Biomedical subjects

J Kakavas

Publications and source records attributed to J Kakavas.

5 recordsLinked to original sources

PubMed1996

Fractional urea clearance in continuous ambulatory peritoneal dialysis: effects of volume disturbances.

The effects of volume disturbances on the KT/V were investigated prospectively in 133 consecutive urea clearance studies on patients on continuous ambulatory peritoneal dialysis (CAPD). Four subjects (group A) had fluid loss (actual weight < dry weight), 57 (group B) were studied on the basis of their dry weight, 58 (group C) had moderate fluid excess (0.5% of dry weight), and 14 patients (group D) had severe fluid excess (> 5% of dry weight). The KT/V was calculated on the basis of dry weight and actual weight with V obtained from the Watson anthropometric formulae which were applied either uncorrected or with a correction for changes in body water from dry weight conditions. The groups compared by variance analysis. The following weekly KT/V estimates were obtained: (1) using dry weight V: group A 1.81 +/- 0.17, group B 2.0 +/- 0.59, group C 1.79 +/- 0.46, group D 1.85 +/- 0.37 (no difference between groups); (2) using uncorrected actual weight V: group A 1.85 +/- 0.15, group B 2.05 +/- 0.59, group C 1.77 +/- 0.45, group D 1.78 +/- 0.37 (group B had a higher KT/V than group C, p < 0.05), and (3) using corrected actual weight V: group A 1.93 +/- 0.14, group B 2.05 +/- 0.59, group C 1.70 +/- 0.43, group D 1.63 +/- 0.36, (group B had a higher KT/V than either group C or group D, both at p < 0.01). In CAPD, fluid deficit is rare and causes a small increase in KT/V, whereas fluid retention is frequent and causes a decrease in KT/V. This decrease is pronounced in patients with severe fluid excess. The uncorrected Watson formulae underestimate V and, consequently, overestimate KT/V in CAPD patients with fluid excess.

Aged↗

PubMed1995

Cross-sectional analysis of erythropoietin use in CPD: its relation to azotemic index clearances.

The association between the use of erythropoietin and urea or creatinine clearance was studied in two populations on continuous peritoneal dialysis (CPD) residing either at an altitude of 1600 m (n = 194) or at sea level (n = 108). Among peritoneal and total KT/V urea and creatinine clearance (CCr) indices, only total CCr was lower in the high altitude group receiving erythropoietin than in the corresponding group not receiving erythropoietin (68.0 +/- 34.9 vs 82.9 +/- 40.9 L/1.73 m2 weekly, p < 0.01). However, 24-hour urine volume and urinary KT/V urea and CCr were consistently lower in the groups receiving erythropoietin than in those not receiving erythropoietin. Total weekly KT/V urea < or = 1.70 and CCr < or = 52 L/1.73 m2 were considered indicators of inadequate CPD. Although the percent of patients receiving erythropoietin did not differ overall between groups with adequate and those with inadequate CPD, a trend towards more frequent use of erythropoietin was found in the sea level group with inadequate CCr versus the group with adequate CCr (28.2% vs 16.9%, p = 0.084). In CPD decreased renal function is associated with more frequent use of erythropoietin. Whether inadequate total urea or creatinine clearance is also associated with more frequent erythropoietin use requires further study.

Altitude↗

PubMedDate not supplied

The relationship between urine volume and drain volume as determinants of fractional urea clearance in continuous peritoneal dialysis.

A logistic regression model developed and validated in Albuquerque identified 24 hr urine volume (UV) and 24 hr drain volume/(body water) (DV/V) as predictors of fractional urea clearance (KT/V) in continuous peritoneal dialysis (CPD). Solution of this model provided DV/V values consistent with KT/V at least equal to a target KT/V for a given UV. The predictive accuracy of these unique DV/V values was tested in urea kinetic studies performed in 108 CPD patients in Thessaloniki and Athens with UV varying between 0 and 2 L/24 h. Two target weekly KT/V values, 1.70 and 1.90, were investigated. The equation DV/V = (5.2811-3.6996 UV)/ 17.554, derived by solving the logistic regression model, detected weekly KT/V > 1.70 (69/108, or 63.9% of the studies) with a sensitivity of 87.3% and a specificity of 60.4%. According to the same equation, the maximal UV consistent with weekly KT/V < or = 1.70 is 1.427 L/24 hr. The equation DV/V = (5.4994-2.6007 UV)/17.007 detected weekly KT/V > 1.90 (44/108, or 40.7% of the studies) with a sensitivity of 90.3% and a specificity of 79.2%. According to this equation, the maximal UV consistent with weekly KT/V < or = 1.90 is 2.115 L/24 hr. Determination of the lowest daily DV consistent with a target KT/V at any daily UV (within a wide range) is feasible in CPD.

Feasibility Studies↗

PubMedDate not supplied

Continuous peritoneal dialysis in heavyweight individuals: urea and creatinine clearances.

