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Biomedical subjects

G Purdie

Publications and source records attributed to G Purdie.

At least 37 records · Page 2Linked to original sources
PubMed1991

Bronchial responsiveness during regular fenoterol therapy: four months prospective study.

Effects of a regimen of regular high dose beta agonist aerosol as sole therapy (fenoterol 400 micrograms qid) on FEV1 and bronchial responsiveness to methacholine provocation were examined monthly in 16 atopic moderately severe asthmatic subjects in an open uncontrolled four months study. Eleven completed the trial, four dropped out on account of severe acute asthma and one with muscle tremor. Overall there was a small significant drop of mean prebronchodilator FEV1 after one month of 0.27 L (95% confidence interval 0.12, 0.42) but not significant thereafter. The increase of bronchial responsiveness (mean decrease of PD20 of 0.50 doubling doses of methacholine) by the end of month four did not reach statistical significance. Our study which explored potentially adverse effects of this beta agonist regimen showed only small changes of doubtful clinical significance. Drop outs due to acute asthma complicate studies such as this and make conclusions difficult.

Adolescent↗
PubMed1990

The pulmonary and extrapulmonary effects of inhaled beta-agonists in patients with asthma.

The cardiovascular, respiratory, and hypokalemic effects of repeated inhalation of fenoterol, albuterol, and isoproterenol were compared in 12 subjects with stable asthma according to a double-blind, crossover design. Ipratropium bromide served as a control providing bronchodilatation without extrapulmonary effects. Subjects inhaled the beta-agonists on an equal-weight basis (400 micrograms) at 0, 30, 40, and 45 minutes. Measurements of heart rate, blood pressure, total electromechanical systole (measure of inotropic activity), preejection period, QTc interval, plasma potassium levels, and forced expiratory volume in 1 second were made 5 minutes after each dose and again at 60 and 75 minutes. There were no differences in the bronchodilating effect between the beta-agonists. However, both fenoterol and isoproterenol resulted in greater positive inotropic stimulation than did albuterol, and fenoterol caused a greater fall in plasma potassium levels than did the other beta-agonists.

Adolescent↗
PubMed1990

A prospective randomized trial of external fixation and plaster cast immobilization in the treatment of distal radial fractures.

Distal radial fractures are common, and many methods of treatment have been reported but there are no studies that compare the different treatment methods. This randomized prospective study demonstrated no advantage in using an external fixator to immobilize reduced distal radial fractures over closed reduction and plaster cast immobilization in patients less than 60 years of age. The external fixator group had a significant complication rate.

Aged↗
PubMed1990

Multiple sclerosis in Australia and New Zealand: are the determinants genetic or environmental?

The prevalence of multiple sclerosis (MS) has been recently reported from nine regions of Australia and New Zealand. There is a marked variation of prevalence with latitude. MS is seven times more common in southern New Zealand than in tropical Queensland. On current evidence, it is suggested that in both countries this variation is predominantly due to environmental rather than genetic factors.

Australia↗
PubMed1990

The cardiovascular effects of beta adrenergic agonist drugs administered by nebulisation.

The cardiovascular effects of equal doses (5 mg) of nebulised fenoterol, salbutamol and terbutaline were compared in 12 healthy individuals in a double-blind, placebo-controlled study. Measurements of heart rate, blood pressure, systolic time intervals, QTc interval and T-wave amplitude were made at baseline and at 15, 30, 45, 60 and 90 minutes after nebulisation. Fenoterol caused significantly greater chronotropic electrocardiographic and inotropic effects than either salbutamol or terbutaline. The peak effects after terbutaline occurred later than those after fenoterol or salbutamol.

Adult↗
PubMed1990

Should treatment of mild to moderate hypertension be targeted? Results from a Markov cohort model incorporating multiple risk factors.

A series of guidelines for the treatment of mild to moderate hypertension have recommended that individuals with multiple cardiovascular risk factors should start treatment sooner, or at a lower level of diastolic pressure, compared with patients with an isolated elevation of blood pressure. A Markov cohort model was constructed to examine this claim. The cohorts consisted of mild to moderately hypertensive men with added cardiovascular risk factors: smoking, raised serum cholesterol, and presence of left ventricular hypertrophy on electrocardiogram. The results of the model confirm that the prognosis of hypertension is highly dependent on the presence of other risk factors. The average remaining life expectancy of two patients of identical age and level of diastolic pressure varied by as much as 10 to 24 years, depending on the presence of other risk factors. Depending on the patient, the gain in life expectancy due to treatment of hypertension ranged from 0.11 years to 1.03 years. However, the results also indicated that the additional benefit as a result of 'targeting' in people with multiple risk factors did not exceed 0.47 years for any of the patient categories analysed. The nature of these conclusions remained unaltered despite the use of quality-adjusted life years (QALYs), and varying assumptions about the benefit of treatment. In comparison the model indicated that the benefits of smoking cessation among hypertensive men were three to eight times greater than the expected benefits from antihypertensive therapy.

