Plasma ghrelin levels in patients undergoing haemodialysis and peritoneal dialysis.

BACKGROUND: Ghrelin has been characterized as a relevant physiologic regulator of appetite and body weight in humans. However, the potential relationships between ghrelin levels, inflammation and malnutrition in dialysis patients have not been adequately studied. METHODS: We used a cross-sectional design to study 20 haemodialysis (HD) and 21 peritoneal dialysis (PD) patients, and compared their plasma ghrelin (PGhr) levels with that of an age-matched control group. We also explored correlations between ghrelin and selected hormonal, renal adequacy, nutritional and inflammation markers in both groups. RESULTS: PGhr levels were higher in HD (median 119.8 pg/ml, range 71.1-333.7, P = 0.001) and PD (99.3, range 45.8-578.5, P = 0.045) patients than in healthy controls (78, range 29-158) (HD vs PD, not significant). Ghrelin levels were strongly and inversely correlated with age (r = -0.46, P = 0.02 for patients; r = -0.61, P = 0.001 for controls). Except for a positive correlation between ghrelin and growth hormone (r = 0.48, P = 0.002), univariate analysis failed to detect associations between PGhr and the measured hormonal values, renal adequacy, nutritional indicators and markers of inflammation. However, multivariate analysis revealed significant inverse correlations between PGhr levels and nutritional markers, including subjective global assessment (P = 0.013), albumin (P = 0.001), transferrin (P = 0.01) and protein nitrogen appearance (as an estimate of protein intake) (P = 0.035), after controlling for the confounding effect of age. CONCLUSIONS: PGhr levels were moderately and similarly increased in patients undergoing HD and PD. Age was a strong determinant of PGhr levels, both in uraemic patients and in healthy controls. Dialysis adequacy, residual renal function and inflammation did not appear to influence ghrelin levels in these patients. The negative correlation between PGhr and nutritional markers suggests that low dietary intake causes increases in ghrelin secretion in dialysis patients.     

Citrate regional anticoagulation in haemodialysis

The use of citrate as an anticoagulant in haemodialysis is for patients who are recognised to be at risk if systemically anticoagulated. This paper describes a trial of use of a technically simple procedure involving the use of small volumes of citrate solution. It introduces the measurement of plasma citrate levels in a population of stable patients on regular dialysis treatment. Using synchronous pre- and post-dialyser blood samples, measurement of the whole blood clotting times demonstrated the restriction of anticoagulation to the extracorporeal circulation. It is concluded that citrate anticoagulation is safe, acceptable and simple for use in haemodialysis for patients at risk from systemic anticoagulation.     

Non-invasive monitoring of effective dialysis dose delivered to the haemodialysis patient

Assessment of normalized dialysis dose Kt/V actually deliveredto the patient carries the drawback of requiring several bloodor dialysate samplings and urea concentration measurements.In order to easily quantify Kt/V, we validate here the routineimplementation of an original technique for the non-invasive,on-line, and fully automatic estimation of total mean urea clearance.This estimation is obtained from the measurement by a conductivitymethod of the effective ionic dialysance D_R, which is the dialysanceof electrolytes taking into account ultrafiltration and recirculation. The observed increase in D_R with ultrafiltration rate and decreasein D_R with elevation of access recirculation ratio show thatthe estimation of D_R is affected by ultrafiltration and recirculationin a consistant manner. The mean value K_eff of ionic dialysanceD_R was compared with the value K_dc of effective urea clearanceobtained by dialysate collection during 12 haemodialysis sessions.The similarity (magnitude of variation 5%) between the ionicdialysance K_eff and the effective urea clearance K_dc supportsthe validity of the equivalence between the transfer characteristicsof electrolytes and urea through the dialyser membrane. Givenan estimate of the urea distribution volume V, this estimationof effective urea clearance by ionic dialysance measurementallows an on-line estimation of the normalized dialysis doseKt/V actually delivered to the patient.     

Quality of life on chronic dialysis: comparison between haemodialysis and peritoneal dialysis.

