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Biomedical subjects

F Leahy

Publications and source records attributed to F Leahy.

13 recordsLinked to original sources

Evaluating the cost-effectiveness of orthodontic provision.

The assessment of orthodontic provision is important to determine if treatment was necessary and undertaken appropriately. The ICON objectively quantifies orthodontic treatment need, complexity and outcome and is a valuable occlusal index in the assessment effectiveness of orthodontic care. It is possible to develop cost-effectiveness models by analysing the costs and effectiveness of orthodontic treatment. Several methods are illustrated to compare the orthodontic provision of specialist orthodontists.

Cost of Illness↗

Lyme disease.

Explore the source record for details and available documents.

Child, Preschool↗

Relationship between respiratory muscle strength, nutritional status, and lung volume in cystic fibrosis and asthma.

We measured static inspiratory and expiratory pressures (PImax and PEmax) in 29 patients with asthma for comparison with a previously reported group of 25 patients with cystic fibrosis (CF) and 80 normal control subjects. The purpose of the study was to assess the relationship between respiratory muscle strength, nutritional status, lung volumes, and training effect of the increased work of breathing in patients with chronic air-flow limitation. PEmax was similar in the asthma group, CF group, and normal control subjects despite a significant degree of malnutrition in the CF group (mean body mass percentile (BMP), 78 versus 107% in the asthma group, p less than 0.001). There was no correlation between BMP and PImax or PEmax in either study group. PImax, when corrected for lung volume, was greater than age- and sex-matched control values in 24% of the patients with CF and 48% of the patients with asthma. We conclude that respiratory muscle strength is not related to nutritional status (as measured by BMP) in patients with CF and asthma. Above-normal inspiratory muscle strength may result from a training effect of the increased work of breathing in both CF and asthma, regardless of nutritional status.

Adolescent↗

The effect of anticholinergic treatment on postexertional wheezing in asthma studied by phonopneumography and spirometry.

Postexertional wheezing is an important clinical sign of nonspecific airway hyperreactivity. We have studied wheezing after exercise in 6 asthmatic subjects, 13 to 20 yr of age, using spectral analysis of recorded tracheal sounds. Automated spectral characterization was used to measure wheezing as a proportion of respiratory time. Anticholinergic treatment with ipratropium bromide (Atrovent) was compared with placebo to investigate effects on postexertional wheezing, and pulmonary function was compared with the result of respiratory sound analysis. Atrovent did not abolish exercise-induced bronchospasm but improved preexercise lung function and thereby caused a parallel upward shift in the response curves. Wheezing after Atrovent was significantly less, later in onset, and mainly expiratory at 20 min after exercise. Wheezing as a percentage of total respiratory time correlated well with FEV1, Vmax50, and SGaw. Analysis of respiratory sounds and automated quantification of wheezing may be a useful complementary test of bronchial obstruction in asthma.

Adolescent↗

Sarcoidosis of the larynx in a child.

Sarcoidosis is a multisystem disease of unknown etiology characterized by non-caseating granulomatous inflammation of various organs, but most frequently involving the lungs of young adults. Sarcoidosis is rare in the pediatric age group, however numerous extensive reviews have been published. The most commonly seen initial manifestations in childhood are non-specific constitutional symptoms such as lethargy, fatigue and malaise, followed by cough, dyspnea, fever, weight loss, and lymphadenopathy in order of decreasing frequency. The diagnosis is one of exclusion and is established when clinical and radiological findings are supported by histological evidence of widespread non-caseating epithelial cell granulomas in more than one organ, or a positive Kveim test. Laryngeal involvement is usually part of the systemic disease, but isolated laryngeal sarcoidosis has been reported in adults. We report here a case of isolated laryngeal sarcoidosis in a 13 year old girl. The differential diagnosis and management are discussed.

Adolescent↗

Response to cold air hyperventilation in normal and in asthmatic children.

To assess the sensitivity of isocapnic hyperventilation with cold air in detecting airway hyperreactivity in asthmatic children, we studied 13 asthmatic patients (mean age 11.1 years) and 10 normal children. Cold air challenge consisted of 4 minutes of moderate hyperventilation plus another 4 minutes of maximal hyperventilation, both with subfreezing air (-16 degrees to -18 degrees C). Exercise and IHCA tests were done within 5 days and in random sequence. Mean (+/- SE) maximal % delta FEV1 after IHCA was 27 +/- 5.1% in the asthmatic children vs 4.5 +/- 1.2% in the normal subjects (P less than 0.01), even though there were no significant differences in the maximal minute ventilation equivalent between the two groups. Mean maximal % delta FEV1 after exercise was 31.7 +/- 5.6 in the asthmatic group. There was no difference in the sensitivity of the exercise and IHCA tests to detect bronchospasm in asthmatic children. Airway obstruction after IHCA was sharp and brief: maximal at 3 minutes after challenge, and back to 10% of baseline after 11 minutes. In seven asthmatic children the refractoriness to cold air and exercise was studied by repeating each test within 30 minutes; all seven showed significant refractoriness to exercise, and six showed no refractoriness to IHCA. We conclude that exercise and cold air-induced bronchospasm have different physiologic mechanisms, and that cold air testing can be used as a routine challenge to identify airway hyperreactivity in children.

