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Biomedical subjects

C F Robertson

Publications and source records attributed to C F Robertson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Chronic idiopathic bronchiolitis of infancy.

The clinical and morphological features are presented of eight infants who developed a chronic respiratory illness in the first year of life characterised by tachypnoea and inspiratory crackles on auscultation. The median age at the onset of symptoms was 1 month (range 1 day to 7 months). Five of the infants required supplemental oxygen. Chest radiographs showed only non-specific perihilar alveolar shadowing and generalised hyperinflation. Investigations into the cause of the illness in these infants, including studies for infection, cardiac disease, and gastrooesophageal reflux, were negative, and an open lung biopsy sample was subsequently taken from each infant. Histological examination showed mild lymphocytic bronchiolar infiltration only in six of the eight infants. The other two biopsy samples were normal. Seven of the infants were given a trial of steroids by mouth (mean duration of treatment four months) without any apparent benefit. These infants have now been followed up for a median duration of 21 months (range 1-9 years). All have shown continuous improvement, with either the end of oxygen treatment (three patients) or the use of low flow oxygen only at night (two patients). All have normal development and all but one have normal growth. Chest examination has become normal in four subjects. In the remainder the inspiratory crackles have persisted, although they have decreased markedly in all patients. It is proposed that these infants have a previously unreported respiratory entity and that the clinical and lung biopsy sample findings reported here predict a favourable medium term prognosis.

Bronchiolitis↗
PubMed1997

Cough receptor sensitivity in children with acute and non-acute asthma.

BACKGROUND: Cough is a major symptom in some children with asthma. The relationship between cough and the severity of asthma is ill defined. A study was undertaken to test the hypotheses that, in children with asthma who cough as a major part of their asthma symptoms, cough receptor sensitivity (CRS) is heightened during an acute severe exacerbation of asthma but not in the non-acute phase and airway calibre or its change correlates with CRS. METHODS: Spirometric measurements and the capsaicin CRS test were performed on children admitted to hospital for an acute severe exacerbation of asthma. Nasal secretions were tested for viruses. The children were grouped into those who usually cough with asthma episodes and those who do not. The tests were repeated 7-10 days and 4-6 weeks later. The CRS outcome measure used was the concentration of capsaicin required to stimulate two (Cth) and five coughs (C5). RESULTS: The CRS of the group who coughed (n = 15) was significantly higher than those who did not cough (n = 16) (mean difference log Cth 0.77 mumol (95% CI 0.35 to 1.18), C5 0.72 mumol (95% CI 0.26 to 1.18)) during acute asthma but not after the exacerbation. CRS was not significantly different between groups based on the presence of a viral infection. Neither forced expiratory volume in one second (FEV1) nor its change correlated with CRS nor its change. CONCLUSIONS: In children with asthma CRS is heightened in acute severe asthma in the subgroup of children who have cough as a significant symptom with their asthma episodes. In acute and non-acute asthma CRS does not correlate with FEV1.

Acute Disease↗
PubMed1997

Airway hyperresponsiveness and cough-receptor sensitivity in children with recurrent cough.

In children, recurrent cough is a common presenting symptom that may represent asthma. We tested the hypotheses that children with recurrent cough have increased cough-receptor sensitivity (CRS) or airway hyperresponsiveness (AHR). Skin prick testing, the capsaicin CRS test, and hypertonic saline (HS) challenge were performed in 44 children (median age: 8.9 yr) with recurrent dry cough (> or = 2 episodes of cough, each lasting > or = 2 wk, within a period of 12 mo) and 44 controls. Measures of CRS were the concentration of capsaicin required to stimulate > or = 2 coughs (Cth) and > or = 5 coughs (C5). During the coughing period, Cth (mean log: 0.62 [95% CI: 0.43 to 0.81]) and C5 (mean log: 1.15 [95% CI: 0.86 to 1.44]) of the subjects without AHR were significantly lower (p = 0.0026, 0.027, respectively) than Cth (mean log: 1.27 [95% CI: 0.88 to 1.66]) and C5 (mean log: 1.79 [95% CI: 1.21 to 2.37]) of the subjects with AHR and those of the controls (p = 0.0002 and 0.0001). During the cough-free period, there was no difference in CRS among the groups. In subjects who demonstrated AHR, the provocation dose causing a > or = 15% fall in FEV1 (PD15) during the cough period was significantly lower (p = 0.005) than that during the cough-free period. We conclude that AHR or increased CRS is present during the coughing phase in children with recurrent cough.

