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Biomedical subjects

G J Canny

Publications and source records attributed to G J Canny.

51 records · Page 3Linked to original sources
PubMed1987

Pharmacokinetics of inhaled salbutamol in patients with cystic fibrosis versus healthy young adults.

We studied the disposition of inhaled salbutamol in adolescents with cystic fibrosis (CF) and compared it with the pharmacokinetics of the drug given by the intravenous and inhaled routes in healthy adults. After inhalation of salbutamol, CF patients had a significantly larger area under the concentration-time curve derived from amounts of drug in the systemic circulation. The differences in serum concentration of salbutamol were not reflected in differences in change of heart rate. We conclude that the rate and extent of pulmonary absorption of inhaled salbutamol in patients with CF differ from those in healthy adults.

Administration, Inhalation↗
PubMed1987

Evaluation of a sustained-release theophylline product in children with asthma.

The purpose of this study was to determine the dose requirements and dose interval of a sustained-release theophylline sprinkle preparation (Somophyllin-12) necessary to maintain therapeutic serum theophylline concentrations in children with asthma. Eighteen patients aged 3-7 years (subgroup 1) and 21 patients aged 8-12 years (subgroup 2), who had been on continuous theophylline therapy with Somophyllin-12, completed the study. Prior to entry into the study, each patient's dosage of Somophyllin-12 was titrated to achieve predose and peak (4-hour postdose) theophylline levels in the therapeutic range (8-20 mg/L). The patients subsequently had predose and peak serum theophylline levels determined at baseline (week 0) and at weeks 2 and 4 of the study. The majority of children maintained theophylline levels in the therapeutic range throughout the 4-week trial, and t-tests showed no significant change from baseline in mean values of peak, trough, or peak-trough theophylline differences in either patient subgroup at weeks 2 and 4. Nevertheless, some individual patients had considerable variation from baseline in peak and trough theophylline levels at follow-up visits. Dosage requirements standardized for weight were significantly higher in patients in subgroup 1 than in subgroup 2 (21.3 +/- 4.5 mg/kg per day versus 17.5 +/- 4.7 mg/kg per day; p less than 0.05). The majority of the patients required 12-hourly administration of Somophyllin-12, but seven of 39 patients required 8-hour dosing.(ABSTRACT TRUNCATED AT 250 WORDS)

Asthma↗
PubMed1986

Effects of nutritional status on exercise performance in advanced cystic fibrosis.

Initial evaluation of 22 patients with cystic fibrosis (CF) on entry into a trial of home oxygen therapy was used to elucidate the possible effects of poor nutritional status on exercise performance in CF. The patients had advanced lung disease (mean FEV1, 36 percent predicted) and all had a stable resting PaO2 less than or equal to 65 mm Hg. Nutritional status was determined by calculating weight as a percentage of ideal for height (Wt/Ht) for each subject. Exercise testing consisted of a progressive exercise test on a cycle ergometer to measure maximum work capacity (Wmax), and a steady state test at 50 percent of baseline Wmax. During the steady state test, cardiac output (Q) and stroke volume (SV) were computed by the indirect Fick (CO2) method. Wmax, SV, Q and lung function results are expressed as percent predicted. Mean (+/- SD) Wmax was 58 +/- 15 percent predicted. Wmax correlated with both FEV1 and Wt/Ht, but FEV1 and Wt/Ht were not related. During steady state exercise, 12 of 22 patients had a SV less than 80 percent predicted. SV correlated with Wt/Ht, but not with lung function. Thirteen of the 22 patients had a Wt/Ht less than or equal to 90 percent and were considered malnourished. When compared with the well-nourished patients (Wt/Ht greater than 90%), these malnourished subjects had significantly lower mean values for Wmax%, SV% and Q% predicted, but not for lung function parameters. We conclude that: in patients with CF and advanced lung disease, nutritional status plays a significant role in determining exercise capacity; lower exercise tolerance of malnourished patients is an independent effect, as nutritional status and lung function were not related; and malnourished patients with CF have an altered cardiac performance on exercise testing which is due to a reduced SV rather than an impaired heart rate response.

Adolescent↗
PubMed1986

Methacholine inhalational challenge in the evaluation of chronic cough in children.

The medical records of 58 children (age range, 7 to 16 years) who presented with chronic cough were retrospectively analyzed to determine the value of methacholine (MCH) bronchial challenge in reaching a specific diagnosis. Baseline lung function tests were normal in all subjects, apart from an elevated residual volume/total lung capacity ratio (RV/TLC) in 11 patients, and a reduced midexpiratory flow rate (FEF25-75) in five of these patients. Thirty-one patients had a positive response to MCH, but these patients could not be identified on the basis of clinical criteria or spirometric parameters. MCH-positive patients did have a significantly higher RV/TLC than did MCH-negative patients. Twenty-seven of the 31 MCH-positive patients responded to a trial of bronchodilator therapy (albuterol/theophylline), confirming the diagnosis of cough variant asthma in these patients. We conclude that children with chronic cough should be considered for methacholine challenge in order to identify patients who are likely to benefit from specific bronchodilator therapy.

