A 2 year evaluation of diabetic patients on continuous ambulatory peritoneal dialysis

Nineteen diabetic patients with end-stage renal disease on CAPD were evaluated over a 2 year period. All but one patient was insulin-dependent, with a mean age of 47.7 years. Average time on CAPD was 16.1 months (range, 2–28 months). Thirteen patients were followed for more than 12 months, and nine for more than 18 months. The mean training period was 22.9 days. Good blood glucose control was obtained with intraperitoneal (IP) insulin in all of the patients. Mean blood glucose levels of 125±23.08 mg/dl were achieved with 103±38.5 U/day of regular IP insulin. Glycosalated hemoglobin decreased from a mean of 12.7±2.35% before CAPD to 10.08±0.97% during CAPD. Peritoneal creatinine clearance remained stable during the study period, with a concommitant decrease (P<0.001) in the mean residual renal creatinine clearance. The incidence of peritonitis was one episode per 7.8 patient-months. Average length of hospitalization was 33.24 days/year. Visual acuity remained stable after 1 year in 73% of the 26 eyes evaluated. No amputations were required in move than 2 years of follow-up. Actuarial survival was 100% at 1 year and 86% at 2 years, and the technique survival of CAPD was 91 and 79%, respectively. These results demonstrate that CAPD is a good dialysis procedure for treating diabetic patients with chronic renal failure, and it offers the advantage of controlling glycemia better than other dialysis methods.     

残余肾功能状态对腹膜透析效能的影响

目的:前瞻性观察终末期肾衰(ESRF)患者在腹膜透析(PD)治疗后残余肾功能(RRF)对透析效能及相关临床指标之间的影响。方法:所有患者按残余肾小球滤过率(rGFR)水平将其分为A组(GFR0~2ml/min)、B组(GFR2·1~4ml/min)和C组(GFR>4ml/min)。每3个月进行一次临床随访,全面评估患者的全身情况及透析状态,包括血压、身高、体重、体重指数(BMI)、尿量(UV)、残余肾肌酐清除率(Ccr)、每周总尿素氮表现率(Kt/Vtotal)、每周肌酐总清除率(WCcrtotal)、蛋白氮呈现率(nPNA)、残余肾尿素及Ccr。对比观察不同RRF状态患者透析状况和部分临床及生化指标变化。尿量<100ml/d或Ccr<1·0ml/min视为无尿。结果:三组不同残肾状态患者Kt/vtotal和Ccr分别为1·75±0·35、2·07±0·54、2·46±0·50和53·4±11·2、66·6±11·2、97·6±22·1(L/Wks),各组之间差异非常显著(P<0·001)。三组不同残余肾Kt/v和Ccr分别占总体kt/v的12·4%、27%、45·7%及总体Ccr的18·3%、47·3%和65·3%,三组间相比差异亦显著(P<0·01)。此外,三组间高血压发生率、心胸比例及左心室肥厚(LVH)亦存在一定差异,C组心脏增大的病例明显低于A、B两组。RRF状态与透析效能呈正相关。本组患者除2例在透析治疗时即无尿,128例患者中有31例(24·2%)发生无尿,其中原发病为血管炎综合征及糖尿病肾病各占4例和7例,其无尿发生率分别占本病种的66·7%及25·9%;另20例无尿患者为肾小球肾炎或其它疾病,占此类疾病的20·6%。此外,发生无尿患者中有5例(16·1%)透析时尿量<300ml/d。结论:PD患者的残余肾仍然是清除体内代谢产物的重要途径,同时也影响血压及心血管系统并发症。     

Autonomic dysfunction in non-diabetic continuous ambulatory peritoneal dialysis patients as measured by sympathetic skin response