BACKGROUND: Quality of life (QOL) assessment in patients on chronic haemodialysis (HD) or peritoneal dialysis (PD) has only rarely been carried out with the generic Euroqol-5D questionnaire. METHODS: All chronic HD and PD patients in the 19 centres of western Switzerland were requested to fill in the validated Euroqol-5D generic QOL questionnaire, assessing health status in five dimensions and on a visual analogue scale, allowing computation of a predicted QOL value, to be compared with the value measured on the visual analogue scale. RESULTS: Of the 558 questionnaires distributed to chronic HD patients, 455 were returned (response rate 82%). Fifty of 64 PD patients (78%) returned the questionnaire. The two groups were similar in age, gender and duration of dialysis treatment. Mean QOL was rated at 60+/-18% for HD and 61+/-19% for PD, for a mean predicted QOL value of 62+/-30 and 58+/-32% respectively. Results of the five dimensions were similar in both groups, except for a greater restriction in usual activities for PD patients (P = 0.007). The highest scores were recorded for self-care, with 71% HD and 74% PD patients reporting no limitation, and the lowest scores for usual activities, with 14% HD and 23% PD patients reporting severe limitation. Experiencing pain/discomfort (for HD and PD) or anxiety/depression (for PD) had the highest impact on QOL. CONCLUSIONS: QOL was equally diminished in HD and PD patients. The questionnaire was well accepted and performed well. Improvement could be achievable in both groups if pain/discomfort and anxiety/depression could be more effectively treated.     

血液高凝恶性肿瘤患者PICC同步抗凝效果探讨

目的探讨血液高凝状态恶性肿瘤患者经外周静脉置入中心静脉导管(PICC)同步抗凝治疗预防静脉血栓的效果。方法将60例血液高凝状态恶性肿瘤患者随机分为观察组和对照组各30例,对照组PICC置管期间按常规方法预防静脉血栓发生,观察组增加同步抗凝治疗即低分子肝素钠5000U皮下注射,1～2次/d,使用时间≤15d。结果观察组PICC置管后15d血小板计数显著低于对照组,未发生静脉血栓,PICC置管时间显著长于对照组(均P0.01)。结论血液高凝状态恶性肿瘤患者PICC置管同步抗凝治疗可显著改善其血液高凝状态,预防静脉血栓形成,延长PICC置管时间,有利于患者顺利完成治疗。     

Phosphate removal in haemodialysis: Effect of two different dialysis membranes

Summary: Phosphate removal with two different dialysis membranes (a standard cellulose acetate membrane and a high performance cellulose diacetate membrane) were studied in ten haemodialysis patients. All patients were dialysed sequentially with two membranes (surface area was 1.5 m²) against bicarbonate buffered dialysis for 4 hours three times a week. With the diacetate membrane, the instantaneous clearances of urea and phosphate after 1 hour of haemodialysis were significantly higher than with the cellulose membrane. Also, the weekly total amount of urea and phosphate removal were significantly increased with the diacetate membrane (a 15% increase in urea and a 16% increase of phosphate). Although there was a significant increase in urea reduction ratio and significantly lower post dialytic plasma urea concentration with the diacetate membrane, these for phosphate did not reach statistical significance. These data suggest that the use of the diacetate membrane potentially offer clinical benefit. However, whether 16% of phosphate removal could improve clinical control of serum phosphate levels will need further investigation.     

Tandem plasma-exchange and haemodialysis in a paediatric dialysis unit

Background  

The simultaneous use of plasma-exchange (PE) and haemodialysis (HD), known as tandem PE and HD (TPH), may be an additional resource for treating patients who need both therapies at the same time. However, little experience is reported in the paediatric setting.     

Daily haemodialysis: dialysis for the 21st century

SUMMARY: Most patients with end stage renal disease (ESRD) currently undergo haemodialysis three times a week. In an effort to improve morbidity, mortality and quality of life in such patients, several small clinical studies have been conducted to evaluate the benefit of short daily haemodialysis (over 90–120 min) and nocturnal slow haemodialysis (overnight for 8–10 h). Although limited by study design and small patient numbers, the results of these studies offer promise that patients who undergo daily haemodialysis benefit from improved long-term outcomes. the most striking benefits of daily haemodialysis are improved quality of life and better blood pressure control with fewer or no antihypertensive medications. Other advantages of daily haemodialysis include higher haemoglobin levels with lower erythropoietin dosages, better nutrition and improved energy as a result of more physiological and efficient dialysis. Nocturnal haemodialysis has also been reported to improve sleep apnoea and control plasma phosphate concentration. Economic advantages of daily haemodialysis arise as the result of lower medication costs and less expensive at-home care. Early data suggest that there may be improvements in survival and reduced hospitalization in patients who receive daily versus conventional haemodialysis.     

