SUNScholar - Browsing by Author "Stewart, R. I."

Browsing by Author "Stewart, R. I."

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The adult respiratory distress syndrome in association with diabetic keto-acidosis: A case report
(Health & Medical Publishing Group, 1987-04) Botha, J.; Van Niekerk, D. J. T.; Rossouw, D. J.; Stewart, R. I.
ENGLISH ABSTRACT: A 41-year-old man presented in stupor, with ketoacidosis and acute severe respiratory failure. He had a history of alcohol abuse and had been on insulin therapy for diabetes secondary to chronic pancreatitis for 11 years. The condition was rapidly progressive and the patient died within 5 hours of presentation of profound hypoxia and hypotension despite aggressive therapy. Autopsy confirmed the clinical diagnosis of 'shock lung'. None of the more commonly associated precipitating factors of adult respiratory distress syndrome could be detected clinically or at autopsy and the pathogenesis of the condition remains elusive.
Assessment of the 2,4 km run as a predictor of aerobic capacity
(Health & Medical Publishing Group, 1990-09) Burger, S. C.; Bertram, S. R.; Stewart, R. I.
ENGLISH ABSTRACT: Since the 2,4 km run time test is routinely used in military training programmes as an indicator of aerobic capacity and its possible improvement, an atemtp was made to: (i) establish a regression equation of VO2(max) v. 2,4 km run time in a group of 20 young military volunteers; and (ii) determine whether this equation could be used to predict VO2(max) reliably from the 2,4 km time obtained from another group. Before and after training, VO2(max) was measured in all subjects using a treadmill test, and 2,4 km run time was determined in the field. Linear regression equations using the 2,4 km run time as the independent variable accounted for 76-92% of the variance in VO2(max), while the standard error of the estimate varied from 2,24-2,91 ml/kg/min. In the second test group, the directly measured VO2(max) was 59,89 ± 0,99 ml/kg/min, while the mean values estimated from the regression equation of the first group was 59,61 ± 1,16 ml/kg/min (P< 0.001). It was concluded that, in the population studied, the 2,4 km run time in the field reliably predicts VO2(max) measured during treadmill exercise in the laboratory.
Exercise in patients with chronic obstructive pulmonary disease
(Health & Medical Publishing Group, 1985) Stewart, R. I.
Patients with chronic obstructive pulmonary disease (COPD) may incur exercise limitation by any one or combination of disturbances in breathing mechanics, oxygen transport, respiratory muscle metabolism or respiratory regulation and sensation. In spite of the increased ventilation demand/capacity ratio in these patients, the relationship between breathing mechanics, respiratory muscle fatique, the adequacy of alveolar ventilation and the development of exertional dyspnoea is neither clearly defined nor predictable from data obtained with the patient at rest. The issue of oxygen transport during exercise has been complicated by confusion between arterial hypoxia and inadequate volume of oxygen transported to the tissues, which frequently may differ qualitatively and quantitatively. The cardiac output response to exercise in patients with COPD is therefore critical in determining oxygen transport. This response is also impossible to predict from resting lung mechanics, pulmonary arterial blood pressure, arterial oxygen testing, which includes measurement of all the variables mentioned, it is impossible to define clearly the cause of exercise-induced symptoms in patients with COPD. Exercise training with and without supplemental oxygen has been shown to improve exercise tolerance in these patients, but the precise mechanism of this improvement remains obscure.
Filling pressures of the heart during anaesthesia
(Health & Medical Publishing Group, 1985) Coetzee, A.; Stewart, R. I.; Hattingh, P.
The validity of extrapolating central venous pressure (CVP) to left ventricular (LV) filling pressure as gauged from the pulmonary artery wedge pressure (PAWP) was investigated in 9 subjects undergoing lung resection. Correlations existed between CVP and PAWP before, during and after surgery, and between changes in CVP and PAWP during surgery. There was, however, a wide scattering of the data around the regression lines, and an inability of the CVP and changes therein to predict the actual and directional change in PAWP in specific individuals. Caution is therefore advised in assessing the LV filling pressure from the CVP in patients undergoing lung resection during any phase of the peri-operative period.
Human chorionic gonadotrophin and weight loss : a double-blind, placebo-controlled trial
(Health & Medical Publishing Group, 1990) Bosch, B.; Venter, I.; Stewart, R. I.; Bertram, S. R.
Low-dose human chorionic gonadotrophin (HCG) combined with a severe diet remains a popular treatment for obesity, despite equivocal evidence of its effectiveness. In a double-blind, placebo-controlled study, the effects of HCG on weight loss were compared with placebo injections. Forty obese women (body mass index > 30 kg/m2) were placed on the same diet supplying 5000 kJ per day and received daily intramuscular injections of saline or HCG, 6 days a week for 6 weeks. A psychological profile, hunger level, body circumferences, a fasting blood sample and food records were obtained at the start and end of the study, while body weight was measured weekly. Subjects receiving HCG injections showed no advantages over those on placebo in respect of any of the variables recorded. Furthermore, weight loss on our diet was similar to that on severely restricted intake. We conclude that there is no rationale for the use of HCG injections in the treatment of obesity.