Adult↗
PubMed1989

The benefits and risks of treating mild to moderate hypertension.

The risks and benefits of treating mild to moderate hypertension (defined as a diastolic blood pressure level between 90-114 mm Hg) were quantified in order to assist clinical decision making. Presenting such information ought to be an essential part of the process of obtaining the patient's consent for treatment. Using estimates from clinical trials that antihypertensive drug therapy reduces all-cause mortality by 11% and stroke incidence by 39%, the benefits of treatment--expressed as the average number of people needing to be treated annually in order to prevent one death--ranges from 333 to 3393 in men, and from 508 to 5094 in women. The average number of people needing to be treated annually to prevent one stroke ranges from 281 to 4292 in men, and from 253 to 13,477 in women. The benefits of treatment are greatest in men, in the older age groups, and at higher diastolic blood pressure levels. Compared to the benefits, the annual risk of developing a side effect of the medication is much higher.

Adult↗
PubMed1989

Variability in antihypertensive drug therapy in general practice: results from a random national survey.

A random national survey of 50 general practitioners was undertaken to ascertain current trends in the pharmacological management of hypertension. Forty general practitioners entered the study, and scripts written by them over a two month period in 1988 were collected and recorded by the pharmaceutical pricing offices of the health department. The general practitioners provided details on whether the script had been written for hypertension, as well as the age and sex of the patients. Information from 37 general practitioners was available for study, involving 2675 scripts written for hypertension for 1858 patients. Sixty point two percent of the treated hypertensives were female, and 58.9% were aged over 60 years. The most commonly prescribed antihypertensives were the diuretics (47.1% of patients) and beta blockers (47.9%). They were followed by angiotensin converting enzyme inhibitors (18.2%) and calcium antagonists (9.7%). There was substantial variability in the prescription of antihypertensives with respect to the age and sex of the patients treated; the mean costs and duration of supply of different generic drug types; and the prescribing habits of general practitioners. By generic type, the mean monthly costs of therapy ranged from $3.77 (diuretics) to $48.19 (calcium antagonists). The age and sex adjusted geometric mean script costs ranged from $17.78 to $49.11 per month (median: $29.30). It seems unlikely that the observed degree of variability is explained by differences in the severity of hypertension between general practice populations.

Adrenergic beta-Antagonists↗
PubMed1989

A comparison of the extent and duration of hypokalaemia following three nebulized beta 2-adrenoceptor agonists.

The hypokalaemic effects of equal doses (5 mg) of fenoterol, salbutamol, terbutaline and an equal volume of saline administered by nebulization were compared in eight healthy subjects. Plasma potassium was measured at 15-min intervals for 60 min and at 90 min, 2, 4 and 6 h following administration. Fenoterol, salbutamol and terbutaline all significantly decreased plasma potassium when compared to saline; however, the magnitude and duration of this effect differed between the active agents. Both fenoterol and terbutaline significantly reduced plasma potassium for 4 h whereas salbutamol was only different from 30 to 120 min. The maximum decrease occurred with fenoterol (-0.78 mmol/l), followed by terbutaline (-0.70 mmol/l) and salbutamol (-0.33 mmol/l). Both terbutaline and fenoterol had a significantly greater effect compared with salbutamol. When administered by nebulization fenoterol and terbutaline are likely to have a greater hypokalaemic effect than salbutamol and this effect is likely to be more long lasting.

Administration, Inhalation↗
PubMed1989

Individual variability of amiodarone distribution in plasma and erythrocytes: implications for therapeutic monitoring.

