Domiciliary oxygen for chronic obstructive pulmonary disease

BACKGROUND

Domiciliary oxygen therapy has become one of the major forms of treatment for hypoxaemic chronic obstructive pulmonary disease (COPD) patients.

OBJECTIVES

To determine the effect of domiciliary oxygen therapy on survival and quality of life in patients with COPD.

SEARCH STRATEGY

Randomised controlled trials (RCTs) were identified using the Cochrane Airways Group COPD register using the search terms: home OR domiciliary AND oxygen. Searches were current as of January 2005.

SELECTION CRITERIA

Any RCT in patients with hypoxaemia and COPD that compared long term domiciliary or home oxygen therapy with a control treatment.

DATA COLLECTION AND ANALYSIS

Data extraction was performed independently by two reviewers.

MAIN RESULTS

Six randomised controlled trials were identified. Survival data was aggregated from two trials of the treatment of nocturnal oxygen therapy in patients with mild to moderate COPD and arterial desaturation at night. Survival data was also aggregated from two trials of continuous oxygen therapy versus no oxygen therapy in mild to moderate COPD. Data could not be aggregated for the other two trials because of differences in trial design and patient selection. Nott 1980: continuous oxygen therapy versus nocturnal oxygen therapy: there was a significant improvement in mortality after 24 months (Peto odds ratio 0.45, 95% confidence interval 0.25 to 0.81). MRC 1981: domiciliary oxygen therapy versus no oxygen therapy: there was a significant improvement over five years in mortality in the group receiving oxygen therapy (Peto odds ratio 0.42, 95% confidence interval 0.18 to 0.98). In the two studies of nocturnal oxygen versus no oxygen therapy in patients with COPD and arterial desaturation at night: there was no difference in mortality between treated and non treated groups for either trial or when the trials were aggregated. In the two trials of long-term oxygen therapy versus no oxygen therapy in COPD patients with mild to moderate hypoxaemia: there was no effect on survival for up to three years of follow up.

AUTHORS' CONCLUSIONS

Long-term home oxygen therapy improved survival in a selected group of COPD patients with severe hypoxaemia (arterial PaO2 less than 55 mm Hg (8.0 kPa)). Home oxygen therapy did not appear to improve survival in patients with mild to moderate hypoxaemia or in those with only arterial desaturation at night.

Survival on long-term oxygen therapy in chronic airflow limitation: from evidence to outcomes in the routine clinical setting

BACKGROUND

Two previous randomized controlled trials (RCT) demonstrated that the administration of long-term oxygen therapy (LTOT) improved survival in selected patients with hypoxic chronic obstructive pulmonary disease (COPD) or chronic airflow limitation (CAL).

AIMS

The aim of the present study was to investigate whether the survival of CAL patients prescribed LTOT at Flinders Medical Centre (FMC) was gender and age related, and equivalent to that of the previous RCT.

METHODS

A list of patients prescribed domiciliary oxygen therapy for CAL at FMC was generated from Respiratory Unit records and hospital financial records for the supply of this therapy. Survival was compared with that reported for the original RCT, and for Swedish and Belgian COPD patients. Factors influencing survival were studied.

RESULTS

Five hundred and five (249 males, 256 females) patients were prescribed LTOT for CAL at FMC during the study period and included in the survival analysis. The patients were elderly with multiple comorbidities. Survival was less than for the control arms of the previous RCT (apart from the Medical Research Council Working Party (MRC) female group) but comparable with recent overseas data. Overall crude survival was 75.1%, 51.3%, 18.9% and 1.1% at 1, 2, 5 and 10 years respectively. Females experienced longer survival than males. Multivariate analysis indicated that age, forced expiratory volume in 1 s, body mass index (BMI) and the number of comorbidities were prognostic indicators for females; BMI was a prognostic indicator for males. A survival advantage existed for females using at least 19 h concentrator oxygen per day.

CONCLUSIONS

In routine practice, survival of unselected CAL patients with multiple comorbidities is less than that reported in the original RCT.

A review of long-term oxygen therapy for chronic obstructive pulmonary disease

This study aimed to review the evidence for the use of long-term oxygen therapy for patients with chronic obstructive pulmonary disease (COPD). The design was a systematic Cochrane review of randomized controlled trials (RCTs) of long-term oxygen therapy for COPD and main outcome measure was survival on home oxygen therapy. Five RCTs were identified. Data from two trials of nocturnal oxygen therapy in mild to moderate hypoxaemia were aggregated. Data from the other three trials could not be aggregated because of differences in trial design and patient selection. Treatment with continuous versus nocturnal oxygen therapy produced a significant improvement in mortality after 24 months [Peto odds ratio 0.45, 95% confidence interval (95% CI) 0.25-0.81] for the continuous therapy group. Treatment with oxygen therapy versus no oxygen therapy showed a significant improvement in mortality after five years in the group receiving oxygen therapy (Peto odds ratio 0.42, 95% CI 0.18-0.98). There was no difference in mortality for patients with COPD and mild to moderate daytime hypoxaemia and nocturnal desaturation receiving nocturnal oxygen therapy versus no oxygen therapy or sham treatment. Long-term oxygen therapy versus no oxygen therapy in patients with COPD and moderate hypoxaemia had no effect on survival. In conclusion, long-term oxygen therapy improved survival in a selected group of COPD patients with severe hypoxaemia but few co-morbidities. Long-term oxygen therapy did not improve survival in patients with moderate hypoxaemia or in those with mild to moderate hypoxaemia and arterial desaturation at night.

