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Biomedical subjects

L I Landau

Publications and source records attributed to L I Landau.

At least 19 recordsLinked to original sources
PubMed1992

Placebo-controlled trial of prednisolone in children intubated for croup.

Many studies have attempted to find out whether steroid treatment is beneficial in children with croup, but the results have been inconclusive. We have done a prospective placebo-controlled study of the effect of prednisolone on two clinical endpoints--the duration of intubation and the need for reintubation. Reasons for exclusion were age under 6 months, congenital airway anomalies, and previous intubation. 70 eligible children were randomly assigned treatment with prednisolone 1 mg/kg (n = 38) or placebo (n = 32) every 12 h given by nasogastric tube until 24 h after extubation. 11 (34%) placebo-treated and only 2 (5%) prednisolone-treated patients required reintubation after accidental or elective extubation (p = 0.004, Fisher's exact test; odds ratio 8.9, 95% confidence interval 1.7-59.3). Survival analysis with log-normal regression showed that the duration of intubation was shorter with steroid therapy (p less than 0.003) and increasing age (p less than 0.02), but was not influenced by endotracheal tube size or abnormality on chest radiograph. The median duration of intubation was 138 (95% CI 118-160) h in children who received placebo and 98 (85-113) h in the prednisolone group. Steroid therapy reduces the duration of intubation and the need for reintubation in children intubated for croup.

Age Factors↗
PubMed1992

Nebuhaler versus wet aerosol for domiciliary bronchodilator therapy. A multi-centre clinical comparison.

OBJECTIVE: To compare the clinical effectiveness and patient acceptance of a large spacer device (Nebuhaler) for delivery of metered dose aerosol (MDI) terbutaline with nebulised wet aerosol terbutaline. DESIGN: Randomised open crossover study over two sequential four week treatment periods, following a two week run-in. SETTING: Multi-centre including five adult thoracic units and three paediatric centres throughout Australia. PATIENTS: Thirty-eight adults and 23 children with clinical asthma and reversible airflow obstruction (increase in forced expiratory volume in one second [FEV1] of greater than or equal to 15% in response to inhaled bronchodilator) entered the study proper. Six adults and one child withdrew. INTERVENTIONS: Terbutaline was administered four times daily via Nebuhaler/MDI or nebuliser. Clinical assessment with spirometry and peak flow readings was made after run-in and at the end of each treatment period. Patients recorded on diary cards daily peak expiratory flow rates and symptom scores and comparisons of these results for each treatment period were made. At the completion of the study patients answered a treatment preference questionnaire. RESULTS: No differences were found between the two treatment periods in diary card peak flow recordings and symptom score data, and in clinical assessment of spirometry and peak expiratory flow rates. There were also no differences between spirometry and peak flow values recorded at the clinic at randomisation and at the end of each treatment period, suggesting stable basal airflow obstruction over the period of the study. Thirty-two per cent of adults and 52% of children preferred the Nebuhaler/MDI combination, mainly because of convenience of use. Treatment preference was not related to any measured index of lung function. CONCLUSIONS: MDI terbutaline delivered via Nebuhaler provides clinical benefit similar to that of wet aerosol terbutaline in the long-term domiciliary management of patients with stable airflow obstruction.

Adult↗
PubMed1992

Relationship between urinary cotinine level and diagnosis in children admitted to hospital.

The reported association between passive smoking and respiratory illness in children has been based on the parents' assessment of their own level of smoking. To more critically evaluate a causal relationship between passive smoking and childhood ill health, we used urinary cotinine, which is the major metabolite of nicotine and has a long half-life, to objectively quantitate the level of passive smoking in children. Urine was collected from 609 children (median age 3.8 yr, range 1 month to 17 yr) on admission to hospital; cotinine levels were obtained in 491 of these samples, and a comprehensive respiratory questionnaire was completed for 468 children. Statistical analysis was carried out on transformed data using both parametric and nonparametric statistics. Cotinine levels in the children correlated with the parents' current smoking (p less than 0.001). Elevated levels were found in the 41 children admitted with bronchiolitis compared with a group of a similarly aged children with nonrespiratory illnesses (p less than 0.02). Elevated levels were not found for any other diagnosis. We conclude that the urinary cotinine approach has provided objective evidence linking passive smoking to hospital admission for bronchiolitis in infants.

Adolescent↗
PubMed1991

The influence of a family history of asthma and parental smoking on airway responsiveness in early infancy.

