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Biomedical subjects

J E Cotes

Publications and source records attributed to J E Cotes.

At least 55 records · Page 3Linked to original sources
PubMed1989

Respiratory symptoms and impairment in shipyard welders and caulker/burners.

All 607 men, aged 17 to 69, comprising a stratified sample of workers from one shipyard completed a respiratory questionnaire, clinical examination, and detailed spirometry. Chest radiographs were available on 332 men. Among the men aged 50-69 the prevalence of persistent cough and phlegm (chronic bronchitis) was 40%, of wheeze on most days 25%, and undue breathlessness on exertion 25%. After allowing for age the relative risk of welders and caulker/burners having these symptoms were respectively 2.8, 2.2, and 3.1 compared with other shipyard tradesmen. The effects were of comparable magnitude to and interacted with those of current smoking. Among the welders and caulker/burners who smoked, the relative risk of developing chronic bronchitis or undue breathlessness was related to the average fume exposure; the relative risk of wheeze was related to the average fume exposure in all smoking categories, with the strongest association in the ex-smokers. The occurrence of wheeze was also associated with a history of previous metal fume fever. A history of pleurisy but not of pneumonia was related to the fume exposure in the welders. After allowing for age and stature, forced expiratory volume (FEV1) was on average higher in young welders (age less than 30) than other tradesmen. In welders and caulker/burners who were current or ex-smokers, FEV1 and PEF were reduced in relation to the average fume exposure (mean reductions respectively 0.25 l and 0.99 l s-1). The FEV1% (of forced vital capacity), the flow rates at small lung volumes (MEF50%FVC and MEF25%FVC), the mean transit time, and its standard deviation were also reduced by fume exposure or the declines with age were increased, or both. No impairment was demonstrable in the non-smokers and many men had given up smoking with apparently beneficial results. The occupational component of the respiratory impairment related mainly to exposures in the past; information was needed on the effects of present conditions in the industry.

Adolescent↗
PubMed1989

Relation of lung function and exercise capacity to mood and attitudes to health.

Results of psychometric tests were obtained on 161 male welders and other tradesmen in heavy industry who had recently been made redundant. Anxiety and depression were scored on the Hospital Anxiety and Depression Scale, and negative attitudes and beliefs regarding breathlessness and related aspects of respiratory health on a semantic differential scale. Scores for attitudes and beliefs about health and personal disability were pooled to give a general attitude score. Personality was rated on a standard scale. Subjects completed a questionnaire on respiratory symptoms and underwent routine spirometry, measurement of carbon monoxide transfer factor for the lung, and a progressive exercise test on a cycle ergometer. Scores for anxiety, depression, and negative mental attitudes were significantly intercorrelated; subjects with disordered personality profiles had above average scores for anxiety and depression. The psychometric scores were associated with clinical grade of breathlessness, lung function, and the physiological response to exercise. The general attitude score could be predicted from the anxiety and depression scores and from lung function expressed relative to age and stature, the combination of mood score and FEV1 explaining 38% of the variance in general attitude score. The general attitude score accounted for more than half the explained variance in the clinical grade of breathlessness and contributed more to the variance in maximal oxygen uptake (R2 = 0.11) than FEV1. It was associated with the level of habitual activity but not with smoking category, wheeze, chronic cough or phlegm. Thus attitude to disability reflected the subject's assessment of his exercise capacity and was closely related to the clinical grade of breathlessness.

Adult↗
PubMed1988

Indirect estimation of maximal oxygen uptake for study of working populations.