Die invloed van oefening-geinduseerde brongokonstriksie op georganiseerde sportdeelname
(Health & Medical Publishing Group, 1990) Terblanche, E.; Stewart, R. I.
Approximately 70-80% of all asthma sufferers develop acute airway obstruction with exercise, while at least 7% of children in the general population develop exercise-induced bronchoconstriction. The purpose of this study was: (i) to determine whether children in the Cape Peninsula who suffer from asthma and/or exercise-induced bronchoconstriction are as inactive and uninvolved in sport as asthmatic children in the USA; and (ii) whether this uninvolvement is a direct result of their susceptibility to exercise-induced bronchoconstriction. An in-depth study was done on the intensity, frequency and level of participation in sport by children with asthma and/or exercise-induced bronchoconstriction compared with a control group of healthy children without a history of asthma or exercise-induced bronchoconstriction. Children with asthma and/or exercise-induced bronchoconstriction generally maintained a similar level of sport participation as healthy children, and only children with serious asthma or exercise-induced bronchoconstriction experienced limitations with regard to physical activity. It was found that, in contrast to children in the USA, non-participation in sport could not be explained by asthma and/or exercise-induced bronchoconstriction.
'n Nie-indringende benadering tot pulmonere hemodinamika
(HMPG, 1981-08) Lewis, C. M.; Stewart, R. I.
Currently available investigative methods employed in the evaluation of the pulmonary circulation involve cardiac catheterization and, in respect of exercise determinations, only supine data have been recorded. Consequent upon a 3-year study of pulmonary haemodynamics and gas exchange at rest and during exercise on the treadmill in patients with chronic hypoxaemic lung disease, correlations have been established which accurately characterize the venous admixture (Q(VA)/Q(t), the quantitative expression of hypoxaemia), cardiac output and pulmonary artery pressure (PA), permitting the prediction of these variables in the erect posture. The employment of fibre-optic oximetry obviates the need for arterial cannulation. The relevant regression formulae are as follows: Q(VA/Q(t) = 8,85 x In (Hb (100 - SaO2) x heart rate/VO2 - 3,66 (r = 0.97; SEE = 2,43) PA(m) (resting) = 0,4516 (Q(VA/Q(t)) + 8,2 (r = 0,90; SEE = 2,7) PA(m) (exercise) = 1,453 (Q(VA)/Q(t)) + 3,8 (r = 0,96; SEE = 4,0) Cardiac output may be derived directly from VO2 and the known components of Q(VA)/Q(t), and total pulmonary vascular resistance in turn from Qt and PAm. Direct comparison of the predicted values derived by this means with actual determinations yielded no systematic differences. The clinical application of these principles ensures reliable estimates of haemodynamic variables, without resort to invasive techniques, during free movement and graded exercise testing.
The prevalence of exercise-induced broncho-constriction in Cape Town schoolchildren
(Health & Medical Publishing Group, 1990) Terblanche, E.; Stewart, R. I.
An attempt was made to determine: (i) the prevalence of exercise-induced bronchoconstriction among white and coloured schoolchildren in Cape Town; and (ii) the validity of an exercise test for the diagnosis of asthma in the general population. Children (698 white and 494 coloured) were randomly drawn from schools in the northern suburbs of Cape Town. Each child participated in a standard 6-minute exercise test and spirometric measurements were taken before and 10 minutes after exercise with a portable spirometer. The diagnosis of asthma was based on a questionnaire and personal questioning and included those children who, in the past or at present, suffered episodic or continuous airflow obstruction, which was responsive to a bronchodilator. The criterion for the diagnosis of exercise-induced bronchoconstriction was a 10% decline in forced expiratory volume in 1 second after exercise. The prevalence of exercise-induced bronchoconstriction was significantly higher among white children (5,87%) than coloured children (4.05%). The sensitivity of the exercise test was 0.31 and the specificity 0.97. In contrast to the results of hospital-based studies, the negative predictive value of an exercise test (95%) was found to be greater than the positive predictive value (46%). It is therefore concluded that exercise testing is not a useful screening test for epidemiological use; it is probably useful as a challenge test for detecting asthma in the individual patient when the likelihood of the disease is high.
The standard of spirometry in the RSA
(Health & Medical Publishing Group, 1991) Basson, E.; Stewart, R. I.
