Acute kidney injury in critically-ill adult patients with seasonal influenza infection.

BACKGROUND: Acute kidney injury (AKI) occurs in 22.4 - 100% of critically-ill hospitalized patients with influenza infection. In up to 2/3, it is severe enough to necessitate renal replacement therapy. We aimed to document the incidence of AKI among patients with influenza-related critical illness and its relation to clinical outcomes. METHODS: We conducted a retrospective observational study of all adult patients with acute respiratory illness and laboratory-confirmed influenza infection admitted to non-surgical intensive care units at the University Medical Centre Ljubljana between January 1, 2016, and March 31, 2016. RESULT: Our sample consisted of 28 adult patients with mean age in years of 57.5 ± 20.2. Incidence of AKI was 71.4%. Mortality was 28.6% (35% in patients with AKI and 41.6% in patients who required renal replacement therapy). CONCLUSIONS: Influenza-related critical illness is rare but can cause AKI in a large proportion of affected patients. In this setting, requirement for renal replacement therapy could be associated with increased mortality risk.
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Does Guidewire Exchange Influence Infection Rate Related to Catheters Used for Vascular Access in Children on Chronic Hemodialysis?

A central venous catheter (CVC) can either be inserted "de novo" or placed by guidewire exchange (GWE). From September 1998 to September 2015, 32 children (19 boys, 13 girls) were hemodialyzed in our unit by using a CVC. The mean age at CVC insertion was 12.6 ± 0.5 years. A total of 121 uncuffed catheters were placed, either "de novo" or by GWE in 64 (52.9%) and 57 (47.1%) cases, respectively. The most frequent cause for line revision was catheter dysfunction in 40/121 (33.1%) patients. The overall incidence of bacteremia was 1.5/1000 catheter-days. The incidence in newly inserted and GWE catheters was 1.4 and 1.7/1000 catheter-days, respectively. The difference did not reach statistical significance (P = 0.939). The infection rate correlated with patient age, and was higher in younger children (P = 0.006). GWE is an effective option of line revision, and did not influence the infection rate in our study.

Citrate Extended High Cut-Off Hemodiafiltration for Renal Recovery in Patients With Multiple Myeloma.

We proposed a combination of convective and diffusive transport mechanisms as high cut-off (HCO) post-dilution hemodiafiltration dialysis technique to optimize serum immunoglobulin free light chains (FLCs) removal which may improve dialysis dependent renal failure in patients with multiple myeloma. To reduce bleeding risk regional citrate anticoagulation was successfully used for the first 7 h followed by 1 h anticoagulant-free hemodiafiltration to avoid citrate accumulation. We retrospectively assessed the effect of FLCs reduction on the renal outcome of 28 patients treated with 133 citrate extended post-dilution HCO (Theralite 2100; Gambro, Lund, Sweden) hemodiafiltration sessions between 2010 and 2016. Renal recovery was demonstrated in 61% of all patients. Twenty-three patients achieved more than 50% reduction of FLCs concentrations and 88% of those became dialysis independent. Our experience supports the extended citrate HCO hemodiafiltration as a good treatment strategy that enable a sustained reduction in serum FLCs concentration and recovery of renal function.

Temporary Catheters as a Permanent Vascular Access in Very Elderly Hemodialysis Patients: Frequency of Complications and Interventions.

The choice of vascular access in very elderly hemodialysis patients can be complex. Data on the frequency of interventions and complications when temporary catheters are used for long periods in this population are lacking. All incident patients ≥80 years old, dialyzed over non-tunneled catheters, were included and the frequency of interventions (re-insertions and wire-exchanges) and complications (catheter-related blood stream infections) were recorded. In 31 patients aged 84 ± 4 years, dialyzed for 1.4 ± 1.1 years, 87 interventions were needed (2.02/patient-year). The median time to first intervention was 5.5 months and the 1-year intervention-free rate was 32%. There were three catheter-related blood stream infections (0.2/1000 access-days), comparing favorably to tunneled catheters. To conclude, temporary catheters are associated with a low rate of complications and an acceptable rate of interventions. Therefore, they could be the optimal vascular access in very elderly patients when the placement of an arterio-venous fistula is not feasible.