Adolescent↗
PubMed1997

Lower airway inflammation in infants and young children with cystic fibrosis.

Airway inflammation is an important component of cystic fibrosis (CF) lung disease. To determine whether this begins early in the illness, before the onset of infection, we examined bronchoalveolar lavage (BAL) fluid from 46 newly diagnosed infants with CF under the age of 6 mo identified by a neonatal screening program. These infants were divided into three groups: 10 had not experienced respiratory symptoms or received antibiotics and pathogens were absent in their BAL fluid; 18 had clear evidence of lower respiratory viral or bacterial (> or = 10(5) CFU/ml) infection; and the remaining 18 had either respiratory symptoms, taken antibiotics, or had < 10(5) CFU/ml of respiratory pathogens. Their BAL cytology, interleukin-8, and elastolytic activity were compared with those from 13 control subjects. In a longitudinal study to assess if inflammation develops or persists in the absence of infection, the results of 56 paired annual BAL specimens from 44 CF infants were grouped according to whether they showed absence, development, clearance, or persistence of infection. In newly diagnosed infants with CF, those without infection had BAL profiles comparable with control subjects while those with a lower respiratory infection had evidence of airway inflammation. In older children, the development and persistence of infection was accompanied by increased inflammatory markers, whereas these were decreased in the absence, or with the clearance, of infection. We conclude that airway inflammation follows respiratory infection and, in young children, improves when pathogens are eradicated from the airways.

Anti-Bacterial Agents↗
PubMed1997

A new use for an old Holter monitor: an ambulatory cough meter.

Cough is commonly used as an outcome measure in clinical studies, although the subjective reporting of cough is unreliable when compared to objective measures. We describe an inexpensive new ambulatory cough meter that is based on a disused Holter monitor. The cough meter consists of a Holter monitor and a cough processor, designed on a computer to select the most appropriate filters. The cough meter was then validated against the overnight tape recorder on 21 occasions in 18 children (aged 6-15 yrs). The agreement between the cough meter and the tape recorder was good (mean difference of -0.3 coughs x h(-1); limits of agreement -2.2 to 1.7 coughs x h(-1)). We conclude that our newly described ambulatory cough meter provides a valid and inexpensive method of objectively monitoring cough for up to 24 h.

Adolescent↗
PubMed1996

Asthma management in eastern Australia, 1990 and 1993.

OBJECTIVE: To compare the prevalence and management of asthma before and after institution of the National Asthma Campaign. DESIGN: Repeat population-based cross-sectional analytic surveys. SETTING: Eastern Australia (Sydney, Brisbane, Melbourne, and the Hunter Valley, New South Wales) in September 1990 and 1993. SUBJECTS: Primary school children and their parents from 33 schools (8746 children) in 1990 and 40 schools (10 106 children) in 1993. OUTCOME MEASURES: Frequency of respiratory symptoms; diagnoses of asthma; medications; lung function measurements; possession of a peak flow meter and a written action plan. RESULTS: Age and sex distribution of the subjects and the reported prevalence of asthma were similar in 1990 and 1993. The frequency of reported episodes of wheezing and troublesome cough increased significantly in children between 1990 and 1993. Asthma management improved in accordance with current recommendations, with significantly decreased use of regular inhaled bronchodilator medication in children and increased use of preventive medication, monitoring of lung function by doctors and use of peak flow meters and written action plans in both children and adults. CONCLUSION: There is evidence that the National Asthma Campaign may have contributed to increased awareness and improved management of asthma in children and adults in eastern Australia.

Adult↗
PubMed1996

Short-term efficacy of ultrasonically nebulized hypertonic saline in cystic fibrosis.