The complexity of amiodarone disposition in blood and tissues gives rise to difficulty in determination of optimal therapeutic monitoring strategies. We have defined the within-patient variability of plasma and erythrocyte amiodarone and desethylamiodarone concentrations and electrocardiogram intervals [PR and corrected QT (QTc)] in 27 patients each sampled on three to four occasions during long-term stable amiodarone therapy. All individual repeated measurements were included in the concentration-effect analysis. The mean within-patient coefficients of variation for amiodarone and desethylamiodarone were significantly greater in erythrocytes, 46.0 and 24.5%, respectively, compared with plasma, 12.7 and 12.3%. Amiodarone and desethylamiodarone were significantly greater in erythrocytes, 46.0 and 24.5%, respectively, compared with plasma, 12.7 and 12.3%. Amiodarone and desethylamiodarone were strongly correlated (r = 0.29 p less than 0.004). There was a 10-fold variability in erythrocyte amiodarone for a given plasma level. These data emphasize the highly variable cellular distribution of amiodarone and desethylamiodarone in the same patient on stable dosage over time. Plasma amiodarone was significantly correlated with dosage (r = 0.98), and percent change in QTc, (r = 0.56, p less than 0.0001), but there was a fourfold variation in plasma amiodarone for a given QTc. Side-effect frequency was not related to plasma or erythrocyte amiodarone or desethylamiodarone concentrations. A clinically useful relationship between plasma concentration and effect could not be consistently demonstrated for amiodarone in the same individual during stable dosage.

Adult↗
PubMed1989

Bronchial gland duct ectasia in fatal bronchial asthma: association with interstitial emphysema.

To determine the incidence of bronchial gland duct ectasia in fatal asthma and its association with interstitial emphysema, the histological features of 72 patients in whom death was considered to be due to asthma, and 72 matched control subjects in whom sudden death was not attributed to asthma, were reviewed. In all cases and controls, sections of two or more blocks of lung tissue stained with haematoxylin and eosin were obtained at necropsy. Bronchial gland duct ectasia was diagnosed if there was more than one abnormally dilated epithelial lined protrusion from a bronchus, extending through the smooth muscle layer. A histological diagnosis of asthma was made if four of the five following criteria were present: mucus plugging, basement membrane thickening, epithelial shedding, submucosal eosinophil leucocyte infiltration and smooth muscle hypertrophy. A histological diagnosis of asthma was made in 53 of 72 clinical cases of fatal asthma and in five of 72 control subjects. Interstitial emphysema was present in 10 clinical cases of fatal asthma, all of whom had bronchial gland duct ectasia and a histological diagnosis of asthma. Interstitial emphysema was not observed in control subjects. It is concluded that bronchial gland duct ectasia is a common histological feature of severe asthma, and that interstitial emphysema may be consequent on rupture of these dilated gland ducts.

Asthma↗
PubMed1989

The cardiovascular effects of inhaled fenoterol alone and during treatment with oral theophylline.

We have investigated whether oral theophylline potentiated the cardiovascular effects of fenoterol administered by metered-dose inhaler. Eight healthy subjects were investigated on four occasions. On successive days (1 and 2), the subjects were given doses of 400 micrograms, 600 micrograms, and 800 micrograms of fenoterol at 15-minute intervals (total dose, 1.8 mg) or matched placebo. Systolic time intervals, blood pressure, and the ECG were recorded at baseline and five minutes after each inhalation. Thereafter, the subjects were treated with slow-release theophylline for eight days. On days 9 and 10, the procedures on days 1 and 2 were repeated. The order of treatment was applied according to a crossover Latin-square design. The effects after theophylline alone were no different from placebo. Theophylline potentiated those hemodynamic effects of fenoterol due to enhanced cardiac sympathetic tone (mean +/- SE) as measured by a decrease in Q-S2I (-41.6 +/- 7.6 ms vs -27.3 +/- 5.9 ms; p = 0.0004), an increase in systolic BP (23.5 +/- 2.8 mm Hg vs 9.0 +/- 5.3 mm Hg; p = 0.00001), and an increase in heart rate (15.8 +/- 1.6 bpm vs 9.1 +/- 3.7 bpm; p = 0.0013). The responses mediated by beta 2-adrenergic receptor stimulation, namely, a decrease in PEP and diastolic BP, were not potentiated. Although fenoterol prolonged the Q-Tc interval and decreased T-wave amplitude, these effects were not potentiated by theophylline. Oral theophylline potentiates the positively inotropic and chronotropic effects of fenoterol.

Administration, Inhalation↗
PubMed1988

The blocked bed: a prospective study.

A prospective study of all patients (15 years and over) admitted to acute medical beds at a medium sized general hospital was carried out. For each patient, demogaphic data, day and time of admission, consultant in charge and the main reason for admission, were recorded. The patients hospital stay was analysed to determine the extent of the bed blocking problem. Sixty-two percent of total days stay required acute medical intervention, 32% was spent receiving nursing care only, 4% paramedical activities and 3% awaiting outside medical consultations. The three major factors found to influence total days stay were age, living situation and reason for admission. Patients over 75 years, living alone or who were admitted with a cerebrovascular accident/for nursing care were identified as bed blockers. An age related geriatric service may speed up the recovery of these patients and result in a more appropriate use of hospital resources.

Acute Disease↗