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Biomedical subjects

R M Cayton

Publications and source records attributed to R M Cayton.

At least 19 recordsLinked to original sources
PubMed1992

The effect of ipratropium bromide on maximal exercise capacity in asthmatic and non-asthmatic men.

The effect of 0.5 mg nebulized ipratropium bromide (IB) on the cardio-respiratory responses to a progressive maximal cycle exercise test was compared with a matched placebo (P) in eight mild asthmatic and eight non-asthmatic men. The forced expiratory volume in l s (FEV1) in the asthmatic group was higher after ipratropium bromide both at rest [IB, mean 4.07 (SD 1.18) l versus P, 3.83 (1.29) l, P less than 0.05] and after exercise [IB, 3.64 (1.31) l versus P, 3.30 (1.40) l, P less than 0.02]. Since the percentage fall in the FEV1 after exercise was not significantly changed by ipratropium bromide [IB, -12 (11)% versus P, -16 (14)%], the improvement in the post-exercise FEV1 in the asthmatic group is attributable to the pre-exercise bronchodilatation. The resting and post-exercise FEV1 in the non-asthmatic group were also significantly higher after ipratropium bromide. However, neither group showed any differences in the cardio-respiratory, haemodynamic or subjective responses to the progressive maximum exercise test when ipratropium bromide was compared with placebo. These results demonstrate the absence of significant cardio-respiratory effects during exercise with this relatively high dose of ipratropium bromide, in patients with mild asthma and in non-asthmatic subjects. No ergogenic effect on maximal exercise performance was shown to question its use by asthmatic athletes engaged in high level competition.

Adult↗
PubMed1991

Cardio-respiratory responses to exercise following treatment of acute severe asthma.

Asthmatic patients are encouraged to adopt a normal and active life-style. However, following treatment of acute severe asthma, patients may ask for advice about taking exercise. Serial measurements of the cardio-respiratory responses to continuous work load exercise, were made in asthmatic patients convalescing following hospital treatment of an acute exacerbation. Eighteen asymptomatic patients, (seven male) aged 18-48 years, were studied. The first test was performed within 1 week of admission, when the mean (SD) peak expiratory flow rate (PEFR) was 88 (20)% predicted normal and the arterial oxygen tension (PaO2) was 13.1 (1.4) kPa. No significant differences in the mean cardio-respiratory responses, from the last minute of exercise, were found during the 4-week study. There were no significant differences in the four tests, between the resting PEFR, lowest post-exercise PEFR or % change in PEFR. Also, there were no significant differences in the pre-exercise, end of exercise and recovery (10 min after exercise) PaO2, between the four tests. However, taking the four tests as a whole, significant relationships were found between the recovery PaO2 and the lowest post-exercise PEFR, expressed in absolute terms (r = 0.515, P less than 0.001), and as a percentage of predicted normal (r = 0.533, P less than 0.001); and also between the recovery PaO2 and the % change in PEFR after exercise (r = 0.299, P less than 0.05). It is suggested that a formal exercise test should be performed in convalescent asthmatics wishing to participate in active sports. Patients with exercise-induced asthma may then be identified and treated appropriately.

Acute Disease↗
PubMed1991

The effect of sustained-release theophylline in nocturnal asthma.

Nocturnal symptoms are common and often disabling in asthmatic subjects. Furthermore, they often persist, in spite of appropriate dosages of inhaled beta 2-agonists and topical steroids. In such a clinical situation, theophylline preparations may have a therapeutic role. This double-blind, placebo-controlled, cross-over trial was designed to evaluate the effectiveness of a twice-daily Bioavail slow-release theophylline capsule in a group of out-patient asthmatics, with a history of nocturnal and/or early morning wheeze or chest tightness. Theophylline was initially prescribed and monitored in an 'open' phase to obtain the drug dosage required to achieve a serum level in the therapeutic range of 10-20 mg/l. In the ten patients who completed the study, serum theophylline levels were stable throughout. During active treatment there was an improvement in morning peak expiratory flow rate (PEFR), and a reduction in measurements of diurnal variation. In addition, the bronchodilator response to an inhaled beta 2-agonist was preserved. Bioavail theophylline has thus been shown to be an effective agent in the management of adults with nocturnal asthma.

Adult↗
PubMed1990

The twenty-metre shuttle-running test: a combined test for maximal oxygen uptake and exercise-induced asthma?

