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Biomedical subjects

G J Cropp

Publications and source records attributed to G J Cropp.

11 recordsLinked to original sources
PubMed1979

Effects of relaxation training on pulmonary mechanics in children with asthma.

An experiment, designed to overcome shortcomings in previous work, was conducted to investigate the potential symptomatic benefits of relaxation training in the treatment of asthma in children. Fourteen chronic, severely asthmatic children received three sessions in which they rested quietly, followed by five sessions of relaxation training, and finally three sessions of relaxing as trained previously. Pulmonary function was assessed, in a manner far more definitive than in previous studies, before and after each session, and three additional times at 30-minute intervals thereafter. Tension in the frontales muscles, heart and respiration rates, and skin temperature and conductance were also monitored. Heart rate and to some extent muscle tension results tended to confirm the attainment of relaxed states. However, the lung function results failed to substantiate the previous, preliminary findings of a clinically meaningful change in pulmonary function following relaxation. The status of relaxation in the treatment of asthma was discussed.

Adolescent↗
PubMed1975

The role of the parasympathetic nervous system in the maintenance of chronic airway obstruction in asthmatic children.

To evaluate the role of the parasympathetic nervous system in the mediation and maintenance of reversible airway obstruction in perennially asthmatic children, we measured pulmonary function in 18 patients before and after the administration of atropine sulfate aerosol. The bronchodilatory effects of atropine were compared with those of isoproterenol hydrochloride and placebo aerosols. Placebo aerosol did not change any of the pulmonary functions tested. Atropine and isoproterenol aerosols improved forced expiratory flows, airway resistance, and specific airway conductance significantly and to the same degree. Hyperinflation was significantly lessened by atropine, but not by isoproterenol. Because atropine is not a direct smooth muscle relaxant, but rather a selective blocker of cholinergically induced smooth muscle tone, any significant improvement in the lung function of chronically asthmatic children by atropine suggests that at least some of their reversible airway obstruction is induced and maintained by parasympathetically mediated bronchial smooth muscle constriction.

Airway Obstruction↗
PubMed1975

Relative sensitivity of different pulmonary function tests in the evaluation of exercise-induced asthma.

Sixty asthmatic children were exercised on a bicycle ergomete rand had pulmonary function tests perormed before and repeatedly after exercise. Pulmonary function measurements included airway resistance (Raw), specific airway conductance (SGaw), functional residual capacity (FRC), peak expiratory flow rate (PEFR), maximum mid-expiratory flow (MMEF), forced expiratory volume during first second of expiration (FEV1), and forced vital capacity (FVC). At any one time during the post-exercise observation period decreases in SGaw were greater than changes in any other pulmonary function test, making SGaw the most sensitive test for the detection of exercise-induced airway obstruction in asthmatics. Beyond five minutes after exercise PEFR and MMEF were reduced by exercise approximately equally, but somewhat less often and less markedly than SGaw. Exercise-induced reductions in FEV1 were less marked and less frequent than decreases in PEFR and MMEF, and reductions in FVC were the least severe and least often observed abnormality. Decreases in SGaw were significantly, but not linearly correlated with decreases in PEFR, MMEF, FEV1, FVC, and FEV1/FVC. There were statistically significant linear correlations between exercise-induced increases in FRC and decreases in FVC and between increases in Raw and FRC. If we accept that increases in Raw and FRC indicate increases in large and small airway obstruction respectively, exercise-induced decreases in FVC may indirectly suggest acute hyperinflation and thus small airway obstruction. Although the positive correlation between Raw and FRC indicated that both large and small airway obstruction developed after exercise in many of our asthmatics, increases in Rae were usually greater than increases in FRC, suggesting that large airway obstruction tends to be greater than small airway obstruction in exercise-induced asthma.

Airway Obstruction↗
PubMed1975

Grading, time course, and incidence of exercise-induced airway obstruction and hyperinflation in asthmatic children.

We evaluated clinical status and pulmonary function in 60 perenially asthmatic and 11 normal children before and repeatedly after incrementally increasing bicycle ergometer exercise. The changes in clinical status and pulmonary function which were elicited by strenuous exercise were graded by an air exchange and a physiological grading system respectively. Normal children showed no significant clinical or physiological changes after exercise. Strenuous exercise elicited significant deteriorations in clinical and physiological measurements in 36% to 77% of asthmatic girls and 46% to 90% of asthmatic boys, the frequency depending on the test used to determine exercise-induced abnormalities. The incidence of exercise-induced asthma (EIA) was statistically significantly higher in asthmatic boys than girls. The higher incidence of EIA in boys was primarily due to a larger number of very severe attacks in boys than girls; mild and moderate EIA was about equally common in the two sexes. Most patients with EIA developed large and small airway obstruction, although large airway obstruction tended to be the predominant and the more severe abnormality. Clinical and physiological abnormalities, regardless of severity, were usually most marked during the first ten minutes after exercise and lessened thereafter. Mild EIA usually lasted for only 15 minutes or less; severe EIA improved, but usually did not resolve within 35 minutes of exercise. There were three patinets in whom the severity of EIA got worse after exercise and an additional seven in whom the improvement was minimal. In these ten patients isoproterenol aerosol terminated EIA, indicating that exercise-induced large and small airway obstruction in asthmatic children is primarily, if not solely, due to bronchospasm.

Adolescent↗