Adolescent↗

Arterial oxygen desaturation following salbutamol inhalation in acute asthma.

The practicality and accuracy of a new ear oximeter was evaluated. The SaO2 measured with this instrument correlated significantly with simultaneous SaO2 measurements with another ear oximeter in 12 children (age three months to 20 years) with chronic pulmonary or cardiac diseases (r = 0.93, p less than 0.001), and also correlated significantly (r = 0.96, p less than 0.001) with calculated SaO2 based on blood gas measurements of blood from the left side of the heart obtained during cardiac catheterization. The SaO2 was then measured continuously and readings were taken before and five, 15, and 30 minutes after salbutamol inhalation by face mask in 18 children. Following treatment, mean PEFR increased significantly, and mean SaO2 was significantly lower than preinhalation values at five and 15 minutes postinhalation. At 30 minutes, SaO2 had returned to control values. In nine of 18 subjects, SaO2 fell greater than or equal to 5 percent. This response was not predictable on the basis of different parameters (treatment, heart rate, PEFR). The findings suggest that supplemental O2 may be required during the first 30 minutes posttreatment.

Acute Disease↗

The effects of chronic hyperinflation, nutritional status, and posture on respiratory muscle strength in cystic fibrosis.

We measured maximal static inspiratory and expiratory pressures (PImax and PEmax) in 25 patients with cystic fibrosis (CF) and 80 normal control subjects to determine whether chronic hyperinflation and malnutrition reduce PImax and PImax/PEmax, respectively. In addition, we examined the effect of posture on pressures generated. We used a diminution in PEmax as an index of a malnutrition effect on pressures generated. The patients with CF, although significantly hyperinflated (ratio of residual volume to total lung capacity, 0.49), generated PImax values similar to those of the control subjects (p greater than 0.05). Despite evidence of malnutrition (mean body mass percentile, 78%) the PEmax values of patients with CF and those of control subjects were comparable (p greater than 0.05). There was no postural effect on pressures generated in the normal subjects or the CF group as a whole. We conclude that respiratory muscle strength is normal or supranormal in CF, despite chronic hyperinflation and malnutrition.

Adolescent↗

The effect of 2% CO2, 100% O2, theophylline and 15% O2 on "inspiratory drive" and "effective" timing in preterm infants.

We studied 20 preterm infants (B.W. 1440 +/- 80 g (S.E.); G.A. 33 +/- 1 wk) to determine the effect of respiratory stimulants and depressants on respiratory output as measured by VE = VT . f, and VE = VT/Ti . Ti/Ttot. These 20 infants were divided in four groups of five infants. Each group received a respiratory stimulant (2% CO2, 100% O2 or theophylline) or'a respiratory depressant (15% O2). VT/Ti is mean inspiratory flow and represents a mechanic translation of neuronal output. Ti/Ttot is a dimensionless number and has been defined as effective timing. Each study consisted of 3-5 min while the infant breathed 21% O2, followed by 5 min breathing 2% CO2, 100% O2 or 15% O2. The effect of theophylline was assessed by 48-72 h after the initial dose. The respiratory stimulants caused an increase in VT with little or no change in f; 15% O2 produced a decrease in f primarily. According to the newer approach, 2% CO2, 100% O2 and theophylline produced an increase in "inspiratory drive" with little or no change in "effective" timing; 15% O2 decreased "effective" timing primarily via an increase in Te. These findings suggest that the paradoxical decrease in ventilation during hypoxia in preterm infants may not be solely dependent on the central depressant effects of O2. At least in part, the mechanism may be due to a direct action of low O2 on elements controlling expiratory time.

Carbon Dioxide↗

Lysozyme in the tears of newborn babies.

Tear lysozyme concentration was measured in term, preterm, and small-for-dates infants using a modification of the lysoplate technique. The lysozyme concentration was greater in the term infant than in preterm and small-for-dates infants. The values were found to increase with birthweight and gestation to a term value which is similar to that described in adults. There was no relationship between the lysozyme concentration and the rate of tear production.

Birth Weight↗

Spectral analysis of breath sounds in normal newborn infants.

To determine whether breath sounds in newborns are different from those described in older subjects, fast Fourier transform and power spectra analysis were performed on recorded breath sounds from 14 normal newborns. A respiration-triggered sampling technique was applied to compare early, middle, and late phases of inspiration and expiration, using a thoracic impedance signal. Peak frequencies were found in the range described for normal breath sounds in older subjects, and the frequency range of breath sounds was similar to that reported for older children and adults. The difference in breath sound quality of normal newborns appears to depend on the sound intensity during expiration. In contrast to older subjects, newborns showed only slightly less sound intensity during expiration; in the late phases of inspiration and expiration this intensity was almost equal.

Female↗