Search PubMed⌕ Search

Biomedical subjects

C Burgess

Publications and source records attributed to C Burgess.

At least 55 records · Page 3Linked to original sources
PubMed1996

Trial of a "credit card" asthma self-management plan in a high-risk group of patients with asthma.

BACKGROUND: The "credit card" asthma self-management plan provides the adult asthmatic patient with simple guidelines for the self-management of asthma, which are based on the self-assessment of peak expiratory flow rate recordings and symptoms. OBJECTIVE: The study was a trial of the clinical efficacy of the credit card plan in a high-risk group of asthmatic patients. METHODS: In this "before-and-after" trial, patients discharged from the emergency department of Wellington Hospital, after treatment for severe asthma were invited to attend a series of hospital outpatient clinics at which the credit card plan was introduced. Questionnaires were used to compare markers of asthma morbidity, requirement for emergency medical care, and medication use during the 6-month period before and after intervention with the credit card plan. RESULTS: Of the 30 patients with asthma who attended the first outpatient clinic, 26 (17 women and 9 men) completed the program. In these 26 participants, there was a reduction in both morbidity and requirement for acute medical services: specifically, the proportion waking with asthma more than once a week decreased from 65% to 23% (p = 0.005) and the proportion visiting the emergency department for treatment of severe asthma decreased from 58% to 15% (p = 0.004). The patients attending the clinics commented favorably on the plan, in particular on its usefulness as an educational tool for monitoring and treating their asthma. CONCLUSIONS: Although the interpretation of this study is limited by the lack of a randomized control group, the findings are consistent with other evidence that the credit card asthma self-management plan can be an effective and acceptable system for improving asthma care in a high-risk group of adult patients with asthma.

Adolescent↗
PubMed1996

Partial vs full beta-receptor agonism. A clinical study of inhaled albuterol and fenoterol.

STUDY OBJECTIVE: To compare the maximal extrapulmonary effects of the beta-agonists albuterol and fenoterol in eight healthy volunteers. SUBJECTS AND METHODS: In this double-blind study, we have examined the maximum cardiac effects (electromechanical systole [QS2I]--a measure of inotropy, heart rate, BP) and metabolic effects (plasma K+ and cyclic adenosine monophosphate [cAMP]) of repeated inhalation of albuternol and fenoterol. In eight healthy volunteers, 400 microg of each drug was administered every 10 min until QS2I and plasma K+ had reached a plateau (+/- 0.1 mmo l/L for K+, and +/- 10 ms for QS2I). The maximum response (Emax) and the dose of albuterol required to produce 50% of the maximum response to fenoterol (ED50F) were calculated. RESULTS: The Emax for fenoterol was significantly greater than albuterol for plasma K+ (-1.4 vs -1.03 mmol/L; p<0.002), QS2I (-71.8 vs 57.5 ms; p=0.047), and cAMP (33.8 vs 18.1 nmol/L; p<0.002). The dose required to produce the ED50f was significantly greater for albuterol than for fenoterol with potency ratios of 1.75, 1.61, and 2.26 for plasma K+, QS2I, and cAMP, respectively. There were no significant differences between fenoterol and albuterol with respect to heart rate (Emax, 44.9 vs 32.5 beats/min; p=0.19; potency ratio, 1.98; p=0.052). CONCLUSIONS: These findings suggest that albuterol behaves as a partial agonist at beta-receptors when compared with fenoterol, and that when inhaled in doses currently recommended for severe asthma, albuterol will result in lesser maximum cardiac and metabolic effects than fenoterol. These findings are consistent with the hypothesis that the property of full receptor agonism may contribute to the increased risk of death associated with fenoterol.

Administration, Inhalation↗
PubMed1995

End of the New Zealand asthma mortality epidemic.