A maximal multistage 'twenty-metre shuttle-running test' has already been developed to estimate maximal oxygen uptake (VO2 max). This field test requires little equipment or expertise, can be performed simultaneously by several subjects, and is widely used in physical education lessons. The present study assessed the potential for this test to provoke exercise-induced asthma in 73 schoolboys, aged 15-16 years. Measurements of the forced expiratory volume in one second (FEV1) were made at rest and 10 min after the twenty-metre shuttle-running test; exercise-induced asthma was defined as greater than a 10% fall in FEV1 after exercise. The pupils achieved 73 +/- 19 shuttles (mean +/- SD) giving a VO2 max of 47.0 +/- 5.3 ml kg-1 min-1. Exercise-induced asthma was documented in eight pupils (11%); two were known asthmatics who, despite taking pre-exercise B2 agonist treatment, had sharp falls in FEV1 (-25.4 and -25.6%); two had previously experienced occasional chest tightness or wheeze with exercise (-16.5 and -13.2% fall FEV1); but four were asymptomatic, with no previous asthmatic symptoms (-20.0, -18.2, -15.3 and -11.4% fall FEV1). This study has demonstrated the potential of the twenty-metre shuttle-running test to provoke exercise induced-asthma, and may therefore be a useful clinical test to assess for exercise-induced asthma when an estimate of VO2 max would also be helpful. Furthermore, physical education teachers should take basic precautions when using this test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Association between risk factors for coronary heart disease in schoolboys and adult mortality rates in the same localities.

Risk factors for coronary heart disease were compared in fifth year boys (15-16 years old) from two schools that were chosen from localities with a fourfold difference in adult mortality from coronary heart disease. One school was in an underprivileged urban locality in the area of increased incidence of heart disease ('high risk') and the other in a semi-rural affluent locality with an incidence of heart disease similar to the national average ('low risk'). Smoking, hypertension, hypercholesterolaemia, obesity, physical fitness, and inactivity were evaluated as risk factors for coronary heart disease. Smoking, increased body fat, poor diet, and physical inactivity were found increased among pupils from the school in the high risk area compared with those in the low risk area. Lipids, maximum oxygen uptake, and hypertension were similar in both schools. The risk of coronary heart disease seems to reflect the adult mortality rates in the area. To reduce the overall incidence of coronary heart disease, health education should be directed towards prevention of smoking, improving diets, and increasing amounts of activity among school children, with special attention directed toward children in regions where there is a high mortality from coronary heart disease among adults.

Adolescent↗
PubMed1990

Effects of exercise on gas exchange in patients recovering from acute severe asthma.

The effect of exercise on gas exchange was studied in 17 patients (seven male and 10 female) recovering in hospital from acute severe asthma. On admission the patients (mean age 26 (SD 8) years) had a mean peak expiratory flow (PEF) of 26.8% (5.7%) predicted, a mean arterial oxygen tension (PaO2) of 8.63 (1.26) kPa, and a mean alveolar-arterial oxygen difference (A-aDO2) of 5.98 (1.34) kPa. Once resting symptoms had resolved (after 3.7 (1.6) days) patients performed a constant load exercise test (100 watts for men, 75 watts for women) on a bicycle ergometer for five minutes. PEF was measured before exercise and at five minute intervals for 30 minutes after exercise. Blood gas tensions were measured on capillary blood before, during, and 10 minutes after exercise. Treatment was not interrupted for this study. Mean PEF at rest was 87.6% (21.1%) predicted and showed no significant change after exercise. Mean PaO2 was 13.13 (1.37) kPa before exercise; it showed no significant change during exercise (13.93 (1.34) kPa) or 10 minutes after exercise (13.50 (2.15) kPa). Mean A-aDO2 also showed no change, being 1.82 (1.31) kPa before exercise, 1.79 (1.27) kPa during exercise, and 2.53 (0.93) kPa after exercise. It is concluded that moderate exercise carried out shortly after treatment for acute severe asthma is unlikely to result in worsening gas exchange during or after exercise if resting PEF, PaO2 and A-aDO2 have attained normal or near normal values.

Acute Disease↗
PubMed1989

Effect of nebulised salbutamol on maximal exercise performance in men with mild asthma.

The effect of 5 mg nebulised salbutamol on the cardiorespiratory responses to a progressive maximal exercise test was investigated in eight asthmatic (mean forced expiratory volume in one second (FEV1) 3.48 (1.0) litres) and eight non-asthmatic men. Exercise tests were performed on a bicycle ergometer after administration of nebulised salbutamol or matched saline placebo. In the asthmatic subjects salbutamol increased the resting FEV1 by 11%. The mean (SD) percentage fall in FEV1 after exercise did not change significantly (salbutamol 9.4 (12.8); placebo 15.0 (8.0], but because the FEV1 before exercise was increased the lowest FEV1 after exercise was also significantly higher after salbutamol than placebo (3.60 (1.13) v 2.85 (0.80) litres). Despite the improvement in FEV1 before exercise there was no significant difference in maximal workload, oxygen uptake, heart rate, or ventilation during exercise after salbutamol compared with placebo in the asthmatic patients. Tidal volume was higher at maximal exercise after salbutamol but there was no change in perception of breathlessness or exertion in the asthmatic subjects. During submaximal progressive exercise the perceived rate of exertion was reduced in the asthmatic patients and oxygen pulse was reduced in both groups owing to a small and non-significant increase in heart rate. The FEV1 and cardiorespiratory response to the progressive maximal exercise test in the non-asthmatic subjects were otherwise unchanged after salbutamol. The results suggest that 5 mg nebulised salbutamol has little effect on the cardiorespiratory responses to progressive maximal exercise in patients with mild asthma and in non-asthmatic subjects. Salbutamol in this dose may reduce the severity of exercise induced asthma, but no ergogenic effect on maximal exercise performance was shown.