Mucolytics for bronchiectasis

BACKGROUND

Bronchiectasis is predominantly an acquired disease process representing the end stage of a variety of unrelated pulmonary insults. It is defined as a persistent irreversible dilatation and distortion of medium-sized bronchi. Patients diagnosed with bronchiectasis frequently have difficulty exporating the infected sputum. Mucolytic agents target hyper-secretion or changed physiochemical properties of sputum to make it easier to clear. One drug, recombinant human DNase, breaks down the DNA that is released at the site of infection by neutrophils.

OBJECTIVES

The objective of this review was to assess the effects of ingested or inhaled mucolytics in people with bronchiectasis.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register, reference lists of relevant articles. We also contacted experts in the field and drug companies.

SELECTION CRITERIA

Randomised trials of mucolytic treatment in people with bronchiectasis but not cystic fibrosis.

DATA COLLECTION AND ANALYSIS

Data extraction was performed independently by two reviewers. Study authors were contacted for confirmation.

MAIN RESULTS

Three trials were included, but none of their data could be aggregated in a meta analysis. Compared to placebo, high doses of bromhexine with antibiotics eased difficulty in expectoration (weighted mean difference -0.53, 95% confidence interval -0.81 to -0.25 at 16 days). There was also a reduction in sputum production with bromhexine (weighted mean difference -21.5%, 95% confidence interval -38.9 to -4.1 % at day 16). Compared to placebo, recombinant human DNase showed no difference in forced expiratory volume or forced vital capacity in one study and was reported to have a significant negative effect on forced expiratory volume in another study. Adverse effects, including influenza-like symptoms, were more common in the group receiving recombinant human DNase.

REVIEWER'S CONCLUSIONS

There is not enough evidence to evaluate the routine use of mucolytics for bronchiectasis. High doses of bromhexine coupled with antibiotics may help with sputum production and clearance.

An association between length of stay and co-morbidity in chronic airflow limitation

OBJECTIVE

To examine factors which impact on the length of stay and readmission for patients with chronic airflow limitation at a South Australian hospital from December 1996 until March 1998.

DESIGN

Discharges from Flinders Medical Centre for patients aged > or = 18 years, where chronic airflow limitation was an active problem, and including a subset with a primary diagnosis of chronic airflow limitation, were identified, retrospectively, by the center's Clinical Coding Service from the hospital's in-patient separation database.

SETTING

Flinders Medical Centre, Adelaide, South Australia.

OUTCOME MEASURES

Length of stay; number of co-morbidities; readmission within 28 days.

RESULTS

Five-hundred and twenty discharges (male:female, 258:262) with a primary diagnosis of chronic airflow limitation (ANDRG-3 177, chronic obstructive airways disease) were identified. Readmission within 28 days was related to the number of co-morbidities and to age. A relationship between length of stay and the number of co-morbidities was identified. A mean length of stay of 6.39 days was found for patients with less than five co-morbidities, 5.36 at their first admission to Flinders Medical Centre and 3.25 at their first admission to Flinders Medical Centre with no co-morbidities. These mean lengths of stay fall below overseas data previously published and are consistent with Kong's estimate of an ideal mean length of stay of 3.2 days when a clinical management guideline is used in low-risk chronic airflow limitation patients.

CONCLUSIONS

Length of stay and readmission to hospital within 28 days of patients with a primary diagnosis of chronic airflow limitation is at least partly related to the number of co-morbidities and to age. The study has highlighted the difficulty of relying on changes to aggregate data as outcome measures for these patients.

Adhesion molecule expression on epithelial cells infected with respiratory syncytial virus

Respiratory epithelium is both a target and an effector of airway inflammation. Adhesion molecules on epithelium play an important role in a variety of airway diseases. Respiratory syncytial virus (RSV) is the most important pathogen for airway diseases in infants. The expression of adhesion molecules on epithelium in RSV infection, however, is unclear. The expression of selected adhesion molecules and major histocompatibility complex (MHC) class I and II antigens on a human alveolar type II epithelial cell line (A549) infected with RSV was investigated by means of flow cytometry and immunocytochemistry. The results showed that intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were expressed on A549 cells at a low level. E-cadherin and MHC class I antigen were constitutively expressed on the cells. RSV infection of A549 cells significantly upregulated the expression of ICAM-1, VCAM-1 and MHC class I and II antigens on these cells. RSV infection also altered the expression of E-cadherin on A549 cells. Immunostaining showed that E-cadherin was mainly upregulated around or in RSV-induced giant cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances the expression of adhesion molecules and major histocompatibility complex antigens. These changes may play an important role in the pathophysiology of respiratory syncytial virus disease.

Trends in hospital readmission for asthma: has the Australian National Asthma Campaign had an effect?

OBJECTIVES

To describe patterns of hospital readmission for asthma in South Australia from 1989 to 1996, in relation to implementation of the National Asthma Campaign.

DESIGN AND SETTING

A comparison of hospital admissions in South Australia of patients aged between one year and 49 years for three conditions: asthma (or respiratory failure with asthma as an underlying condition) and two control conditions--diabetes and epilepsy. Individuals were identified by Medicare number and date of birth.

OUTCOME MEASURES

Hospital readmission within 28 days and within one year.

RESULTS

Overall, by 1996, there was a statistically significant decline in the risk of readmission for asthma within 28 days of 18% and within one year of 17% compared with 1989 readmission rates. There were no reductions in the risk of readmission for diabetes or epilepsy, suggesting that the decline in risk of readmission for asthma was greater than the underlying effects of general changes in hospital casemix.

CONCLUSIONS

The decline in risk of readmission may reflect changes in asthma severity or improved management practices. However, hospital readmission rates still remain high, and to further reduce readmissions for asthma there is a need to identify factors related to presentation for asthma at accident and emergency departments.