BACKGROUND: Airway responsiveness to inhaled nonspecific bronchoconstrictive agents has been demonstrated in normal, healthy infants. However, it is unknown whether airway responsiveness is present from birth or if it develops as a result of subsequent insults to the respiratory tract. To investigate this question, we assessed airway responsiveness in 63 normal infants at a mean age of 4 1/2 weeks. METHODS: Respiratory function was measured with use of the partial forced expiratory flow-volume technique to determine the maximal flow at functional residual capacity (VmaxFRC). The infants inhaled nebulized histamine at sequentially doubled concentrations (0.125 to 8.0 g per liter), until a concentration was reached at which the VmaxFRC fell by 40 percent from the base-line value (PC40) or until a concentration of 8.0 g per liter was reached. We also assessed maternal serum levels of IgE, cord-serum levels of IgE, the infants' skin reactivity to several allergens, and the parents' responsiveness to histamine and obtained family histories of asthma and smoking. RESULTS: Airway responsiveness was increased in infants with a family history of asthma (n = 19; median PC40, 0.78 g per liter; 95 percent confidence interval, 0.44 to 1.15; P less than 0.01), parental smoking (n = 13; median PC40, 0.52 g per liter; 95 percent confidence interval, 0.43 to 5.40; P less than 0.05), or both (n = 20; median PC40, 0.69 g per liter; 95 percent confidence interval, 0.37 to 2.10; P less than 0.05), as compared with the infants with no family history of asthma or smoking. The infants with no family history of asthma or smoking had a median PC40 of 2.75 g per liter (95 percent confidence interval, 1.48 to 4.00). No significant relations were detected between the immunologic variables and the PC40 in the infants. CONCLUSIONS: This study indicates that airway responsiveness can be present early in life and suggests that a family history of asthma or parental smoking contributes to elevated levels of airway responsiveness at an early age.

Asthma↗
PubMed1991

Effect of salbutamol on oxygen saturation in bronchiolitis.

Inhaled sympathomimetic agents are often used in bronchiolitis with little objective evidence of benefit. The arterial oxygen saturation (SaO2) reflects the adequacy of ventilation-perfusion balance. The aim of the current study was to determine the effect of inhaled salbutamol on SaO2. In a randomised, double blind study, 21 infants, admitted with bronchiolitis positive for respiratory syncytial virus, had continuous SaO2 measurements made before and after nebulised salbutamol or placebo. SaO2 was recorded over 30 minutes for a baseline, then during the 10 minutes of first nebulisation with either salbutamol or saline, then over 30 minutes after nebulisation, the 10 minutes of second nebulisation with the alternate regime, and another 30 minutes after this second nebulisation. Desaturation occurred after salbutamol and saline nebulisation. The fall in SaO2 with salbutamol was seen whether infants received it as the first or second nebulisation. The fall in SaO2 after saline was seen when given first, but not when given after salbutamol. The decrease in SaO2 was greater and more prolonged with salbutamol than with saline. Routine nebulised aerosol sympathomimetic treatment during acute bronchiolitis cannot be recommended.

Albuterol↗
PubMed1991

Longitudinal analysis of lung function growth in healthy children and adolescents.

Lung function and height in 242 8-yr-old and 299 12-yr-old children without known or suspected predisposition to lung disease were measured annually over 6 and 8 yr, respectively. Growth of forced expiratory volume in 1 s (FEV1), vital capacity, and expiratory flow after expiring 50% of vital capacity were statistically modeled by age and height by use of a multivariate normal model for longitudinal data. This method has the flexibility to fit an appropriate (not necessarily linear) mathematical description of average lung function while concurrently modeling the covariance between measures on the same individual. Differences in lung function growth between girls and boys, pre- and post-puberty, showed that girls had a steadier though less pronounced increase in lung function with height. In boys, before puberty there was deficit in lung volume relative to height (not evident in girls), which was compensated for by rapid growth after puberty. The standard error of FEV1 predictions based on current height and age were more than halved when measurements of FEV1, age, and height taken 1 yr before were incorporated. We found evidence for dysanaptic growth in childhood. Fitted models have application to early detection of departures from healthy lung function.

Adolescent↗
PubMed1991

Bronchial responsiveness and lung function in recurrently wheezy infants.

