PubMed Health⌕ Search

Biomedical subjects

J E Cotes

Publications and source records attributed to J E Cotes.

At least 19 recordsLinked to original sources
PubMed1992

Standardization of single-breath transfer factor (TLCO); derivation of breathholding time.

Breathholding time is usually defined using the procedure of Ogilvie et al. or of Jones and Meade; these procedures depend on knowing when inspiration begins and, for the latter, when it ends. Some alternative procedures do not require this information. With a view to standardizing the measurement, transfer factor of the lungs for carbon monoxide (TLCO) was measured in 18 adults with labile airflow obstruction, who were assessed before and after inhalation of salbutamol. The inflection points defining the start and end of inspiration were defined visually (method 1), and by extrapolation of the linear part of the inspiratory limb of the single-breath trace (method 2). The spirograms met recognized standards of quality and were rated by experienced observers. Compared with method 1 the TLCO and related indices by method 2 were lower using the procedure of Jones and Meade and higher using the procedure of Ogilvie et al. in each case by, on average, 1.0%. The within- and between-day variabilities were independent of the method used. Thus, the extrapolation and visual methods yielded interchangeable results when applied by experienced operators. However, extrapolation may be easier for inexperienced operators.

Albuterol↗
PubMed1991

Is respiratory function diminished?

An association between diminished respiratory function and an environmental agent should reflect the magnitude of the exposure and not be due to technical error, bias, confounding factors, or chance. Bias is difficult to avoid; the best course is to make comparisons within a population of exposed individuals, not between them and a control group; the population should be defined and a high response rate achieved. The principal confounding factors are age, smoking, and other environmental exposures; their effects should be fully estimated for the population in question as otherwise they will be wrongly attributed to the environmental agent. Finally, the results should be scrutinized and, if possible, a second independent study should be planned.

Cross-Sectional Studies↗
PubMed1990

Longitudinal respiratory survey of shipyard workers: effects of trade and atopic status.

A respiratory sample survey of 609 shipyard workers was conducted in 1979: the men were reassessed an average of 7.2 years later. The 53 deaths between the surveys were related to age, level of lung function and smoking but not to trade as a welder or caulker/burner. Of the survivors, 488 (88%) were seen, including 425 men who had retired or been made redundant. Redundancy was related to age, smoking, and respiratory symptoms; the average reduction in duration of employment per symptom was 0.44 years. Changes in respiratory symptoms included onset of chronic bronchitis and wheeze on most days (numbers respectively 77 and 109) and increased breathlessness on exertion (n = 89); significant related factors included smoking, previous metal fume fever or pneumonia, and, for breathlessness, trade as a welder or caulker/burner. Electrocardiographic evidence for myocardial ischaemia was also associated with increased breathlessness. The annual declines in FEV1 and other spirometric indices were related to age, to being a smoker at the time of the initial survey, and to trade as a welder or caulker/burner compared with trades that did not involve welding or burning. There was significant interaction between these effects. In a subsample of 124 redundant workers there was also significant interaction between the effects of fumes and atopy (skin test positive to common antigens) or a raised serum IgE concentration. It was concluded that welding fumes interacted with smoking and an atopic constitution to cause respiratory impairment. The results related mainly to exposures in the past and were not necessarily relevant for present day conditions in the industry.

Age Factors↗
PubMed1990

Rating respiratory disability: a report on behalf of a working group of the European Society for Clinical Respiratory Physiology.

A rating procedure for respiratory disability has been developed; it entails measuring the symptom-limited maximal oxygen uptake or estimating the maximal uptake from the results of a submaximal exercise test and other relevant variables. The derivation assumes a linear scale of disability between the limits 0% and 100% which are defined. The percentage disability of 157 men with respiratory limitation of exercise has been used to delineate empirical grades of disability. These are of similar form to those used for grading respiratory impairment. More information is needed with a view to validation.

Disability Evaluation↗
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↗