Domicilary oxygen for chronic obstructive pulmonary disease

BACKGROUND

Long-term domiciliary oxygen therapy has become one of the major forms of treatment for hypoxaemic chronic obstructive pulmonary disease (COPD) patients.

OBJECTIVES

To determine the effect of domiciliary oxygen therapy on survival and quality of life in patients with COPD.

SEARCH STRATEGY

Randomised controlled trials (RCTs) were identified using the Cochrane Airways Group COPD register using the search terms: (home OR domiciliary) AND oxygen.

SELECTION CRITERIA

Any RCT in patients with hypoxaemia and COPD that compared long term domiciliary or home oxygen therapy with a control treatment.

DATA COLLECTION AND ANALYSIS

Data extraction was performed independently by two reviewers.

MAIN RESULTS

Four randomised controlled trials were identified. Data from none of these trials could be aggregated because of differences in trial design and patient selection. NOTT 1980, continuous oxygen therapy versus nocturnal oxygen therapy: there was a significant improvement in mortality after 24 months (Peto odds ratio 0.45, 95% confidence interval 0.25 to 0.81). MRC 1981, domiciliary oxygen therapy versus no oxygen therapy: there was a significant improvement over five years in mortality in the group receiving oxygen therapy (Peto odds ratio 0.42, 95% confidence interval 0.18 to 0.98). Fletcher 1992, nocturnal oxygen versus no oxygen in patients with COPD and arterial desaturation at night: there was no difference in mortality at 36 months. Gorecka 1997, long term oxygen versus no oxygen in moderate hypoxaemia: there was no effect on survival for up to three years of follow up.

REVIEWER'S CONCLUSIONS

Long term oxygen therapy improved survival in a selected group of COPD patients with severe hypoxaemia (arterial PO2 less than 8.0 kPa). Long term oxygen did not appear to improve survival in patients with moderate hypoxaemia or in those with only arterial desaturation at night.

Randomised controlled trial of general practice based asthma clinics

OBJECTIVE

To compare the effects on asthma morbidity of asthma clinics based in general practice with standard general practice care.

DESIGN AND SETTING

A randomised controlled trial in eight general practices. Patients, general practitioners and outcomes assessors were not blinded to treatment allocation.

PARTICIPANTS

195 patients with asthma aged 5-64 years; 191 completed the trial.

INTERVENTION

Three asthma clinic sessions over six months involving nurse counselling, education about asthma management, spirometry and consultation with the general practitioner.

MAIN OUTCOME MEASURES

Patients reporting days lost from work or school, number of days lost, the presence of morning or nocturnal asthma symptoms, use of an action plan, medication use, current smoking, hospitalisation, and emergency visits.

RESULTS

Asthma clinics were associated with a greater reduction in nocturnal symptoms, an increase in the ownership of peak flow meters and an increase in the number of patients commencing or resuming smoking. Both control and intervention groups showed similar improvement in days lost from work or school, the presence of symptoms, use of an action plan and taking reliever medication.

CONCLUSION

Our study does not show that asthma clinics are more effective than standard general practice care in reducing asthma morbidity. It is uncertain how much of the improvement in outcomes was due to the asthma clinic, the influence of the study itself upon patients and practitioners, or other factors, such as the tendency for a patient's asthma management to improve over time.

Minimum lung function for breath alcohol testing using the Lion Alcolmeter SD-400

The aim of this study was to determine the minimum lung function required by an individual to complete a breath alcohol test successfully using a Lion Alcolmeter SD-400. A total of 331 subjects routinely referred to a busy clinical respiratory function laboratory for assessment of their lung function were tested. A total of 52 (15.7%) of these subjects were unable to provide an adequate sample after two attempts. The majority of the group (86.5%) were female. There was considerable overlap of the minimum lung function parameters between those subjects who were unsuccessful at all attempts and those who were successful. The failure rate of the subjects using the Lion Alcolmeter SD-400 was approximately 50% of that found in a previous study of the Lion SD-2.

Effects of long-term oxygen therapy on quality of life and survival in chronic airflow limitation

Chronic airflow limitation (CAL) is a major contributor to the burden of ill-health in Australia and, where hypoxia is present, can be treated with home oxygen therapy (HOT). At Flinders Medical Centre, a prospective longitudinal study was undertaken to examine the impact of HOT on the health-related quality of life (HRQoL) of subjects with CAL. All eligible adult patients, aged < 80 yrs, with a primary diagnosis of CAL who met the prescription guidelines of the Thoracic Society of Australia and New Zealand were offered HOT and invited to participate. After baseline assessment, subjects were followed-up 3, 6 and 12 months after commencement of HOT. Physiological assessment and three validated HRQoL measures were applied, the Nottingham Health Profile (NHP), the Chronic Respiratory Questionnaire (CRQ) and, for a subset of the patients, the Medical Outcomes Study short-form 36-item questionnaire (SF-36). This study reports the results from January 1, 1991 to July 31, 1997. One hundred and fourteen CAL patients were included in the study. Female subjects experienced significant improvements from baseline in the energy, emotional reactions, sleep and physical mobility areas of the NHP, in the fatigue, emotional function and mastery dimensions of the CRQ and in the role-physical, vitality, role-emotional, and mental health dimensions of the SF-36. Males experienced significant improvements in the emotional reactions, sleep and social isolation areas of the NHP, in the fatigue dimension of the CRQ and in the vitality dimension of the SF-36. Some of the improvements in the various domains persisted for > 6 months. Female patients prescribed home oxygen therapy appear to have a greater overall improvement in health-related quality of life and survival than males. Follow-up is continuing.

