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Biomedical subjects

P Keshaviah

Publications and source records attributed to P Keshaviah.

At least 19 recordsLinked to original sources
PubMed2001

Resource limitations and strategies for the treatment of uremia. A dialysis unit in the Himalayan foothills.

India has made great strides in health care since gaining independence in 1947. Much still needs to be done. Scarce health care resources are directed at priorities that include infant and maternal mortality, immunizations, malnutrition, communicable disease prevention, and access to protected water and sanitation. There is, therefore, no government reimbursement for treatment of patients with ESRD (estimated incidence of 100 per million population). Transplantation, the modality of choice in India, benefits only 2-3% of ESRD patients. Hemodialysis is primarily used short-term for pretransplant stabilization. A very small minority of patients is placed on maintenance hemodialysis or CAPD. The annual cost of renal replacement therapies is more than 10 times the per capita gross national product. Financial constraints pose ethical problems for the nephrologist related to adequate prescriptions and compliance. Preventing the progression of kidney disease and reducing the cost of disposables through indigenous manufacture are initiatives that need to be explored.

Costs and Cost Analysis↗
PubMed1997

Comparison of methods to predict equilibrated Kt/V in the HEMO Pilot Study.

The ongoing HEMO Study, a National Institutes of Health (NIH) sponsored multicenter trial to test the effects of dialysis dosage and membrane flux on morbidity and mortality, was preceded by a Pilot Study (called the MMHD Pilot Study) designed to test the reliability of methods for quantifying hemodialysis. Dialysis dose was defined by the fractional urea clearance per dialysis determined by the predialysis BUN and the equilibrated postdialysis BUN after urea rebound is completed (eKt/V). In the Pilot Study the blood side standard for eKt/V was calculated from the predialysis, postdialysis, and 30-minute postdialysis BUN. Four techniques of approximating eKt/V that eliminated the requirement for the 30-minute postdialysis sample were also evaluated. The first adjusted the single compartment Kt/V using a linear equation with slope based on the relative rate of solute removal (K/V) to predict eKt/V (rate method). The second and third techniques used equations or mathematical curve fitting algorithms to fit data that included one or more samples drawn during dialysis (intradialysis methods). The fourth technique (dialysate-side) predicted eKt/V from an analysis of the time-dependent profile of dialysate urea nitrogen concentrations (BioStat method; Baxter Healthcare, Inc., Round Lake, IL, USA). The Pilot Study demonstrated the feasibility of conventional and high dose targets of about 1.0 and 1.4 for eKt/V. Based on the blood side standard method, the mean +/- SD eKt/V for patients randomized to these targets was 1.14 +/- 0.11 and 1.52 +/- 0.15 (N = 19 and 16 patients, respectively). Single-pool Kt/Vs were about 0.2 Kt/V units higher. Results were similar when eKt/V was based on dialysate side measurements: 1.10 +/- 0.11 and 1.50 +/- 0.11. The approximations of eKt/V by the three blood side methods that eliminated the delayed 30-minute post-dialysis sample correlated well with eKt/V from the standard blood side method: r = 0.78 and 0.76 for the single-sample (Smye) and multiple-sample intradialysis methods (N = 295 and 229 sessions, respectively) and 0.85 for the rate method (N = 295). The median absolute difference between eKt/V computed using the standard blood side method and eKt/V from the four other methods ranged from 0.064 to 0.097, with the smallest difference (and hence best accuracy) for the rate method. The results suggest that, in a dialysis patient population selected for ability to achieve an equilibrated Kt/V of about 1.45 in less than a 4.5 hour period, use of the pre and postdialysis samples and a kinetically derived rate equation gives reasonably good prediction of equilibrated Kt/V. Addition of one or more intradialytic samples does not appear to increase accuracy of predicting the equilibrated Kt/V in the majority of patients. A method based on dialysate urea analysis and curve-fitting yields results for equilibrated Kt/V that are similar to those obtained using exclusively blood-based techniques of kinetic modeling.

