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Biomedical subjects

J M Couriel

Publications and source records attributed to J M Couriel.

25 records · Page 2Linked to original sources
PubMed1984

Changes in lung, airway, and chest wall function in boys and girls between 8 and 12 yr.

Maximum expiratory flows, maximum inspiratory and expiratory pressures, and lung volumes were measured in 248 8-yr-old and 215 12-yr-old healthy school children. Eight-year-old girls had smaller total lung capacity but higher volume-corrected expiratory flows than boys. Maximum expiratory flow and total lung capacity increased more in girls than in boys between 8 and 12 yr. Girls had a greater increase in residual volume (0.23 liter for girls, 0.16 liter for boys) as well as lower maximum expiratory and inspiratory pressures (P less than 0.001). Girls have smaller lung volumes than boys, so one would expect smaller airways in girls, but girls generate greater flows, indicating that their airways are possibly wider than those of boys. There is also evidence of unequal growth of the airways and air spaces between 8 and 12 yr. Chest wall development appears less in girls than boys and the difference becomes more marked at 12 yr.

Body Height↗
PubMed1984

Assessment of proximal airway obstruction in children by analysis of flow-volume loops.

The usefulness of maximal expiratory and inspiratory flow-volume (F-V) loops was assessed in ten children with clinical evidence of tracheal or laryngeal obstruction. Normal values from 514 healthy children are presented. Measurement of maximal flow, and expiratory/inspiratory flow ratios and observation of the characteristic contours of the F-V loops distinguished between proximal and peripheral airways obstruction in all cases. Most children over the age of 7 years could perform the test adequately. F-V loop analysis is a valuable technique in the assessment of the child with proximal airway obstruction. Unlike endoscopic and radiological investigation, it measures the functional rather than the anatomical degree of obstruction, and provides a simple non-invasive way of monitoring the response to treatment.

Adolescent↗
PubMed1984

Response to acute hypercapnia in the parents of victims of sudden infant death syndrome.

The ventilatory response to acute hypercapnia was studied in 68 parents of victims of sudden infant death syndrome and 56 control subjects. Tidal volume, inspiratory time, and total respiratory cycle time were measured before and immediately after a vital capacity breath of 13% CO2 in oxygen. Instantaneous minute ventilation, mean inspiratory flow (tidal volume/inspiratory time), and respiratory timing (inspiratory time/total respiratory cycle time) were calculated. Both groups of subjects showed a marked increase in tidal volume (48.4% +/- 26.5%), instantaneous minute ventilation (56% +/- 35%), and tidal volume/inspiratory time (56.8% +/- 33.5%) after inhalation of the test gas, with little change in inspiratory time/total respiratory cycle time. There were no significant differences between the two groups for ventilation before or after inhalation of the test gas. The ventilatory response to acute hypercapnia is mediated by the peripheral chemoreceptors. These results suggest that an inherited abnormality of peripheral chemoreceptor function is unlikely to be a factor leading to sudden infant death syndrome.

Acute Disease↗
PubMed1982

Long term pulmonary consequences of oesophageal atresia with tracheo-oesophageal fistula.

Lung function was studied in 20 children, aged 8-17 years, who had successfully repaired oesophageal atresia with tracheo-oesophageal fistula. Spirometry and plethysmography showed mild restrictive lung disease. Airways obstruction was assessed using maximal expiratory and inspiratory flow-volume loops in air and after breathing a helium-oxygen mixture. Analysis of the flow-volume data demonstrated significant obstruction at the level of the trachea and little evidence of small airways disease. Bronchial hyperreactivity, as assessed by histamine challenge, was present in 22% of subjects. Respiratory and oesophageal symptoms were common, but decreased in frequency with increasing age. The mechanisms involved in the frequent respiratory symptoms these children suffer are discussed in the light of the physiological findings.

Adolescent↗
PubMedDate not supplied

Distribution of ventilation in young children with cystic fibrosis.

We attempted to measure the distribution of ventilation in 24 children who had cystic fibrosis (CF) and 58 control subjects (ages 3.9-6.8 years) using the multiple breath nitrogen washout (MBNW) test. Moment analysis was performed on the MBNW curve, and the first and second moment ratios were derived. Only 40 (49%) of the children were able to complete the test satisfactorily and success was related to age (P less than 0.01). Children who had CF had higher moment ratios, both first and second, than did controls (P less than 0.001); also, CF subjects who had more severe symptoms had higher moment ratios than did those who had minimal symptoms (P less than 0.005). The first moment ratio had a lower coefficient of variation than did the second (14% vs 31%) and, in 8 children who performed the test in duplicate, it also had a lower index of intrasubject variability (6.4% vs 15.1%). Both ratios were lower than those described in older children and in adults, which is consistent with the more rapid washout seen in this age group. Although moment analysis of the MBNW curve can be performed in approximately 50% of children 4 to 6-years-old, the complexity of the test, the apparatus, and the analysis and the high failure rate in children under the age of 6 are likely to restrict its use to research studies in specialized pediatric respiratory laboratories.

Age Factors↗