OBJECTIVE: To study whether or not continuous peritoneal dialysis (CPD) can provide acceptable levels of normalized urea and creatinine clearance in heavyweight individuals. DESIGN: Retrospective analysis of urea and creatinine clearance studies. SETTING: CPD patients followed in four dialysis units in Albuquerque, two dialysis units in Thessaloniki, and two dialysis units in Athens. PARTICIPANTS: One hundred and ninety-nine patients on CPD with 266 clearance determinations between 1991 and 1995. INTERVENTIONS: The heavyweight group consisted of 22 patients (24 clearance studies) weighing 100 kg or more (109 +/- 8.7 kg) at the time of the clearance study. All subjects were obese. The reference group consisted of 177 CPD subjects (242 clearance studies) of normal weight (68.7 +/- 12.2 kg). Urea fractional clearance (KT/V) and normalized creatinine clearance (Ccr) were compared between the heavyweight and the reference groups. MAIN OUTCOME MEASURES: The lowest acceptable weekly levels were set at 1.70 for KT/V and 54.4 L/1.73 m2 for Ccr. RESULTS: Weekly KT/V was 1.75 +/- 0.41 in the heavyweight group and 1.94 +/- 0.52 in the reference group (p = 0.047). Corresponding weekly Ccr levels were 64.0 +/- 24.3 and 77.6 +/- 40.3 L/1.73 m2, respectively (p = 0.021). In the heavyweight group, 13 studies (54.2%) had acceptable KT/V values compared to 160 studies (66.1%) in the reference group (NS). Corresponding values for acceptable Ccr were 17 (70.8%) and 165 (68.2%), respectively (NS). Drain volume was 12.96 +/- 4.40 L/24 hours in the heavyweight group and 9.63 +/- 2.58 L/24 hours in the reference group (p = 0.001). High daily exchange volume was delivered by a combination of daily continuous ambulatory peritoneal dialysis (CAPD) and nocturnal automated peritoneal dialysis (APD) in 13/16 heavyweight studies. This combination was tolerated better than any other method of delivering a large daily exchange volume. CONCLUSION: Although normalized urea and creatinine clearances are lower in obese, heavyweight individuals than in lean CPD subjects with lower weight, approximately equal percentages of these two groups achieve acceptable clearance levels. However, heavyweight individuals require larger-than-usual daily exchange volumes. The preferred way to deliver these large dialysate volumes is a combination of daily CAPD and nocturnal APD.

Body Weight↗

PubMedDate not supplied

Fractional urea clearance estimates using two anthropometric formulas in continuous peritoneal dialysis: sex, height, and body composition differences.

OBJECTIVE: To compare estimates of urea volume (V) and KT/V obtained by the Watson and Hume anthropometric formulas, and to identify the similarities and differences between these estimates. DESIGN: Theoretical analysis applying wide variations in the determinants of anthropometric V (age, height, weight) in hypothetical women and men. Analysis of urea kinetic studies performed in patients on continuous peritoneal dialysis (CPD). SETTING: Four dialysis units in Albuquerque, two in Athens, and two in Thessaloniki. PARTICIPANTS: Three hundred and two CPD patients who had 440 urea kinetic studies. INTERVENTION: Standard urea clearance was performed by 24-hour collections of urine and drained dialysate followed by blood sampling. V was estimated by both the Watson and Hume formulas. MAIN OUTCOME MEASURES: Estimates of V and KT/V were compared separately in women and men by Student's t-test, linear regression, and limits of agreement (mean difference +/- 2 SD). The agreement of the KT/V estimates was also tested by the kappa ratio using a value of 1.70 weekly as the lowest acceptable K/TV. RESULTS: The theoretical analysis indicated important disagreement only in extreme variations from the ordinary in height and, to a lesser extent, weight. Differences due to height variation were pronounced only in hypothetical women. CPD patient findings were as follows: in women, Watson V and weekly KT/V were 30.4 +/- 4.4 L and 2.10 +/- 0.61, respectively. Corresponding Hume estimates were 30.3 +/- 5.4 Land 2.1 2 +/- 0.66, respectively. Corresponding estimates for men were 40.5 +/- 5.7 L and 1 .92 +/- 0.57 (Watson) plus 41.4 +/- 5.6 L and 1.88 +/- 0.57 (Hume), respectively. By linear regression, KT/V(Hume) = -0.083 + 1.052 (KT/V(Watson)), r = 0.961 (women); and KT/V(Hume) = -0.026 +/- 0.992 (KT/V(Watson)), r = 0.985 (men). Limits of agreement were -1.41 L and 2.10 L for V, and -0.15 and 0.14 weekly for KT/V. In 94.3% of the cases, KT/V(Watson) and KT/V(Hume) agreed (both > 1 .70 or both < 1 .70 weekly). Kappa ratio was 0.875 (excellent agreement). The concordant and discordant groups differed in height and degree of obesity, in agreement with the theoretical analysis. CONCLUSION: The Watson and Hume formulas provide similar estimates of V and KT/V in CPD patients. Differences may be noted only if women's height or, to a lesser extent, both sexes' weight is at a great variance with the ordinary values.

Adult↗