Chronic Hemodialysis in Small Children.

When peritoneal dialysis is inapplicable, chronic hemodialysis (HD) becomes the only available treatment option in small children. Due to small patient size, central venous catheters (CVC) are mainly used for vascular access. Over the past 4 years, four children weighing less than 15 kg received chronic HD in our unit. A total of 848 dialysis sessions were performed. Altogether, 21 catheters were inserted. In all but one occasion, uncuffed catheters were used. Catheter revision was performed 15 times during the study period, either due to infection or catheter malfunction. The median number of catheter revisions and the median line survival was 3.0/patient-year and 53 days (range; 6-373 days), respectively. There were 14 episodes of catheter related infections requiring 11 CVC revisions (78.6%). The median rate of line infections was 2.8/patient-year. Chronic HD in small children is demanding and labor intensive. Issues pertain mainly to CVCs and limit its long-term use.

Fate of Central Venous Catheters Used for Acute Extracorporeal Treatment in Critically Ill Pediatric Patients: A Single Center Experience.

Renal replacement treatment (RRT) is required in severe acute kidney injury, and a functioning central venous catheter (CVC) is crucial. Twenty-eight children younger than 16 years have been treated at the University Medical Centre Ljubljana between 2003 and 2012 with either acute hemodialysis (HD) and/or plasma exchange (PE), and were included in our study. The age of the patients ranged from 2 days to 14.1 years. Sixty-six CVCs were inserted (52% de novo, 48% guide wire). The sites of insertion were the jugular vein in 20% and the femoral vein in 80%. Catheters were in function from 1 day to 27 days. The most common cause for CVC removal or exchange was catheter dysfunction (50%). CVCs were mostly inserted in the femoral vein, which is the preferred site of insertion in acute HD/PE because of the smaller number of complications.

Use of myoglobin as a marker and predictor in myoglobinuric acute kidney injury.

Serum creatine kinase (CK) is routinely used as a marker in the assessment of rhabdomyolysis and acute myoglobinuric kidney injury (Mb-AKI), while the use of myoglobin is much less explored in this respect. We retrospectively analyzed the incidence of Mb-AKI (creatinine [Cr] > 200 µmol/L) and the need for hemodialysis (HD) in 484 patients (70.5% males) with suspected rhabdomyolysis, grouped according to peak serum myoglobin (A: 1-5 mg/L, B: 5-15 mg/L, C: >15 mg/L). The median peak myoglobin was 7163 µg/L. Both peak Cr and peak CK were significantly higher in group C. The incidence of Mb-AKI was 24.6% in group A, 38.6% in group B (P < 0.01 vs. group A), and significantly higher (64.9%) in group C (P < 0.001 vs. groups A and B). Fifty-one patients (10.5%) needed HD, the proportion increasing from 6.7% in group A, and 12.3% in group B (NS), to 28.1% in group C (P < 0.001 vs. group A, P 0.01 vs. group B), and reaching 36.8% with myoglobin >20 mg/L. Creatine kinase correlated with the severity of rhabdomyolysis, but less so with Mb-AKI. The peak Cr levels were not significantly different between patients divided by CK 60 µkat/L, or grouped into CK tertiles or quartiles. A significant proportion of patients with rhabdomyolysis experienced Mb-AKI, whose frequency increased in parallel with myoglobin levels. Myoglobin levels above 15 mg/L were most significantly related to the development of AKI and the need for HD. Blood myoglobin could serve as a valuable early predictor and marker of rhabdomyolysis and Mb-AKI.

Some kinetic considerations in high cut-off hemodiafiltration for acute myoglobinuric renal failure.