Shedding of L-selectin and PECAM-1 and upregulation of Mac-1 and ICAM-1 on neutrophils in RSV bronchiolitis

Bronchiolitis is characterized histologically by epithelial necrosis and peribronchial infiltration of leukocytes, with a high percentage of neutrophils in the airways. We investigated the expression of adhesion molecules (CD11a, CD11b, CD18, CD31, CD54, and CD62L) on neutrophils from nasopharyngeal aspirates (NPAs) and peripheral blood (PB) of infants with respiratory syncytial virus (RSV)-induced bronchiolitis. The expression of CD31 and CD62L on neutrophils from NPAs is decreased and the expression of CD11b, CD18, and CD54 on neutrophils from NPAs is increased compared with cells from PB of RSV-infected infants. The expression of CD18 and CD54 on neutrophils from PB of RSV-infected infants is also increased compared with cells from PB of control infants. Shedding of CD31 and CD62L on neutrophils in RSV infection may contribute to the neutrophil emigration from blood to airways; the upregulation of Mac-1 (CD11b/CD18) and CD54 on neutrophils may help explain the high percentage of neutrophils in the airways of RSV bronchiolitis; and the upregulation of Mac-1 may be involved in the increased neutrophil-airway epithelial adhesion in RSV infection.

The apoptosis of neutrophils is accelerated in respiratory syncytial virus (RSV)-induced bronchiolitis

Neutrophils are the predominant inflammatory cell in the lung tissues and airways in RSV infection, and can augment the epithelial cell damage induced by RSV. Neutrophil apoptosis has been suggested to be a mechanism to reduce the potential for tissue injury. The apoptosis of neutrophils from nasopharyngeal aspirates (NPA) (n = 19) and peripheral blood (PB) of infants with RSV bronchiolitis (n = 11) and PB from healthy controls (n = 9) was investigated. Monoclonal antibody against CD95 (Fas) and a binding protein Annexin V were used to determine the apoptosis of neutrophils. The expression of CD11b and CD18 on neutrophils was also detected with flow cytometry. The mean fluorescence intensity (MFI) of CD95 on neutrophils from RSV+ NPA was increased compared with cells from control PB (73.6 +/- 7.6 versus 31.5 +/- 4.3); the MFI of Annexin V, CD11b and CD18 on neutrophils from RSV+ NPA was up-regulated compared with cells from both control PB (105.3 +/- 18.1 versus 11.8 +/- 1.5; 1683 +/- 153.3 versus 841.1 +/- 72.3; 517 +/- 50.5 versus 147 +/- 8.7, respectively) and RSV+ PB (105.3 +/- 18.1 versus 35.8 +/- 4.1; 1683 +/- 153.3 versus 818 +/- 141.2; 517 +/- 50.5 versus 260 +/- 25.8, respectively). Furthermore, the percentage of neutrophils expressing Annexin V and the MFI of CD18 on neutrophils from RSV+ PB were increased compared with neutrophils from control PB. In addition, both CD11b (MFI) and CD18 (MFI) correlated with Annexin V (MFI) on neutrophils. We conclude that neutrophil apoptosis in RSV bronchiolitis is accelerated; and CD11b/CD18 may play an important role in RSV infection by influencing neutrophil apoptosis.

Neutrophils induce damage to respiratory epithelial cells infected with respiratory syncytial virus

The mechanisms by which respiratory syncytial virus (RSV) infection induces bronchiolitis and airway disease are unclear. The presence of large numbers of polymorphonuclear leukocytes (PMN) in the airways of infants with RSV infection suggests a potential role of PMN in airway injury associated with RSV infection. To investigate the potential role of neutrophils in RSV bronchiolitis, human alveolar type II cells (A549 cells) were infected with different doses of RSV for 6-48 h. A 51Cr-releasing assay was used to measure PMN-induced damage and image analysis was used to determine PMN adhesion and detachment of epithelial cells. The results showed that RSV infection of epithelial cells enhanced PMN adherence in a dose- and time-dependent pattern, RSV infection alone could damage and detach epithelial cells to a limited extent and PMN significantly augmented RSV infection-induced damage and detachment of epithelial cells. These data suggest that respiratory syncytial virus infection of respiratory epithelial cells enhances neutrophil adhesion to the epithelium and that activated neutrophils augment the damage and detachment of epithelium infected with the virus. Polymorphonuclear leukocytes may contribute to the pathogenesis of respiratory syncytial virus airway disease by inducing epithelial damage and cell loss.

The MOS SF-36 health survey questionnaire in severe chronic airflow limitation: comparison with the Nottingham Health Profile

This study documents the cross-sectional, health-related quality of life (HRQOL) measures obtained at baseline for patients with severe chronic airways limitation (CAL) being assessed for home oxygen therapy (HOT) at the Flinders Medical Centre, Adelaide, South Australia. Two generic quality of life instruments, the Nottingham Health Profile (NHP) and the Medical Outcomes Study (MOS) short form 36-item questionnaire (SF-36), were administered by interview to the same patients to permit comparisons to be made between the two instruments. SF-36 mean scores were also compared with scores obtained in separate studies of a South Australian elderly general population and of groups of Australian subjects with various medical and psychiatric conditions. NHP mean scores were compared with scores from an elderly group of Adelaide residents from a household survey. HRQOL measures were obtained for 60 patients, 32 males and 28 females. At assessment for HOT, patients with severe CAL were experiencing severe impairment in their quality of life in comparison to age-matched South Australian norms, with physical disability the major limitation. There were several significant correlations between the domains of the SF-36 and the NHP which were predominantly gender-specific. Only small decrements in mental health were found with the SF-36 questionnaire. The SF-36 and the NHP appear to provide discrepant information for severely disabled CAL patients for the subjective domains of emotional and mental health.