In 1989, a case-control study reported that inhaled fenoterol was associated with the epidemic of asthma deaths that had affected New Zealand since 1976. The New Zealand Department of Health issued warnings about the safety of fenoterol and restricted its availability. The associated time trends are consistent with the hypothesis that fenoterol was the main factor in the New Zealand asthma mortality epidemic. The epidemic commenced when fenoterol was introduced in 1976, and the New Zealand death rate remained the highest in the world for more than a decade. After publication of the case-control study, the death rate fell by half and has now remained low for a further 3 years (1990-92). Time-trend data do not suggest a class effect of inhaled beta-agonists in the epidemic: there was no association between beta-agonist sales and the start of the epidemic, and total sales of inhaled beta-agonists actually increased slightly during 1989-90 when the epidemic came to an end. Time-trend data are also inconsistent with the hypothesis that the epidemic may have occurred because of underprescribing of inhaled corticosteroids. Similarly, time-trend data is incosistent with hypotheses postulating a major role of social factors such as unemployment. Data on time trends should be assessed with caution, because time trends in asthma deaths can be affected by many factors. Nevertheless, the New Zealand time trends are consistent with fenoterol being the main cause of the New Zealand asthma mortality epidemic and are inconsistent with a significant role for other suggested causes.

Administration, Inhalation↗
PubMed1994

The influence of increased health care costs on general practitioner consultations and prescription collection.

AIM: Increased health service charges have led to concern that some patients may be unable to meet these costs, which could compromise their care. Increased costs may affect general practitioner attendance, and/or the collection of a prescription. This study examines both of these factors. METHODS: Between 18 August and 14 September 1992, questionnaires were sent to the consenting patients of 19 general practitioners from the Hutt Valley requesting information regarding the general practice (GP) visit and the prescription. The information included the reason for the GP visit, whether there was any delay and its duration, the reason for any delay, the cost of the visit and whether a prescription was received. Data regarding the prescription included the cost and whether all, some, or none of the items were uplifted, and whether the patient had a community service card. RESULTS: 489 (86%) returned completed questionnaires and 426 received a prescription. Of these, 164 were group 1 community service card holders; one was a group 2 community service card holder; 186 were group 3; 59 did not specify their group; 18 had a chronic-user card. Forty percent (194 patients), delayed going to their doctor, 118 by more than 3 days. The most common reasons for delay were hope that their condition may improve spontaneously and the cost of the consultation or prescription. Possession of a community service card was a significant factor in delay with group 3 (high wage earners) more likely to delay than group 1 (p < 0.0005). Only two patients did not present their prescription. Ninety-three percent of those receiving a prescription presented for dispensing within 24 hours. Ninety-two percent of patients paid for all their prescription items. CONCLUSIONS: Delay in obtaining treatment is common and occurs primarily at the general practitioner consultation. It primarily affects those individuals who were classified as group 3, the group that has taken the burden of recent health service charges increases.

Adolescent↗
PubMed1994

The effect of hypercapnia and hypoxemia on the cardiovascular responses to isoproterenol.

BACKGROUND: The reason for the increased risk of death with fenoterol and isoproterenol in asthma is unknown but may relate to their cardiovascular effects. Deaths from asthma usually occur outside hospital where hypoxemia, with or without hypercapnia, may exist. Both of these states can influence the cardiovascular system. We investigated whether different gas mixtures modified the cardiovascular effects of isoproterenol. METHOD: Nine healthy men were randomly assigned to receive each of three gas mixtures to achieve (1) normoxia-normocapnia, (2) hypercapnia (end-tidal PaCO2, 50 mm Hg), (3) hypoxemia-hypercapnia (arterial oxygen saturation, 90%; PaCO2, 50 mm Hg). Isoproterenol was administered with each of the gas mixtures. Cardiovascular measurements of heart rate, blood pressure, cardiac index, ejection fraction, fractional shortening, electromechanical systole, and the QTc interval were made before administration of the gases, as well as before and 5 minutes after isoproterenol administration. RESULTS: The changes after hypercapnia were not significantly different from those after normoxia-normocapnia. Hypoxemia-hypercapnia increased heart rate, systolic and diastolic blood pressure, QTc interval, cardiac index, ejection fraction, and fractional shortening. Isoproterenol increased heart rate, systolic blood pressure, QTc interval, cardiac index, ejection fraction, and fractional shortening while the subjects breathed the normoxia-normocapnia gas mixture. It caused similar changes with the other gas mixtures. The changes were additive. CONCLUSION: Isoproterenol and hypoxemia-hypercapnia will increase myocardial oxygen demand and could prove to be detrimental in severe asthma.

