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Biomedical subjects

C F Robertson

Publications and source records attributed to C F Robertson.

At least 73 records · Page 4Linked to original sources
PubMed1995

Role of bronchoalveolar lavage in children with lung disease.

The aim of the present study was to evaluate the clinical role of bronchoscopic and nonbronchoscopic bronchoalveolar lavage (BAL) in the diagnosis of infectious and interstitial lung disease in children. BAL was performed using three 1 mL.kg-1 aliquots of normal saline, with the flexible bronchoscope (Olympus 3.6 or 4.8 mm) wedged in a segmental or subsegmental bronchus of the lobe that showed most abnormality on chest radiograph. In seven children with severe diffuse lung disease who were intubated, a nonbronchoscopic suction catheter lavage was performed. Fluid cultures and cellularity were evaluated using identical methods for both techniques. Between January 1993 and April 1994, 41 BAL were performed in 32 children aged 2 months to 17 yrs (median 8 yrs). Of these lavages, 14 were in heart and heart-lung transplant recipients, 11 in children known to be immunocompromised, and 16 in children who had a lung biopsy for interstitial lung disease or who had presumed infective lung disease. Transbronchial biopsies (TBB) or open lung biopsies were performed coincident with 19 BAL procedures. In all transplant recipients without clinical symptoms, BAL and TBB cultures were negative and BAL cellularity was normal. TBB did not reveal infection or rejection in any of these patients. A diagnosis of infection was made by BAL in 1 out of 8 transplant recipients with clinical symptoms, and a diagnosis of rejection was made by TBB in 3 out of 8 patients. In 6 out of 11 BAL in immunocompromised children, an infectious agent was found in the BAL fluid. In three other patients who had an open lung biopsy, an interstitial lung disease was diagnosed. In these patients, BAL was abnormal but not diagnostic. In summary, BAL proved helpful in the diagnosis of infective lung disease, but had little value in the diagnosis of rejection or parenchymal noninfective lung disease in children.

Adolescent↗
PubMed1994

Repeatability of response to hypertonic saline aerosol in children with mild to severe asthma.

Non-isotonic aerosols are being used more commonly to perform bronchial provocation tests. In contrast to histamine and methacholine challenge tests they appear to have higher specificity and a higher predictive value. The aim of the present study was to assess the reproducibility of the response to challenge with 4.5% hypertonic saline administered via an ultrasonic nebulizer in children with mild to severe asthma. Seventeen children with asthma aged 10 to 14 years completed two or three challenge tests at the same time of day within a 10 day period. Of these 17 children 9 had mild, 4 moderate, and 4 severe asthma. Children inhaled 4.5% hypertonic NaCl from an ultrasonic nebulizer with an output of 1.9 to 2.5 mL/min (Timeter) using the protocol developed by Anderson with modifications. A fall in forced expiratory volume in 1 second (FEV1) from baseline of 15% or more was considered a positive response and PD15 was calculated. In 16/17 subjects a greater than 15% fall in FEV1 occurred consistently on all study days. One subject with moderate asthma had a less than 15% fall in FEV1 on both study days. The coefficient of repeatability for PD15 was 1.8. This equals 0.85 of a doubling dose difference between the two or three measurements of PD15. The cumulative time of aerosol inhalation causing a fall in FEV1 > or = 15%) (PT15) showed a coefficient of repeatability of 1.59, similar to 0.67 doubling dose difference. The PD15 and PT15 were highly significantly correlated. The 4.5% NaCl challenge test yields good reproducibility in children with mild to severe asthma under laboratory conditions.

Adolescent↗
PubMed1994

Successful treatment of epiglottitis with two doses of ceftriaxone.

