Search

Background. Citrate anticoagulation is gaining popularity in renal replacement therapies (RRT) for critically ill patients. In order to study whether citrate accumulates in septic shock patients, we determined citrate in plasma and dialysate during continuous venovenous haemodiafiltration (CVVHDF). Methods. An automated routine determination of citrate was set up using a commercial kit (citrate lyase method). Twelve patients with septic shock on CVVHDF and citrate anticoagulation were studied ex vivo for citrate levels in systemic and circuit blood and in the ultrafiltrate (at 0, 0.5, 1, 3, 6, 9, 12, 24, 48 and 72 h). Results. In vitro blood studies showed a near unit correlation between the plasma measured and predicted citrate concentrations for an exclusive extracellular distribution of citrate. Median systemic arterial citratemias were 0.09 (0.06–0.12) mmol/L (Time 0) and 0.23 (0.18–0.31) mmol/ L during treatment; median sieving coefficient for citrate was 0.95 (0.88–1.02) and did not change with different volumes of CVVHDF effluent (from 1350 to 5100 mL/h). Net citrate and calcium removal by filter significantly correlated with effluent volume (r ¼ 0.85 and 0.78, respectively). Median citrate load entering in the patients’ bloodstream was 13.60 (9.1–19.6, n ¼ 68) mmol/h. Although cost analysis of the citrate test demonstrated a minimally increased daily cost (from 2.96 to 3.51V), saving costs could be potentially relevant with more extended use of citrate anticoagulation. Conclusions. In septic shock patients with liver dysfunction citratemia is useful in guiding clinical application of RRT, where the citrate losses in the ultrafiltrate can be efficiently modulated by increasing the effluent volume.

Anticoagulation during renal replacement therapy remains an important challenge for burn patients due to their high risk of bleeding. In this study we compared the efficacy and safety of citrate anticoagulation to heparin anticoagulation for hemodiafiltration (HDF) in severe burn patients, focusing on metabolic tolerance and handling of citrate.Retrospective observational study (January 2000-December 2007) at a university teaching hospital. Among 548 patients admitted with burns, 70 severe burn septic shock patients (median age 57.5 years, interquartile range 42-76 years; median burned surface area 40%, interquartile range 30-60%) who underwent HDF for more than 24 h were included.Of the 70 HDF patients, 31 at high risk of bleeding were treated with citrate and 39 with heparin, with a mortality rate of 70.9 and 71.8%, respectively. In continuous venovenous hemodiafiltration (CVVHDF), the filter survival was higher with citrate, and hemorrhagic complications were lower (0.035 vs. 0.145 episodes/day, respectively). During citrate CVVHDF [median delivered dialysis dose: 578.9 ml kg(-1) day(-1) (461.5-769.2 ml kg(-1) day(-1))] in catecholamine-supported patients (norepinephrine 0.53 μg kg(-1) min(-1)), no metabolic derangements in pH, bicarbonates, Na+, K+, Ca++, and ionized calcium were observed. Systemic citratemia was within the normal range (0.4 mmol/l) and was associated with a marked citrate removal in the effluent (5 patients, 36-60% of infused amount).In septic shock burn patients, citrate for CVVHDF was efficient and safe, and superior to heparin for hemorrhagic complications and filter survival. Observed metabolic stability was most likely due to a marked loss of citrate in effluent volume and subsequent low total citrate load for the patient.

Background. Automatic systems for stabilizing blood pressure (BP) during dialysis are few and only control those variables indirectly related to BP. Due to complex BP regulation under dynamic dialysis conditions, BP itself appears to be the most consistent input parameter for a device addressed to preventing dialysis hypotension (DH). Methods. An automatic system (ABPS, automatic blood pressure stabilization) for BP control by fluid removal feedback regulation is implemented on a dialysis machine (Dialog Advanced, Braun). A fuzzy logic (FL) control runs in the system, using instantaneous BP as the input variable governing the ultrafiltration rate (UFR) according to the BP trend. The system is user-friendly and just requires the input of two data: critical BP (individually defined as the possible level of DH risk) and the highest UFR applicable (percentage of the mean UFR). We evaluated this system’s capacity to prevent DH in 55 RDT hypotension-prone patients. Sessions with (treatment A) and without (treatment B) ABPS were alternated one-by-one for 30 dialysis sessions per patient (674 with ABPS vs 698 without). Results. Despite comparable treatment times and UF volumes, severe DH appeared in 8.3% of sessions in treatment A vs 13.8% in treatment B (� 39%, P ¼ 0.01). Mild DH fell non-significantly (� 12.3%). There was a similar percentage of sessions in which the planned body weight loss was not achieved and dialysis time was prolonged. Conclusions. In conclusion, FL may be suited to interpreting and controlling the trend of a determined multi-variable parameter like BP. The medical knowledge of the patient and the consequent updating of input parameters depending on the patient’s clinical conditions seem to be the main factors for obtaining optimal results.

Continuous renal replacement therapies (CRRTs) have become increasingly popular in the past 10 years. The reasons for their wide acceptance in critical care nephrology are numerous, and all trace b...