Although most wheezy infants are considered asthmatic, they generally respond poorly to antiasthma treatment, and there is inadequate knowledge about the pathologic mechanisms that cause wheezing at this age. The aim of this study was to determine whether the strong association between wheezing and bronchial responsiveness (BR) seen in older subjects was also present in infants. We compared BR with inhaled histamine in 19 recurrently wheezy infants with a group of age-, height-, weight-, and sex-matched control infants. Maximal flow at FRC (VmaxFRC) was determined from partial expiratory flow-volume curves generated using the "squeeze" technique. Histamine was delivered during 1 min of tidal breathing in doubling concentrations from 0.125 g/L to a maximum of 8 g/L or until VmaxFRC fell by 40% (PC40). The median baseline VmaxFRC for the wheezy infants was 100.0 ml/s compared with 182.0 ml/s for the control infants (p less than 0.01). However, there was no significant difference in the PC40 between the two groups (2.1 versus 2.3 g/L).

Asthma↗
PubMed1990

Increased paediatric admissions with asthma in Western Australia--a problem of diagnosis?

A study of hospital admissions of paediatric cases with asthma over a 17-year period (1971-1987) in Western Australia was performed retrospectively. Hospital admission rates for asthma increased in all paediatric age-groups with the most dramatic increase occurring in the youngest (zero- to four-years') age-group. This increase in hospital admissions for asthma has been accompanied by a rapid decline in admissions for other paediatric respiratory conditions that share a potential diagnostic overlap with asthma. Hospital admission rates for asthma have reached a plateau at the major paediatric teaching hospital in the State from 1977 and Statewide from 1983. Diagnostic transfer has contributed significantly to the reported increase in hospital admissions for asthma over the past two decades.

Adolescent↗
PubMed1990

Tracking of lung function in healthy children and adolescents.

Two hundred twenty-six healthy school children, with a mean age of 8.8 years; 62 girls mean age 8.8, 48 boys mean age 12.6 and 51 girls mean age 12.6 years at the start, were enrolled in a longitudinal study of lung function and tested annually for 5 years. All were free of respiratory symptoms, and none smoked more than five cigarettes per week during the 5 years. Static and dynamic lung volumes (other than residual volume), maximum expiratory and inspiratory flows, and maximum mouth pressures "track," that is, individuals remain at a constant deviation from the sample mean over time. The data indicate that these measurements of lung function in healthy individuals grow in constant proportion relative to other healthy children and adolescents.

Adolescent↗
PubMed1990

Methodological aspects of flow-volume studies in infants.

Although valuable information is being obtained using new techniques to assess infant respiratory mechanics, there have been several concerns about the methodology. These relate to the possibility that chloral hydrate may affect flow-volume measurements by altering upper airway caliber. There is also the possibility that physiological changes may be induced by inhalation of non-pharmacologic and pharmacologic nebulized solutions. The aim of this study was to investigate these phenomena in a group of normal infants. Thoracic gas volume was determined and respiratory mechanics measured using the passive and forced expiratory flow-volume techniques. Respiratory function was assessed in infants before and after 1) sleep was induced by administration of chloral hydrate (n = 10, mean age, 21 weeks); 2) inhalation of nebulized saline (n = 10, mean age, 19 weeks); 3) inhalation of nebulized salbutamol (n = 7, mean age, 22 weeks). A fall in tidal volume was found following administration of chloral hydrate but no significant change was seen in any other respiratory parameter. In addition, no change was seen in any parameter post-saline or salbutamol nebulization. This study provides data which support several basic assumptions made about the infant flow-volume techniques and should provide useful background information for future studies using these techniques.

Albuterol↗
PubMed1990

Time course of change in oxygen saturation and peak expiratory flow in children admitted to hospital with acute asthma.

The time course for recovery of the arterial oxygen saturation (SaO2) in acute childhood asthma is unknown. Serial measurements of SaO2 were made in 47 children during an acute attack of asthma that required admission to hospital. Adequate serial peak expiratory flow (PEF) measurements were possible in 28 children (mean age 8.3 years; group A), but not in the other 19 children (mean age 3.2 years; group B). Measurements of PEF and SaO2 were recorded twice daily before and 30 minutes after they had received salbutamol by nebuliser. Initial SaO2 values (mean (SD) %) were similar in groups A and B at 92.2 (3.5) and 92.4 (2.9). For the children in group A, PEF plateaued 36 hours after admission and SaO2 plateaued 12 hours later. Mean PEF improved after each dose of nebulised salbutamol during the first 36 hours, whereas mean SaO2 increased only after the first dose. SaO2 increased more rapidly in group B. Length of hospital stay was not related to initial SaO2 or PEF values. These data suggest that in children admitted to hospital for acute asthma arterial oxygen saturation is low at admission, recovers more slowly than airway function, reflects bronchodilatation with salbutamol only when SaO2 is low, and recovers more rapidly in younger children than in older children.

