administered as small particles, but not as large particles, obtunded this response, which suggests that the aerosol was capable of penetration to alveolar level. Upon this background, a clinical study was designed to compare the effects of lignocaine with placebo both given as small-particle aerosols. Six patients, including two with diffuse alveolar pathology and four with chronic airflow obstruction, were studied. Respiratory frequency was determined before and after the aerosol, and exercise tolerance and breathlessness were measured with a 6 min walking test and visual analogue scales. After lignocaine there was no clinical evidence of anaesthesia of the upper airways but bronchoconstriction occurred. While no overall effect of lignocaine on dyspnoea was apparent, individual patients showed some evidence of benefit.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗
PubMed1985

Treatment of malignant pleural effusions with intrapleural Corynebacterium parvum or tetracycline.

Thirty two patients with malignant pleural effusion were randomly allocated to treatment with intrapleural Corynebacterium parvum or tetracycline hydrochloride in an attempt to prevent symptomatic recurrence of pleural fluid. Success in preventing recurrence of fluid at one month, using up to 2 doses of each drug, was 14 of 16 cases for Corynebacterium parvum, 5 of 9 for tetracycline given via an intercostal needle, and 6 of 7 for tetracycline given through an intercostal tube. These difference were not statistically significant. Corynebacterium parvum was significantly more likely to produce pyrexia equal or greater than 38 degrees C (P less than 0.001) and pain requiring analgesia (P less than 0.05) than tetracycline hydrochloride. Corynebacterium parvum is a useful agent for the management of malignant pleural effusion, but is associated with more side effects than tetracycline.

Bacterial Vaccines↗
PubMed1984

Immunological abnormalities in patients with chronic bronchial suppuration: a possible relationship with endotoxaemia.

Chronic bronchial suppuration has been associated with elevations in immunoglobulin levels, circulating autoantibodies and immune complexes but the cause is obscure. In order to investigate one possible explanation we studied eight male subjects (mean age 54.9 years, range 39-68) and 16 female subjects (mean age 45.2 years, range 24-68) with bronchial suppuration attributed to bronchiectasis. Gram-negative organisms were found in the sputum of 95% of subjects. Forty per cent (10 subjects) had elevations in immunoglobulin levels and 60% (15 subjects) had circulating autoantibodies. Eighty-eight per cent (21 subjects) had mild-moderate increases in the level of C-reactive protein. Endotoxin was detected using the limulus amoebocyte lysate test in 50% (12 subjects). Endotoxin was found only in patients with an immunological abnormality and was more likely to be detected in those with both elevated immunoglobulins and circulatory autoantibodies. It is suggested that the endotoxin may be of aetiological significance in the development of autoantibodies and elevations of immunoglobulin levels.

Adult↗
PubMed1983

AIDS in 1959?

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Acquired Immunodeficiency Syndrome↗
PubMed1983

Dose-response comparison of ipratropium bromide from a metered-dose inhaler and by jet nebulisation.

The dose-response relationships of the anticholinergic bronchodilator drug ipratropium bromide were studied. Cumulative doses totalling 288 micrograms ipratropium were given by inhalation of a liquid aerosol from a Wright nebuliser to each of 10 patients with stable, moderately severe airflow obstruction. Up to 80% of the maximum achievable bronchodilator response, as assessed by a rise in the patients' mean forced expiratory volume in one second (FEV1), was obtained with a cumulative total dose of 72 micrograms; with additional doses beyond 72 micrograms there was no significant further improvement. In the same patients the effects of administration of cumulative doses of ipratropium to a total of 72 micrograms from a Wright nebuliser were compared with those achieved with a metered-dose inhaler. Bronchodilatation was assessed by measurement of peak expiratory flow rate, FEV1, forced vital capacity, thoracic gas volume and specific airways conductance (sGaw). No significant difference was observed in the response at any dose level between the wet and the dry aerosols. By fitting a curve to the mean values of FEV1 and sGaw an estimate was made of the dose of ipratropium bromide required to produce 99% of the achievable bronchodilator response. For FEV1 this dose was 78 micrograms when ipratropium was inhaled as a nebulised solution from the Wright nebuliser and 82 micrograms when it was inhaled from the metered-dose inhaler; for sGaw the respective values were 54 and 58 micrograms. In these patients with stable airflow obstruction there was no therapeutic advantage in the use of ipratropium bromide as a wet aerosol.