ObjectivesThe purpose of this study was to evaluate the prevalence of autonomic dysfunction in non-diabetic continuous ambulatory peritoneal dialysis patients and to investigate its risk factors using the sympathetic skin response.MethodsWe performed a cross-sectional study on 113 non-diabetic continuous ambulatory peritoneal dialysis patients using the sympathetic skin response, a non-invasive test to detect sympathetic sudomotor deficit.ResultsSixty-six patients (58.4%) showed an abnormal sympathetic skin response suggesting a sympathetic sudomotor deficit. Patients were then categorized into two groups according to their sympathetic skin response result. The baseline clinical data, nutritional and dialysis adequacy indices of the two groups were compared. Patients with an abnormal sympathetic skin response are significantly older (54.9 ± 12.52 vs 61.79 ± 12.16 years, p=0.004), more malnourished with a lower albumin (35.79 ± 2.41 vs 33.98 ± 4.92 g/L, p=0.012) and normalized protein nitrogen appearance values (0.99 ± 0.17 vs 0.93 ± 0.16 g/kg/day, p=0.046). Further, they have a lower residual renal function as calculated by weekly renal Kt/V (0.63 ± 0.61 vs 0.29 ± 0.35, p=0.001) or renal creatinine clearance (41.35 ± 40.2 vs 21.96 ± 27.22 L/wk/1.73 m², p=0.006). Patients with an abnormal sympathetic skin response are also receiving a smaller dialysis dose as calculated by the total weekly Kt/V (2.13 ± 0.6 vs 1.83 ± 0.41, p=0.004) or the total creatinine clearance (82. 42 ± 37.34 vs 66.81 ± 25.38 L/wk/1.73 m², p=0.017).ConclusionBased on sympathetic skin response, autonomic dysfunction is common among non-diabetic continuous ambulatory peritoneal dialysis patients. Patients with autonomic dysfunction are significantly older, more malnourished, have low residual renal function and are receiving a smaller dialysis dose. A prospective study is warranted to investigate the reversibility of autonomic dysfunction after an increment in dialysis dose.     

Does dialysis therapy improve autonomic and peripheral nervous system abnormalities in chronic uraemia?

OBJECTIVES: Autonomic nervous system (ANS) dysfunction and peripheral neuropathy occur in patients with chronic renal insufficiency. Adequate renal replacement therapy should prevent development or correct these abnormalities. DESIGN AND SUBJECTS: We studied retrospectively ANS and peripheral neuropathy in 32 patients with chronic uraemia who received either haemodialysis (16) or peritoneal dialysis (16) therapy, and compared the observed dialysis efficiency with changes in neurological function. METHODS: Heart rate variability (HRV) time domain indices and peripheral sensory nerve conduction studies were followed for a mean of 2.9 years. The adequacy of haemodialysis (HD) efficiency was estimated by Kt/V, an index of fractional urea clearance. Adequacy of continuous ambulatory peritoneal dialysis (CAPD) was estimated on the basis of the patient's wellbeing and nutritional status as excellent, satisfactory or poor. Based on observed changes in HRV time domain measures, the observations were divided in three subgroups: improved, unchanged or deteriorated. RESULTS: The peripheral sensory nerve conduction studies were abnormal in 38% of the patients and did not change significantly during the study. Improvement in HRV time domain measures occurred in HD patients with mean Kt/V > 1.20 or in CAPD patients with satisfactory or excellent response to dialysis treatment. Values of Kt/V < 0.85 in HD patients were associated with progressive deterioration of autonomic neuropathy. Diabetic patients (n = 4) differed from others as their HRV was grossly abnormal and did not improve. CONCLUSIONS: The adequacy of haemodialysis is a predictor of improvement of cardiac autonomic nervous function in chronic uraemia. The same trend of improvement was seen also in CAPD patients.     

Bedeutung von PET und Kt/V für die Peritonealdialyse

PET should be monitored 4 weeks after the start of peritoneal dialysis (PD) and then yearly, and Kt/V every 3 months. PET makes it possible to determine different velocities of glucose absorption (from the dialysate) and of the transport of such low-molecular-weight substances as creatinine and urea (from blood to dialysate), and in particular to calculate the prognosis of the long-term ultrafiltration capacity of the peritoneum in each PD patient. Kt/V is a measure of the urea clearance both of the peritoneum and of the actual kidneys; it seems that preservation of any residual renal function has a more significant positive influence on patient survival and on the technical course than does an increase of the dialysis dose. It is accepted that PD is working efficiently when Kt/V is over 1.7. Besides PET and Kt/V clinical (well-being, eating behaviour, whether body weight is steady, functional capacity) and other (blood pressure, neurological status, degree of anaemia, calcium/phosphate ratio) criteria are also important in the evaluation of whether PD treatment is adequate.     