Optimal anticoagulation strategy in haemodialysis with heparin-coated polyacrylonitrile membrane.

BACKGROUND: Binding of polycationic unfractionated heparin onto the modified AN69 polyacrylonitrile membrane, whose surface electronegativity has been neutralized by layering polyethyleneimine (AN69ST), produces stable coating. We investigated whether the heparin-coated membrane was suitable for regular haemodialysis with low heparin doses. METHODS: Sheep were instrumented for extracorporeal circulation perfusing a dialyser equipped with either the AN69ST or the original AN69 membrane. Dialysis sessions were performed after priming the dialyser with heparinized saline. The session was conducted without systemic administration of heparin. In chronic haemodialysis patients, the AN69ST membrane was tested for safety, clotting and thrombin generation according to protocols of 4-h haemodialysis sessions with tapered heparin doses. The goal was to define optimal heparin requirements with the heparin-coated membrane in the setting of continuous or intermittent administration of heparin. Both unfractionated and low molecular weight heparin (LMWH) (enoxaparin) were tested. RESULTS: In sheep, systemic heparin-free haemodialysis was conducted for 6 h without clotting using the heparin-coated dialyser. In the same conditions, massive clotting was observed within 90 min of dialysis with the native AN69 membrane. In man, through kinetic measurements of activated partial thromboplastin time (APTT), heparin anti-Xa concentration and thrombin-anti-thrombin complexes levels (TAT), significant dialyser clotting was avoided when APTT and anti-Xa concentration at 180 min of dialysis, were maintained at >40 s and >0.2 IU/ml, respectively. With the AN69ST heparin-coated membrane, thrombin generation was reduced then suppressed, as compared with the original AN69, primed in the same conditions. Safety of haemodialysis conducted with the AN69ST heparin-coated membrane and low doses of unfractionated heparin (50% reduction of the reference dose) was validated by a survey of 2590 sessions in 32 patients. Doses of LMWH were also safely reduced by 50%. In addition, haemodialysis without systemic administration of heparin was possible with minor risk of clotting. CONCLUSION: During the rinsing phase, the ionic interactions between the new AN69ST polyacrylonitrile membrane and unfractionated heparin induce stable heparin coating. This allows a significant reduction of systemic anticoagulant requirements without increasing the risk of clotting, both in the experimental setting and in the chronic haemodialysis patients. Further studies are required to assess this advantage in patients with acute renal failure and at risk of bleeding and to reduce the metabolic consequences of long-term treatment with heparin.     

Albumin dialysis without anticoagulation in high-risk patients: an observational study

Severe liver failure causes coagulopathy and high bleeding risk. Albumin dialysis with Molecular Adsorbent Recirculating System (MARS) (Gambro, Lund, Sweden) is useful for treatment. However, anticoagulation during its use is of uncertain value. We omitted heparin‐saline priming and intradialytic heparin and examined its effects. Albumin dialysis was performed in critically ill patients with intermittent circuit saline flushes (2664 ± 2420 mL per treatment). A total of 12 patients (M : F = 10:2; age 49 ± 9 years) were thus treated: 6 for fulminant hepatic failure and 6 for acute‐on‐chronic liver failure. The overall hospitalization duration was 31 ± 30 days. A total of 44 treatment sessions were performed (average 8 ± 7 sessions per patient). Prescribed versus achieved MARS duration were 13 ± 3 versus 11 ± 4 h, P < 0.05. Twenty‐three percent (10/44) of MARS sessions clotted, 11% (5/44) of treatments were electively terminated, and 2% (1/44) developed vascular catheter occlusion. Spontaneous bleeding occurred in 9% (4/44). Pre‐ versus post‐MARS systemic and blood circuit transmembrane pressures (mm Hg), and albumin dialysate afferent and efferent pressures were all stable. Coagulation indices were (pre‐ vs. post‐MARS): (i) prothrombin time (seconds): 36 ± 30 versus 42 ± 33, P = 0.143; (ii) activated partial thromboplastin time (seconds): 78 ± 43 versus 88 ± 45, P = 0.117; and (iii) platelet count (×10³/µL): 87 ± 40 versus 76 ± 48, P = 0.004. Systemic blood solute concentrations pre‐ versus post‐MARS were: (i) serum urea (mg/dL): 22.4 ± 19.6 versus 14.0 ± 8.4, P < 0.05; (ii) serum creatinine (mg/dL): 2.8 ± 2.3 versus 1.9 ± 1.5, P < 0.05; (iii) total bilirubin (mg/dL): 29.5 ± 8.8 versus 20.5 ± 5.1, P < 0.05; and (iv) plasma ammonia (µg/dL): 186 ± 85 versus 129 ± 66, P < 0.05. Anticoagulant‐free albumin dialysis remained effective despite frequent circuit clotting. This led to significant exacerbation of thrombocytopenia although bleeding risk remained low.     

