Relationship between segmental and whole-body phase angle in peritoneal dialysis patients.

The relation between the right-side (RS) electrical impedance phase angle (PA) and segmental PA in five configurations at 50 kHz was analyzed in 23 peritoneal dialysis male patients before complete drainage of the abdominal cavity. The impedance vector (Z/H) components were standardized by the height H of the subjects (R/H and Xc/H). BIVA software was used to analyze the individual RS vector. The Pearson correlation was used to analyze the correlation between RS and segmental configurations. Student's t test and Hotelling's T2 test were used to analyze the separation of groups obtained by BIVA. The highest significant Pearson correlation was between RS and right leg total (RLEGT) in a longitudinal direction (r=0.925, P<0.001). We obtained a significant difference (P<0.05) in R/H, Xc/H (for RS and RLEGT) using Hotelling's T2 test, and in PA using Student's t test. The transverse measurement in the leg (RTRLEG) showed the lowest correlation (r=0.261). In conclusion, we can obtain similar information through the phase angle, whether RS is measured or if we measure on RLEGT. The phase angle of the transverse measurements provides different information from the phase angle of the longitudinal measurements.

Thoracic versus whole body bioimpedance measurements: the relation to hydration status and hypertension in peritoneal dialysis patients.

The whole body bioimpedance technique is a highly promising non-invasive, reproducible, fast and inexpensive bed-side method for monitoring hydration status. Using segmental bioimpedance measurements, it is possible to obtain information about the fluid change in each body segment (Song, Lee, Kim and Kim 1999 Perit. Dial. Int. 19 386-90). In this pilot study we have measured 25 male patients (30-65 yr, BMI 20-32 kg m(-2)) undergoing continuous ambulatory peritoneal dialysis (CAPD). Tetrapolar impedance measurements were obtained using the right-side technique (whole body), and a segmental impedance method focused in the thorax region. Blood pressure (BP) measurements were taken manually with a sphygmomanometer. Patients were classified as either stable (group 0) or unstable (group 1) using clinical parameters of overall cardiovascular risk. The Mahalanobis distance (dM2) was calculated for the mean blood pressure (BP(mean)), and the impedance parameter R normalized by body height H for the right-side (R(RS)/H) and the thorax segment (R(TH)/H). Differences between groups were significant (p < 0.0001) for R(TH)/H and for BP(mean), and less significant (p = 0.016) for R(RS)/H. Group 1 patients showed a small dM2 as compared with a reference patient (a critical patient with acute lung edema) with high BP(mean) and low values of R(TH)/H and R(RS)/H. Moreover, Group 0 patients showed a larger dM2 with respect to the reference patient, with lower BP(mean) and higher values of R(TH)/H and R(RS)/H. All patients classified as unstable by clinical assessment were correctly classified using R(TH)/H in conjunction with BP(mean) using dM2. Segmental-monofrequency non-invasive bioimpedance of the thoracic region could provide a simple, objective non-invasive method of support for facilitating the clinical assessment of CAPD patients.

[Guidelines on peritoneal dialysis and daily practice]. / Guías de diálisis peritoneal y la práctica diaria.

Adequate dialysis is defined as the quantity and the quality of the dialysis that is necessary for the patient to remain in good state, with no uremic symptoms, obtaining a longer survival with the best possible corrections of his uremia-related metabolic and systemic changes, and with the minimum possible morbidity in addition to a good quality of life. The good operation of a peritoneal dialysis schedule calls for a set of criteria and standards, as well as management clinical protocols according to which the healthcare team manages the dialysis technique and its complications, and uniforms the steps to be taken. Such protocols should be agreed to by the whole of team that enforces them, and should be submitted to a continuous update process based on the team's own experiences and also on the scientific literature. The results are periodically evaluated. Useful quality standards of clinical management, based on scientific evidence and on the opinions of expert nephrologists are needed with the aim to go in depth into specific aspects of the daily clinical action, by means of a rigorous and regular systematic review process that reflects all new advancements and technologies. The U.S. National Kidney Foundation (NKF) published in 1997 the Dialysis Outcome Quality Initiative (DOQI) which were the first action guidelines, with the aim to improve dialysis' quality and results. The objective of the clinical guidelines is to act as an updating method and to unify criteria by contributing scientific evidence.

Atrial natriuretic factor in patients on continuous ambulatory peritoneal dialysis.