Mixed-mode therapy: kinetic analysis and acute clinical evaluation

A mixed therapeutic modality was devised in which patients with chronic renal failure were treated with a combination of continuous ambulatory peritoneal dialysis (CAPD; two daily 4-hour exchanges per day; 16 h dry belly) and hemodialysis (1 session per week). Kinetic modeling analysis indicated that a time-averaged urea concentration equivalent to CAPD could be obtained with a Kt/V value of 1.2-1.6, depending on patient parameters, for the single-weekly hemodialysis. The therapy format was acutely evaluated in a 2-week clinical trial on 4 patients. Excursions in small-solute concentration were virtually equivalent to those predicted from theory. Adequate fluid removal was obtained in the 2 CAPD exchanges and blood pressure was well controlled. As a result of the success of the acute trials, and since this format may offer potential lifestyle advantages to patients who possess dual access, a chronic trial of mixed-mode therapy seems advised.     

Incremental peritoneal dialysis - yes

The incremental modality at the start of peritoneal dialysis (Incr-DP) is implicit in the definition of adequacy, which is expressed as the sum of dialysis clearance and renal clearance.Theoretically, it is possible to demonstrate that with a glomerular filtration rate at the start of dialysis of 6 mL/min, the minimum Kt/V target of 1.70 indicated by the current guidelines is easily exceeded with both 2-exchange of CAPD (incremental CAPD) and APD of 3 or 4 weekly sessions (Incr-APD), with a daytime icodextrin dwell. The GSDP (Peritoneal Dialysis Study Group) census data suggest that Incr-DP favors the choice of peritoneal dialysis. Although limited to a few studies with a relatively small number of patients, data show that Incr- CAPD is associated with a better quality of life, the achievement of Kt/V targets, and satisfactory ultrafiltration. The clearance of medium molecules is equivalent in Incr-DP and full-dose PD as it depends on the duration of the dwell and not on the number of exchanges. The maintenance of body weight, protein intake and peritoneal permeability may be explained by the lower glucose load with Incr-DP. The preservation of residual renal function is similar to that recorded with full-dose PD, while the peritonitis rate seems to be lower. The favorable results reported in the literature and the indications of the most recent guidelines about the importance of reducing the exposure to glucose to a minimum and safeguarding the patient's quality of life in our opinion further justify the use of Incr-DP.     

Radioiodine dosimetry in patients with end-stage renal disease receiving continuous ambulatory peritoneal dialysis therapy

In patients with end-stage renal disease (ESRD), Na131I dosages for thyroid cancer may have to be reduced to avoid excess radiation doses to red marrow, because radioiodine is primarily excreted by kidneys. In ESRD patients receiving continuous ambulatory peritoneal dialysis (CAPD) therapy (three to five 2-L exchanges daily) creatinine clearance rates are very low (mean, 7 mL/min), and radioiodine clearance rates may be proportionately reduced. Thus, radioiodine kinetic studies were performed in two hypothyroid CAPD patients with thyroid cancer, in eight euthyroid CAPD patients, and in eight thyroid cancer patients with normal renal function. All received Na131I or Na123I orally, with serial blood, urine, and/or dialysate sampling for 24-70 h. Dosimetry calculations were performed using the MIRDOSE3 computer program. In CAPD patients, serum radioiodine half-times were 5 times longer, and radioiodine clearance rates by urine plus dialysate were 20% of those in patients with normal renal function. Na131I dosages for the two CAPD patients with thyroid cancer were reduced from 150 mCi [5.6 gigabecquerels (GBq)] to 26.6 mCi (0.98 GBq) and 29.9 mCi (1.11 GBq), respectively, resulting in radiation doses to red marrow and total body comparable to those in patients with normal renal function who received a mean of 148 mCi (5.5 GBq) Na131I. Thus, in patients receiving continuous ambulatory peritoneal dialysis therapy, 5-fold reductions in radioiodine clearance rates require 5-fold decreases in Na131I dosages to avoid excessive radiation doses to total body and red marrow.     