The very elderly dialysis patient: Indication and discontinuation of dialysis

1. When the current available data in the literature is summarized it becomes evident that the majority of it supports the position that it is, at least for medical reasons, not advisable to exclude patients over the age of 80 years from chronic dialysis. 2. It is correct to say that the refusal of dialysis therapy for elderly dialysis patients would lead to a not insignificant cutting of costs, although elderly patients are not as 'expensive' as younger dialysis patients. 3. The decision to exclude patients over 80 from dialysis treatment is difficult, in our opinion, to support ethically. 4. The refusal of therapy by a dialysis patient--independent of his age--can only occur with his/her consent, as long as the patient is clearly conscious of the decision. 5. Should the patient no longer be in the condition to exercise his/her autonomy, and there is no AD, the Surrogate's Court must be consulted. 6. AD can be seen as helpful, since they not only make the decisions for physicians easier, but also because they can be seen as an act of care for family members. 7. Whenever dialysis therapy is discontinued the problematic nature of so-called essential care should be carefully considered, especially if no clear position has been taken in an AD.     

Individualized anticoagulation with dermatan sulphate for haemodialysis in chronic renal failure

Background: Dermatan sulphate (DS) is a selective thrombin inhibitor with antithrombotic properties and low bleeding potential. In preliminary studies it was reported to be effective for preventing clot formation in the haemodialysis circuit. Methods: Ten patients on maintenance haemodialysis for chronic renal failure underwent three consecutive investigation phases. In phase 1 (individual dose titration), repeated dialyses were preformed with increasing doses of DS until successful dialysis was obtained in two sessions at the same dose. In phase 2, individualized DS doses were validated by a randomized crossover comparison with the individual heparin dose of each patient. In phase 3, each patient underwent 24 consecutive dialyses with DS over 8 weeks. Successful dialysis was defined as completion of the procedure without visible clot formation in the bubble traps and lines or a greater than 20% decrease in dialyser capacity. Dialysis efficiency (decrease in serum urea and creatinine, Kt/V), APTT prolongation, bleeding time, and DS plasma concentrations were also assessed. Results: Phase 1: successful dialysis was achieved in nine patients with 4 mg/kg DS as a predialysis intravenous bolus followed by continuous infusion of 0.65 mg/kg/h. One patient required 5 mg/kg plus 1.3 mg/kg/h. Phase 2: no statistically significant differences were found between DS and heparin in any of the investigated variables. Residual dialyser capacity and dialysis efficiency indexes indicated equivalent efficacy. Phase 3: residual dialyser capacity and dialysis efficiency did not change with time. There was no accumulation of DS in plasma. No bleeding or thrombocytopenia were observed. Conclusions: The dose of DS can be individually titrated to suppress clot formation during haemodialysis as efficiently as with individualized heparin. Such an individualized DS regimen maintains its anticoagulant efficacy and is safe in prolonged use. Key words: anticoagulation; clinical trial; dermatan sulphate; haemodialysis; heparin      

Determinants of haemoglobin carbamylation in haemodialysis and peritoneal dialysis patients.