A total of 345 shipyard workers (aged 23 to 47) volunteered to perform progressive exercise on a cycle ergometer (15 W/min increments) up to the symptom limited maximum. The results were used to obtain maximal oxygen uptake (nO2 max), the oxygen uptake at a respiratory exchange ratio of unity (nO2 at R1.0), and cardiac frequency at an oxygen uptake of 45 mmol/min (fC45). In this group 156 men (45% of initial population) attained nO2 max as defined, 108 (31%) withdrew or did not exercise maximally, and 49 (14%) had transient electrocardiographic abnormalities. For the 156 men extrapolation of the relation of cardiac frequency on oxygen uptake to the predicted maximal cardiac frequency resulted in overestimation of nO2 max by 9.6%. nO2 Max per kg body mass was negatively correlated with body mass. nO2 Max (mean value 130.6 mmol/min) was described in terms of age, fat free mass, smoking (yes or no), and level of habitual activity (rated 1 to 4): the standard error of the estimate (SEE) was 17.3 mmol/min (R2 0.42); the equation was suitable for reference values. For estimating the nO2 max of individual men an empirical relation based on nO2 at R1.0, fC45, fat free mass, and % body fat had an SEE of 12.1 mmol/min (R2 0.67). Seventy six per cent of men (88% of those who exercised) attained nO2 at R1.0 (oxygen uptake approximately 73% of maximum). Thus the nO2 max could be estimated in a higher proportion of men than could achieve nO2 max. The estimate is appropriate for assessing exercise capacity in relation to employment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Relationship of lung function to radiographic reading (ILO) in patients with asbestos related lung disease.

The 1980 International Labour Office (ILO) classification of posteroanterior chest radiographs was used to obtain the scores for profusion of small opacities and pleural abnormalities of 172 men with confirmed or suspected disease of the lungs due to asbestos. After allowance had been made for age, stature, and smoking habit the quantitative score for area of diffuse pleural thickening seen in profile on both lateral chest walls contributed to reductions in inspiratory capacity, expiratory reserve volume, and forced expiratory flow rates. Occlusion of one or both costophrenic angles in the presence of diffuse thickening was associated with further reduction in inspiratory capacity. Profusion of small opacities was associated with a reduction in transfer factor. Diffuse pleural thickening and occlusion of costophrenic angles were associated with relatively low values for the forced expiratory flow rates (MEF50FVC) and FEV1/FVC, whereas small opacities were associated with relatively high values. Thus overall increased, normal, or reduced values of MEF50FVC and FEV1/FVC might occur, depending on the distribution of the radiographic abnormalities. The findings contribute to the validation of the ILO pleural scores; those for diffuse pleural thickening and occlusion of costophrenic angles should be used jointly with the scores for profusion of parenchymal small opacities in interpreting the lung function of persons exposed to asbestos.

Adult↗
PubMed1988

Lung function impairment as a guide to exercise limitation in work-related lung disorders.

The hypothesis that exercise limitation of respiratory origin can be predicted accurately from the lung function impairment has been tested using maximal oxygen uptake (VO2max) as the dependent variable in a multiple regression analysis. The subjects were 157 men who met objective criteria for exercise being limited by respiratory impairment. VO2max (mean value, 1.38 L min-1) was described by FEV1 and single-breath lung transfer factor (diffusing capacity) for carbon monoxide (TL') singly or in combination, but the accuracy was poor (at best, standard error of the estimate, 0.36 L min-1; r2, 29.1%). FEV1 could be replaced by FVC and FEV1/FVC. Description of VO2max was improved by also including in the equation the variables age, fat-free mass, and submaximal exercise ventilation (VE). Transfer factor did not then contribute significantly. VO2max as percent of predicted (mean value of 60%) was described by %FVC or %FEV1, but the accuracy was poor (SEE, 16.0%; r2, 14%). Prediction was improved somewhat by the alternative use of inspiratory vital capacity and FEV1/FVC. Transfer factor did not contribute additional information; however, inclusion of VE materially improved the accuracy (SEE, 12.9%; r2, 44%). Among a subgroup of 35 men whose lung disease was due to asbestos, %TL' or transfer factor measured using a multibreath estimate of residual volume (%TLCO) made a small contribution to the explained variance, e.g.: %VO2max = 0.44% FEV1 -0.78 VE + 0.16% TLCO + 52.3 SEE 7.27%. This equation also described the %VO2max of all subjects (SEE, 13%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Measurement technique influences the response of transfer factor (TICO) to salbutamol in patients with airflow limitation.