Adequacy testing in peritoneal dialysis: a five years experience in a single dialysis center

BACKGROUND: An increasing number of patients is treated with peritoneal dialysis (PD). Adequacy testing in PD has gained wide interest because of its shown relation with morbidity and mortality. METHODS: We describe retrospectively the 5 years follow-up (1993-1998) of adequacy testing of our PD patient population on 1 January 1998. We were used to change the PD regime if Kt/Vurea was < 1.7. RESULTS: On 1 January 1998 there were 57 patients on PD treatment (41 patients on CAPD, 16 on CCPD). The total PD group adequacy values are given on 1 January 1998. During the 5 years follow-up residual renal Kt/Vurea declined, from a mean value of 0.51 to zero. Mean values of total Kt/Vurea remained unchanged (2.01 at the start, 1.83 at 3 years, 1.91 at 5 years) as a consequence of an increase in peritoneal Kt/Vurea. CONCLUSIONS: We were able to maintain a reasonable dialysis adequacy in time by adjusting the total daily PD fluid amount, despite the total loss of residual renal function in 5 years. However, it will be difficult to reach the newest DOQI guidelines, especially in patients with total loss of their residual renal function and in patients with a larger body surface area.     

The adequacy of peritoneal dialysis in a single Chinese center

ObjectiveTo assess the adequacy of peritoneal dialysis in Chinese by analyzing the relationship between weekly urea kinetics (Kt/V) and clinical outcomes.MethodsA total of 146 patients on continuous ambulatory peritoneal dialysis for more than 6 months in the Shanghai Renji Hospital between July 1997 and March 1999 were enrolled into this study. They were assigned to three groups according to weekly Kt/V: Group A, Kt/V less than 1.7; Group B, Kt/V between 1.7 and 2; and Group C, Kt/V greater than 2. Patient and technique survivals were analyzed by using the log rank method.ResultsThe overall 2-year actuarial patient and technique survivals were 90% and 76%, respectively. The 2-year actuarial patient survival was 78% for Group A, 97% for Group B, and 96% for Group C (p<0.05). The 2-year technique survival was 56% for Group A, 88% for Group B, and 88% for Group C. Both actuarial patient and technique survivals in Group A were significantly lower (p<0.05) compared with the other two groups.ConclusionThe study showed that clinical outcomes in Groups B and C patients were similar. However, patients with weekly Kt/V values less than 1.7 had poorer clinical outcomes compared with patients from groups B and C. We conclude that Chinese patients who were receiving peritoneal ambulatory dialysis may benefit from weekly Kt/V greater than 1.7.     

Ionic dialysance and quality control in hemodialysis

Quantification of dialysis is based on the measurement of effective urea clearance (K), dialysis dose (Kt) or normalized dialysis dose (Kt/V). During the last 20 years, Kt/V was the single parameter actually useful for quantifying dialysis efficiency, because it can be calculated from just blood or dialysate urea concentrations at the beginning and at the end of the dialysis session. However the calculation of the normalized dialysis dose (Kt/V) actually delivered to the patient cannot be performed during each dialysis session, because of the need of urea concentration measurements. Ionic dialysance is a new parameter easily measured on-line, non-invasively, automatically and without any cost during each dialysis session by a conductivity method. Because ionic dialysance has been proved equal to the effective urea clearance taking into account cardiopulmonary and access recirculation, it is becoming an actual quality-assurance parameter of the dialysis efficiency.     

Evaluation of pre- and postdilutional on-line hemodiafiltration adequacy by partial dialysate quantification and on-line urea monitor.

