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Biomedical subjects

J F Miles

Publications and source records attributed to J F Miles.

11 recordsLinked to original sources
PubMed2005

Defining and investigating difficult asthma: developing quality indicators.

BACKGROUND: There is no agreed definition of 'difficult asthma' or what investigations should be available to investigate these patients. Patients with difficult asthma remain symptomatic on high levels of treatment and are high users of medical resources. AIM: To develop a set of quality indicators for the definition and investigation of difficult asthma. METHOD: Modified RAND Appropriateness Method was used. An expert panel composed of nine hospital asthma specialists who run 'difficult' asthma clinics and were identified from a short list of key workers in the field. Indicators were rated as necessary to define and investigate difficult asthma. RESULTS: Difficult asthma was defined as 'symptoms persisting beyond therapy consistent with step 4 of the British Thoracic Society (BTS) guidelines' (high dose inhaled corticosteroids and long acting beta(2)-agonists). Eighty-three indicators were identified (40 relating to definition and 43 relating to investigations). Of these 32 (39%) were rated as necessary: 7 out of 40 (18%) for defining difficult asthma and 23 out of 43 (53%) for investigations. Indicators of high medical resource usage were characteristic of the 'difficult' nature of the management of patient with difficult asthma. A framework for the investigation of these patients was created. CONCLUSION: The listed performance indicators identify a range of requirements that are necessary to define difficult asthma. Targeting of real needs in this group of patients will lead to better patient care and reduction of 'waste' in provision of healthcare.

Anti-Asthmatic Agents↗
PubMed1999

Pulmonary function and respiratory symptoms in a population of airport workers.

OBJECTIVES: To assess the prevalence of respiratory symptoms and to measure spirometry in a sample of employees of Birmingham International Airport, United Kingdom, to examine whether occupational exposure to aircraft fuel or jet stream exhaust might be associated with respiratory symptoms or abnormalities of lung function. METHODS: Cross sectional survey by questionnaire and on site measurement of lung function, skin prick tests, and exhaled carbon monoxide concentrations. Occupational exposure was assigned by job title, between group comparison were made by logistic regression analysis. RESULTS: 222/680 full time employees were studied (mean age 38.6 y, 63% male, 28% current smokers, 6% self reported asthma, 19% self reported hay fever). Upper and lower respiratory tract symptoms were common and 51% had one or more positive skin tests. There were no significant differences in lung function tests between exposure groups. Between group comparisons of respiratory symptoms were restricted to male members of the medium and high exposure groups. The adjusted odds ratio (OR) for cough with phlegm and runny nose were found to be significantly associated with high exposure (OR 3.5, 95% confidence interval (95% CI) 1.23 to 9.74 and 2.9, 1.32 to 6.40 respectively) when the measured confounding effects of age and smoking, and in the case of runny nose, self reported hay fever had been taken into account. There was no obvious association between high exposure and the presence of shortness of breath or wheeze, or for the symptoms of watering eyes or stuffy nose. CONCLUSIONS: These findings support an association in male airport workers, between high occupational exposures to aviation fuel or jet stream exhaust and excess upper and lower respiratory tract symptoms, in keeping with a respiratory irritant. It is more likely that these effects reflect exposure to exhaust rather than fuel, although the effects of an unmeasured agent cannot be discounted.

Adult↗
PubMed1998

Brittle asthma.

We believe that the asthma phenotypes we have defined as types 1 and 2 brittle asthma appear to be defined subgroups of asthma. For example, we have characterised patients with type 1 brittle asthma, as defined in this review, on the basis of peak flow variability and treatment and these patients remain a separate group when assessed by other means such as psychosocial factors, immunoglobulin levels, and atopy. The question remains as to whether they are truly separate groups with entirely different pathogenetic influences or whether they simply represent the severe end of the spectrum. Our suggested classification into types 1 and 2 forms a useful start for studies of this condition, although prospective evaluation of patients with severe asthma is the only way of substantiating the validity of these definitions which will then enable investigation of possible mechanisms. However, these patients are rare and in order to study them as a group a national register would need to be set up along the lines of the West Midlands Brittle Asthma Register, perhaps recruiting all "at risk" patients and then using this resource as a means of exploring the different asthma phenotypes within this broad grouping, including brittle asthma.

Anti-Asthmatic Agents↗
PubMed1997

Psychological morbidity and coping skills in patients with brittle and non-brittle asthma: a case-control study.