The kinetics of myoglobin in severe rhabdomyolysis and dialysis-dependent myoglobinuric acute kidney injury (Mb-AKI) is still not well elucidated, and more detailed knowledge could improve the now empiric use of rapid extracorporeal myoglobin removal by high cut-off (HCO) hemodialysis treatments. Eighteen adult patients with severe dialysis-dependent Mb-AKI (median serum concentration of myoglobin 57.4 mg/L) participated in the prospective clinical study, assessing myoglobin kinetics during HCO hemodiafiltration (HCO HDF). High initial serum concentrations of myoglobin (median 57.4 mg/L), together with protracted myoglobin appearance in the blood, indicated a large accumulation of myoglobin in body fluids. Extra-renal endogenous metabolic myoglobin clearance was delayed, with a slow exponential fall in serum myoglobin (t½ 35 h). A mean myoglobin clearance of 90-94 mL/min, a reduction ratio of 80%, and a rapid exponential fall (t½ 1 h) in serum and dialysate myoglobin were achieved by HCO HDF. Half of the cumulative myoglobin removal was accomplished in 3-5 h, with an additional removal of 7% each hour thereafter. A 2.4-fold rebound in serum myoglobin followed the HCO procedures. Large amounts of myoglobin are released into the circulation, and its endogenous metabolic clearance in dialysis-dependent Mb-AKI is slow. Owing to its rapid and highly efficient myoglobin elimination, HCO HDF may represent a valuable tool in the initial management of severe Mb-AKI, with a potential for earlier application in the future.

Dialysis patients after kidney graft failure: Slovenian experience.

Increased mortality has been reported in patients starting dialysis after kidney graft failure. In this study we analyzed this subgroup of dialysis patients based on the data from the Slovenian Renal Replacement Therapy Registry. Patients starting dialysis after graft failure in the period between 2004 and 2008 were identified from the registry. Demographic, clinical and treatment data, as well as survival were compared to incident dialysis patients, who were on the waiting list or preparing for enrollment. There were 49 patients starting dialysis after 7.9 ± 6.4 years spent with a functioning graft and a total of 13.7 ± 7.4 years on renal replacement therapy. Their mean age was 48.3 ± 11.0 years (vs. 48.2 ± 13.9 years in incident patients, P = 0.96), 53% were male, and all were on hemodialysis. By the end of 2008, 8 (16%) patients had been re-transplanted (after a median of 27.5 months) and 11 (23%) had died (after a median of 1.4 months of dialysis). The cause of death was infection in five patients, a cardiovascular event in three, malignancy in two, and a cerebrovascular event in one patient. Deceased patients were significantly older, but similar to survivors in other parameters. Unadjusted one- and three-year survival rates after graft failure were both 77%, which was significantly worse than in incident patients (P < 0.001). To conclude, patients after graft failure have increased mortality in the first year after starting dialysis, but patients surviving the first year have good survival thereafter. Studies focusing on the early period after graft failure are necessary to improve outcomes.

High cut-off membrane hemodiafiltration in myoglobinuric acute renal failure: a case series.

Acute renal failure is a major complication of rhabdomyolysis. New membranes for hemodialysis have been developed with a high cut-off pore size allowing efficient removal of myoglobin. We report on six patients treated by hemodiafiltration with a high cut-off membrane (HCO-HDF) for myoglobinuric acute renal failure. Rhabdomyolysis was caused by infection in two patients, by a statin in one patient and a non-traumatic crush in another, and followed cardiovascular surgery in two others. Ten HCO-HDF procedures were performed. A high cut-off hemofilter was used, with citrate anticoagulation and postdilutional fluid substitution of 2-3 L/h, dialysate flow 500 mL/min, and blood flow within 250-300 mL/min. Albumin losses were replaced by infusion of human albumin solution, and the mean myoglobin reduction ratio was 77% (range, 62-89%). An excellent clearance of 81 mL/min (range 42-131 mL/min) was achieved. Nearly 5 g of myoglobin was removed into the dialysate collected in one of the procedures. A high rebound in serum myoglobin, on average to 244% of the post-procedure myoglobin level, was observed. The four patients alive at the time remained anuric for a week. Slow myoglobin elimination with a mean half-time of 39 h (range 19-59 h) was observed in that period. Highly efficient myoglobin removal by high cut-off membrane hemodiafiltration was demonstrated in our patients. Rapid redistribution from the extracellular fluid and sustained myoglobin release were suggested by the high rebound observed. Elimination of myoglobin within the body was shown in our study to occur slowly during the period of anuria.

Vascular access in children on chronic hemodialysis: a Slovenian experience.