Blood Urea Nitrogen↗
PubMed1995

The solute removal index--a unified basis for comparing disparate therapies.

The removal-based SRI can be applied to the CAPD setting, and this new index of dialysis dose is numerically equal to the KT/V for a continuous therapy like CAPD. This is not true for hemodialysis where the SRI is numerically lower than the KT/V. If therapy prescriptions for CAPD, APD, and HD are all adjusted to provide the same removal at the same predialysis BUN, then the values of SRI will be the same in all three modalities despite differences in the frequency and duration of the therapy modalities. This is a major advantage of the SRI over KT/V in that it provides a unified, intuitive basis for comparing disparate therapies. The peak concentration hypothesis is implied in this approach because the therapies have equivalent SRI when there is matching of the peak predialysis BUN of APD and HD with the steady-state BUN of CAPD. However, if KT/V is used as the basis of comparison for different modalities, the weekly KT/V has to be adjusted with a scaling factor that varies with the frequency of dialysis. A different scaling factor will apply for daily APD versus that for thrice-weekly HD. The requirement of a scaling factor and the variability of this factor with therapy frequency complicate therapy comparisons based on KT/V. This complication is avoided with the SRI. Further, as detailed in a prior publication (1), the SRI has several advantages over the KT/V index for hemodialysis therapy, which include the avoidance of clearance corrections for access recirculation, cardiopulmonary recirculation, and compartmental disequilibrium.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Urea Nitrogen↗
PubMed1994

Comparison of different measurements of lean body mass in normal individuals and in chronic peritoneal dialysis patients.

To evaluate different methods of measuring lean body mass (LBM) in chronic peritoneal dialysis (CPD) patients, we first made comparisons in seven normal subjects. Seven methods (total body potassium [TBK] counting, bioelectrical impedance with calculations according to Segal and Deurenberg, near-infrared interactance with and without exercise level included as a variable, anthropometric measurements, and creatinine kinetics) were compared with the standard method of underwater weighing (UW) for measuring LBM. Significant correlations with LBM measured by UW (r > 0.938) were found with LBM measured by all other methods. Compared with UW, the best result in normals was found with TBK as it had high r values, small y-intercepts, and slopes of regression lines close to unity in both measurements of LBM and %LBM; in addition, fat-free mass index by TBK best approximated that by UW and TBK had the lowest mean prediction error with UW. In 11 patients on CPD, LBM was measured by all the above methods except UW. Significant correlations of all methods with LBM measured by TBK used as the reference standard were noted (all r > 0.76) in the CPD population. The LBM measured by creatinine kinetics correlated best (by kilograms or percentage of body weight [%BW]) with LBM from TBK compared with the other methods in which values tended to be higher. The fat-free mass index by creatinine output was nearest to the fat-free mass index by TBK. The root mean square prediction error was lowest between LBM by creatinine output and that by TBK. The findings support the concept of measuring creatinine outputs in CPD patients for estimates of LBM as an index of nutritional status as well as for creatinine clearances as an index of adequacy. Total body potassium and creatinine output measurements of LBM reflect the LBM at normal body fluid volumes ("dry weight") and may be better indices of nutrition in dialysis patients than the other techniques, which include excess fluid in the LBM.

Adult↗
PubMed1994

Urea index and other predictors of hemodialysis patient survival.