The aim of this study was to compare the levels of the atrial natriuretic factor (ANF) and the renin system in patients on continuous ambulatory peritoneal dialysis (CAPD) with patients on chronic hemodialysis (HD). We studied three groups. The CAPD group comprised 10 patients (25-66 years); the HD group: 10 patients (35-69 years), before (pre-HD) and after (post-HD) a HD session. The control group comprised 10 subjects with normal renal function (29-65 years), matched for age, height, weight, and diastolic pressure with the CAPD group. Blood pressure (BP) and blood samples for plasma renin activity (PRA), plasma aldosterone (PA), and ANF were taken. The BP and levels of ANF, PRA and PA were: in the control group, 121 +/- 15/75 +/- 4 mmHg, 7.3 +/- 5.6 pmol/L, 1.1 +/- 0.8 ng/mL/hour, 0.4 +/- 0.3 nmol/L. In the CAPD group, 132 +/- 26/76 +/- 12 mmHg (NS), 8.3 +/- 3.5 pmol/L (NS), 5.6 +/- 4.4 ng/mL/hour (p < 0.001), 4.9 +/- 4.0 nmol/L (p < 0.001). In the pre-HD, 159 +/- 25/95 +/- 12 mmHg (p < 0.001), 16.0 +/- 8.5 pmol/L (p < 0.005), 11.99 +/- 9.0 ng/mL/hour (p < 0.001), 2.6 +/- 2.3 nmol/L (p < 0.001). In the post-HD, 145 +/- 29/84 +/- 15 mmHg (p < 0.05 vs CG), 13.4 +/- 6.9 pmol/L (p < 0.05 vs control), 14.9 +/- 10.3 ng/mL/hour (p < 0.001 vs control), 3.8 +/- 2.9 nmol/L (p < 0.001 vs control).(ABSTRACT TRUNCATED AT 250 WORDS)

Bioelectrical impedance vector analysis in haemodialysis patients: relation between oedema and mortality.

In this work, bioelectrical impedance vector analysis (BIVA) method is used in a sample of haemodialysis patients in stable (without oedema) and critical (hyperhydrated and malnutrition) states, in order to establish the relation between hyperhydration (oedema) and mortality. The measurements obtained were single frequency (50 kHz), tetrapolar (hand-foot) complex impedance measurements (vector components are: resistance R and reactance Xc). The impedance components were standardized by the height H of the subjects, (R/H and Xc/H) to obtain de impedance vector Z/H, that is represented in the RXc plot (abscise R/H, ordinate Xc/H). Measurements were performed on a sample of 74 patients (30 men and 44 women, 18-70 year, body mass index (BMI), 19-30 kg m(-2)) at the Saturnino Lora University Hospital in Santiago de Cuba. The 46 stable patients comprised 28 men and 18 women; the 28 critical patients 16 men and 12 women. The reference population consisted of 1196 healthy adult subjects living in Santiago de Cuba (689 men and 507 women, 18-70 year, BMI 19-30 kg m(-2)). We used the RXc plot with the BIVA method to characterize the reference population using the 50%, 75% and 95% tolerance ellipses. Student's t-test and Hotelling's T2-test were used to analyse the separation of groups obtained by means of clinical diagnosis and those obtained by BIVA. We obtained a significant difference (P < 0.05) in R/H, Xc/H and phase angle (PA) in men as in women between the location of Z/H vectors in the RXc graph and the separation made by the doctors between stable and critical patients. Critical (hyperhydrated) patients were located below the inferior pole of the 75% tolerance ellipse, whereas stable patients were within the tolerance ellipses. Some cases classified as stable by the clinic were classified as hyperhydrated by BIVA with 100% sensitivity and 48% specificity. In conclusion, the BIVA method could be used to classify patients by hydration state and to predict survival. Advantages of the method are its simplicity, objectivity and that it does not require the definition of patient dry weight.

[Influence of chronic renal failure and of its treatment on serum erythropoietin]. / Influencia de la insuficiencia renal crónica y de su tratamiento en la eritropoyetina sérica.

BACKGROUND: In order to know the influence of dialysis treatment in erythropoietin production, serum erythropoietin (Ep) has been studied in patients with anemia due to chronic renal failure (CRF). METHODS: Thirty six of them in hemodialysis (HD), 10 in continuous ambulatory peritoneal dialysis (CAPD) and 18 in predialysis stage (PD) and their results were compared to two control groups, including 72 healthy controls (HC) and the second one 89 iron deficiency anemia patients (ID). RESULTS: Patients had lower Hb and Ep levels than the other groups. Although Ep was higher in CAPD and PD. Ep levels were similar to HC values, and lower than ID levels. It could be demonstrated any correlation between Hb and Ep in CRF patients, however a negative exponential correlation was demonstrated in ID patients between Hb and Ep (r = -0.83; p less than 0.00001). In summary, Ep is higher in CAPD and in PD than in HD, but the levels are lower than they should be expected. CONCLUSIONS: These data confirm an Ep production failure in most of IRC patients and it seems likely that Ep treatment could be effective to treat the anemia of CRF.

