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A previously healthy two year old boy had an adenoviral infection at the age of 13 months and developed hyperlucency of the left lung, chronic respiratory distress, and failure to thrive. Bronchodilators and steroid treatment had no effect. Radionuclide lung scans using an intravenous bolus of xenon-133 both before and after treatment showed substantially reduced function on the hyperlucent side and modestly reduced function on the other side. Fibreoptic bronchoscopy showed no structural abnormalities. Partial forced expiratory flow volume (PEFV) curves, generated from end inspiration by rapid compression of the chest wall with an inflatable jacket, were obtained from the total respiratory system and from each lung separately by inflating a Fogarty catheter in the contralateral mainstem bronchus. Expiratory flow rates and volumes during both tidal breathing and PEFV manoeuvres were considerably decreased in the hyperlucent lung. PEFV curves from the "healthy" right lung and from the total respiratory system were similar in shape and showed a moderately obstructive pattern. The right lung ventilated about four times as much as the left when measured by bronchospirometry and about three times as much when measured by the radionuclide technique. The lung scans appeared to reflect adequately the functional abnormality in this infant with the Swyer-James syndrome. [ABSTRACT FROM AUTHOR]

Lung function was measured in 28 infants with cystic fibrosis and repeated in 17 of the infants during the first year of life. Thoracic gas volume (TGV) and specific airway conductance (sGaw) were measured plethysmographically and maximum forced expiratory flow at functional residual capacity (VmaxFRC) was derived from the partial expiratory flow-volume curve. At the time of the initial evaluation respiratory function was correlated with the clinical condition of the infants but not with age. There was a good correlation between sGaw and VmaxFRC when both were expressed as percentages of the predicted normal values. On the basis of the normal range for sGaw the infants were divided into two groups. Group A (n = 9), who had normal sGaw, were younger and had a lower clinical score and normal VmaxFRC and TGV values. Group B (n = 19), who had low sGaw, had increased TGV and decreased VmaxFRC. There was no correlation with age for any measure of lung function for the population as a whole. Repeat testing was undertaken at intervals in 17 representative infants. In most of these infants the relation between sGaw and VmaxFRC was maintained; there was no evidence that VmaxFRC was affected before sGaw. There was no functional evidence that the earliest changes in cystic fibrosis occur in small airways, as reflected by changes in VmaxFRC in infancy. [ABSTRACT FROM PUBLISHER]

To compare the refractory period that follows exercise and isocapnic hyperventilation, 10 asthmatic children performed two pairs of challenge tests in random order at least six hours apart. In pair A a hyperventilation challenge was followed by an exercise challenge and in pair B the order was reversed. Both pairs of tests were done while the children were breathing cold dry air. Tests were matched in terms of work load, ventilation, and end tidal carbon dioxide tension (PCO2). The mean percentage fall in FEV1 (delta FEV1) after the first challenge (hyperventilation) of pair A and the first challenge (exercise) of pair B were the same (30% (SEM 2%)) and 30% (4%) respectively). The mean delta FEV1 of the exercise test following hyperventilation in pair A and of hyperventilation following exercise in pair B was 22% (4%) and 18% (4%) respectively. Both these latter results were significantly lower than the respective delta FEV1 when the challenge was the first test of the pair. Although the mean refractoriness index (reduction in induced asthma in the second test of each pair compared with the first test) was greater when exercise was the first challenge, the difference was not significant. [ABSTRACT FROM AUTHOR]

To evaluate the effect of negative ionisation of inspired air on bronchial reactivity, 11 asthmatic children were challenged twice by exercise and 10 were challenged twice by histamine inhalation. The children breathed negatively ionised air (4 X 10(5) - 10 X 10(5) ions/cm3) or control room air in random order in a double-blind fashion. All challenges were matched in terms of basal lung function and the exercise tests were matched in terms of ventilation and respiratory heat loss. Exercise-induced asthma was significantly attenuated by exposure to negatively ionised air, the mean postexercise fall in one-second forced expiratory volume (FEV1) being 29% (SE 5%) of the initial value after the control and 21% (3%) after the ionised air test (p less than 0.02). Ten of the 11 subjects developed less exercise-induced asthma while breathing ionised air. Although the median dose of histamine (cumulative breath units) which caused a constant fall in FEV1 for each individual was higher with the ionised air challenge than with the control challenge the difference was not significant. Five of the 10 subjects were less sensitive to histamine and the other five more sensitive when breathing ionised air. It is concluded that negative ionisation of inspired air can modulate the bronchial response to exercise but the effect on the response to histamine is much more variable. [ABSTRACT FROM AUTHOR]