The mortality of dialysis patients in the United States has been a concern since the US Renal Data System 1989 report, which showed a lower survival rate in the United States compared with Europe. The differences were thought to be multifactorial, including case mix, malnutrition, and adequacy of dialysis. We reviewed the Regional Kidney Disease Program's 1976 to 1989 database for the pattern of co-morbidity, dialysis therapy, and low serum albumin in 1,082 nondiabetic and 691 diabetic patients followed to September 15, 1991. The number of patients over 60 years of age has increased by 15% to 20% per year since 1982. The primary renal diagnoses for nondiabetic patients have shifted from 26% glomerulonephritis, 18% vascular and hypertension, and 15% interstitial kidney disease cases during the period from 1976 to 1982 to 19% glomerulonephritis, 35% vascular and hypertension, and 10% interstitial disease cases during the period from 1986 to 1989. Co-morbidity as single and multiple conditions has increased from 66% to 85% in diabetic patients and from 57% to 66% in nondiabetic patients. The number of patients with two or more co-morbid conditions has increased 1.5-fold in nondiabetic patients and twofold in diabetic patients from the 1976 to 1982 period to the 1986 to 1989 period. Urea index and albumin were determined for these patients and were averaged as a risk factor. A Cox regression analysis was used to determine the relative risk of death of such characteristics as age, renal diagnosis, co-morbidity, urea index (KT/V), and albumin in nondiabetic and diabetic patients. Urea index was divided into ranges of less than 1.0 (mean, 0.9), 1.0 to less than 1.2, 1.2 to less than 1.4, and > or = 1.4 (mean, 1.6). The relative risk of death in nondiabetic patients was 0.65 (P = 0.0012) for KT/V 1.2 to less than 1.4 and 0.67 (P = 0.0029) for KT/V > or = 1.4 (mean, 1.6) compared with 1.0 to less than 1.2 as the baseline. In the diabetic patients, the relative risk of death was 0.70 (P = 0.009) for KT/V 1.2 to less than 1.4 and 0.59 (P = 0.0001) for KT/V > or = 1.4 (mean, 1.6) compared with 1.0 to less than 1.2. In the diabetic patients, KT/V > or = 1.4 also was significantly different from 1.2 to less than 1.4 as it impacted on death rates.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Relationship between body size, fill volume, and mass transfer area coefficient in peritoneal dialysis.

A peritoneal dialysate fill volume of 2 L has become the standard of clinical practice, but the relationships between body size, fill volume, and mass transfer area coefficient (KoA) have not been well established. These relationships were studied in 10 stable peritoneal dialysis patients who underwent six peritoneal equilibration studies (2 h each) at fill volumes of 0.5, 1, 1.5, 2, 2.5, and 3 L. The concentration-time profiles for urea, creatinine, and glucose were measured at each fill volume, and residual volumes were calculated from the preceding dwell period. A modified Henderson equation was used to calculate the KoA for the three solutes as a function of fill volume. By normalizing the KoA for each solute to the value at 2 L, the data for all three solutes collapsed onto the same trend line when plotting the normalized KoA versus dialysate volume. Between 0.5- and 2-L fill volumes, the average normalized KoA increases in an almost linear fashion, its value almost doubling over this range. Between 2- and 3-L fill volumes, there is less than a 10% change in the normalized KoA. However, fill volumes for peak urea KoA were found to increase with increasing body surface area (R = 0.76), being around 2.5 L for an average-sized patient and increasing to between 3 and 3.5 L for body surface areas > 2 m2. To maximize solute transport, these relationships between body size, volume, and KoA should be considered when choosing fill volumes for continuous ambulatory peritoneal dialysis and automated peritoneal dialysis and when deciding reserve and tidal volumes for tidal peritoneal dialysis.

Body Surface Area↗
PubMed1993

Age and indices of adequacy and nutrition in CAPD patients.

We have examined the correlations of age with 95 demographic, clinical, and laboratory parameters in a continuous ambulatory peritoneal dialysis (CAPD) population. Significant inverse correlations were found with lean body mass, dialysate creatinine concentration, serum creatinine concentration, and dialysate creatinine nitrogen output in grams per week; all these findings are compatible with the well-known decrease in muscle mass with aging. Urea nitrogen output in dialysate and urine predicts Kjeldahl nitrogen output in urine and dialysate applying the Randerson equation similarly in older and younger CAPD patients. The relationship of normalized net protein catabolic rate to weekly urea clearance normalized to total body water is similar for older and younger CAPD patients. Older and younger patients have similar values for serum albumin concentration. In conclusion, the findings suggest that comparable weekly creatinine clearances should yield much lower serum creatinine concentrations in older patients. Poor protein intakes in the elderly should not be attributed to age if weekly urea clearances are low. Increases in protein intake in response to increases in urea clearances are similar in older and younger CAPD patients.