Progressive lung disease in patients with cystic fibrosis (CF) is caused by thick secretions, which cause airway obstruction and subsequent colonization and infection by inhaled pathogenic microorganisms. Recently, recombinant human DNase has been shown to reduce the viscoelasticity of sputum in patients with cystic fibrosis and to improve lung function. Ultrasonically nebulized hypertonic saline (HS) has been demonstrated to enhance mucociliary clearance and sputum expectoration by rehydrating airway secretions, and may therefore provide a low cost alternative. We studied the changes in pulmonary function and symptoms in a group of patients with CF who have moderate to severe lung disease. The patients were evaluated following 2 weeks of treatment with HS in an open-label study. Subjects were randomly allocated to receive 10 ml of either 0.9% NaCl (IS) or 6% NaCl (HS). Twice daily, prior to physiotherapy, treatments were delivered by a portable ultrasonic nebulizer. To prevent bronchoconstriction, 600 mg of salbutamol was administered prior to the nebulized solutions. A symptom score was recorded and spirometry was performed on day 0 before therapy was started, on day 14 (the last day of therapy), and on day 28 (14 days after the last treatment with either IS or HS). Fifty-two patients (32 males), with a mean age of 16.2 (range 7-36) years completed the study. There was no difference in baseline characteristics between the two groups. Following 2 weeks of treatment, there was a significant improvement from baseline in FEV1 of 15.0 +/- 16.0% (mean +/- SD) in patients treated with HS, compared with a change of 2.8 +/- 13% in those on IS therapy (P = 0.004). Furthermore, there was a subjective improvement in the effectiveness of chest physiotherapy as reported by those using HS (P = 0.02). The treatment was well tolerated. We conclude that in patients with CF, ultrasonically nebulized hypertonic saline improves lung function in a way similar to that reported for human recombinant DNase when inhaled over a 2 week period. Nebulized saline also enhances the perception of effectiveness of chest physiotherapy.

Administration, Inhalation↗
PubMed1996

Aerosol deposition in infants with cystic fibrosis.

Twenty asymptomatic infants with cystic fibrosis (CF) were studied to determine the amount of radiolabeled aerosol [99m technetium diethylenetriamine penta acetic acid (Tc99m DTPA)] deposited in the respiratory system and its distribution. Aerosols were generated by jet nebulization systems that were used in the wards and the laboratory. Subjects were studied in three groups: group A (n = 10) was sedated with chloral hydrate; children inhaled an aerosol of 7.7 microns mass median diameter (MMD); group B (n = 5) was not sedated, using the same nebulization system (same aerosol particle size as group A); and group C (n = 5) was not sedated; these children inhaled an aerosol with an MMD of 3.6 microns. Normal saline plus 4 mCi of Tc99m bound to DTPA was added to each nebulizer. A closed system was used to collect the expired aerosol. Radioactivity in each infant and in the equipment was measured with a gamma camera on completion of nebulization. In groups A and B, the percentages of the total dose deposited in the lung were 0.97 +/- 0.35% and 0.76 +/- 0.36%, respectively. In group C, 2.0 +/- 0.71% was deposited in the lung (P < 0.01). Deposition in the nose, mouth, and pharynx was least in group C (P < 0.01). In groups A and B, the intrathoracic deposition occurred predominantly in the trachea and main bronchi, whereas in group C, significantly more aerosol was deposited in the lung region. There was marked inter-subject variability in the percentage of aerosol deposition within the three groups. There was no correlation between percentage of aerosol deposited in the respiratory system and age, height, or weight. Sedation did not have a significant effect on deposition of aerosol in infants. This study indicates that only a small proportion of nebulized solution is deposited in the lungs of infants and that this proportion is influenced by the particle size of the aerosol. The smaller particle size (3.6 microns MMD) was deposited in the lung better than large particles.

Aerosols↗
PubMed1996

A rare tumor masquerading as an empyema: pleuropulmonary blastoma.

Pleuropulmonary blastoma, although rare, should be considered in the differential diagnosis of children who present with a pleural effusion and symptoms of respiratory tract infection when the empyema fails to respond to medical management. A case of a 2-year-old boy with this rapidly growing tumor is reported. The treatment and outcome of pleuropulmonary blastoma in children is reviewed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Validation of questionnaire and bronchial hyperresponsiveness against respiratory physician assessment in the diagnosis of asthma.