Acute Disease↗
PubMed1990

Bronchial responsiveness to histamine in infants and older children.

Normal infants have been shown to respond to a relatively low concentration of inhaled histamine. However, those studies used partial maximal expiratory flow volume (PMEFV) curves to assess lung function. In order to directly compare responsiveness between infants and older children, we compared bronchial responsiveness to histamine between a group of 45 normal infants, median age 4 wk (range 2 to 6 wk) and a group of 30 nonasthmatic older children, median age 10 yr (range 5 to 15 yr) using PMEFV curves in both groups to assess lung function. In the infant group, PMEFV curves were generated using the forced expiratory flow volume technique. For the older children, PMEFV curves were generated by voluntary effort. The provocative concentration of histamine that produced a 40% fall (PC40) in maximum flow at functional residual capacity (VmaxFRC) was calculated from the PMEFV curves. The geometric mean PC40 of the infants (1.02 g/L) was lower than the geometric mean of the older children (3.4 g/L) (p less than 0.001). However, these results were then corrected for dilution of the aerosol due to air entrainment (AE). Corrected values of PC40 were not significantly different between infants and older children. These results demonstrate the importance of accounting for AE in the evaluation of histamine responsiveness and suggest that bronchial responsiveness may be similar in normal infants and older children.

Adolescent↗
PubMed1989

Lung function values from a longitudinal study of healthy children and adolescents.

From a cohort of 543 healthy children and adolescents, subjects were studied annually to obtain longitudinal data so that precise predictive values for lung volumes and flows from ages 8 to 19 years could be obtained. Strict guidelines for subject selection and pulmonary function testing were used. These data are presented in a readily usable form as equations, graphs, and tables.

Adolescent↗
PubMed1989

Management of asthma: a consensus statement.

In developing these international guidelines there were several unifying themes in the diagnosis and simple management of childhood asthma. For the purposes of the meeting, asthma was operationally defined as 'episodic wheeze and/or cough in a clinical setting where asthma is likely and other rarer conditions have been excluded'. In making a diagnosis of asthma, a full history is a prerequisite. Additional tests are only used to support clinical impression and to provide objective evidence for therapeutic recommendations. General features of a multidisciplinary approach include an appreciation of the importance of psychosocial factors, counselling, and education. Drugs should be prescribed in a rational sequence: beta 2-stimulants for mild episodic wheeze; sodium cromoglycate for mild to moderate asthma; inhaled steroids for moderate to severe asthma; with xanthines, ipratropium bromide, and oral steroids having their place in more persistent and severe cases. Children and their parents should be reassured that if asthma is properly controlled there is no reason why the child should not lead a normal and physically active life. The management of asthma is rewarding and return to 'normal' lifestyle is nearly always possible with active participation in sporting activities.

Acute Disease↗
PubMed1989

Response of normal infants to inhaled histamine.

The age at which nonspecific bronchial hyperresponsiveness (BHR) is first seen in humans is unknown, though both genetic and environmental factors have been implicated in its development. The current study aimed to establish whether BHR to histamine can be demonstrated in normal infants. Twelve infants, mean age of 7.8 months (range, 3 to 18 months), were studied. None had any history of a previous significant respiratory illness. Respiratory function was monitored using the maximal flow at function residual capacity (VmaxFRC) obtained with the forced expiratory flow-volume technique. Histamine was inhaled in doubling concentrations from 0.125 to 8 g.L-1. A greater than 30% fall in VmaxFRC was considered a response. All infants responded to histamine, the geometric mean concentration for their response being 1.4 g.L-1. Associated transient changes for the group were an increase in respiratory rate (p less than 0.02) and a fall in SaO2 (p less than 0.001). Forced expiratory flow-volume curves were concave in all infants after the last dose of histamine. We speculate that humans are born with "bronchial hyperresponsiveness" and that genetic or environmental factors determine which infants lose it thereafter.

Bronchi↗
PubMed1989

The effects of ipratropium bromide and fenoterol nebulizer solutions in children with asthma.

The effects of nebulized solutions of ipratropium bromide and fenoterol combined were compared with the response to either preparation alone in single dose and longer-term administration in children who had asthma. The combination produced a slightly greater response than either alone, especially in peak expiratory flow. Over a 1-month period, there were no significant differences in symptom scores or lung function parameters between the combination of ipratropium bromide and fenoterol and fenoterol alone in a group of children who had asthma. It is possible that the addition of ipratropium bromide to a sympathomimetic drug may be useful in a subgroup of asthmatics, particularly if there is a considerable large airway contribution to bronchial narrowing.

Adolescent↗