Epiglottitis in childhood is caused by Haemophilus influenzae type b. The usual antibiotic treatment at the Royal Children's Hospital, Parkville, Victoria is a five day course of chloramphenicol. Increasingly, third generation cephalosporins are being used to treat invasive H influenzae type b infections and preliminary data suggest that they can be used successfully for epiglottitis. In a prospective, randomised trial, the efficacy of a short course (two days) of ceftriaxone was compared with that of five days of chloramphenicol for the treatment of epiglottitis. The ability of these treatment regimens to eradicate H influenzae type b from the throat was also studied. Fifty five children were enrolled over an 18 month period. Epiglottitis was diagnosed clinically and confirmed on inspection of the epiglottis at direct laryngoscopy. Fifty three (96%) of 55 patients had H influenzae type b detected from at least one site: 44/52 (85%) from blood cultures, 41/47 (87%) from throat swab, and 6/8 (75%) as H influenzae type b urinary antigen. Children were randomised to receive either ceftriaxone 100 mg/kg intravenously followed by a single dose of 50 mg/kg 24 hours later (28 patients), or chloramphenicol 40 mg/kg intravenously, then 25 mg/kg eight hourly for five days, intravenously then by mouth (27 patients). All household contacts and patients receiving chloramphenicol received rifampicin 20 mg/kg daily for four days. Index patients randomised to ceftriaxone were not treated with rifampicin. There was no significant difference in outcome between the two groups with respect to the mean duration of fever, the duration of intubation, or the length of hospital admission. The proportion of patients colonised with H influenzae type b four weeks after discharge was not significantly different between the two groups: ceftriaxone 5/22 (23%) versus chloramphenicol and rifampicin 3/23 (13%). A short course of ceftriaxone was successful in treating all patients with no significant side effects and no relapses. A short course of ceftriaxone is a safe, efficacious, and economic alternative to the standard treatment in children with epiglottitis.

Ceftriaxone↗
PubMed1994

Measurement of functional severity of asthma in children.

The usefulness of surveys for measuring the severity of asthma in school-age children depends on the availability of reliable and valid questionnaires. The aim of this study was to develop a measure of functional severity of asthma over the previous 12 mo, for use in population studies and in investigating treatment regimens. Of 10,198 children surveyed, 9,192 (90%) in school Years 2, 7, and 10 (mean ages 8, 13, and 16 yr) in Melbourne were screened for wheeze. The parents of the 1,267 children with wheeze were interviewed. Symptoms and restriction of activity due to asthma were analyzed using factor analysis and the partial credit version of the item response theory measurement model. The result was a continuous severity scale that was highly consistent with the data, and with goodness of fit statistics indicating the severity of 97% of children was well described by the scale. The scale correlated significantly with school absence due to wheeze (r = 0.35), functional impairment during the 2 wk before interview (Functional Status II-R [FSII-R], r = 0.30), visits to medical care for wheeze (r = 0.22), and amount of medication (r = 0.36). For descriptive purposes, a simple index with four bands of severity was developed from the continuous severity scale: low severity (47% of children with wheeze), moderate (30%), mild (18%), and high (5%). The scale and index facilitate standardized description of the impact of asthma on daily life on the basis of responses to six survey questions.

Absenteeism↗
PubMed1994

Prevalence of asthma and wheeze in Hong Kong schoolchildren: an international comparative study.

Comparison of asthma prevalence between populations is difficult because of lack of uniformity of methodology and agreement on the definition. This study aims to determine and compare the prevalence of wheeze and respiratory symptoms in Hong Kong schoolchildren with that in Melbourne children by using identical questionnaires. Schools were randomly selected in different regions of Hong Kong and three age groups (7, 12 and 15 yrs) were chosen for the study. The Chinese version of the questionnaire used in a recent Melbourne survey was distributed to children for completion by their parents. A total of 1,800 questionnaires was issued and 1,689 returned (response rate = 94%). The prevalence of wheeze in the past 12 months was 7 (5.1-8.0), 5 (3.0-6.7) and 4 (1.7-5.6) % for 7, 12 and 15 year olds, respectively. The prevalence of a history of asthma in the respective age groups was 10 (7.1-12.9), 8 (7.5-9.2) and 7 (5.0-9.6) %, respectively. Whilst a history of wheeze ever was more common in boys than in girls and 12 yr olds (14% vs 5%), wheeze in the past 12 months was more common in boys than in girls aged 7 yrs (9 vs 4%). We conclude that the prevalence of wheeze and asthma in school children was low in Hong Kong compared to Melbourne. Environmental differences between the two regions may be important in the pathogenesis.