Adult↗
PubMed1982

Role of pulmonary function tests in the prevention of bleomycin pulmonary toxicity during chemotherapy for metastatic testicular teratoma.

Thirty-eight men were treated for metastatic teratoma with up to four courses of chemotherapy, each containing 90 mg bleomycin. Routine pulmonary function tests (PFTs) were performed before each course to assess their value in detecting bleomycin pulmonary toxicity. PFTs were repeated 2-5 yr after completion of chemotherapy in 10 disease-free survivors. Analysis of changes in individual PFT values showed a fall in the carbon monoxide diffusing capacity (DLco) after 90 mg bleomycin (P less than 0.005). The DLco remained depressed with subsequent doses of bleomycin, but there was no further statistically significant fall. There was no significant change in any other PFT. Similarly, late PFT values showed no significant change. There was no correlation between changes in the visible extent of metastases as assessed from the chest radiography and changes in serial PFTs. It is concluded that routine PFTs are unnecessary if the total bleomycin dose in less than or equal to 360 mg, unless there are particular risk factors. Late drug-induced pulmonary damage is unlikely to develop after treatment withdrawal.

Adolescent↗
PubMed1980

Effect of an extension tube on the bronchodilator efficacy of terbutaline delivered from a metered dose inhaler.

A double-blind within-patient investigation was performed to determine whether the interposition of an extension tube (10 cm length X 3.2 cm diameter) between a metered dose inhaler and the mouth alters the bronchodilator efficacy of terbutaline sulphate. On two consecutive study days 14 adult patients with stable reversible airways obstruction inhaled a cumulative dose of 500 micrograms of terbutaline which was delivered from a metered dose inhaler with or without the extension tube attached and received placebo in a similar manner. The drug was inhaled in doses of 125, 125, and 250 micrograms at 20 minutes intervals. The following measurements were made: forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow rate (PEFR), thoracic gas volume (TGV), and specific airways conductance (sGaw). These were done immediately before and at five and 15 minute intervals after each dose, and were repeated 90, 120, 180, 240, and 300 minutes after the first inhalation of terbutaline. Administration of terbutaline with and without an extension tube achieved significant bronchodilation at all dose levels in all respiratory variables (p < 0.001). There was no statistically significant difference in FEV1, FVC, PEFR, and sGaw values at any time or dose level with either method of administration. The use of the extension tube did not impair the efficacy or duration of action of inhaled terbutaline.

Adult↗
PubMed1975

The lungs in renal failure.

Pulmonary function was studied in 55 patients with renal failure and no clinical or radiographic evidence of lung disease. A defect of gas transfer was found to be the rule due to a reduction in the diffusing capacity across the alveolar capillary membrane; this abnormality appeared to be related to the severity of the renal impairment. There was also a restrictive ventilatory defect which was more marked in male than in female patients. The significance of these findings is discussed, and attention is drawn to their relevance for patients receiving immuno-suppressive therapy or renal transplantation, in whom pulmonary complications are relatively common.

Acute Kidney Injury↗
PubMed1972

Asthma in the elderly.

Fifteen patients who developed asthma after the age of 60 years are reported. Attention is drawn to apparent difficulties of diagnosis in this age group. A history of chronic bronchitis is common, and a change in symptoms, especially the abrupt onset of increased breathlessness, wheezing, and paroxysmal nocturnal dyspnoea, should arouse suspicion of the development of asthma. A past or family history of allergy is confirmatory evidence, as is the presence of blood or sputum eosinophilia. Retrosternal pain is not uncommon, and angina pectoris or left ventricular failure must be excluded. Chest radiographs showed changes consistent with old quiescent tuberculosis in five patients; careful follow-up is therefore essential as asthma in this age group often requires steroid therapy.

Aged↗
PubMed1972

Respiratory diseases.

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Alveolitis, Extrinsic Allergic↗