The aim of our study was to report our experience with arteriovenous fistulas (AVFs) and non-cuffed central venous catheters (CVCs) in children and adolescents with end-stage renal disease (ESRD) on hemodialysis (HD). The children with ESRD (18 years or younger) who were hemodialyzed at the Center of Dialysis and Transplantation, Children's Hospital, Ljubljana, in the period between December 1998 and December 2010 were included in our retrospective study. We recorded the data considering the CVCs and AVFs used for HD. Thirty-one children (13 females, 18 males) with ESRD received HD treatment. The mean patient age when HD was started was 13.3 ± 3.4 years. Altogether, 35 AVFs were created, and the primary failure rate was 25.7% (9/35). The time to maturation was 4.0 ± 2.5 months. The mean patency of the AVF was 42.5 ± 51.9 months. Seventy-seven CVCs (non-cuffed) were inserted in the observation period; 89.6% of the CVCs were inserted in the jugular vein, and citrate locking was used in the interdialysis period. The CVCs were removed after 0.1-17.4 months (3.6 ± 3.7 months). The incidence of bacteremia was 0.9 episodes per 1000 catheter days. The preferred vascular accesses for pediatric hemodialysis are native AVFs; however, a single lumen, non-cuffed, citrate-locked CVC placed in a jugular vein can be acceptable as a long-term vascular access when AVF cannot be constructed or used.

Surgical thrombectomy of thrombosed arteriovenous grafts by interventional nephrologists.

The aim of our retrospective study was to present the success of surgical thrombectomy in acutely thrombosed, arteriovenous (AV), expanded polytetrafluoroethylene (ePTFE) grafts. Patients from hemodialysis centers in Slovenia were admitted to our dialysis center after acute thrombosis of their AV graft to undergo surgical thrombectomy under local anesthesia as an outpatient procedure. In 55 chronic hemodialysis patients, of whom 26 were men (47.3%), with a mean age of 63 ± 13 years (range 35-84 years), and diabetes mellitus in 11 patients (20%), 59 ePTFE AV grafts thrombosed. A total of 129 thrombectomies were performed, on average 2.2 ± 2.1 per graft (range 1-13). Primary patency (defined as the time from AV graft creation to first thrombosis) was 638 ± 633 days (range 10-2586, median 418 days), secondary patency (defined as the time from first thrombectomy to abandonment) was 451 ± 472 days (range 0-1994, median 305 days), and cumulative patency (defined as the time from creation to abandonment) was 1089 ± 685 days (range 25-3020, median 1031 days). In 46 (78%) of the AV grafts, the first thrombectomy was successful. The secondary patency rates after 1, 2, 3, 4, and 5 years were 76%, 66%, 54%, 14%, and 14%, respectively (13/59 unsuccessfully thrombectomized grafts were excluded). Cumulative patency after 1, 2, 3, 4, and 5 years was 88.1%, 67.8%, 44.7%, 27.1%, and 16.9%, respectively. In conclusion, surgical thrombectomy after thrombosis of an AV graft in the arm or thigh, performed by interventional nephrologists and followed, if required, by angioplasty, significantly prolonged the patency of the majority of thrombosed AV grafts.

Two single-lumen noncuffed catheters in the jugular vein as long-term vascular access: a preliminary report.

Two single-lumen, noncuffed catheters in the same jugular vein have been used as preferred vascular access in our hemodialysis (HD) and apheresis patients in past years. The aim of this retrospective study was to analyze the clinical outcome of such a vascular access and the reasons for catheter removal. In 129 adult patients, aged 69 ± 13 years, 56% males, treated by HD (121 patients) or apheresis (8 patients), two single lumen, pre-curved 8 Fr catheters (Medcomp, Harleysville, PA, USA) inserted into the same jugular vein were used as vascular access between January 2009 and April 2010. The catheters were inserted into the left jugular vein in 21 patients, and into the right jugular vein in 108 patients. A 30% solution of trisodium-citrate was used as a locking solution, and 2% mupirocin ointment was routinely applied to the exit site. The catheters were removed in 86 patients after 1-288 days, median 17.5 days. In 74 patients, there was either no need for further dialysis or an arteriovenous fistula was constructed (17 patients). In 10 patients, wire exchange was performed for correction of a displaced functional catheter (after 6-201 days), and in only two patients the catheters were removed due to infection on days 10 and 184. The longest period of a catheter functioning without intervention was 387 days. Fifteen patients died with functional catheters left in place (duration 1-387 days). In four patients, the catheters were still functional at the time of analysis (duration 198-268 days). Another nine patients were transferred to other dialysis centers (after they had been followed up at our center lasting for 1-63 days), with no data on their outcome after transfer. Fifteen patients were lost to follow up after insertion. Two single-lumen, noncuffed catheters in the same jugular vein, locked with 30% citrate, seem to be a safe and long lasting method of vascular access for hemodialysis and apheresis in some patients, but further prospective studies are needed to evaluate the clinical outcome of this type of vascular access.