Initial trends in quality of life and survival in CAL patients on domiciliary oxygen therapy

Domiciliary oxygen therapy has become a major form of treatment for chronic airflow limitation (CAL), and has been demonstrated to increase survival and reduce hospitalization. The impact of long-term domiciliary oxygen therapy on health-related quality of life is less clear. This study was conducted to document prospectively the quality of life and survival of patients with CAL after being prescribed domiciliary oxygen therapy at the Flinders Medical Centre in South Australia. The study sample consisted of 57 adult patients (29 males and 28 females, aged 80 yrs or less) with severe CAL referred to the Respiratory Unit for domiciliary oxygen therapy. Prior to the commencement of oxygen therapy, baseline physiological assessment was performed and the Nottingham Health Profile (NHP), the Chronic Respiratory Disease Questionnaire (CRDQ), a Quality of Life Thermometer (QOLTH) and Life Satisfaction Index (LSI) were used to measure the health-related quality of life (HR-QOL). Follow-ups occurred at 3 and 6 months after the commencement of home oxygen therapy. Quality of life at baseline was not correlated with the physiological parameters of lung function and blood gas analysis. However, considerable correlation was found between two of the quality of life instruments used. The female patients on home oxygen therapy experienced some improvement in several dimensions of quality of life measured by the instruments. The observations were less clearcut for males. By the time the patients' physiological and clinical condition has deteriorated for them to fulfil prescription guidelines for home oxygen therapy, patients with chronic airflow limitation are experiencing a marked reduction in quality of life. However, the strength of the reported findings must be tempered by remaining questions over the validity of the instruments and their responsiveness to change; and by the small number of enrolments so far, and the relatively short period of follow-up.

The changing prevalence of asthma-like respiratory symptoms in South Australian rural schoolchildren

OBJECTIVE

To describe the changing prevalence of wheezy breathing and doctor-diagnosed asthma, as obtained by questionnaire data, from the years 1984-92 in a sample of South Australian rural schoolchildren.

METHODOLOGY

A cross-sectional study of three populations of schoolchildren from the South Australian rural towns of Burra (mid-north), Gladstone (mid-north) and Kingston (southern, coastal). The cumulative or lifetime prevalences and the 12-month period prevalence (current) of respiratory symptoms were estimated from questionnaire data obtained from parental responses for 1032 schoolchildren aged from 5 to 18 years, and compared with prevalences obtained from a previous study.

RESULTS

The overall cumulative prevalence of wheezy breathing in 1992 was 36.2%, an increase from 24.1% in 1984 with a 12-month period prevalence of 25.0%. The 1992 cumulative prevalence of doctor-diagnosed asthma was 23.3%. There was no difference in the prevalence of wheeze between the three rural regions studied. A trend to a higher prevalence of doctor-diagnosed asthma in one of the three regions was thought to be due to medical specialist input.

CONCLUSIONS

The cumulative prevalence for wheeze among school-age children in South Australian rural communities has increased in the period 1984-92. There were no regional differences in the cumulative prevalence rates. The results confirm previous studies in Victoria and New South Wales.

The comprehensibility of Australian educational literature for patients with asthma

BACKGROUND

Education of patients with asthma is aimed at improving their knowledge, skills and attitudes, and thus compliance and control. Patient information pamphlets play a role in education, medication information and informed consent processes, and must be understood. We assessed the comprehensibility of Australian pamphlets on asthma.

METHOD

50 Australian pamphlets on asthma (written in English for adults) were selected from the Asthma Foundation, a teaching hospital in South Australia, the pharmaceutical industry, the National Asthma Campaign and specialist books and journal articles. The Australian Rix readability formula was used to estimate the grade of reading difficulty, and thus comprehensibility, of these patient information pamphlets (grade 1 = most comprehensible; grade 12 = most difficult).

RESULTS

The mean grade of reading difficulty of the 50 patient information pamphlets was 8 (SD, 1.4; range, 6-11). One-third were written at or above grade 9 and two-thirds were at or above grade 8.

CONCLUSION

As recent educational attainment data suggest that up to 52% of 15-69-year-olds in Australia comprehend text at or below grade 7, a substantial number of pamphlets on asthma are beyond the reading and comprehension abilities of many of their target population.

Trends in chronic obstructive pulmonary disease mortality in Australia

OBJECTIVE

To examine trends in mortality from chronic obstructive pulmonary disease in the Australian population from 1964 to 1990.

DESIGN

Review of national data on deaths from chronic obstructive pulmonary disease. We calculated direct annual age-standardised mortality rates for women and men (based on the 1976 age distribution of the Australian population), cumulative mortality rates and future mortality trends. Age-standardised mortality rates based on the world standard population were calculated and compared with mortality rates from lung cancer.

RESULTS

Male age-standardised mortality increased 1.6-fold from 1964 to 1970 and subsequently declined. In 1990 the male mortality rate was 5% less than in 1964. Female age-standardised mortality has shown a 2.6-fold increase from 1964 to 1990.

CONCLUSIONS

Chronic obstructive pulmonary disease seems likely to be a major health problem in Australia for many years to come. If present trends continue, female mortality from chronic obstructive pulmonary disease may equal male mortality by the middle of the next decade.