Adolescent↗
PubMed1994

Effect of tidal volume on the output and particle size distribution of hypertonic saline from an ultrasonic nebulizer.

The purpose of the present study was to measure the output and particle size distribution of hypertonic saline from an ultrasonic nebulizer over the range of tidal volumes (VT) used in an epidemiological survey of asthma in children. A Starling pump was used to generate different VTs from 250 to 500 ml, at different respiratory rates of 12 and 20 breaths.min-1, to cover the normal range of respiratory pattern of children aged 7-14 yrs. The Starling pump was connected to a Timeter Compuneb Ultrasonic Nebulizer Model MP 500 with 24 cm of corrugated aerosol tubing, ID 2.2 cm, and a two-way non-rebreathing valve. Nebulizer output was measured by weighing the nebulizer chamber plus tubing and valve before and after each nebulization. To measure particle size distribution, a Malvern Particle Sizer M 3.0 (laser diffraction) was used, with a special adapter attached between valve and Starling pump. Nebulizer output increased linearly from 1.6 to 2.5 ml.min-1 for VT 250 to 500 ml, with little influence by the respiratory frequency. Furthermore, we found that in the range of VT = 300-500 ml the mass median aerodynamic diameter (MMAD) was 2.61 microns, with 100% of the particles less than 5 microns, whereas at VT = 150-250 ml the MMAD was 8.89 microns, with 90% larger than 5 microns. As output from this ultrasonic nebulizer correlates linearly with tidal volumes, size correction may not be necessary in hypertonic saline challenge tests in children. Above a VT of 300 ml, the MMAD is in the respirable range, with 100% of particles less than 5 microns.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Treatment of asthma in children and adolescents: the need for a different approach.

OBJECTIVE: To provide a concise, balanced summary of the principles of management of asthma in children and adolescents. DATA SOURCES: Current medical literature and the clinical experience considered during the deliberations of the Australian Paediatric Asthma Special Interest Group. KEY ISSUES: There is evidence of both under-treatment and over-treatment of childhood asthma in Australia. The spectrum of asthma severity is very broad, most children with asthma having mild infrequent episodes that do not require regular preventive therapy. The guidelines presented here provide a framework for accurately assessing the pattern and severity of asthma, identifying those children who require preventive therapy and making a rational decision about the appropriate preventive agent and delivery device. CONCLUSIONS: When prescribing preventive therapy, a careful assessment of the relative risks and benefits should be made in the light of the underlying asthma severity. The level of therapy should be reconsidered regularly to ensure control is maintained with minimum dosages, particularly for inhaled corticosteroids. Recommendations are provided to ensure a normal quality of life for children with asthma, with guidelines to minimise adverse effects of therapy.

Adolescent↗
PubMed1993

International comparison of asthma prevalence in children: Australia, Switzerland, Chile.

The aim of the study was to determine if the prevalence of symptoms suggestive of asthma in school-age children was similar in three countries with differing language and culture. To answer this question, we used the same instrument, translated appropriately, for schoolchildren in Melbourne, Australia, St. Gallen, Switzerland, and La Serena, Chile. A three page respiratory symptoms questionnaire was issued to schools for distribution to children for completion by parents and return to the school. Three age groups were selected for study, based on the average age of the school grade. Grades were used with average ages of 7, 12, and 15 years, respectively. A total of 26,628 questionnaires were issued to parents (Australia, 10,981; Switzerland, 4,464; Chile, 11,183). The response rates for each country were 89% for Australia, 97.5% for Switzerland, and 71% for Chile. The prevalence of wheezing in the last 12 months for 7 year olds was 23.1% in Melbourne, 7.4% in St. Gallen, and 26.5% in La Serena; for 12 year olds it was 20.9% in Melbourne, 6.0% in St. Gallen, and 21.1% in La Serena; for 15 year olds it was 18.6% in Melbourne, 4.5% in St. Gallen, and 17.7% in La Serene. A history of wheezing was more common in boys than girls at age 7 in Melbourne and St. Gallen, but not La Serena. This difference was less at age 12 and was not seen at age 15. Among those who had reported wheezing in the last 12 months, bronchodilator use was reported by 83% (1,611/1,948) from Melbourne, 46% (118/259) from St. Gallen, and 47% (538/1,140) from La Serena.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Optimum use of a spacer device.