Adult↗
PubMed1993

Cross sectional assessment of weekly urea and creatinine clearances and indices of nutrition in continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: To perform a cross sectional analysis in 71 patients on continuous ambulatory peritoneal dialysis (CAPD) to identify significant correlations of weekly small solute clearances and indices of nutritional status with each other and with patient demographics and other commonly monitored clinical and laboratory parameters. DESIGN: This was a retrospective, cross sectional analysis in 71 patients on CAPD from less than 1 to 105 patient-months (average, 20 months). SETTING: An outpatient CAPD program. PATIENTS: All patients on CAPD in our program at the time of the study willing to undergo the clearance and nutritional status measurements. INTERVENTIONS: No interventions other than the monitoring of their status. MAIN OUTCOME MEASURES: Weekly small solute clearances, dietary protein intake, serum albumin, lean body mass, net protein catabolic rate, and urinary and dialysate nitrogen. RESULTS: Weekly Kt/V urea (weekly urea clearance normalized to total body water) of at least 1.7 and weekly total creatinine clearances (liter/week/1.7 m2) of at least 50 are associated with net protein catabolic rates (PCR) greater than 0.9 g/kg of normalized body weight in average CAPD patients. Kt/V urea and net PCR correlate significantly with serum albumin. High transporters identified by the peritoneal equilibration test have greater albumin losses and lower serum albumin concentrations. Estimates of lean body mass correlate significantly with serum albumin and net PCR; lean body mass correlates significantly and inversely with age. CONCLUSIONS: Greater small solute clearances are associated with better nutritional status.

Adult↗
PubMed1993

Urea kinetic and middle molecule approaches to assessing the adequacy of hemodialysis and CAPD.

The historical bases and implications of the urea kinetic and middle molecule approaches to assessing the adequacy of hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) are reviewed in this paper. A critical reappraisal of the findings of the National Cooperative Dialysis Study (NCDS) demonstrates the importance of small solute removal on clinical outcomes of morbidity and mortality in the hemodialysis setting. The applicability of these results to CAPD is examined in the light of differences in transport characteristics of hemodialysis membranes and the peritoneal membrane. It is shown that small solute removal is important even in assessing CAPD adequacy and that past comparisons of hemodialysis and peritoneal membrane transport may have been flawed. The extrapolation of NCDS results to CAPD on the basis of the peak concentration hypothesis is presented along with a review of several longitudinal, cross-sectional, and multicenter studies of CAPD morbidity and mortality.

Humans↗
PubMed1992

Adequacy of peritoneal dialysis: a review of quantitative and qualitative approaches.

This paper reviews the qualitative and quantitative approaches to assessing the adequacy of peritoneal dialysis. The quantitative measures reviewed include the KT/V urea index, the dialysis index, the weekly creatinine clearance, and the creatinine efficiency number. Studies that support as well as refute these measures are reviewed briefly. Many of these studies are retrospective analyses of longitudinal data in small numbers of patients or prospective cross-sectional studies. A prospective, longitudinal study involving large numbers of patients is required to resolve some of the controversies regarding the adequacy of peritoneal dialysis.

Creatinine↗
PubMed1992

Adequacy of CAPD: a quantitative approach.