Minimum respiratory function for breath alcohol testing in South Australia

The aim of this study was to determine if inability to complete a breath alcohol test successfully, using a Lion Alcolmeter SD-2 or Drager Alcotest 7110, was related to any of the standard parameters obtained from the lung function spirometry test. A total of 153 subjects referred to a clinical laboratory for routine lung function testing were tested using the Alcolmeter, 158 using the Alcotest, with 69 subjects completing tests on both instruments. Of the 153 patients who volunteered to use the Alcolmeter, 49 (32%) were unable to produce a valid test effort on this instrument. One subject failed to complete a satisfactory test using the Alcotest, and one was unable to master the technique. There was considerable overlap of the minimum value for each of the lung function parameters of those subjects who could or could not successfully complete the breath alcohol test. It is recommended that changes are made to both of the instruments, the techniques used and the legislation, to minimize the number of breath alcohol testing failures and to reduce the variability of the results.

A profile of respiratory symptoms in urban and rural South Australian school children

This report describes the cross-sectional analyses of data from the first year of a longitudinal study using questionnaire and respiratory function data over a 5 year period from a sample of rural South Australian school children. The cumulative or lifetime prevalences of respiratory symptoms were estimated in 825 rural and 1261 urban school children aged between 5 and 15 years in order to determine if the prevalence rates differed between rural and urban school children. The study found the overall cumulative prevalence of asthma and/or wheezy breathing (AWB) to be 24.1% in the rural school children compared to 27.6% in the urban school children. Most children developed AWB symptoms before the age of 7 years, with 20% reporting moderately severe symptoms and 10% having more than one attack per fortnight. The cumulative prevalence of bronchitis, loose/rattly cough (BLRC) differed significantly between the rural school children (34.1%) and urban school children (47.9%). The BLRC symptoms preceded the development of AWB in many cases. Urban school children also reported a higher prevalence of atopic conditions.

The Flinders experiment in medical education revisited

OBJECTIVE

The undergraduate medical curriculum of the Flinders University of South Australia is reviewed and evaluated against American recommendations for the basic education of doctors practising in the 21st century.

DATA SOURCES

Two previous articles in The Medical Journal of Australia describing earlier versions of the Flinders curriculum and the report on General Professional Education for the Physician of the Association of American Medical Colleges.

DATA SYNTHESIS

The Flinders curriculum attempts to fully integrate the teaching of medical science and clinical disciplines. The earliest version of the curriculum emphasised horizontal integration of normal structure and function of body systems, followed by abnormalities of these systems, and finally clinical practice. The second version introduced vertical integration of basic science and clinical medicine within a body system. The present version attempts to balance the demands of horizontal and vertical integration. An important feature of all versions is the large proportion of time allowed for elective studies in most years of the course.

CONCLUSIONS

The Flinders curriculum has been able to adapt to the changing needs of medical education because its organisation is relatively free from the constraints of departmental rivalry over resources.

Home oxygen therapy: an audit of survival

A retrospective audit of the medical records and respiratory function data of 186 subjects placed on long term continuous home oxygen therapy between 1979 and 1988 was undertaken. Kaplan-Meier survival curves were constructed for subjects with Chronic Obstructive Airways Disease (COAD) and Interstitial Lung Disease (ILD). There was an almost twofold greater mortality rate for COAD subjects at 12 months when compared to the Medical Research Council Working Party (MRC) and the Nocturnal Oxygen Therapy multicentre clinical trials (NOTT). However, the mean values of the baseline physiological parameters were similar to these major studies of long term oxygen therapy. Survival of ILD patients was significantly less than COAD patients (p less than 0.001). Within both disease categories, females survived significantly longer than males. Within the COAD category the observed sex difference was not abolished when the data was controlled for age, Pco2, Po2 and pack-years (as an estimate of total cigarette consumption). However, prior smoking history appeared to modify the male-female difference in COAD survival. These are the first Australian survivorship data for patients on long term oxygen therapy. The more adverse survival figures compared with the overseas studies may reflect the co-existence of other diseases.

Bronchial hyperresponsiveness in two populations of South Australian rural schoolchildren

This report describes the cross-sectional analyses of the results obtained from the first year of a longitudinal study designed to investigate the natural history of bronchial hyperresponsiveness in association with reported respiratory symptoms in children attending the Burra and Kingston Community Schools. Bronchial hyperresponsiveness to methacholine was measured using a modified Yan technique. Prevalence rates of respiratory symptoms were obtained using the Tasmanian Asthma Foundation Questionnaire. Considerable overlap of reported symptoms of asthma and/or wheezy breathing and bronchitis and/or loose and productive cough was observed suggesting that a clear distinction between such symptoms in childhood may not be possible. Analyses of data showed the prevalence of reactive airways in children to be 21.3% in Burra and 22.0% in Kingston. These values were the same as results obtained from an earlier pilot study in Burra and similar to results from Wagga Wagga (19.6%) and Auckland (20.1%) but higher than from Belmont (15.5%) and Villawood (15.3%). Increased bronchial hyperresponsiveness was associated with the reporting of symptoms of asthma and/or wheezy breathing (odds ratio, 5.04; 95% confidence interval, 2.18-11.74) and bronchitis and/or loose and productive cough (odds ratio, 2.28; 95% confidence interval, 1.02-5.13), at any time in the child's life. Of children with no reported symptoms 10% also had demonstrable bronchial hyperresponsiveness.