BACKGROUND: An association between psychological morbidity and asthma is well recognized and an increase in negative psychosocial factors in brittle asthma has been previously reported. Such factors, apart from affecting patient perceptions, may alter patients' self-management of their condition. METHODS: We have undertaken a case-control study on 29 well characterized brittle and non-brittle asthmatics in the West Midlands Region to assess their level of psychological morbidity, using the General Health Questionnaire (GHQ) and the living with asthma questionnaire, and their responses to changes in asthma symptoms, using the Asthma Symptom Checklist and a taped interview. RESULTS: Significant differences in GHQ (mean score brittle 19.5 vs non-brittle 7.2, P = 0.0002) and living with asthma (mean score brittle 1.30 vs non-brittle 1.00, P = 0.002) reinforced the presence of psychological factors in this group of patients with severe asthma. Interviews regarding responses to hypothetical asthma attacks showed that patients with brittle asthma delayed seeking medical attention more often than those with non-brittle asthma and instead preferred to self-administer beta-agonist medication. Sixteen (55.2%) of the 29 patients with brittle asthma would have delayed 7 days before seeking medical attention in a slow onset attack compared with 6/29 (20.7%) in the non-brittle group. In a fast onset attack 14 (48.3%) patients with brittle asthma would not have summoned help, despite finding it difficult to walk to the kitchen for a drink whereas in the non-brittle group 24 out of 29 (82.8%) would have summoned help. Levels of family support tended to be lower in patients with brittle asthma (mean family APGAR 7.3 vs 8.65 P = 0.09). CONCLUSIONS: Brittle asthma is associated with greater psychological morbidity and altered strategies for coping with deteriorating asthma symptoms. Attention should be paid to the presence of such factors in the management of patients with brittle asthma.

Adrenergic beta-Agonists↗
PubMed1996

Potential effects of correction of inaccuracies of the mini-Wright peak expiratory flow meter on the use of an asthma self-management plan.

BACKGROUND: Patient self-management plans for asthma use peak expiratory flow (PEF) meter readings for decisions on adjusting asthma treatment. PEF meters have been shown to be inaccurate and the effect of this inaccuracy on such treatment plans has been determined. METHODS: PEF measurements were made by 127 severe asthmatic patients at least twice a day for at least two weeks using a mini-Wright meter. The daily variation from "best" PEF and the within day PEF variability were calculated before and after correction for the meter's known inaccuracy. The effect of this data correction on the number of days when trigger points were reached for changing asthma therapy was then determined. RESULTS: Continuous PEF readings were available from 114 subjects with a median of 157.5 days of data per subject (range 15-489 days). Correction of the PEF data led to the number of days of satisfactory asthma control being reduced in 72% of subjects with just one subject showing an increase in satisfactory control. Data correction reduced the percentage of total days of satisfactory control from 46% to 36% of days, and increased the days requiring more inhaled steroids from 33% to 36%. The days on which a course of oral corticosteroids was required increased from 16% to 23%. CONCLUSIONS: The accuracy of PEF meters significantly influences the interpretation of currently used asthma self-management plans. Managing asthma with the corrected PEF data would have increased the amount of treatment received by these patients since the severity of the asthma was underestimated by the raw data.

Adolescent↗
PubMed1996

Oesophageal reflux and asthma.

Asthma and gastro-oesophageal reflux commonly occur together but the association in any individual may or may not be causal. Aspiration of gastric acid into the trachea has been demonstrated in some patients with asthma with concomitant falls in lung function, while acid in the lower oesophagus can exacerbate asthma by a vagal reflex following stimulation of lower oesophageal receptors. Conversely, asthma can lead to worsening reflux both through the use of smooth muscle relaxing anti-asthma medication and by the mechanical effects of hyperinflation reducing lower oesophageal sphincter pressures. The effects on asthma following treatment of reflux has been anecdotally reported to be successful in some individuals, particularly those with severe reflux, but surgery should be reserved for individuals only after failure of medical treatment and should be aimed at improving reflux symptoms rather than improving asthma control.

Asthma↗
PubMed1995

The performance of Mini Wright peak flow meters after prolonged use.

The accuracy of 84 new and 35 old Mini Wright peak flow meters were tested using a servo-controlled pump system. The 95% confidence limits for flow measurement across the range of the new meters was between +/- 151 min-1 at the lower end of the range and +/- 28 l min-1 at the top of the range. The readings for 22 (63%) of the old meters (age range 1-13 yr) were within these 95% confidence limits. For the remaining 13 old meters (age range 1-13 yr) whose readings were not within these limits, there were 11 meters with readings falling below and two meters with readings above these limits. Twelve of these old meters were washed and retested and there was no significant change in their readings. Twenty of the new meters were retested after 1 yr of continuous use and their readings were significantly higher with a median value of 5 l min-1 across the range, although only two of these 20 meters had readings outside the 95% confidence limits set from the 84 new meters. It is concluded that whilst Mini Wright meters aged up to 14 yr can give readings which are as good as new meters, some meters demonstrate significant changes in readings after only 1 yr and washing did not correct this change. It is recommended that clinicians prescribing peak expiratory flow (PEF) meters should be responsible for checking the patient's meter as well as their PEF readings at clinic visits.