Adult↗
PubMed1987

Blood fuel metabolites in asthma during and after progressive submaximal exercise.

Ten male stable asthmatic subjects and 10 matched control subjects performed a progressive exercise test on a treadmill to 85% of their predicted maximum heart rate. Blood lactate, pyruvate, hydrogen ion, glucose, alanine, glycerol and total ketone body concentrations were measured at frequent intervals during and up to 60 min after exercise. Carbon dioxide production, oxygen consumption, ventilation, respiratory exchange ratio and oxygen saturation were also measured during and up to 10 min after exercise. There were no significant differences between the asthmatic and control subjects in levels of carbon dioxide production, oxygen consumption and ventilation. The respiratory exchange ratio was greater in the asthmatic subjects during recovery from exercise (P less than 0.05). No changes in oxygen saturation were observed during exercise in either group. In both asthmatic and control subjects, lactate, pyruvate, hydrogen ion, alanine and glycerol concentrations showed an increase from baseline levels, reaching maximum levels up to 10 min after exercise and returning to baseline within 1 h after exercise. Total ketone body concentrations decreased during exercise. There were no significant differences between the asthmatic and control subjects in the concentration of any metabolite over the study period. These data indicate that fuel metabolism during and after short-term progressive exercise is similar in stable asthmatic and normal subjects.

Adult↗
PubMed1986

Comparison of right ventricular weight at necropsy in interstitial pulmonary fibrosis and in chronic bronchitis and emphysema.

The ventricular weights in 43 patients with interstitial pulmonary fibrosis were retrospectively compared with those in 172 patients with emphysema and chronic bronchitis. The mean right ventricular weight of patients with interstitial pulmonary fibrosis and those with emphysema and chronic bronchitis was 85.5 g (SD 23.2) and 88.8 g (34.3), respectively. Thirty five patients (81%) with interstitial pulmonary fibrosis had a right ventricular weight over 65 g compared with 124 (72%) of those with emphysema. Fifty three per cent of both those with interstitial pulmonary fibrosis and those with chronic bronchitis and emphysema had a right ventricular weight greater than 80 g. Differences between the two groups were not significant. These results suggest that the prevalence of right ventricular hypertrophy and pulmonary hypertension in interstitial pulmonary fibrosis is similar to that found in chronic bronchitis and emphysema.

Aged↗
PubMed1985

A double-blind comparison of amoxycillin with trimethoprim in acute exacerbations of chronic bronchitis.

Thirty-seven patients with untreated acute exacerbations of severe chronic bronchitis (mean FEV1 0.81), were entered into a double-blind randomized trial comparing amoxycillin 250 mg three times a day with trimethoprim 200 mg twice a day, each given for seven days. Seventeen patients received amoxycillin, from which there was one treatment failure, and 18 patients received trimethoprim, amongst which there were six treatment failures. There were no major differences between the treatments, in this small group of patients, although a significant difference (in favour of amoxycillin) was demonstrated in the patients' subjective dyspnoea score. Because of the difficulties in collecting sufficient patients from a single centre, the definition of the possible role of trimethoprim alone in the treatment of acute axacerbations of chronic bronchitis may have to await multicentre trials.

Aged↗
PubMed1979

Triamcinolone in corticosteroid-resistant asthma.

In an uncontrolled study 38 patients with chronic asthma were treated for up to 4.5 years (mean 2.9) with depot injections of triamcinolone acetonide. About half had proved difficult to control on large doses of corticosteroid tablets. Three-quarters were helped and the incidence of hospital admission amongst them was reduced. Side effects were tolerable and adrenal function was only moderately depressed. Spirometry showed continuing improvement up to three years after starting triamcinolone. Whether similar improvement could have been achieved by a different dosage regimen of corticosteroid tablets or whether it might have ocurred spontaneously was not tested. A controlled trial seems warranted.

Adult↗
PubMed1978

A comparison of salbutamol given by pressure-packed aerosol or nebulization via IPPB in acute asthma.

Salbutamol was given by pressure-packed aerosol or nebulizer via IPPB to patients with acute asthma to compare the effectiveness of these methods of inhalation. The results show that both methods produce significant bronchodilatation even in patients admitted with moderately severe asthma (FEV1 about 38% predicted) but a slightly greater improvement may be achieved by IPPB nebulization. Our findings indicate that supervised inhalation of a pressure-packed aerosol of salbutamol may be useful for the initial treatment of asthmatic attacks but confirm the marginal advantage of IPPB nebulization, which should be reserved for patients unable to inhale from a pressure-packed aerosol or failing to respond to its treatment.

Acute Disease↗
PubMed1977

Lignocaine aerosol and persistent cough.

Four patients with intractable cough improved for periods of between one and six weeks after treatment with 400 mg of lignocaine by aerosol spray. Suprisingly the lignocaine increased airways resistance in some of them. It is suggested that the excessive cough is due to excessive sensitivity of tracheal cough or irritant receptors, secondary to mucosal damage. The dangers of lignocaine inhalation are referred to.

Adult↗