Adult↗
PubMed1994

Confounding by severity does not explain the association between fenoterol and asthma death.

Three recent case-control studies from New Zealand, and one from Saskatchewan, Canada, have found that fenoterol increases the risk of death in patients with severe asthma. It has been suggested that these findings may be due to confounding by severity, if fenoterol was selectively prescribed to more severe asthmatics. This 'confounding by severity' hypothesis has now been investigated in further analyses of data from the New Zealand case-control studies. This analysis found that among patients whose asthma was severe enough to require hospital admission (the population in whom the case-control studies were conducted), fenoterol was not preferentially prescribed to the more severe asthmatics. There was greater co-prescribing of other drugs with fenoterol (compared with salbutamol) during the later years of the epidemic, but these differences did not explain the excess risk associated with fenoterol, and there was little evidence of greater co-prescribing during the earlier years of the New Zealand epidemic of asthma deaths. There was no association between the prescription of fenoterol and markers of acute asthma severity or psychosocial problems. Patients were not selectively changed to fenoterol as a result of a severe attack resulting in a hospital admission. Most importantly, in the case-control studies of asthma deaths, the inhaled fenoterol relative risk increased when the analysis was restricted to sub-groups defined by markers of chronic asthma severity; whereas the relative risk would have decreased towards 1.0 in these sub-group analyses if the overall elevated risk for fenoterol was due to confounding by severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1994

Application of the Rotter scale of internal-external locus of control to determine differences between smokers, non-smokers and ex-smokers in their general locus of control.

This paper will relate to empirical research undertaken whilst studying for BA(Hons) in Applied Social Studies by Independent Study. The researchers are both nurses, and colleagues were among the participating subjects. The research took the form of applying the Rotter (1966) scale for internal versus external locus of control to three groups, namely smokers, non-smokers and ex-smokers. Previous studies have indicated that smokers have a more external locus of control than non-smokers. A sample of 60 subjects included 20 in each group (smokers, non-smokers and ex-smokers), of whom a high proportion were nurses and white collar workers within the 25-50 age group. Analysis of the results revealed that there was no significant difference between the scores of the three groups. However, when analysing the scores of nurses only there was a significant difference between smokers and non-smokers. Suggestions will be made as to why this difference in findings occurs.

Adult↗
PubMed1994

The effects of sympathomimetics on the cardiovascular system of sheep.

1. Sheep hearts have been used to study the effects of beta-adrenoceptor (beta-AR) agonists in order to better understand the effects of common asthma treatment drugs on heart rate, cardiac power output and cardiac pathology. Hearts have been examined both in vivo and in vitro. 2. In whole anaesthetized sheep, isoprenaline, fenoterol and salbutamol induced dose-dependent increases in heart rate. Hypokalaemia in response to salbutamol was accentuated in hypoxia. Many of these hearts showed significant myocardial lesions. Hypoxia alone caused no significant cardiac response. 3. As expected, the beta 1-AR agonist dobutamine caused dose-dependent increases in heart performance (heart rate and cardiac power output). Both responses were blocked by metoprolol and propranolol. The beta 2-AR agonist salbutamol caused dose-dependent increases in heart rate and although cardiac output increased, cardiac power output remained unchanged as a consequence of the fall in peripheral resistance. The heart rate changes were blocked by metoprolol. Importantly, propranolol blocked both the heart rate response and the fall in peripheral resistance. 4. Isolated atrial strips showed a right shift of their dose-response curve to isoprenaline in the presence of the highly selective beta 2-AR antagonist ICI 118,551 at concentrations above 1 x 10(-8) mol/L. 5. We conclude that the sheep heart shows many pharmacological characteristics of the human heart which makes it a good pharmacological model in addition to its being amenable to many common techniques available for humans.

Albuterol↗
PubMed1994

Prescribed drug therapy and near-fatal asthma attacks.