BACKGROUND: The Tasmanian Asthma survey (TAS) and the International Study of Asthma and Allergies in Childhood (ISAAC) have used questionnaires to measure the prevalence of asthma in adults and children. We have investigated the validity of these questionnaires by comparing response to questionnaire with a physician assessment of asthma status in the past 12 months. METHODS: Ninety-three adults were given the TAS questionnaire to complete and 361 children were given the ISAAC questionnaire. Ninety-one adults and 168 children completed bronchial challenge with hypertonic saline. A consultation with a respiratory physician blinded to the results of the questionnaire and bronchial challenge was given to all subjects. RESULTS: In both adults and children, questionnaires showed high agreement with respiratory physician diagnosis with respect to asthma symptoms in the past 12 months. For the TAS questionnaire the positive and negative predictive values (95% confidence limits) for physician diagnosis for adults were 0.89 (0.68-0.98) and 0.94 (0. 86-0.98) respectively. The instrument was also sensitive 0.80 (0. 58-0.93) and highly specific 0.97 (0.90-0.99). For the ISAAC questionnaire the positive and negative predictive vales for physician diagnosis of asthma in children were 0.61 (0.50-0.71) and 0.94 (0.88-0.98) respectively. Sensitivity and specificity were 0.85 (0.73-0.93) and 0.81 (0.76-0.86) respectively. Compared to the physician diagnosis, the sensitivity of bronchial hyperresponsiveness (BHR) for asthma was low for adults 0.39 (0.21-0. 61) and children 0.54 (0.48-0.67) as were the positive predictive values: 0.55 (0.31-0.79) for adults and 0.64 (0.449-0.77) for children. A definition of asthma requiring both a positive questionnaire response and BHR was highly specific but not sensitive for adults 0.37 (0.20-0.59) or children 0.47 (0.35-0.60). CONCLUSIONS: Both the TAS and ISAAC questionnaires are valid instruments for the determination of asthma symptoms in the past 12 months.

Adolescent↗
PubMed1996

Inhaled hypertonic saline increases sputum expectoration in cystic fibrosis.

OBJECTIVE: To determine whether inhalation of hypertonic saline (HS) increases sputum expectoration in patients with cystic fibrosis (CF). METHODOLOGY: Ten adolescents with CF, who were receiving inpatient treatment for a pulmonary exacerbation, were enrolled in a controlled cross-over clinical trial. After inhalation of beta adrenergic drug to prevent possible broncho-constriction, each patient inhaled for 10 min either 0.9% isotonic saline (IS) or 6% HS prior to routine physiotherapy. The following day the patient received the alternative solution. Seven patients undertook a second block after 1-5 days. Outcome measures included weight of sputum, a visual analogue score to assess the subjective feeling of a cleared chest after physiotherapy, and spirometry. RESULTS: Sputum expectoration (median; Q1,Q3) from the beginning of the inhalation of HS or IS to the final spirometry measure 60 min post-physiotherapy was significantly greater after HS than IS [17.2g (11.7, 34.8) vs 11.3g (6.5, 16.1): P = 0.006]. A clinical score of the patient's own judgement of a cleared chest was significantly better after HS than IS. Spirometry results did not change following either of the two inhalations. CONCLUSIONS: These data show that the inhalation of 6% HS prior to physiotherapy can increase sputum expectoration in patients with CF and suggest that HS might be an effective, safe and cheap adjunct to regular physiotherapy in patients with CF.

Administration, Inhalation↗
PubMed1996

Evaluation of bronchial responsiveness to exercise in children as an objective measure of asthma in epidemiological surveys.