Single-breath transfer factor obtained using a multibreath estimate of alveolar volume (TI) was measured before and after salbutamol in twenty patients with reversible airflow limitation. The effective breathholding time was calculated by four methods due respectively to Ogilvie and colleagues as modified by the American Thoracic Society (ATS), ATS Epidemiological Standardization Project (ESP), Jones and Meade in which allowance was made for the time of sample collection and a simplified method in which the allowance for sampling was in terms of volume, not time. Two patients could perform the test procedure only after salbutamol. Amongst the remainder the transfer factor calculated using a single-breath estimate of alveolar volume (TI') was on average 12% less than TI. Carbon monoxide transfer coefficient (KCO), TI and TI' were highest by the ESP method and lowest by the Ogilvie method. Inhalation of salbutamol (200 gamma) did not affect TI' by any method or TI and KCO by the Jones and Meade method but results by the other methods were reduced; in the case of the modified Ogilvie method the reduction was 3.9%. This error was due to overestimation of effective breathholding time by neglecting the reduction of 39% which occurred in the time of sample collection. The time of inspiration was unchanged whilst the time of deadspace washout was reduced by 16%. After bronchodilatation the absence of a change in TI' was due to the overestimation of effective breathholding time being offset by an increase in the proportion of alveolar volume measured by the single-breath procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Respiratory effects of a single saturation dive to 300 m.

Lung function and the response to exercise were monitored in seven diver/welders who took part in a test saturation dive to 300 m for an average duration of 12 days; decompression took an average of nine days. Immediately after the dive the forced vital capacity was increased above base line by on average 0.51, the forced expiratory volume by 0.281 and peak expiratory flow rate by 0.71 s-1. There was no change in flow rate at small lung volumes (FEF 75% FVC). Recovery was complete and appeared to have a half time of 28 days. Transfer factor of the lungs for carbon monoxide (TlCO) was reduced by on average 9.6% after the dive but while partial recovery occurred, the values at one year were on average lower than those observed initially. The reason is unclear. One subject developed transient oxygen toxicity with stiff lungs and increased ventilation and cardiac frequency during submaximal exercise; a second subject developed similar changes but without accompanying symptoms. There is need for detailed physiological surveillance of people undertaking deep dives; this should be undertaken in circumstances that permit accurate measurements and full subject cooperation.

Adult↗
PubMed1986

Accuracy of gas analysis in lung function laboratories.

Fifty lung function laboratories in England and Wales analysed test gas mixtures of carbon monoxide and helium. Most of them also analysed mixtures of oxygen and carbon dioxide in nitrogen. The percentage accuracy of the results was within 1% of the expected value in only 14% of determinations of carbon monoxide concentration, 28% for carbon dioxide, 37% for helium, and 48% for oxygen. The accuracy of ratios of two concentrations of helium and carbon monoxide was better than that of the individual gas samples. Overall the variation in results between laboratories was wide, the coefficient of variation ranging from about 3% for analysis of helium to 9% for carbon dioxide. This variation affected the values calculated for carbon monoxide transfer factor, where 20% were in error by more than 5%, and for the calculated value of the respiratory exchange ratio, where the interlaboratory coefficient of variation was about 10%. Errors in analysis were due to unsatisfactory calibration of analysers; five oxygen analysers had large zero errors; five carbon monoxide analysers and one helium analyser had notably curvilinear calibration curves. Insufficient information was obtained to ascertain the nature of the errors in analysis of carbon dioxide. Given the improvements in instrumentation, these results are evidence for deterioration in analytical standards in lung function laboratories from the standards of 20 years ago.

Carbon Dioxide↗
PubMed1985

"Invalidity" due to chronic bronchitis and emphysema: how real is it?

Hospital discharges and deaths attributed to chronic bronchitis and emphysema have fallen in recent years while the number of those receiving invalidity benefit for these conditions has remained constant. One hundred and fifty seven such persons were invited to take part in this study, in which the diagnosis, degree of respiratory impairment, and other factors contributing to disability were reviewed. The scope for rehabilitation was considered. One hundred subjects agreed to take part; 96 were men and 70 were over 60 years. In only 67 was the main diagnosis chronic bronchitis and emphysema. There was a bimodal distribution of functional impairment, most being severely disabled, but in 20 the FEV1 was within the normal range. Among these asthma was more common and psychological factors were important. Economic factors contributed to "invalidity," especially among those with a normal FEV1. For 32 of the 57 who had declined to take part some information was available from hospital records. The findings in this group were similar. There was little scope for rehabilitation in the group as a whole as motivation was poor. Less than half had ever seen a chest physician. Specialist assessment before invalidity benefit is claimed is probably desirable.

Aged↗