On-line highflux hemodiafiltration (HDF) is a clinically interesting and effective mode of renal replacement therapy, which offers the possibility to obtain an increased removal of both small and large solutes. The fundamental role of urea kinetic monitoring to assess dialysis adequacy in conventional hemodialysis has been widely studied. Both direct measurement of the urea removed by the modified direct dialysate quantitation (mDDQ) based on partial dialysate collection (PDC) and dialysate-based urea kinetic modeling (DUKM) using urea monitor have been advocated. The validity of this assessment tool in the patients with on-line HDF remained unclear. The aims of this investigation were (1) to compare the delivered Kt/V, urea mass removal (UMR), solute removal index (SRI) and normalized protein catabolic rate (nPCR) between pre- and postdilutional high-flux HDF; (2) to verify and compare the efficiency of pre- and postdilutional HDF using DUKM with on-line dialysate urea sensor, and mDDQ with partial dialysate collection. During both mode of HDF, the paired analysis urea removed and Kt/V showed no significant difference. Using mDDQ, mean values for predilutional mode were as follows: Kt/V 1.53 +/- 0.01 UMR, 16.8 +/- 0.3 g/session; urea clearance 178 +/- 18 ml/min; SRI 75.5 +/- 7.7%; urea distribution volume (V) 28.3 +/- 1.2 liters; nPCR 1.34 +/- 0.18 g/kg/day; on the other hand, mean values for postdilutional mode were Kt/V 1.58 +/- 0.01; UMR 17.10 +/- 0.28 g/session; urea clearance 184 +/- 21 ml/min; SRI 77.2 +/- 3.5%; urea distribution volume, 27.8 +/- 1.5 liters; nPCR 1.34 +/- 0.19 g/kg/day. The mean value of urea generation rate was 5.82 +/- 1.12 mg/min during HDF. Our results showed that dialysis adequacy was achieved with both high-volume predilutional HDF and postdilutional HDF. These two modes of HDF provided similar and adequate small solute clearance. In addition, we found that on-line analysis of urea kinetics is a reliable tool for quantifying and assuring delivery of adequate dialysis.     

Assessment of Dialysis Dose in Critically Ill Maintenance Dialysis Patients

Maintenance dialysis patients are admitted more frequently to the intensive care unit (ICU) and have higher ICU mortality than the general population. It is unclear if such dialysis patients receive adequate dialysis in the ICU setting. Using the Daugirdas formula for calculation of spKt/Vurea, single treatment delivered dialysis dose was assessed in 85 critically ill maintenance hemodialysis patients during their first ICU dialysis session. Weekly delivered spKt/Vurea was determined in the surviving 64 patients and compared with their corresponding delivered outpatient dialysis dosages. Outcome measures were ICU and in‐hospital mortality and mortality at 6 and 12 months after discharge. Prescribed dose of the first ICU dialysis was a spKt/Vurea of 1.43 ± 0.11, the single treatment delivered dose was 1.02 ± 0.14. The weekly prescribed ICU Kt/Vurea was 4.25 ± 0.12 and delivered ICU Kt/Vurea was 3.48 ± 0.19. Patients with sepsis had the lowest mean spKt/Vurea values (0.87 ± 0.12). Serial measurements of delivered dialysis dose suggest that this gap is explained by variability of volume of urea distribution. ICU mortality was 25% and was related to APACHE II score, but not to delivered intermittent hemodialysis dose. Critically ill maintenance dialysis patients receive suboptimal dialysis doses. The impact of short‐term underdialysis on survival of hospitalized maintenance dialysis patients remains unknown. Assessment of dialysis adequacy should be routinely performed in these patients and delivered dialysis should be tracked through the initial clinical course.     

Continuous ambulatory peritoneal dialysis. Eight years of experience at a single center

