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Biomedical subjects

G Virga

Publications and source records attributed to G Virga.

At least 19 recordsLinked to original sources
PubMed1999

Day-to-day variability of adequacy indexes in peritoneal dialysis.

BACKGROUND: The achievement of dialysis adequacy targets in peritoneal dialysis (PD) is assessed by the calculation of the Kt/V and creatinine clearance (C(Cr)) obtained by collecting dialysate and urine, usually two or three times a year. Prescription decisions are based on such adequacy assessments, regardless of any variability in the single measurements. The aim of our study was to assess the day-to-day variability of common dialysis adequacy parameters and to evaluate its impact on the adequacy indexes in PD. METHODS: Twenty-four patients (14 CAPD, 10 APD) at two centres were studied by means of a triple dialysate and urine collection for a period of 1 week. Variability in the findings for a given patient was expressed by the coefficient of variation (CV%) calculated for peritoneal (p), renal, and total (tot) adequacy parameters. The target Kt/V and C(Cr) values were recalculated on the basis of variability. RESULTS: Kt/V was less variable (CV 4.0 and 4.4% for peritoneal Kt/V (pKt/V) and total Kt/V (totKt/V) respectively) than C(Cr) (4.7 and 6.0% for peritoneal creatinine clearance (pC(Cr)) and total creatinine clearance (totC(Cr)) respectively) and proved to be a more reliable indicator of adequacy in terms of the CV. Both variability parameters became worse if renal clearance was added to peritoneal clearance. CV in APD proved to be no different from CAPD for all the parameters considered. In our centres dialysis adequacy target correction for variability provided safe values for weekly Kt/V (pKt/V=1.78-2.10 and totKt/V=1.82-2.15 target 1.7-2.0) and C(Cr)/1.73 (pC(Cr)=53.7-64.4 l and totC(Cr)=55.1-66.1 l; target 50-60 l). CONCLUSIONS: Evaluating the adequacy of PD by means of a single measurement should take into account the weekly variability as demonstrated by a triple dialysate and urine collection. Standard adequacy targets can be corrected to allow for variability. Thus one can obtain safe values for prescription decisions based on a single collection result.

Adult↗
PubMed1998

Continuous tidal peritoneal dialysis (CTPD) prescription and adequacy targets.

NKF-DOQI guidelines suggest a Kt/V value of 2.1 and a creatinine clearance (CRCL) value of 63 L/1.73 m2 of body surface area per week as minimum targets in continuous cycling peritoneal dialysis (CCPD). Those targets are obtained by adapting the CAPD guidelines. The aim of our study was to verify the possibility of reaching the suggested targets with continuous tidal peritoneal dialysis (CTPD) and to check target modification in this automated treatment. Eight anuric patients underwent four consecutive CTPD sessions with increasing total prescribed volumes (17 L, 22 L, 27 L, and 32 L; night 9 h; fill 2.2 L; tidal 75%, day 2 dwells). The Kt/V increase was significant (P = 0.012), unlike that of CRCL, with larger volumes. Two patients did not reach target Kt/V, and four did not reach target CRCL. The volume normalized for 1.73 m2 corresponding to DOQI targets was 19.6 +/- 2.6 L for Kt/V and 20.2 +/- 2.4 for CRCL. The overall Kt/V was 2.29 +/- 0.66 and CRCL was 57.3 +/- 16.5 L/1.73 m2. CRCL/Kt/V overall ratio was 25.6 +/- 4.7 and significantly different from the target ratio (63/2.1 = 30, P < 0.001). The CRCL/Kt/V ratio showed a significant decrease with larger volumes (P = 0.001, linear trend P < 0.001). Adequacy targets can be reached only in some patients on CTPD even with high dialysis volumes. The changes in the CRCL/Kt/V ratio in relation to dialysis volume can be considered for adaptation and evaluation of adequacy targets in automated treatments.

Creatinine↗
PubMed1998

Symptoms in hemodialysis patients and their relationship with biochemical and demographic parameters.