Standards for high-quality lung function testing have not yet been formally adopted in the RSA, despite the increase in the performance of spirometry. A study was undertaken to determine the standard of spirometry in clinical practice in this country. Forty-five spirometer users agreed to participate. Responses to a questionnaire, administered by personal interview, were graded according to the proportion of correct or appropriate answers: completely unsatisfactory < 33.3%; poor 33.3-66.6%; and satisfactory > 66.6%. Only 6 spirometers were regularly calibrated. Knowledge of international standards for spirometry, the basic working mechanism of the spirometer being used and calibration ranged from poor to completely unsatisfactory in most of the practices. Instructions to the patient for performing the manoeuvres were satisfactory, but evaluation of the result for acceptability, reproducibility, selection of the best test and diagnosis of a positive bronchodilator response were generally completely unsatisfactory. Only 18 practitioners knew the source of the reference values they used and 5 had proved their validity with a sample. Fourteen of the 45 practitioners were unable to make the correct diagnoses from two typical test results. Of the 45 practitioners, 40 were interested in a course in practical, clinical spirometry. In the light of the predominantly unsatisfactory results obtained in this study, we consider clinical spirometry to be an urgent priority for all levels of medical education.
Standardisation of spirometry
(Health & Medical Publishing Group, 1991) Stewart, R. I.; Basson, E.
The suggested technical specifications in this document apply to apparatus used by clipicians for the diagnosis of common respiratory diseases and are to be considered as the minimum acceptable standards. Specifications, features and practices which are desirable, but not obligatory, are also presented. It is accepted that a need exists for more sophisticated apparatus for specialised indications (e.g. for use in an academic institution for training or research, or for standardisation of other respiratory equipment). For sophisticated apparatus more stringent specifications a~ply, some of which can be found in the original documents.
Supravalvular aortic stenosis in the adult : a case presentation with unique associated features
(Health and Medical Publishing Group -- HMPG, 1981-05) Przybojewski, J. Z.; Stewart, R. I.; De Wet Lubbe, J. J.
A 42-year-old symptomatic woman with possible adult Williams's syndrome (mental retardation, 'elfin facies' and supravalvular aortic steosis (SVAS)) is documented. This patient displayed many unique features in addition to the severe SVAS (peak systolic gradient 96 mmHg): there was an associated persistent left superior vena cava draining into the coronary sinus, mitral valve prolapse (Barlow's syndrome) and complete right bundle-branch block on ECG. Peripheral pulmonary artery stenosis was absent. M-mode echocardiography in the adult with SVAS is described for the first time in the literature, as is the use of the 60° cross-sectional scan. Both these non-invasive procedures proved of value in the diagnosis. The degree of subendocardial ischaemia, as determined by the 'endocardial viability ratio', was calculated and the possible mechanisms producing angina pectoris with 'coronary artery hypertension' in this condition are discussed. The literature on associated mitral valve abnormalities in SVAS is reviewed. A successful surgical result was obtained; the various forms of operation are outlined.
Ventilation during steady-state exercise in patients with chronic obstructive pulmonary disease : a preliminary study
(Health & Medical Publishing Group, 1985) Stewart, R. I.; Lewis, C. M.
In this preliminary study 20 patients with chronic obstructive pulmonary disease (COPD) walked on the treadmill until symptoms limited further exercise. When minute volume exceeded 60% of the predicted maximum breathing capacity the arterial carbon dioxide partial pressure was frequently low, thus indicating hyperventilation; the arterial oxygen partial pressure also declined on exercise. In only 2 patients was there alveolar hypoventilation. Although other factors may be operative, the hyperventilation in some patients with COPD may be induced by an exertional decline in alveolar oxygen partial pressure. In 4 patients the exercise tidal volume exceeded the resting inspiratory capacity, indicating a decline in functional residual capacity and increased work of breathing. It is concluded that there is a need further to assess patients with COPD in respect of the association between exertional dyspnoea, alveolar ventilation and lung mechanics.
Weight loss in obese women - exercise v. dietary education
(Health & Medical Publishing Group, 1990) Bertram, S. R.; Venter, I.; Stewart, R. I.
It was postulated that a nutrition-education programme was as effective an adjunct to a diet-based weight-loss programme as an exercise regimen. Forty-five obese female volunteers were placed on the same 5000 kJ diet and were then assigned to each of three therapy groups: (i) an exercise group, involving three 1-hour exercise sessions per week (15 women); (ii) a lecture group involving a weekly 1-hour group lecture session (15); and (iii) a control group (15) who received only the diet and no activity. Weight loss, body fat loss (%) and daily energy intake reductions were equally reduced in the subjects in all three groups who completed the programme. There was, however, a significantly higher dropout rate in the control group. Taking this into account, the weight loss in the two test groups was similar and greater than that of the control group. We conclude that, in the short term, dietary education was as effective as exercise in promoting dietary compliance and weight loss.

Browsing by Author "Stewart, R. I."

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