Adolescent↗
PubMed1985

Fatal pulmonary hypertension following renal transplantation.

We present a case of fatal pulmonary hypertension occurring in a child several years following renal transplantation for membranoproliferative glomerulonephritis. Premortem investigations failed to reveal a cause for the pulmonary hypertension. Histological features in the lung at autopsy were consistent with a diagnosis of PVOD. The possible common pathogenesis of these seemingly unrelated disorders is discussed.

Adolescent↗
PubMed1984

Radionuclide assessment of cardiac performance in cystic fibrosis. Reproducibility and effect of theophylline on cardiac function.

A study was designed to evaluate the reproducibility of right and left ventricular ejection fraction measurements (RVEF, LVEF) by equilibrium radionuclide angiography in cystic fibrosis (CF) and to determine the effect of the acute administration of aminophylline on RVEF and LVEF in this disease. Both RVEF and LVEF were measured at rest and during incremental supine bicycle exercise by equilibrium radionuclide angiography in 18 patients with CF. In 9 of these patients, radionuclide studies were repeated after an infusion of aminophylline (9 mg/kg), whereas the remaining patients had radionuclide studies repeated after a placebo infusion. No significant increase in mean RVEF or LVEF values either at rest or at peak exercise was seen after aminophylline infusion. In the patients who underwent sequential radionuclide studies without intervening active drug intervention, the mean (+/- standard deviation) variability in RVEF and LVEF measurements between the 2 studies was 2.6 +/- 2% and 3.6 +/- 2.9%, respectively. We conclude that (1) equilibrium radionuclide angiography is a reasonably reproducible technique for serial assessment of biventricular function at rest and during exercise in CF, and that (2) the acute administration of aminophylline does not augment cardiac function either at rest or during exercise in this disease.

Adolescent↗
PubMedDate not supplied

Multiple factors limit exercise capacity in cystic fibrosis.

Exercise testing was performed in 50 patients with cystic fibrosis to determine whether hemodynamic factors limit exercise capacity in the disease. Prior to exercise testing, lung function and blood gas values were measured. Nutritional status was determined by calculating a weight for height (Wt for Ht) ratio for each subject. A progressive exercise test was used to determine maximum work capacity (Wmax). Cardiac output (Q) (indirect Fick method), and stroke volume (SV) were computed during steady-state exercise at 50% Wmax in 21 of 50 patients. Wmax, SV, Q, and lung function results are expressed as per cent predicted. The mean (+/- SD) Wmax was 75 +/- 23%. Multiple regression analysis showed that maximum voluntary ventilation, resting PaO2, and Wt for Ht accounted for 84% of the variance in Wmax. Although some patients had a reduced SV (mean = 96%) during steady-state exercise, all patients achieved a normal cardiac output (mean = 115%). SV correlated with resting PaO2 but not with lung function. We conclude that exercise capacity in cystic fibrosis is influenced by lung function, nutritional status, and resting hypoxemia, but not by cardiac function; the SV limitation noted in some patients may be due to increased pulmonary vascular resistance related to hypoxemia.

Adolescent↗
PubMedDate not supplied

Forced vital capacity and maximal respiratory pressures in patients with mild and moderate scoliosis.

Lung function and maximal respiratory pressures of 24 adolescent females with mild-to-moderate idiopathic scoliosis (spinal curvature 10-60 degrees) were determined and compared with 38 age- and sex-matched controls. Twelve patients with moderate scoliosis (Cobb angle 35-60 degrees) had significantly reduced mean values for FVC (% predicted) and maximal inspiratory pressure (MIP), as compared to the controls. Twelve patients with mild scoliosis (Cobb angle less than 35 degrees) had normal mean values for FVC and maximal respiratory pressures, but five individual patients had FVC values less than 80% predicted. All but one of the patients with mild scoliosis had normal MIP values. FVC (% predicted) was significantly correlated with the degree of spinal curvature (r = -0.466; P less than 0.05) but was not related to MIP. These results indicate that reduced FVC values do occur in patients with mild-to-moderate idiopathic scoliosis and suggest that these low FVC values can be attributed to the rib cage deformity rather than to an inability to generate adequate inspiratory pressures.

Adolescent↗
PubMedDate not supplied

Exercise response and rehabilitation in cystic fibrosis.

Exercise testing can be performed safely in cystic fibrosis patients, and provides a simple and reproducible index of overall health in the disease. A wide variability in exercise capacity of cystic fibrosis patients is found, but, in general, exercise is limited by the degree of lung disease and, to a lesser extent, by compromised nutritional status. Based on the results of exercise tests, patients can then be supplied with individualised exercise prescriptions. Exercise training can be expected to improve the exercise capacity of the majority of cystic fibrosis patients, but pulmonary function generally remains unchanged. Whether exercise rehabilitation will improve the long term prognosis for patients with cystic fibrosis is currently not known.

Adolescent↗