BACKGROUND: Carbamylation is an irreversible process of non-enzymatic modification of proteins by the breakdown products of urea. For haemoglobin (Hb), the extent of carbamylation is a marker of urea exposure and has been proposed as an indicator of the control of uraemia by dialysis, analogous to the use of Hb glycosylation in diabetic patients. METHODS: We performed a cross-sectional study of haemodialysis (HD) and peritoneal dialysis (PD) patients in order to study potential determinants of carbamylated Hb (CarbHb) and to investigate the relationship between CarbHb and established measures of dialysis dose/adequacy by multivariate analysis. RESULTS: In 80 HD patients, CarbHb was independently predicted by post-dialysis urea (r=0.40, P:<0.01), serum albumin (r=0.24, P:<0.05) and serum bicarbonate (r=-0.40, P:<0. 05). No correlation was found between CarbHb and measures of dialysis dose/adequacy (Kt/V, urea reduction ratio, weekly dialysis duration, and normalized protein catabolic rate (nPCR)). In 42 PD patients, serum urea was the only significant independent predictor of CarbHb (r=-0.51, P:=0.001). No relationship was found between CarbHb and Kt/V, corrected creatinine clearance (CrCl) or nPCR in PD patients. CONCLUSIONS: Serum urea is the most consistent independent predictor of CarbHb in dialysis patients. This association in combination with the lack of a relationship with conventional measures of dialysis dose and a positive relationship with serum albumin suggest that a single measurement of CarbHb is unlikely to be a useful indicator of the adequacy of dialysis.     

Psychosocial predictors of non-compliance in haemodialysis and peritoneal dialysis patients.

BACKGROUND: Non-compliance with prescribed therapy significantly impacts dialysis patient care and outcomes. The underlying psychosocial issues leading to non-compliance are not well understood, especially in peritoneal dialysis (PD) patients. METHODS: A multicentre cohort of 119 haemodialysis (HD) patients and 51 PD patients was studied. In-person interviews were conducted with patients and clinical and laboratory data were obtained from medical records. Missed and shortened dialysis treatments/sessions and excessive serum phosphate values provided indicators of non-compliance. Patients' perceived health status, perceived self-health care, depression, perceived control over future health, social support, and disease-specific perceived quality of life were measured, along with current smoking status. Associations of predictor variables with non-compliance indicators were examined in univariate and multivariable analyses. RESULTS: Approximately one-third of both HD and PD patients were non-compliant on at least one indicator. Logistic regression models identified a significant association between smoking and each non-compliance indicator. Patient age (younger) also predicted missed treatments. Perceived (negative) effects of kidney disease on daily life, and (decreased) perceived control over future health also predicted shortened treatments. No significant association was found between dialysis modality (HD vs PD) and non-compliance. CONCLUSION: Smoking, one marker of priority placed on health status, and intrusiveness/control issues should be addressed in intervention efforts to improve compliance in patients treated by HD and PD.     

Hepatitis G virus infection in haemodialysis and in peritoneal dialysis patients

The aim of this study was to detect hepatitis G virus RNA (HGV RNA) and antibodies against the virus envelope protein E2 (anti-E2) in 107 patients either on maintenance haemodialysis (n = 78) or peritoneal dialysis (n = 29) to evaluate the prevalence of HGV infection and to establish its role in liver disease. The total prevalence of HGV infection was of 15.4% among haemodialysis patients, whereas it was 10.3% among peritoneal dialysis patients. HGV RNA was detected in 2 haemodialysis patients (2.6%) and in 3 peritoneal dialysis patients (10.3%). Anti-E2 was found in 10 haemodialysis patients (7.8%), whilst all peritoneal dialysis patients resulted negative. In only 1 patient the alanine aminotransferase level was elevated. This patient underwent liver biopsy that did not reveal evidence of chronic hepatitis. The lower HGV prevalence in haemodialysis patients, when compared with data reported by other European authors, should be related to the lower rate of polytransfused patients in our series (29.5%). Multiple blood transfusions should be considered as the main factor to explain the different prevalence of HGV infection among various European dialysis centres. Detection of both antibody and viraemia is important to establish the real rate of the infection.