One hundred and thirty-four patients using continuous ambulatory peritoneal dialysis (CAPD) for a mean time of 23.1 +/- 18.3 months (range, 1-76.6) from a single center are reviewed with respect to biochemistry, hematology, parameters of dialysis efficiency, nutrition, and the nature and frequency of complications. Cumulative patient survival was 90%, 86% and 75% at 1, 2 and 3 years, and survival of patients using this technique was 75%, 62% and 40% at corresponding time intervals with no difference demonstrated in diabetic patients or in those older than 50 years. Biochemical and hematologic parameters were well maintained with peritoneal creatinine clearance increasing and peritoneal protein loss remaining stable with ongoing CAPD. Loss of ultrafiltration, however, accounted for 17.7% of permanent transfers to alternative therapy. Low serum albumin and elevated serum triglyceride concentrations correlated with mortality, whereas low serum albumin, low cholesterol, and high phosphate levels correlated with morbidity as assessed by frequency of hospital admissions. Dietary protein intake assessed by urea generation rate was significantly lower than that estimated from a 24-hour dietary recall (0.82 vs. 1.02 g/kg/day, p less than 0.01) and with the exception of body mass index and serum albumin, anthropometric and visceral protein measurements showed few correlations with nutritional adequacy. Bacterial peritonitis remained the major complication, although fungal infections made a significant contribution to morbidity and mortality. Overall, CAPD is confirmed to be a satisfactory form of dialysis for all forms of end-stage renal failure and an integral part of any renal replacement program. However, nutritional adequacy and lowering of complication rates require further investigation.     

Monitoring hemodialysis dose with ionic dialisance in on-line hemodiafiltration

Until now, with the ionic dialysance measurement, it has been possible to determine hemodialysis dose in each session of hemodialysis (HD) and in the conventional hemofiltration (HDF) but not in the modality of on-line HDF. Recently it is possible with a new biosensor that allows to measure the dose in on-line HDF. The aim of this study was to evaluate the value of this biosensor in different dialysis situations comparing the dialysis dose measured in blood in comparison with the values obtained from the sensor. We have analysed 192 hemodialysis sessions performed in 24 patients, 15 male and 9 female, mean age of 70.2 +/- 12 years, included in on-line HDF. All treatments were done using 4008H (Fresenius) monitor equipped with on-line clearance monitoring (OCM), that measure, with non invasive monitoring, the effective ionic dialysance equivalent to urea clearance. Every patient received eight dialysis sessions: one with dialysate flow (Qd) 500 ml/min, two with HD and Qd 800 ml/min and five with on-line HDF. Other habitual haemodialysis parameters were no changed, dialysis time 200 +/- 63 min (135-300) and blood flow 421 +/- 29 ml/min (350-450). Initial and final ionic dialysance values (K), final Kt, Kt/V measured with OCM using V of Watson, and Kt/V determined in blood pre and postdialysis concentrations of urea (Daugirdas second generation), were measured. The mean of initial K was 251 +/- 21 ml/min and the final K was 234 +/- 24 ml/min. The Kt measured with OCM was 50.6 +/- 17 L, 51.2 +/- 17 in men and 49.7 +/- 16 in women. The V (Watson) was 34.5 +/- 6 L. The Kt/V measured with the Kt of OCM and V was 1,499 +/- 0.54 and Kt/V measured in blood samples was 1,742 +/- 0.58. The correlation between both values was 0.956. The Kt was different according to dialysis modality used: in HD and Qd 500 was 44.7 +/- 15 L, in HD and Qd 800 was 50.7 +/- 17 and in on-line HDF (22.1 +/- 7 L of reposition volume), was 51.8 +/- 17 L. The Kt/V from blood samples also shows variation: in HD and QD 500 was 1.60 +/- 0.55, in HD and Qd 800 was 1,726 +/- 0.56 and in on-line HDF was 1,776 +/- 0.59. In this study has been observed a close correlation between the new biosensor OCM with the measures obtained from the blood samples. For this reason this sensor it is useful in all modalities of dialysis treatment, included on-line HDF. The sensor was able to discriminate the efficacy of different dialysis modalities used in this study.     