Nedocromil sodium given by the Fisonair spacer should be inhaled immediately. Multiple actuations into the spacer should be avoided. Delay of 20 seconds before sampling reduced the amount of drug available for inhalation in the respirable range by 81%. Placing two actuations into the spacer reduced the amount of drug available by 47%.

Administration, Inhalation↗
PubMed1992

Asthma morbidity in Australia: an epidemiological study.

OBJECTIVE: To examine the prevalence and management of asthma in adults and children in a population sample in eastern Australia. SETTING: A random sample of children from 33 primary schools in Sydney, Melbourne, Brisbane, and the Upper Hunter Valley (New South Wales), and their parents. DESIGN: A cross-sectional analytic survey of 8753 primary school children aged between 5 and 12 years, and their parents (n = 13,945 adults). Asthma prevalence and management practices were determined by parental responses to a questionnaire, and spirometry was performed in children with "probable asthma". RESULTS: Of 8753 children whose parents responded, the prevalence of current wheeze was 19.5% and diagnosed asthma was 17.1%. Of the children with "probable asthma", 30% had their lung function measured in the previous year, and 6% possessed both a peak flow meter and an action plan for their asthma. Undertreatment was likely, as preventive asthma medications (inhaled corticosteroids or sodium cromoglycate) were used regularly by only 25.5% of these children and by 44.3% of children who had asthma symptoms more than twice per week. Children with the diagnosis of asthma reported higher rates of preventive medication use and ventilatory function measurement than children with frequent symptoms without the diagnosis. In the 13,945 adults, the reported prevalence of asthma was 7%, of whom 39% were using preventive medications, 34% had their ventilatory function assessed in the previous year, and 7% had both a peak flow meter and an asthma action plan. CONCLUSIONS: The study illustrated the gap between the current level of asthma management in the community and the standards set by the Thoracic Society of Australia and New Zealand. Undertreatment and suboptimal management of asthma remain important problems in Australia.

Administration, Inhalation↗
PubMed1992

Prevalence of asthma in regional Victorian schoolchildren.

OBJECTIVE: To determine whether the high prevalence of reported asthma in Melbourne schoolchildren is seen in rural Victoria. DESIGN: A questionnaire on respiratory symptoms was distributed to children to be completed by parents and returned to the school. Results were compared with a previous Melbourne study. SETTING: Two hundred and twenty-seven government and non-government primary schools in five rural regions of Victoria: coast, wheatbelt, riverland, highland and Latrobe valley. SUBJECTS: All children enrolled in grade 2 were invited to join the study. Parents completed questionnaires for 4661 children after 4886 questionnaires were distributed (response rate, 95%). MAIN OUTCOME MEASURE: History of wheeze in the past 12 months. RESULTS: The overall prevalence of wheeze in the last 12 months was 23.6%. There was a significant difference overall in this rate across the five rural areas and Melbourne, with the Latrobe Valley (26.2%) and highland areas (25.0%) having the highest rate, and the wheatbelt the lowest (19.6%). The spectrum of severity of asthma was similarly distributed across rural regions, although severe episodes were significantly more frequently reported by parents from rural areas than by parents in Melbourne. The reported use of bronchodilators and diagnosis of asthma showed a similar pattern of variation to that of the 12-month prevalence of wheeze. CONCLUSION: The prevalence of asthma in 7-year-old children is similar for rural Victoria as a whole compared with Melbourne, but there is variability in asthma prevalence in individual rural areas which is difficult to account for in terms of known environmental precipitants.

Asthma↗
PubMed1992

Pediatric asthma deaths in Victoria: the mild are at risk.