Background. As removal of pro-inflammatory cytokines is limited in conventional diffusive or convective extracorporeal therapies, we studied in two polysulphone membranes with an industrial albumin sieving coefficient of 0.05 (Type A) and 0.13 (Type B) cytokine (IL-6, IL-8, IL-1b, IL-1ra, TNF-a) and plasma protein (albumin, cystatin C, total proteins) permeability profiles. Based on the convective membrane permeability, we evaluated in vitro the dialytic modality that could provide an acceptable balance between high cytokine and low albumin clearances. Methods. Cytokine and plasma protein sieving coefficient (SC) and clearance were studied in (i) postdilutional haemofiltration mode at 20% fixed ultrafiltration rate; (ii) haemodialysis mode (dialysate flow rate of 3 and 5 l/h); and (iii) haemodiafiltration mode (dialysate flow rate of 3 or 5 l/h with 0.5 l/h of ultrafiltrate). Results. In haemofiltration mode both Type A and Type B haemodialysers at QB 150 ml/min exhibited similar median SC nearly up to 1 for IL-1b and IL-1ra, at about 0.6 for IL-6, 0.4 for IL-8 and 0.7 for TNF-a, with clearance values ranging from 15 to 30 ml/min. SC were independent of blood flow and were stable throughout the whole experiment. Albumin SC was higher in Type B than in Type A and rapidly decreased from 0.2 to 0.02 and from 0.5 to 0.04 within 3 h for haemodialyser Types A and B, respectively. Cytokine SC was lower in haemodialysis than in haemodiafiltration and haemofiltration mode, and by increasing dialysate flow from 3 up to 5 l/h in both haemodialysis and haemodiafiltration mode, SC for all tested cytokines decreased. However, at 5 l/h clearances were not different or were higher, since increased amounts of dialysate outlet compensated for the decreased SC. Albumin clearances in haemodialysis and haemodiafiltration mode after 360 min at 5 l/h were 0.81 and 0.91 ml/min, respectively. Conclusions. Our studies show that a mixed convective and diffusive technique ensures high cytokine clearances with an acceptable loss of albumin.

Analysis of long-term dialysis results is the cornerstone of renal replacement therapy evaluation. Elderly patients may be considered a crucial cohort, since subtle differences may be enhanced in a population of lower life expectancy. The aim of the study was an analysis, from the Piedmont Registry of Dialysis and Transplantation, of the results obtained in 1981-1992 (northern Italy, about 4,400,000 inhabitants, 21 dialysis centres, open acceptance since mid-1970s) in patients aged > or = 65 years (475 patients started treatment in 1981-1985, 1026 in 1986-1992). As a first treatment, during the 12 years considered acetate haemodialysis decreased sharply; bicarbonate haemodialysis is currently the standard treatment (68%). Peritoneal dialysis is stable (21%), and haemodiafiltration is increasing (8%). Shifts between treatments are frequent: 15% of elderly patients changed treatment at least once in 1991-1992. Nephroangiosclerosis/ischaemic renal disease, undefined causes and diabetes mellitus are the major causes of end-stage renal disease; 57.3% of patients have high risk conditions in addition to age. In this cohort of patients, mean age of new cases starting dialysis significantly increased in 1986-1992 (72.7 +/- 5.4 years) versus 1981-1985 (71.3 +/- 4.5; P < 0.001). Despite this, survival at 2 years increased significantly from 54.6% in the period 1981-1985 to 59% in the period 1986-1992 (P < 0.05). Even in an ageing dialysis population, therefore, choice of an open dialysis system with easy changes among treatments allowed improvement of survival results; further technical advances may help in maintaining present trends.

Renal alterations such as proteinuria, hematuria, and electrolyte disturbances are common in patients with severe burns. Two distinct pictures with an early and a late form of acute kidney failure (ARF) have been described: The early form occurs in the immediate postburns period and can in most cases be effectively prevented by early aggressive fluid resuscitation. The late form develops after 2–3 weeks from initial injury and is usually due to sepsis and multiorgan dysfunction syndrome. In the last 20 years, onset and outcome of acute kidney failure in these patients has been improved by early aggressive burn wound excision, new powerful antibiotics, and early enteral nutrition for maintaining gastrointestinal trophism. In patients with established ARF, early intensive extracorporeal treatment is effective in reaching a mean survival rate of 20–50% of treated patients.

Background: In high-risk bleeding conditions conventional systemic anticoagulation with heparin is a contraindication to renal replacement therapy. We evaluate the feasibility and safety of regional citrate anticoagulation in high-risk bleeding conditions during coupled plasma filtration adsorption (CPFA). Methods: Thirteen critically ill patients (9 severely burned, 4 polytraumas) with septic shock and acute renal failure treated with CPFA-CVVHD by using bicarbonate-based solutions (heparin-CPFA group, 58 sessions) or with CPFA-CVVHF using citrate (citrate-CPFA group, 36 sessions). Results: Plasma flow and used cartridges showed no differences between the citrate-CPFA and heparin-CPFA groups, while lost clotted cartridges were significantly lower in the citrate-CPFA group. Blood ionized calcium (iCa2+), Ca2+ infusion, pH and bicarbonates remained constant during citrate-CPFA, with no difference between pre- and post-cartridge plasma citrate. A significant positive correlation between iCa2+ in blood and ultrafiltrate was present. Conclusions: These results demonstrate the feasibility and safety of regional citrate anticoagulation in severely burned and polytrauma septic patients treated by CPFA.