BACKGROUND: Exercise has been proposed as a useful challenge test for the measurement of bronchial responsiveness in community surveys of the prevalence of childhood asthma. This study aimed to develop a standardised exercise challenge in which the sensitivity to detect asthma was increased by inhalation of dry air. METHODS: Sixty four children aged 12-13 years who had reported wheeze in the past 12 months and 70 control subjects were invited to participate in an exercise challenge at school. Subjects performed eight minutes of cycle exercise while breathing dry air at a workload calculated to produce a minute ventilation of 60% maximum voluntary ventilation during the final three minutes. A fall in forced expiratory volume in one second (FEV1) of 10% or more from baseline was considered a positive test. Data on recent asthma symptoms, asthma morbidity, and use of medication were collected by parent completed questionnaires in those subjects who reported wheeze in the past 12 months. Repeatability of the exercise test was determined in a further 13 children with known asthma. RESULTS: Fifty five children (88%) who reported wheeze in the previous 12 months and 54 control subjects (77%) were studied. Nine subjects in whom baseline FEV1 was less than 75% predicted did not perform the exercise test. Technically unsatisfactory tests were obtained in five subjects. Twenty six (57%) subjects who reported wheeze and three controls (6%) had a positive exercise test, giving a sensitivity of 57% (26 of 46) and specificity of 94% (47 of 50). Estimates of the repeatability of the exercise test showed a mean difference in percentage fall in FEV1 for patients with asthma of 3.08% (95% limits of agreement -7.76% to 13.92%). CONCLUSIONS: Despite attempts to maximise the stimulus to bronchoconstriction in this exercise challenge test, its sensitivity and specificity were not improved in comparison with previous epidemiological studies of the prevalence of asthma.

Adolescent↗
PubMed1996

Alveolar epithelial lining fluid cellularity, protein and endothelin-1 in children with congenital heart disease.

This study applied bronchoalveolar lavage (BAL) to children with congenital heart disease (CHD) prior to elective cardiac catheterization (n = 48), to determine the influence of pulmonary blood flow and viral infection on the alveolar epithelial lining fluid (ELF) concentration of leucocytes, protein and endothelin-1 (ET-1). Lower respiratory tract (LRT) viral infection was defined as either a positive immunofluorescence for virus, or a virus cultured from the bronchoalveolar lavage fluid (BALF). Haemodynamic status was determined at cardiac catheterization. Normative data for BALF, but not ELF parameters, were obtained from 26 asymptomatic, noninfected normal children undergoing elective surgery. In the absence of LRT infection, the BALF macrophage, lymphocyte and neutrophil differential in CHD was not significantly different from the normal controls. In CHD, both increased pulmonary-to-systemic flow ratio (Q'p/Q's) and increased pulmonary artery-to-left ventricular pressure ratio PAP/LVP were associated with a decrease in ELF protein (rs = -0.59; p < 0.0001; and rs = -0.50; p < 0.0001 respectively). A respiratory virus was isolated from the BALF in 8 (17%) of CHD children. Virus isolation was associated with an increased ELF total protein (p < 0.05 vs no infection), a decreased alveolar macrophage differential count (p < 0.01), and an increased neutrophil differential count (p < 0.05). ET-1 was detected in the BALF of 83% of the noninfected CHD children compared to only 23% of the controls (p < 0.001). ELF ET-1 concentrations did not correlate with haemodynamic status in CHD, but were up to 100 times higher than paired plasma levels. We conclude that, in congenital heart disease, both lower respiratory tract viral infection and increased pulmonary blood flow and/or pulmonary vascular pressure influence the alveolar milieu. High alveolar epithelial lining fluid concentrations of endothelin-1 occur in congenital heart disease, but the stimulus for pulmonary endothelin-1 production is unclear.

Bronchoalveolar Lavage Fluid↗
PubMed1996

Capsaicin cough receptor sensitivity test in children.