In prescribing CAPD, general clinical practice is to use the standard regimen of 2L x 4 exchanges/day without regard to patient size, nutritional status, or residual kidney function. The standard regimen is usually adjusted in a trial and error manner reacting to clinical symptoms, life style issues, and patient compliance. The purpose of this paper is to recommend an alternative, quantitative approach based on urea kinetics that is prospective rather than reactive, and objective rather than subjective. The value of urea kinetic-based hemodialysis therapy prescription is well established and applying this knowledge to CAPD is a good starting point. The importance of small solute clearances for CAPD adequacy can be established on both theoretical and clinical grounds. The value of the KT/V urea index, its calculation, scaling factors for CAPD-hemodialysis comparisons, and the correlation between KT/V and weekly creatinine clearances are examined. Residual renal function has a significant impact on small solute clearances, and failure to adjust the therapy prescription to compensate for declining residual kidney function will have a detrimental impact on KT/V and the protein catabolic rate.

Creatinine↗
PubMed1990

Changing risk factor demographics in end-stage renal disease patients entering hemodialysis and the impact on long-term mortality.

Patient survival on hemodialysis has previously been shown to be associated with the presence of comorbid conditions on entrance. Significant comorbid conditions are atherosclerotic heart disease (ASHD), cerebral vascular disease (CVD), nonskin malignancies, chronic obstructive pulmonary disease, diabetes mellitus, and age on entrance to dialysis. Changes in annual mortality have been noted in the United States and at the Regional Kidney Disease Program. The increase in annual mortality was analyzed to determine the impact of risk factors during the time intervals 1976 to 1982 and 1983 to 1987. Patients with no major risk factors have longer survival rates and lower deaths per 1,000 treatment-months from 1983 to 1987 compared with 1976 to 1982. Diabetics have survival rates and deaths per 1,000 treatment-months that are comparable up to age 75. However, over age 75, diabetics have lower survival rates and higher death rates. The presence of comorbid conditions in the diabetic group is high and may account for the increased death rate. The percent of diabetics entering the program has increased from 29% to 48% over the intervals. Nondiabetics with comorbid conditions on entrance had higher deaths per 1,000 treatment-months from 1983 to 1987 compared with 1976 to 1982 across all age categories. Risk factor analysis shows that nondiabetics with major risks are entering with increasing numbers and continuation of comorbid conditions that impact death rates. Peripheral vascular disease, originally not significantly associated with death on dialysis, has dramatically increased from 18% to 60% in nondiabetics with comorbid conditions. In the patients over age 60 with comorbid conditions, 75% of patients now entering dialysis have peripheral vascular disease (PVD). In summary, major shifts in the hemodialysis population have occurred. Diabetics entering dialysis now account for almost 50% of all patients, with the older group having more comorbid conditions. This change alone would increase the annual mortality rate. Patients with comorbid conditions now enter with a higher prevalence of multiple comorbid conditions, which would increase the annual mortality rate. Nondiabetics without comorbid conditions now have better survival across all age categories compared with the previous data. PVD, with its current high prevalence, needs to be reevaluated as a significant risk factor for death on hemodialysis. Therefore, the increase in the annual gross mortality rate is highly predicted based on the change in the diabetic population and the increase in single and multiple comorbid conditions in the nondiabetic population.

Adolescent↗
PubMed1986

Rapid high-efficiency hemodialysis.

Reductions in treatment time are attractive for patients and dialysis centers. However, there are concerns related to treatment adequacy and increased intradialytic symptoms. Treatment times were progressively reduced in 12 stable patients on standard 4-h acetate hemodialysis, solute clearances being increased proportionately, until the tolerance limit manifested by increased complications or 2.5 h of treatment was reached. Once shortened schedules (mean reduction approximately 31%) were achieved, a 2-month surveillance period was initiated, followed by 2 additional months of bicarbonate therapy, treatment time being unchanged. Rapid bicarbonate hemodialysis was associated with a significantly lower incidence of hypotension, nausea, and vomiting than rapid acetate or standard acetate therapies. Fluid removal was comparable with that of standard treatment, and serum chemistry levels remained stable. Based on the success of these studies treatment times have been reduced in greater than 200 patients with high-efficiency bicarbonate therapy for long-term evaluations.

Acetates↗