Symptoms can markedly influence the hemodialysis patients well-being and quality of life. The aim of this paper is to study the frequency of symptoms at home and how these relate to biochemical and treatment variables. Seventy-three hemodialysis patients were questioned on the absence, occasional presence or daily recurrence (score = 0, 1, 2) of 14 symptoms and a record was made of their biochemical parameters, age, time on treatment and KtIV as a function of each symptom. The following relationships were detected: thirst with high Osm and BUN; asthenia with old age and hypoalbuminemia; insomnia with hypercalcemia; hypersomnia with hypoxemia and hypernatremia; anorexia with hypokalemia; dyspnea with old age, hypernatremia and hypokalemia; dysgeusia with hypoxemia; nausea with alkalemia, hypoxemia and low BUN; vomiting with alkalemia. Pruritus, arthralgia, restless legs syndrome, cramp and tremor showed no relationships. Monitoring acid-base balance and plasma electrolytes could help to alleviate symptoms and ameliorate quality of life of hemodialysis patients.

Age Factors↗
PubMed1996

Compliance study in peritoneal dialysis using PD Adequest software.

Poor compliance in peritoneal dialysis (PD) is a significant cause of dropout and morbidity. PD Adequest software, which, through a mathematical model, predicts the effect of the dialysis prescription on the basis of the peritoneal transport, may be used to identify the noncompliant patient. Fifty patients from two dialysis centers, aged 65.9 +/- 1.5 years and on PD for 28.6 +/- 4.7 months, were studied. A peritoneal equilibration test (PET) was carried out and 24-hour urine and dialysate were collected. Total weekly creatinine clearance (CrCl, L/week/1.73 m2) was calculated, as well as the glomerular filtration rate [(GFR), mL/min, mean CrCl and urea nitrogen clearance (UNCI)]. The dialytic schedules used were then introduced into the program and the parameters were recalculated using the software model. Nine patients considered noncompliant from their case histories were used to assess the differences of reference between expected and measured values. The control group was significantly different from the noncompliant group in the percentage of the CrCl and the serum creatinine (sCR) differences. The noncompliance threshold value was calculated from the mean of the lower 95% confidence interval of the compliant group and the higher one of the noncompliant group (-5.3%) for CrCl and vice versa for sCR (+10%), which behaved to the contrary. Reassessing the patients, 11 (22%) were identified as probably noncompliant.

Aged↗
PubMed1996

Normalization of protein equivalent of nitrogen appearance and dialytic adequacy in CAPD.

Caloric-proteic malnutrition is frequently encountered in peritoneal dialysis and is associated with an increased risk of morbidity and mortality. Our paper aims to assess any greater reliability of protein equivalent of nitrogen appearance (PNA) normalization to desirable body weight (dBW) compared to actual body weight (aBW) and resulting implications for the relationship between dialytic adequacy and protein intake in continuous ambulatory peritoneal dialysis (CAPD). We studied 36 patients on CAPD, 24 male and 12 female (aged 66.6 +/- 10.2 years, 24 +/- 29 months on dialysis), collecting dialysate and urine over 24 hours (126 samples) to calculate the PNA according to Randerson and the total weekly KT/V. The total body muscle mass (TBMM) was calculated by anthropometry and the dBW according to Metropolitan Life Insurance tables. Finally, PNA was normalized to aBW (aPNA, g/kg/day) and to dBW (dPNA, g/kg/day). Average aBW proved to be higher than dBW (66.0 +/- 11.1 vs 59.8 +/- 6.9 kg, p < 0.0001) and aPNA lower than dPNA (0.96 +/- 0.31 vs 1.08 +/- 0.3 g/kg/day, p < 0.005). Compared to aPNA, dPNA correlates better with both blood urea nitrogen (BUN) (R2 = 0.702 vs 0.614) and KT/V (R2 = 0.348 vs 0.306). The TBMM is higher in the group with dPNA > or = 1.0 vs < 1.0 g/kg/day (25.5 +/- 0.6 vs 23.1 +/- 0.7 kg, p < 0.02) while, paradoxically, it is lower in patients with aPNA > or = 1.0 vs < 1.0 g/kg/day (22.8 +/- 0.8 vs 25.4 +/- 0.6 kg, p < 0.01). The KT/V of the patients with dPNA < 0.8, 0.8-1.2 and > 1.2 g/kg/day proved to be different (1.52 +/- 0.06 vs 1.80 +/- 0.03 vs 2.04 +/- 0.04, p < 0.005). On analysis of the linear regression, dPNA = 1.0 and 1.2 g/kg/day corresponds to KT/V values of 1.7 and 2.05, respectively. We consider dPNA to be more suitable then aPNA for the correct assessment of protein intake, and a weekly KT/V of 1.7-2.05 as being sufficient to guarantee satisfactory dPNA.