Capsaicin has been used as a tussive agent in studies in adults to determine cough receptor sensitivity. The aim of this study was to determine the tolerance, repeatability and influence of inspiratory flow on the capsaicin cough receptor sensitivity test in children. Thirty children (mean age 11 yrs; range 6-16 yrs) were tested on two different days, to determine the lowest concentration of capsaicin required to stimulate two or more coughs (cough threshold (Cth)), 2-4 coughs (C2), and five or more coughs (C5). Capsaicin was nebulized through a dosimeter, with an arrangement that allowed the subjects to visualize and regulate their inspiratory flow. Using a constant inspiratory flow of 20 L x min(-1), tests were reproducible for C2, C5 and Cth (doubling dose changes of 1.13, 1.03 and 1.08, respectively). An increase in the inspiratory flow from 20 to 60 L x min(-1) significantly increased C2 (19.5 to 46.8 microM; p=0.016) and C5 (46.8 to 128.8 microM; p=0.008). We conclude that in children, the capsaicin cough challenge test: 1) is well-tolerated; 2) is highly repeatable; and that 3) the inspiratory flow significantly influences cough receptor sensitivity and repeatability of the test and should, thus, be regulated.

Adolescent↗
PubMed1995

Obstructive sleep apnoea presenting as failure to thrive in infancy.

OBJECTIVE: To study the postoperative outcome of infants under the age of 18 months in whom an adenotonsillectomy had been performed, with particular emphasis on the pre- and postoperative weight gain and linear growth velocities, and the resolution of symptoms of obstructive sleep apnoea (OSA). METHODOLOGY: A retrospective study of all infants in whom an adenotonsillectomy had been performed during the 5 year period to January 1990. Details of pre- and postoperative outcome variables were obtained by review of hospital and office records and by telephone calls to the parents. RESULTS: Complete data were available for 29 (76%) of the 38 infants in whom an adenotonsillectomy had been performed. The data from these infants are reported. Pre-operatively, all infants had clinical symptoms of OSA, and 52% of infants also presented with failure to thrive (FTT). Seven infants were dysmorphic: three had Down syndrome, three had a craniofacial anomaly and one infant had Mobius syndrome. Following adenotonsillectomy, 23 infants (79%) had complete resolution of their OSA symptoms. Two infants with Down syndrome required a tracheostomy to relieve persistent upper airway obstruction. Eighty-seven per cent of the infants with pre-operative FTT had a significant increase in weight gain velocity postoperatively (mean 195.1 +/- 80.8 s.d. vs 509.8 +/- 249.1 g/month; P < 0.001), including the infants with mild persistent symptoms of OSA. The weight gain velocity of infants who were not failing to thrive pre-operatively did not change significantly following adenotonsillectomy (328.1 +/- 106.9 vs 333.2 +/- 146.4 g/month; P = 0.82). The linear growth velocity of all infants did not change significantly postoperatively. CONCLUSIONS: OSA should be considered in infants with FTT, as adenotonsillectomy is an effective treatment for OSA in infancy, and the weight gain velocity of these infants may increase significantly postoperatively. Overnight oximetry or other physiological studies may be required if the clinical signs and symptoms of OSA are equivocal.

Adenoidectomy↗
PubMed1995

Bronchoalveolar lavage cellularity in healthy children.

The role of bronchoalveolar lavage (BAL) in children remains to be defined, and to date there has been no standardization of acquisition and processing of the BAL fluid. The aim of the present study was to evaluate a standardized protocol for obtaining, processing, and analyzing BAL fluid and to establish reference values for healthy children. Eighteen children 3 mo to 10 yr of age were lavaged with three 1-ml/kg aliquots of normal saline, using a flexible bronchoscope into the right middle lobe. The first aliquot was processed separately; the second and the third were pooled. There was a higher percentage of neutrophils and epithelial cells in the first aliquot. The number of total cells per milliliter (median, Q1 to Q3) in the first aliquot was 60 (45 to 90) x 10(3)/ml; in the pooled sample it was 155 (75 to 257) x 10(3)/ml. Percentages (median, Q1 to Q3) of different cell types in the pooled sample were: macrophages, 91% (84 to 94); lymphocytes, 7.5% (4.7 to 12.8); neutrophils, 1.7% (0.6 to 3.5); eosinophils, 0.15% (0.0 to 0.3). The ratio of helper/cytotoxic T-cells was 0.58 (0.4 to 1). The results of this study demonstrate that BAL, using a standardized protocol adjusting instilled fluid volume by weight, appears to be appropriate in children and that cellular and protein values from healthy children are, apart from differences in lymphocyte subsets, similar to those found in healthy adults.

Age Factors↗