Whole-body and thoracic bioimpedance measurement: hypertension and hyperhydration in hemodialysis patients.

Mono-frequency (50 kHz) and multi-frequency (3 kHz - 1 MHz) whole-body and thoracic segment bioimpedance measurement were doing before and after hemodialysis session in 20 patients. The patients were classified in hypertensive or non-hypertensive according to the mean blood pressure, BPmean. The relation between hyper-hydration in thorax segment through real part of impedance and mean blood pressure was analyzed. Also the bioelectrical impedance vector analysis method was used to analyze the displacement of Z/H vector in order to establish the relation with hyper-hydration (edema). Finally we made multi-frequency measurements with the objective to find a significative change in high and low frequency. We obtained a significant difference (P < 0.05) in impedance parameters before and after HD session. Some patients are located in hyper-hydration zone, below the inferior pole of the 75% tolerance ellipse, whereas others patients were within the tolerance ellipses. The real part of the impedance in thorax region can identify over-hydrated patients with an increased risk for cardiovascular disease associate to hypertension. Multi-frequency bioimpedance measurement show an important change at low and high frequency and indicate that is possible to obtain more information about extra-cellular or intra-cellular fluid status, to find the relation between fluid loads, bioimpedance parameters, extra-cellular water, and blood pressure.

Pharmacokinetics of the combination of ticarcillin with clavulanic acid in renal insufficiency.

The pharmacokinetics of ticarcillin and clavulanic acid were studied by blood and urine assay methods in 25 patients divided into five groups with varying degrees of renal insufficiency i.e. mild, moderate and severe renal insufficiency, almost anuric patients and those requiring haemodialysis (groups A to E). A single dose of 5.2 g Timentin (5.0 g ticarcillin and 200 mg clavulanic acid) was administered intravenously by infusion over 30 min. The average elimination half-life (T1/2) of ticarcillin increased from 0.95 h in patients with creatinine clearance (Clcr) of 80 ml/min to 1.8, 4.4, 6.9 and 11.2 h respectively in mild, moderate and severe renal insufficiency and in almost anuric patients. The T1/2 values for clavulanic acid were 0.75, 0.9, 2.0, 2.5 and 4.8 h in the same groups. The area under concentration-time curve (AUC) for ticarcillin increased from 787 to 2839 mg/l/h and for clavulanic acid from 12.8 to 29 mg/l/h when group mean values from patients with mild and severe renal insufficiency were compared. The plasma clearance (Clpl) of clavulanic acid was in all groups greater than that of ticarcillin i.e. 166 and 100 ml/min vs. 79.2 and 25.0 ml/min when comparing mean values from groups with mild and severe renal insufficiency respectively. The plasma clearance ratio clavulanic acid/ticarcillin increased proportionally to the degree of renal insufficiency from a value of 1.5 in normal subjects to between 3.3 and 3.8 in more advanced cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Triglyceride-rich lipoprotein abnormalities in CAPD-treated patients.

In the present study intermediate-density lipoproteins (IDL) and very-low-density lipoproteins (VLDL) composition, structure, and mass were analysed in fasting uraemic patients on continuous ambulatory peritoneal dialysis (CAPD) (n = 12) and on haemodialysis (HD) (n = 15), and in 15 healthy volunteers. All the groups were matched for sex, age, and time on dialysis. Both groups of patients had elevated very-low-density lipoprotein levels, CAPD patients four and HD group three times that of control. We found a fourfold and a twofold increase in the concentration of IDL cholesterol in the CAPD and HD group respectively when they were compared with the control group. Both groups of patients present an increased VLDL mass. The CAPD group showed a four-fold increase in IDL mass compared with the control group, which indicated a preponderance of large size and suggested that defective IDL clearance was involved. The IDL composition of the CAPD patients was significantly different from that of the HD patients: a twofold increase in IDL mass was observed in the CAPD patients if compared with HD patients. We report new data concerning the metabolism of triglyceride-rich lipoproteins in CAPD treated patients, which confirm the adverse effect of CAPD on serum lipids.