Biochemical studies of N-methyltransferase in human and guinea-pig lung: no apparent role in the pathogenesis of asthma

1. N-Methyltransferase activity was measured in surgical specimens of human lung using phenylethanolamine as substrate. Thirty-three male and seven female patients, age range 19-78 (median 62.5) years were studied. The activity in lung homogenates was 0.59 x 10(-6) units/mg of protein (SEM 0.03, n = 40), with a range of 0.16-1.16 x 10(-6) units/mg of protein. There was no difference (P = 0.97) in activity between males and females. 2. Non-specific N-methyltransferase activity was estimated in 17 of the surgical specimens using beta-phenylethylamine as substrate. This activity was 38.9% (SEM 5.3) of that with phenylethanolamine. Comparative studies with rabbit lung, which has a well-characterized non-specific N-methyltransferase, showed significant differences in substrate specificity between the two species. 3. The apparent Km and Vmax for phenylethanolamine in seven human lung homogenates was 22.0 (SEM 4.6).mmol/l and 1.82 x 10(-6) units/mg of protein (SEM 0.36). The noradrenaline N-methyltransferase (NMT; EC 2.1.1.28) inhibitors SKF 64139-A and LY 134046 did not inhibit this activity up to a concentration of 100 mumol/l. This activity was inhibited 51.4% (SEM 8.6, n = 6) by 100 mumol/l S-adenosyl-L-homocysteine. Immunohistochemistry did not reveal immunoreactive NMT in human lung sections. 4. Comparative studies with guinea-pig lung homogenates demonstrated non-specific N-methyltransferase activity in this species which is similar to the human lung.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy of nedocromil sodium (Tilade) in asthma

Nedocromil sodium is a new antiasthmatic drug with properties similar to sodium cromoglycate. We examined the efficacy of nedocromil sodium compared to placebo in 71 asthmatic patients in a three-centre double-blind parallel group study over 12 weeks. During the study the patients' maintenance inhaled corticosteroids were progressively withdrawn. Nedocromil sodium had an advantage over placebo in the number of withdrawals related to uncontrolled asthma, 14 and 24 respectively (p = 0.03). Changes in symptom scores, peak flow rates and bronchodilator use favoured nedocromil sodium occasionally during the study. The unusual taste of the active drug was reported frequently. Nedocromil sodium is more efficacious than placebo in asthma maintenance, but does not replace inhaled corticosteroids.

Psychiatric morbidity in patients with chronic airflow obstruction

Fifty consecutive patients with chronic airflow obstruction who were admitted to a respiratory unit were assessed medically and psychiatrically. A high rate of psychiatric morbidity (58%) was detected with panic and other anxiety disorders (34%) being particularly prevalent. Various physiological and psychological reasons for the high rate of anxiety disorders are discussed.

Combined bronchodilator protection against histamine-induced bronchoconstriction in man

Sixteen stable asthmatics had the protective effects of inhaled fenoterol (200 micrograms) and inhaled ipratropium bromide (60 micrograms) against standardized histamine inhalation tests at 1 h examined in a randomized double blind fashion. There was no significant difference in the baseline forced expired volume in 1 s (FEV1) for the two study days (P greater than 0.05). There was an increase in FEV1 at 1 h on the fenoterol and ipratropium day compared with the fenoterol day (0.26 versus 0.17 l; P less than 0.05). The geometric mean provocative concentration of histamine to cause a 20% fall in FEV1 (PC20) was 6.31 mg/ml after fenoterol and 8.51 mg/ml after fenoterol and ipratropium (P = 0.038). There was no significant relationship between bronchodilator effect of the bronchodilators and the increase in PC20 from pre-study values, r = 0.307 (P = 0.25) for fenoterol alone and r = 0.195 (P = 0.47) for fenoterol and ipratropium. The relationship between pre-study histamine responsiveness and the increase in PC20 caused by the bronchodilators just failed to reach statistical significance, r = -0.441 (P = 0.09) for fenoterol alone and r = -0.47 (P = 0.06) for fenoterol and ipratropium. The study has shown a greater right shift of histamine responsiveness for combined inhaled fenoterol and ipratropium compared with inhaled fenoterol alone in this group of asthmatics.

The prevalence rate of respiratory symptoms in school children from two South Australian rural communities

The respiratory symptoms and respiratory function of 680 schoolchildren from two rural area of South Australia were studied. The initial results of this prospective, longitudinal study showed that the cumulative prevalence of asthma and/or wheezy breathing was 27.4% in the Burra population and 23.1% in the Kingston population. The cumulative prevalence of one or more attacks of asthma/wheezy breathing amongst Burra (38.8%) and Kingston (23%) children aged up to 8 years was significantly higher than that reported for urban Melbourne children (11%, p less than 0.01). The combined South Australian group reported a cumulative prevalence of asthma/wheezy breathing alone of 10% which was significantly higher than the cumulative prevalence rates in three previous studies reported in Australia (1.8%, 2.6%, 2.7%, p less than 0.01). The highest overall cumulative prevalence of bronchitis/loose or productive cough occurred in the 12 year old Burra children (41.5%). Burra girls had the highest prevalence of bronchitis/loose or productive cough (36.8%) compared to other groups studied at both locations. The parental smoking rate (60.4% in Burra, 57.4% in Kingston) is much higher than the national figure reported by the Bureau of Statistics in 1977 (35.9%). The prevalence of asthma/wheezy breathing is much higher in the South Australian cohort compared to the Queensland and Tasmanian cohorts studied using the same questionnaire. Predicted respiratory function parameters using initial algorithms are similar to those reported for urban Australian children.

