Browsing by Author "Schall, R."

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    A comparison of approximate confidence interval methods for the difference between two independent binomial proportions
    (2002) Nel, M.; Schall, R.; Nel, D.G.; Joubert, G.; Nel, M.; Schall, R.; Nel, D.G.; Joubert, G.
    Conventional methods to determine confidence intervals for the difference between two independent binomial proportions p1 and p2 are prone to violations of the definition interval [-1; 1] for p1-p2 and may have very poor coverage properties. In this paper several less known methods are described. A simulation study was done to compare the different confidence interval methods with respect to length, coverage, zero width interval and violation of the definition interval. The best methods were found to be Mee's and Miettinen and Nurminen's method. These methods, however, are computer intensive. The Jeffreys-Perks and Score interval methods seem to be the best of the more easily calculable methods to use in most practical situations.
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    Clinical experience with Repotin, a locally produced recombinant human erythropoietin, in the treatment of anaemia of chronic renal failure in South Africa
    (Health & Medical Publishing Group, 1996) Swanepoel, C. R.; Moosa, M. R.; Rowland, G. F.; Meyers, A. M.; Botha, B. P.; Smart, A. J.; Goodman, R.; Schall, R.; Keogh, H. J.; Merrifield, E. H.
    Objective. To evaluate the efficacy and safety of Repotin, a locally produced recombinant human erythropoietin (rHuEPO), in the treatment of the anaemia of chronic renal failure (ACRF). Design. The study consisted of two multicentre non-randomised open stages. Setting. Renal units at several teaching hospitals in South Africa. Participants. Haemodialysis patients with haemoglobin (Hb) levels less than 8.0 g/dl were recruited. The first stage examined 26 patients during 12-week period in which the dose of intravenous rHuEPO was adjusted according to haematological response. In the second stage 27 patients were stabilised with intravenous rHuEPO and then maintained at a Hb level above 8.0 g/dl by subcutaneous administration for up to 1 year. Outcome measures. In both stages, outcome was measured by clinical examination, blood pressure, full haematological parameters and blood chemistry. Results. In stage 1, all patients responded to therapy with a statistically significant increase in Hb from geometric means of 6.28 g/dl to 8.50 g/dl (geometric SDs of 1.17 and 1.20 respectively). The doses used ranged from 25 IU to 125 IU/kg (average 47.1). In the second stage, Hb levels reached a mean of 8.06 g/dl (SD 0.9) and were maintained at target range with an average dose of 55.5 IU/kg three times a week. Apart from changes in serum iron, ferritin (associated with increased haematopoiesis) and potassium, there were no significant alterations in blood chemistry. The incidence of adverse events reported during the 12-month second stage was no greater than that reported for other forms of rHuEPO therapy. Conclusion. Repotin is a safe and effective rHuEPO preparation for the treatment of ACRF.
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    Effect of 1% and 2% propofol on blood lipids during long-term sedation
    (Health & Medical Publishing Group, 2002) Coetzee, A.; Blaine, E. M.; Labadarios, D.; Schall, R.; Haus, M.
    Objectives. To compare the effects of 1% and 2% propofol on the maximum and average lipid levels, the relative frequency of hyperlipidaemia, the propofol dose required to achieve an equivalent degree of sedation, the pharmacodynamie effects at the required infusion rates, and the effect on respiratory function. Design. Open, randomised, parallel group, multicentre comparison study. Setting. Intensive care units (ICUs) at the Faculty of Medicine, University of Stellenbosch and at Vergelen Medicity, Somerset West. Subjects. Patients who were artificially ventilated for at least 72 hours in the ICUs and who required sedation or analgesia. Outcome measures. Continuous intravenous infusion of 1% or 2% propofol to provide an administration rate in the range of 1 - 4 mg/kg/h. The initial infusion rate was about 2 mg/kg/h, adjusted to achieve the appropriate level of sedation. Results and conclusions. Seventy-five patients were enrolled in the study, of which 72 were evaluable for safety analysis and 58 were evaluable for efficacy analysis. The total daily dose of propofol (ml/day) in the 2% propofol group was about 60% of that in the 1% propofol group, indicating that the lipid load in the 2% propofol group had only slightly more than half the lipid load in the 1% propofol group. Thirteen of 27 patients (48%) int 2% propofol group had abnormally high triglyceride levels compared with 19 of 31 patients (61%) in the 1% propofol group. Similarly, 1 of 22 patients (4%) in the 2% propofol group had lipaemia compared with 4 of 30 patients (13%) in the 1% propofol group. Abnormal cholesterollevels, alveolar-arterial oxygen tension gradient and daily percentage of time with desired sedation were comparable between the two groups. The observed incidence of raised plasma triglyceride concentrations, and of lipaemia, was lower in the 2% propofol group than in the 1% propofol group, although the differences were not statistically significant. The 2% formulation of propofol appears to be as effective and at least as safe as 1% propofol.