Hemodiafiltration in hypotension-prone elderly uremic patients

Hemodialfiltration (HDF) has shown good efficiency and cardiovascular stability in stable young hemodialysis patients. The aim of this work was to verify whether this is also valid for a population above the age of 65 on bicarbonate dialysis (BD) with frequent intradialytic hypotension episodes and dialysis intolerance. Nine out of 39 patients older than 65 years (M±SD: 72±3 years) treated by BD at our center, were switched to HDF due to frequent episodes of intradialytic hypotension and dialysis intolerance. Three months before and 3 months after the switch to HDF the number of intradialytic hypotensions, the episodes of nausea, vomiting and headache (dialysis intolerance), the intra- and interdialytic weight gain, the duration of dialysis, Kt/V, serum calcium, serum phosphorus, pH, serum bicarbonate levels and serum creatinine levels were recorded. The dialysis bath, containing 35 mmol/l of bicarbonate and 140 mmol/l Na, was identical in both BD and HDF. During HDF a solution containing 27–30 mmol/l of bicarbonate was infused at a rate of 4l/h. The results have shown a sharp reduction in the hypotensive episodes: BD: 18±4 hypotensions/40 dialyses (45%), HDF 6±3 hypotensions/40 dialyses (15%) (p<0.001), a significant reduction in the episodes of dialysis intolerance: BD 4±2 (10%), HDF 1±1 (2%) (p<0.05), a significant increase in Kt/V (p=0.001), a significant increase in protein catabolic rate (PCRn) (p=0.02) after the switch to HDF. There were no significant variations in body weight, intra dialytic weight loss, duration of dialysis, serum calcium, serum phosphorus, pH, serum bicarbonate, serum creatinine between the two methods. In conclusion, our study shows that patients older than 65 complaining of frequent episodes of dialysis intolerance and hypotension on BD, have a better compliance to volume removal and a better dialysis tolerance after the switch to HDF. This fact is associated with an increase in the dialysis efficiency and improvement in protein intake as evaluated by kinetic criteria.     

Dose of dialysis: what index?

Wider patient acceptance criteria in hemodialysis (HD) programs do not seem to completely explain the increasing mortality reported in the United States at a time characterized by reduced treatment time and dose. This raises the question of HD standard and adequacy. It stimulated us to analyze patient survival with unchanged 'old-times' methods. 445 unselected patients have been treated for 22 years by the same unchanged methods (24 m2/week, flat-plate dialyzers, cuprophane membrane, acetate buffer). Their survival data were compared to major HD registries and series. Survival was also evaluated as a function of mean arterial pressure (MAP), urea fractional clearance (Kt/V), and middle-molecule dialysis index (DI). Kaplan-Meier (with log-rank test) analysis and Cox proportional hazard model were used. Survival at short and long term was better in our series. This favorable survival difference was more obvious for older patients at the start of HD. It could not be accounted for by selection bias, but correlated with good MAP control without medication and with higher than usual Kt/V (1.67 +/- 0.41) and DI (1.47 +/- 0.38). Cox analysis including five covariates confirmed that survival was linked to MAP. It suggested that survival improvement might be expected from a DI increment of over 1.38 but not from a Kt/V increment of over 1.60. Adequate dialysis cannot be reduced to numbers; it should include both sufficient small- and middle-molecule diffusion and ultrafiltration with arterial pressure control without need for antihypertensive medication. The long-term satisfactory survival remains the best index of overall dialysis adequacy.     

The role of hematocrit in efficiency of dialysis

To test the role of hematocrit (Hct), particularly when in the nearly normal range, on efficiency of dialysis, we analyzed the urea kinetics for 36 metabolically and hematologically stable patients on regular dialysis treatment and for 7 patients from this group before and after 3 months of treatment with human recombinant erythropoietin (rHuEPO). The volume of distribution of urea (V), the dialyzer clearance (Kd) and Kt/V were plotted against Hct. Hct showed a significant inverse correlation with Kd (r = 0.479, p = 0.003) and Kt/V (r = 0.572, p = 0.0002). Further division of the patients into groups with respect to Hct showed that the lowest Kt/V values were in the group with Hct greater than or equal to 37%. In the patients treated with rHuEPO, Hct rose from 18 +/- 1 to 35 +/- 5% (p less than 0.0001), and Kt/V decreased from 1.22 +/- 0.21 to 1.09 +/- 0.18 (p = 0.037). We conclude that Hct exerts a negative influence on efficiency of dialysis as evaluated by Kt/V. This is important for patients with normal or nearly normal Hct levels as well as for patients treated with rHuEPO, for whom normalization of Hct is pursued.