The effect of bucindolol on the airway function of asthmatics

The airway and cardiovascular effects of separate single oral doses of 50, 100 and 200 mg of bucindolol were compared to those of placebo in a double-blind trial in 16 patients with mild to moderately severe asthma. Heart rate (HR), blood pressure (BP), forced vital capacity (FVC), forced expired volume in one second (FEV1), maximum expiratory flow at 50% of vital capacity (FEF50) and maximum expiratory flow at 75% of expired vital capacity (FEF75) were measured before and at intervals for 4h, when salbutamol (200 micrograms) was inhaled and the measurements repeated 15 min later. There was an interval of at least 4 days between each drug treatment day. Four of the 16 patients developed clinically significant bronchoconstriction with 50 mg (3) or 100 mg (1) of bucindolol and were withdrawn from the study. The remaining patients showed impaired bronchodilator response to salbutamol for each bucindolol dose as compared to placebo. No significant BP or HR effects were measured. Two patients withdrew because of circumstances unrelated to bucindolol induced bronchoconstriction. The development of bucindolol induced bronchoconstriction in this group of mild to moderate asthmatics was not predicted by the level of baseline pulmonary function, or the level of histamine responsiveness. However, there was a weak relationship between bucindolol induced bronchoconstriction and salbutamol induced bronchodilation. There are no definitive asthmatic characteristic to predict the likelihood of significant bucindolol induced bronchoconstriction in this asthmatic population.

Combination bronchodilator therapy in asthma

This study has compared the short-term bronchodilator effects of inhaled anticholinergic (ipratropium bromide) and sympathomimetic (fenoterol) agents alone and in combination in 18 asthmatic patients. the study was of double-blind, placebo-controlled, crossover design. The combination of 60 micrograms ipratropium bromide and 200 micrograms of fenoterol had a greater bronchodilator effect than lower dose combinations or either drug alone. Small but significant gains may be made with combination inhaled bronchodilator therapy.

Assessment of beta-adrenoceptor antagonists in asthmatic patients

1 Bronchial smooth muscle, skeletal muscle and cardiac beta-adrenoceptor antagonism have been compared in twelve asthmatic patients after three beta-adrenoceptor antagonists at two dose levels. The non-selective antagonist propranolol (40 and 160 mg), the non-selective antagonist with partial agonist activity pindolol (5 and 20 mg) and the beta 1-selective antagonist atenolol (50 and 200 mg) were studied on separate occasions. 2 Six placebo days were used in this double-blind crossover study to allow interpretation of individual as well as group results. 3 Bronchial smooth muscle effects were assessed by resting spirometry, histamine inhalation test and spirometric response to inhaled fenoterol. Skeletal muscle effects were assessed by resting tremor and fenoterol induced tremor. 4 Cardiac beta-adrenoceptor antagonism was assessed by measuring the effect on resting heart rate and on maximum heart rate in a standard exercise test. 5 Pindolol tended to cause least change from placebo in resting spirometry, caused significant tremor response, inhibited the fenoterol airway response, and tended to protect against inhaled histamine. 6 Atenolol 60 mg was the only drug to allow a fenoterol airway response similar to placebo. Atenolol increased the inhaled histamine responsiveness. 7 Propranolol 160 mg caused the most reduction in spirometry but also tended to cause the maximum reduction in exercise heart rate. Propranolol caused increased inhaled histamine responsiveness. 8 Initial sensitivity to inhaled histamine did not necessarily predict significant reduction in an asthmatics' spirometry by a beta-adrenoceptor antagonist. The effect of a beta-adrenoceptor antagonist on histamine responsiveness does not correspond to its effect on inhaled beta 2-adrenoceptor agonist responsiveness.

Repeated histamine inhalation tests in asthmatic patients

Histamine inhalation tests were performed in 12 asthmatic patients using a 2-min tidal breathing inhalation technique. The tests were repeated on separate days with 30-, 60-, and 120-min intervals between inhalation tests. On another day the inhalation tests were repeated four times with 40-min intervals between tests. The geometric mean provocative concentrations of histamine needed to cause a 20% fall in forced expiratory volume in 1 sec (PC20) for the group on the latter study day were 1.67, 1.57, and 1.55 mg/ml (p greater than 0.25) indicating no change in sensitivity to inhaled histamine with repeated testing. The results suggest that cumulative dose-response curves for drugs potentially affecting the airways or antagonizing histamine can be constructed within 1 day using histamine inhalation tests. The data also suggested that an individual PC20 result may be sensitively assessed by comparing it to a +/- 2 SD range from the mean of a series of control or placebo PC20 values.

Evaluation of lyophilized heparin syringes for the collection of arterial blood for acid base analysis

The effects of liquid heparin on the analysis of acid/base status of arterial blood include a reduction in PCO2 and an increase in PO2. A study was performed to compare a lyophilised heparin syringe with a liquid heparin glass syringe for collection of blood for acid/base analysis. No significant difference between the variables measured in blood taken in the two syringes was demonstrated.

Bronchial reactivity in Western red cedar induced asthma

A patient with Western red cedar induced asthma is described. The diagnosis was confirmed by a bronchial challenge with Western red cedar saw dust and the subsequent prolonged bronchial reactivity changes were measured using histamine inhalation tests.

Arterial blood gas analysis: potential errors due to the addition of heparin

The effect of sodium heparin on the determination of the major arterial blood gas parameters was studied. The addition of heparin produced errors in all three parameters tested, i.e. PO2, PCO2 and pH. The PCO2 determination was most affected, a 12% decrease being introduced into a 1.5 ml blood sample by the volume of heparin which fills the deadspace of a syringe and needle. Small but statistically significant errors were also produced in PO2 and pH by this heparin concentration. The clinical implications of these findings are discussed and certain measures outlined to avoid such errors.

Differences in immune elimination in inbred mice. The role of low affinity antibody

The rate of elimination of soluble protein antigen injected intravenously differs in different inbred strains of mice previously immunized to the antigen. This difference is apparently related to the affinity of the antibody they produce. Animals producing high affinity antibody eliminate antigen more effectively than those producing low affinity antibody. Passive transfer of antibody shows that the difference of antigen elimination is a property of the antibody, rather than the cellular mechanisms involved. The immunopathological significance of these findings is discussed.