Heart rate, blood pressure, pulsus paradoxus, and cardiac output measured by means of transthoracic electrical impedance cardiography have been recorded in 29 children mean age 10 years +/- 2 SD during status asthmaticus. Changes were recorded over the first two hours of treatment during which all patients received oxygen, intravenous fluid, and hydrocortisone, and were randomly assigned to receive aminophylline, salbutamol, or both. Admission values showed significant correlation of pulsus paradoxus with PaCO2 (r = 0.66). Pulsus paradoxus was greater than 20 mmHg for all patients with PaCO2 above 5.5 kPa. Mean stroke volume and cardiac output were 89% and 131% of the resting convalescent values in the same children. Stroke volume cardiac output and heart rate did not correlate with peak expiratory flow rate or blood gas measurements. Aminophylline and salbutamol together were associated with significantly greater increase in PEF than aminophylline alone (P less than 0.05). Nebulised salbutamol was just as effective as intravenous salbutamol. Heart rate and systolic blood pressure declined significantly after nebulised salbutamol and aminophylline, but not after intravenous salbutamol and aminophylline. Stroke volume and cardiac output did not change significantly in any treatment group. [ABSTRACT FROM AUTHOR]

Seventeen children with unilateral hyperlucent lungs were referred for investigation. Of the 11 who had a referring diagnosis of possible Macleod's syndrome only two were shown to have post-viral bronchiolitis. Three of the 11 had conditions that required surgical treatment and a further two with brochiectasis were treated medically. To avoid confusion we suggest that Macleod's syndrome is reserved exclusively for children with post-viral bronchiolitis. Radioisotopic regional lung function studies were useful in the investigation of the subjects from three points of view. Firstly, they distinguished children with primary perfusion abnormalities and normal ventilation, secondly, they defined the extent of altered respiratory function, and thirdly, they were able to distinguish compensatory emphysema from congenital lobar emphysema. As bronchography and bronchoscopy may be hazardous in small children with poor respiratory reserve, such regional studies may be useful in indicating which patients do not require further invasive investigation. [ABSTRACT FROM AUTHOR]

Exercise-induced asthma (EIA) was provoked by standardized treadmill running for 6 minutes in 15 asthmatic children. The tests were carried out after the administration of a placebo, salbutamol, sodium cromoglycate, choline theophyllinate, and atrophine methonitrate aerosol in randomized fashion on different days. The mean post-exercise percent fall in peak expiratory flow rate was 45-2, 4-1, 19-6, 18-3, and 24-9 respectively. The proportion of children having significant amelioration of their EIA compared with those taking the placebo was 100% for salbutamol, 80% for cromoglycate and theophyllinate, and 60% for atropine. Salbutamol, choline theophyllinate, and atropine were bronchodilators at rest whereas cromoglycate was not, and the ability to suppress EIA was unrelated to bronchodilator effect. Even after bronchodilatation at rest, further broncho-dilatation occurred during the exercise period. [ABSTRACT FROM PUBLISHER]

An infant is described who presented a complex cardiopulmonary problem which was evaluated with the help of new physiological techniques. the infant was born at term after an emergency Caesarian section for fetal distress and was found to have meconium aspiration. He remained persistently tachypnoeic and hypoxic despite high ambient oxygen. Chest radiography suggested cystic lesions at the lung bases, and lung function tests confirmed hyperinflation with delayed nitrogen washout. In addition the child had signs of Fallot's tetralogy, and this diagnosis was confirmed by cardiac catheterization. Because of persistent hypoxia and tachypnoea disproportionate to the cardiac condition, the possibility of localized lung disease was considered. Regional lung function tests were carried out in the neonatal period and again at six months of age useing radioisotopic 13N given by both inhalation and injection. These studies showed gross ventilation/perfusion imbalance in the lungs, particularly marked at the bases, but with enough generalized abnormality to preclude the possibility of surgical intervention. The principles of the measurement of lung mechanics in the newborn by whole-body plethysmography, nitrogen washout, and regional radioisotopic spirometry are outlined. The particular value of these techniques in the evaluation of complex disorders is discussed, especially where both cardiac and pulmonary abnormalities are present. [ABSTRACT FROM AUTHOR]

, , 574-578. A technique for studying the efficacy and duration of action of drugs used in asthma by means of exercise tests is described. The patient runs for six minutes every two hours, four times a day, on a treadmill at a constant speed and slope. The test drug or its placebo is given immediately before the first test of the day, and their effects on the exercise-induced asthma are compared. This enables the immediate protection and duration of action of the test drug to be measured. No change in the severity of post-exercise asthma was found when serial tests were performed during one day after administration of a placebo. In a selected group of 14 children studied with disodium cromoglycate, three patterns were seen. In five patients the drug afforded prolonged benefit, in five others the protection was very short-lived, and in four patients it did not seem to be better than the placebo. The use of the tests is also illustrated with respect to bronchodilator drugs. [ABSTRACT FROM PUBLISHER]