Previous reviews of pediatric asthma mortality have mostly been from hospital-based clinic populations and suggest that only those with severe asthma are most at risk. This report summarizes an investigation, by interviewer-administered questionnaire, into the circumstances surrounding the death in all patients aged 20 years or less who died from asthma in the State of Victoria over a 3 year period from May 1, 1986. During this period, 51 deaths due to asthma were reported. Thirty-three percent of these were judged to have a history of trivial or mild asthma, and 32% had no previous hospital admission for asthma. However, 36% were judged to have had severe asthma, 43% were taking regular inhaled beclomethasone or sodium cromoglycate, and 10% were taking regular oral steroids. Twenty-two percent had a previous admission to an ICU. Death occurred outside hospital in 40 (78%) subjects. In the final attack 63% had sudden onset and collapse within minutes, 12% were found dead, and 25% had acute progression of an established attack. The investigators assessed 39% of the deaths to have had potentially preventable elements. The preventable factors included: inadequate assessment or therapy of prior asthma (68%), poor compliance with therapy (53%), and delay in seeking help (47%). The majority of subjects in this survey could not be classified as "high risk." Therefore, clinicians should ensure that all young patients with asthma are aware of optimal maintenance management, can recognize deteriorating asthma, and follow a clear individualized crisis plan.

Adolescent↗
PubMed1992

Accuracy of asthma death statistics in Australia.

Asthma mortality statistics issued by the Australian Bureau of Statistics (ABS) were compared with clinical data from a survey of asthma mortality. Deaths in Victoria from May 1986 to April 1987 containing 'asthma' in Parts 1 or 2 of the death certificate (N = 405) were reviewed. For each subject, the cause of death attributed by the Victorian Asthma Mortality Survey was compared with the ABS cause of death, by age and sex of the subject. Information on 393 of the 405 deaths investigated by the Victorian Asthma Mortality Survey was analysed. The ABS estimate of the total number of asthma deaths in Victoria was 47 per cent higher than the estimate of the Victorian Asthma Mortality Survey. In subjects under 50 years of age the two estimates were within 10 per cent. The difference between the estimates increased with age at death for persons over 50 years old and was equivalent for males and females. If the assessment by the Victorian Asthma Mortality Survey of the number of deaths due to asthma is accepted as accurate, then the ABS estimate of asthma deaths was reliable for those under 50 years of age. In those who died at an older age, the ABS significantly overestimated the number of deaths due to asthma in Victoria.

Asthma↗
PubMed1991

Prevalence of asthma in Melbourne schoolchildren: changes over 26 years.

OBJECTIVES: To determine the prevalence of asthma in the past 12 months in Melbourne schoolchildren aged 7, 12, and 15 years and to compare the prevalence of a history of asthma with that of 26 years ago. DESIGN: A questionnaire on respiratory symptoms was distributed to children for completion by parents and return to the school. Subjects were selected by a stratified cluster design. SETTING: Government and non-government schools in the greater Melbourne area, Australia. SUBJECTS: 10,981 children. Parents completed questionnaires for 3324 children aged 7, 2899 aged 12, and 2968 aged 15. The overall response rate was 90%. MAIN OUTCOME MEASURES: History of wheeze or asthma in the past 12 months and in lifetime. RESULTS: The prevalences of wheeze in the past 12 months were 23.1%, 21.7%, and 18.6% for 7, 12, and 15 year olds respectively. A history of wheeze was more common in boys than in girls at age 7 (443/1711 v 324/1614) and 12 (418/1767 v 322/1718) but not at age 15. Overall, 78% (1548) of those reporting wheeze also reported a history of asthma and 83% (1611) had used a bronchodilator. The prevalence of a history of asthma among 7 year olds was 46% compared with 19.1% in the 1964 survey, an increase of 141%. CONCLUSIONS: The current prevalence of asthma in Melbourne schoolchildren is high and has risen substantially over the past 26 years.

Adolescent↗
PubMed1991

Paediatric asthma.

The prevalence of asthma among children in our community is already high and is increasing. The author highlights the changes in approach to the management of asthma in children and explains some of the important differences in the treatment of children and adults.

Adult↗