Adult↗
PubMed1995

Correction of glucose concentration interference on Jaffé kinetic creatinine assay in peritoneal dialysis.

Overestimation of creatinine measurement using the Jaffé kinetic method in peritoneal dialysis solutions, due to glucose interference, has been quantified and corrected through the elaboration of linear formulas obtained from 110 recovery and 301 biological tests. The added pure powdered creatinine and enzymatic method were considered as references after proven accuracy. Considering creatinine as well as glucose concentration interference, we obtained correction formulas from multiple regression application. All the computed formulas gave satisfactory corrections but different accuracy levels. The best model in biological samples was: Corrected CR = K1JafféCr + K2Glucose (all values in mg/dl) where K1 = 0.973 and K2 = -0.00035 (Rsq = 0.987, F ratio = 10,945, p = 0.00001). Applying formulas to biological samples there was a drop in accuracy, possibly explained by the presence of numerous unidentified substances in peritoneal dialysis biological samples that can amplify scatter. Every laboratory can reduce the error of the Jaffé kinetic assay by calculating their own correction formula in relation to the method and instrument used, because Jaffé kinetic assay gives different results with different kinetic windows. So, especially when applied to peritoneal dialysis fluid measurements, if a creatinine assay reference method is not available, the correction formula can be applied directly as given. Otherwise the method we have described can be followed with a well-structured creatinine recovery fest to identify and quantify assay interferences.

Analysis of Variance↗
PubMed1995

Role of automated peritoneal dialysis within a peritoneal dialysis program.

We wished to assess the impact of automated peritoneal dialysis (APD) on the peritoneal dialysis (PD) program. From November 1981 to December 1993, 112 patients were started on hemodialysis (HD) as first treatment and 88 on PD [continuous ambulatory peritoneal dialysis (CAPD): 78, APD: 10]; respective average ages were 61 +/- 14 and 62 +/- 13 years. To December 1985, APD was used as first treatment of PD in 1/29 patients (3.4%), while subsequently, on the basis of a clinical and social-aptitude assessment protocol, it was used in 9/59 patients (15.2%) with PD indication and CAPD contraindications (work: 2 patients, partner required: 7 patients). Of the patients who interrupted CAPD, APD was used in 9/21 patients (reason: social aptitude, 28.6%; clinical, 71.4%). Technique survival after 5 years proved no different in HD versus PD (87% vs 82%, p = NS), whereas in HD versus CAPD it was different (87% vs 62%, p < 0.025). The incidence of peritonitis in APD and CAPD with the Y-set was comparable (1/37 vs 1/40 episode/patient-months), while germ distribution was different (p < 0.001) with Staphylococcus epidermidis prevailing in APD (59%). Based on our experience, APD may extend method acceptance criteria and reduce the technique dropout rate in PD; however, connection technique may need to be improved in order to reduce the risk of peritonitis from exogenous contamination.

Automation↗
PubMed1995

Low sodium concentration solution in normohydrated CAPD patients.

The aim of this study was to examine the possibility of increasing sodium and water removal with peritoneal dialysis. Ten patients aged 67.3 +/- 6.2 years, on continuous ambulatory peritoneal dialysis (CAPD) for 28.1 +/- 13.9 months, with no episodes of peritonitis for at least 2 months and clinically normohydrated, gave their informed consent to undergo two consecutive peritoneal equilibration tests (PETs) with dialysis solution at a sodium concentration of 126 mEq/L (low sodium) and 132 mEq/L (normal sodium), both with 2.5% glucose. Net ultrafiltration and sodium mass transfer were 319.4 +/- 178.5 and 443.2 +/- 234.4 mL (p = 0.0346) and 27.7 +/- 24.5 and 28.2 +/- 27.1 mEq (p = NS), respectively. There were no variations in natremia or the transport indices of the studied solutes or in the arterial pressure or heart rate. All patients showed drowsiness or torpor during the low sodium PET and one had cramps. The 126 mEq/L sodium dialysis solution showed no advantages compared to the more common solution, 132 mEq/L. However, further study is necessary to check the potentiality of solutions with different sodium and glucose compositions for both acute and chronic use.

Aged↗