The movement of the chest during breathing has been recorded in normal and asthmatic subjects by means of electronic transducers which measured changes in anteroposterior and lateral diameters. Preliminary studies showed that exercise-induced bronchoconstriction caused distortion of the movement of the diameters in relation to each other and to volume change recorded at the mouth. Because of the thoracic gas compression which occurs during breathing, volume change at the mouth does not represent the change in chest volume and further studies were therefore undertaken in a whole-body plethysmograph. These studies showed that the addition of a resistance to the airway of a normal subject distorted the movement of one diameter (usually the anteroposterior) in relation to the other and to volume. With exercise-induced asthma, the movement of both diameters was affected with the anteroposterior lagging behind the volume change. There was an approximate linear relationship between the degree of distortion and airways resistance in the asthmatic subjects and in one normal subject. The physical sign of costal margin paradox could be related to the severity of the obstruction. [ABSTRACT FROM PUBLISHER]

Bicycle ergometer, treadmill, and free range running exercise have been used to induce bronchoconstriction in 10 asthmatic subjects who were relatively well and free from symptoms at the time of study. Comparisons have been made with normal subjects under similar laboratory conditions. Bronchoconstriction was measured by peak expiratory flow rate before, during, and after each test. Ventilation, pulse rate, and gas exchange were also measured. The work involved in the different types of exercise was matched to produce similar ventilation and pulse rates for any one subject. Exercise-induced bronchoconstriction was significantly less on the bicycle ergometer than on running (treadmill or free range). The normal subjects showed less than one quarter the bronchial lability of the asthmatic subjects in any one test. All subjects had lower respiratory exchange ratios during running compared with cycling and this appeared to correlate with the bronchial lability in the asthmatics, who also had rather higher pulse rates during running. Running involves a proportion of high-efficiency negative work which might partly account for the observed differences. [ABSTRACT FROM PUBLISHER]

The transfer factor of carbon monoxide (TL) has been measured in 40 normal schoolchildren by the steady state method during treadmill exercise. The fractional uptake of CO diminished with increasing oxygen consumption and the nett CO uptake was linearly correlated with oxygen consumption. The TL at two work levels was significantly correlated with height and increased moderately with increasing work. The highest values of TL during strenuous exercise were approximately three times those reported at rest. [ABSTRACT FROM PUBLISHER]

Cardiopulmonary function has been studied at rest and during graded exercise in 11 patients with systemic sclerosis. All patients had multi-system disease, five complained of breathlessness, and four had radiographic evidence of pulmonary fibrosis. All patients had gross effort intolerance. Lung volumes were reduced in half the patients, as was the transfer factor for CO when corrected for lung volume. Airway resistance was normal. Four patients hyperventilated on exercise, but the tidal volume was normal; three developed arterial desaturation during exercise. Six patients had an excessive elevation of blood lactate on exercise and three of these had evidence of muscle disease. Analysis of the exercise data suggested that in seven patients cardiac output and dead space were normal. In four patients there was a pattern of normal cardiac output, increased dead space, and increased venous admixture, suggesting ventilation/perfusion imbalance. There was no correlation between the results of the physiological tests and the extent of clinical involvement with the disease. The possible reasons for this and for the effort intolerance are reviewed. [ABSTRACT FROM PUBLISHER]

We have examined the observer variation in the detection of physical signs in airways obstruction. In the first study, 10 relatively experienced physicians examined 11 patients for the presence of six familiar signs and seven less well-known signs. Six experienced observers then underwent a training period after which they examined another group of 21 patients. The repeatability of all the signs fell about midway between that expected by chance and the maximum possible. There was no difference between the familiar and unfamiliar signs. The training period resulted in a slight but not significant improvement in reliability. [ABSTRACT FROM PUBLISHER]

To evaluate the effect of positive ionisation of inspired air on bronchial reactivity, 12 asthmatic children were twice challenged by exercise in random order. During one test positively ionised air (5-10 X 10(5) ions/cm) was breathed. All challenges were matched in terms of basal lung function and exercise tests were matched in terms of ventilation and respiratory heat loss. Exercise induced asthma was significantly aggravated by exposure to positively ionised air, the postexercise fall in FEV1 (delta FEV1) being 24.7% (SEM and 5.3%) and 35.3% (5%) after the control and ionised air tests respectively (p less than 0.04). It is concluded that positive ionisation aggravates the bronchial response to exercise. [ABSTRACT FROM AUTHOR]

A study of the relation between physical signs and the clinical and physiological pattern of chronic lung disease with obstruction has been carried out on 24 patients with varying degrees of airways obstruction. One sign (the forced expiratory time) was a direct reflection of the obstruction, but a number of other signs which also correlated significantly with the specific airway conductance were probably related to secondary effects on lung volume (increased resonance), disordered pattern of muscle action (tracheal tug and use of accessory muscles) or to excessive swings of intrathoracic pressure (excavation of supraclavicular fossae). Other signs which are regularly present but which did not correlate significantly with the severity of the airways obstruction were often related to other factors such as age or duration of symptoms (tracheal length). The difficulties in deciding the origin of other signs such as wheezes (rhonchi) or costal paradox are discussed. [ABSTRACT FROM PUBLISHER]