Inhaled fenoterol has been associated with an increased risk of death in severe asthmatics, when compared to other adrenoceptor agonists. It is plausible that fenoterol may also increase the risk of near-fatal attacks. We have conducted a case-control study to investigate this hypothesis. The cases comprised Intensive Care Unit (ICU) admissions for asthma in the Wellington region during 1977-1988. For each of these cases, two age-matched controls were selected from asthma admissions to the same hospital during the same period. For the 155 cases and 305 controls, information on prescribed drug therapy was collected from the hospital admission records. The relative risk of a near-fatal asthma attack in patients prescribed inhaled fenoterol was 2.00 (95% confidence interval (CI) 1.35-2.97). An increased risk was also observed for oral theophylline (odds ratio (OR) = 1.88; 95% CI 1.26-2.79). For the 65 cases and 104 controls who had a previous admission for asthma in the previous 12 months, information relating to the previous admission was also collected; an increased risk was once again observed for inhaled fenoterol (OR = 2.18; 95% CI 1.10-4.33) and for oral theophylline (OR = 1.18; 95% CI 0.99-3.57). No other asthma drugs showed significantly increased risks. Although the ICU admission cases had generally been prescribed more asthma drugs than the hospital admission controls, and appeared to have more severe asthma, it is possible that the findings reported here are influenced by confounding by severity. We nevertheless estimate that our findings are consistent with the hypothesis that fenoterol increases the risk of near-fatal asthma attacks, and that they complement previous findings on fatal asthma attacks.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1994

Community-based asthma care: trial of a "credit card" asthma self-management plan.

Although asthma self-management plans are widely recommended as essential in the long-term treatment of adult asthma, there have been few studies examining their use. Our objective was to assess the effect of a "credit card" adult asthma self-management plan in a community experiencing major health problems from asthma, by means of a before and after intervention trial of the efficacy of the "credit card" plan, when introduced through community-based asthma clinics. The participants were 69 Maori people with asthma. The "credit card" plan consisted of written guidelines for the self-management of asthma, based on self-assessment of asthma severity, printed on a plastic card. On one side, management guidelines were based on the interpretation of peak expiratory flow rate (PEFR) recordings, whilst the reverse side was based on symptoms. The outcome measures used were before and after comparison of markers of asthma morbidity and requirement for acute medical treatment; and a structured questionnaire assessing the acceptability and use of the credit card plan. Following the introduction of the plan, the mean PEFR increased from 347 to 389 l.min-1, the percentage of nights woken fell from 30.4 to 16.9%, and the number of days "out of action" fell from 3.8 to 1.7%. The requirements for acute medical treatment also fell during the intervention period. Most participants commented favourably on the content and usefulness of the plan. In the situation of worsening asthma, 28% of subjects found the peak flow side of the card most helpful, 7% the symptoms side, and 48% found both sides equally helpful.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

The myocardial effects of fenoterol, isoprenaline and salbutamol in normoxic and hypoxic sheep.

Three groups, each of four sheep, were randomly allocated under blinded conditions to receive the beta-adrenoceptor agonists, salbutamol, fenoterol or isoprenaline, in doses of 0.5, 2, 8, 32 and 128 micrograms/kg intravenously at 15-minute intervals. A separate group of four animals received equal volumes of saline. Heart rate was recorded immediately prior to each drug administration and serum potassium was measured. Three to 4 days later the experiment was repeated during induced systemic hypoxia and the animals then necropsied. All the agonists produced significant increases in heart rate. During hypoxia, lower heart rates were recorded than in the normoxic experiments. Under conditions of hypoxia, all the beta-agonists produced significant hypokalaemia. Sterile saline had no effect on either heart rate or serum potassium levels. At necropsy, myocardial lesions were found in animals receiving all three beta-agonists. Subendocardial haemorrhage was consistently seen in all animals receiving fenoterol. Multifocal myonecrosis of 3-4 days duration was present in the left ventricle of all animals receiving fenoterol, in two receiving isoprenaline and in two receiving salbutamol. The lesions were most severe in the papillary muscle and were visible grossly in one animal given fenoterol and one given isoprenaline. No lesions were found in the control animals.

Adrenergic beta-Agonists↗