Disinfection↗
PubMed1993

The interrelationship of eclampsia, HELLP syndrome, and prematurity: cofactors for significant maternal and perinatal risk.

OBJECTIVE: To determine if there are differences between mothers and fetuses in eclamptic pregnancies with or without concurrent HELLP syndrome. DESIGN: Retrospective review. SETTING: A single tertiary perinatal centre, the University of Mississippi Medical Center. SUBJECTS: All eclamptic pregnancies treated during a 141 month period from 1980 until the end of 1991. METHODS: Pregnancies were grouped according to the presence or absence of HELLP syndrome subclassified as class 1 = platelet nadir < or = 50,000/microliters, class 2 = platelet nadir > 50,000 to < or = 100,000/microliters, and class 3 = platelet nadir > 100,000 to < or = 150,000/microliters. RESULTS: Among 49,782 live births, there were 117 women with eclampsia prior to delivery (incidence 1:425), 62 of which had HELLP syndrome. The group with HELLP syndrome were delivered significantly earlier (32.1 vs 36.4 weeks), and had lower birthweights (1821 vs 2550 grams) and higher perinatal mortality (113 vs 18:100). They were also transfused more frequently (65% vs 35%), and suffered greater overall serious maternal morbidity and mortality. CONCLUSION: Eclampsia is more likely to be associated with the HELLP syndrome at early gestations. Although eclamptic patients are already at risk, the presence of HELLP syndrome accentuates the risk for adverse maternal-perinatal outcome.

Adolescent↗
PubMed1990

Postpartum eclampsia: a recurring perinatal dilemma.

Because identification of patients at risk and preventive therapies are imperfect, eclamptic seizures continue to occur occasionally during the puerperium. During an 18-year span in a single tertiary medical center, 36 of 254 patients with eclampsia (14.2%) experienced postpartum seizures at a mean gestational age of 35.6 weeks. Early (before 48 hours) postpartum eclampsia was experienced by 72% of patients, and 28% had late (after 48 hours) postpartum eclampsia. Prospectively only 67% of patients were correctly diagnosed, and retrospectively only 83% could be considered to have had preeclampsia before seizure. Hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome was present in 30% of the affected patients. Seven patients were receiving magnesium sulfate by controlled infusion when an eclamptic seizure occurred. The presence or absence of diuresis was unrelated to seizure occurrence. Preeclampsia recurred in 38.5% of subsequent gestations. It appears that HELLP syndrome may be a predisposing factor for eclampsia.

Blood Pressure↗
PubMedDate not supplied

Preservatives in nebulizer solutions: risks without benefit.

Edetate disodium (EDTA) and benzalkonium chloride (BAC) are often present as preservative or stabilizing agents in nebulizer solutions used to treat asthma and chronic obstructive pulmonary disease. Benzalkonium chloride is a potent bronchoconstrictor when inhaled in concentrations similar to those in which it is present in these solutions. Inclusion of BAC (together with EDTA) in the ipratropium bromide (Atrovent) nebulizer solution resulted in paradoxic bronchoconstriction in some asthmatic patients and an overall reduction in bronchodilator efficacy. The presence of BAC in albuterol nebulizer solutions does not affect the short-term bronchodilator response to a single dose, although case reports suggest that its repeated use in patients with severe asthma may result in paradoxic bronchoconstriction. When inhaled by asthmatic subjects, EDTA also causes dose-dependent bronchoconstriction, although it is less potent than BAC. The use of preservative-free bronchodilator nebulizer solutions does not result in clinically significant bacterial contamination if they are dispensed in sterile unit-dose vials, in volumes and concentrations that do not require modification by the user. Despite this evidence, in the United States a number of solutions, including some preparations of albuterol, contain either BAC or EDTA. Current regulations do not require that the concentration of preservatives be documented on the product; however, considerably different doses of BAC are delivered with different products. For example, a standard 2.5-mg dose of albuterol nebulizer solution contains 50 microg of BAC when administered from the multidose dropper bottle and 300 microg from the unit-dose screw-cap product. Furthermore, it is legal for pharmacists to substitute or compound solutions containing high concentrations of BAC when the physician has prescribed a preservative-free product. We recommend that the United States follow the practice of most Western countries and withdraw bronchodilator nebulizer solutions that contain preservatives such as BAC. We further recommend that the solutions should be prepared under sterile conditions, formulated preservative free, and made available in unit-dose vials.

Benzalkonium Compounds↗