Luana Pillon

Asymmetry of the total body water prediction bias using the impedance index

Our purpose was to prove on a geometric basis that the bias of total body water (TBW) prediction equations based on the impedance index is far greater in fluid overloading than in dehydration. We used formal evaluation of conventional bioimpedance regression equations in both normal and abnormal body fluid status. We plotted the hyperboloid function generated from a standard prediction equation for the TBW over the resistance-reactance (RXc) plane containing the bivariate tolerance intervals (ellipses) of the healthy population. The equation estimated 35 L TBW for the average man (both sexes) of 170 cm height. Leaving the center of the tolerance ellipses, over which the function was relatively flat, the predicted TBW rapidly increased to absurd values for the shorter vectors, indicating fluid overloading (e.g., > 100 L for R < 170 ohm). Migration of the longer impedance vectors beyond the upper pole of 95% tolerance ellipse, which is in the dehydration region, produced less biased estimates of TBW (e.g., < 22 L for the extreme R values > 850 ohm). Different formulas produced TBW prediction bias of the same order. Due to the hyperbolic shape, functions of the impedance index are critically dependent on the region of the RXc plane where they are calculated and they produce misleading results in patients with fluid overload.

A Decision Analysis Comparing Three Dosage Regimens of Subcutaneous Epoetin in Continuous Ambulatory Peritoneal Dialysis

SummaryEpoetin (recombinant human erythropoietin: EPO) therapy adds a significant cost to the management of end-stage renal disease, the majority of the extra expense being attributable to its acquisition cost. In a Japanese multicentre, randomised, prospective study, a significant dose-dependent response was documented with epoetin given subcutaneously (SC) once a week or once every 2 weeks to patients receiving continuous ambulatory peritoneal dialysis. Three different dosages were studied over 5 months in patients with a haematocrit (Hct) of 0,28 or less. namely 6000U (107 U/kg), 9000U ( 167 U/kg) and 12 000U (211 U/kg). Epoetin was given weekly for the first 2 months until the target Hcl value of 0.33 was reached.The rates of response were 81. 85 and 100% with the 6000U, 9000U and 12 000U regimens, respectively. Subsequently responders were maintained at the target Hct for an additional 3 months, with the administration frequency eventually being reduced to fortnightly or 4-weekly. Patients in the epoetin 6000U and 9000U groups who did not respond after 2 months’ treatment underwent induction and maintenance with the 12 000U regimen.During the maintenance phase, patients receiving the epoetin 6000U and 9000U dosages required weekly (54 and 64%, respectively) or fortnightly (46 and 36%, respectively) injections. Patients receiving the 12 000U regimen were found to require weekly (9%), fortnightly (73%) or 4-weekly (18%) injections.Using these data, we performed a decision analysis that quantitatively incorporated the probability of attaining and maintaining target Hct levels in all patients (i.e. the effectiveness of epoetin), and direct costs as a function of both cumulative doses and injections required in all 3 strategies over 5 months.Decision analysis indicated that the most cost-effective SC epoetin strategy in patients undergoing peritoneal dialysis is epoetin 6000U weekly for 2 months, followed by maintaining the target Hct with weekly or 2-weekly epoetin 6000U for the next 3 months. Nonresponders should restart epoetin therapy using the 12000U strategy. The 9000U and 12 000U strategies were associated with similar costs, because the economic advantages associated with the lower administration frequency of the 9000U regimen compared with the 6000U regimen were offset by its higher cumulative acquisition cost. In other words, decision analysis indicated that the most cost-effective strategy was to use the lowest effective dose, reserving the highest dosage for patients who do not respond after 2 months.The superiority of this strategy was confirmed by a sensitivity analysis performed on the cost of drug administration, which was varied from zero to

Bioequivalence of deflazacort and prednisone in the treatment of idiopathic nephrotic syndrome: A pilot study

US60 per dose. In addition, consistent results were obtained when the analysis was extended to cover a 1-year treatment period with all 3 strategies.

Prediction of the Third and Fourth Heart Sounds by Doppler Echocardiography.

Abstract To establish the bioequivalence of deflazacort and prednisone in the treatment of idiopathic nephrotic syndrome, we compared the effects of the two drugs on both glomerular and tubular functions in 10 adult patients with proteinuria >3.5 gm/day (range, 3.6 to 14 gm/day). A crossover, randomized clinical trial was conducted over a 3-month period (1-week induction with three 500-mg IV methylprednisolone bolus doses, followed by 5 weeks of treatment with 30 mg/day of deflazacort and 5 weeks with 25 mg/day of prednisone). The treatment sequence, deflazacort-prednisone or prednisone-deflazacort, was randomly assigned. After the crossover period, all patients were treated with 30 mg/day of deflazacort for 3 to 6 months, eventually tapering (30 mg every other day for 2 weeks, then 15 mg every other day for 2 weeks) after remission of proteinuria. At the end of the crossover period, a significantly higher rate (80% vs 20%) of partial remission of nephrotic syndrome (ie, proteinuria

A new method for monitoring body fluid variation by bioimpedance analysis: The RXc graph

Doppler echocardiographic variables were sought for predicting the third and fourth heart sounds, as documented by phonocardiography. Phonocardiographic recordings of gallop sounds and Doppler echocardiographic investigations of mitral inflow and pulmonary venous flow were evaluated in 85 subjects by discriminant and multiple regression analysis. Of 85 subjects 47% had a third sound and 72% a fourth sound, evaluated by phonocardiography. A correct identification of 85% subjects with, and 82% without, the third sound was possible by discriminant analysis using the ratio of peak early diastolic to peak atrial mitral flow velocity (FV), the interval from peak ECG R wave to peak early diastolic mitral FV, and the early diastolic mitral FV deceleration time. At the observed prevalence of the third heart sound (47%), the predictive positive value was 81% and the predictive negative value was 86%. A correct identification of 72% of the subjects with, and 83% without, a fourth sound was possible by discriminant analysis using the ratio of peak early diastolic to peak atrial mitral FV, the interval between the end of atrial mitral FV and the peak ECG R wave, and the duration of pulmonary venous reverse FV at atrial systole. At the observed prevalence of the fourth heart sound (72%) the predictive positive value was 92% and the predictive negative value was 54%. By multiple regression analysis, up to 50% of the amplitude of both gallop sounds was predictable by a combination of Doppler echocardiographic variables.