The influence of need-based, continuous, low-dose iron replacement on hemoglobin levels in hemodialysis patients treated with erythropoiesis-stimulating agents.

Anemia is a common and important complication of chronic kidney disease. Treatment includes the use of erythropoiesis-stimulating agents (ESAs) and iron supplementation. However, the optimal schedule of iron supplementation remains to be defined. Thirty-one long-term hemodialysis patients were treated for 1 year (period 1) with ESAs and an intermittent pulse regimen consisting of 100 mg of iron sucrose administered after different dialysis sessions depending on serum ferritin and other laboratory values, but no more than once per week. During the next 3 years (period 2), patients were treated with ESAs and need-based, continuous, low-dose iron. Iron doses were determined on the basis of values and changes of serum ferritin and transferrin saturation every fourth week after the longest interdialysis time interval. Iron doses ranged from 10 to 60 mg of iron sucrose and were given 1-3 times per week. If grounded, we gradually reduced or even abolished the iron doses. A significant increase in the hemoglobin concentration and hematocrit during period 2 in comparison with period 1 was observed. The use of ESAs did not change significantly during period 2 in comparison with period 1, while the use of iron was significantly lower in period 2. Significantly lower values were obtained for serum ferritin, saturation of transferrin, serum iron, and total serum iron-binding capacity during period 2. A better response to ESA therapy (increase in hemoglobin and hematocrit) is achieved with need-based, continuous, low-dose iron replacement.

Treatment of hyperlipidemic acute pancreatitis with plasma exchange: a single-center experience.

Of the cases of acute pancreatitis, 1-7% are caused by severe hypertriglyceridemia and can be treated with plasma exchange (PE). We report on a large series of patients with acute hyperlipidemic pancreatitis (HLP) treated with PE. In the 1992-2008 period, 50 patients (45 +/- 8 years old, 92% male) with acute HLP were treated with PE, during which 1-2 plasma volumes were exchanged. Heparin was used as anticoagulant in 85% of the procedures, and citrate in the rest. Cholesterol and triglycerides were measured before and after PE. In the 2003-2008 cohort of 40 patients, we retrospectively recorded an Acute Physiology and Chronic Health Evaluation II (APACHE II) score at the first PE session, hospital mortality, and length of hospital stay. A total of 79 PE treatments were done, 1-5 per patient. The volume exchanged was 4890 +/- 1300 mL over a duration of 3.5 +/- 2 h. During the first PE, the triglycerides were lowered from 58.9 +/- 40.8 to 10.8 +/- 10.8 mmol/L, and the total cholesterol was lowered from 20.0 +/- 7.6 to 5.7 +/- 4.3 mmol/L. In 10% of the procedures the plasmafilter was replaced, and in 3% the filter was clotted. Hypotension occurred in 3% of PE and there was one case of gastrointestinal bleeding after PE with heparin anticoagulation. In the 2003-2008 cohort, the median APACHE II score was 5 (range 0-15), the median overall hospital stay was 18 days (range 3-142 days) and the hospital mortality was 15%. To conclude, in acute hyperlipidemic pancreatitis, one to two plasma exchanges effectively reduce the serum triglyceride level. There is a low rate of procedure-related complications. A mortality rate of 15% is considerable.

Membrane plasma exchange for the treatment of thrombotic thrombocytopenic purpura.

The aim of our report is to present our 11-year experience with therapeutic membrane plasma exchange therapy for the treatment of idiopathic thrombotic thrombocytopenic purpura syndrome (TTP). In 56 patients, membrane plasma exchange therapy was initiated immediately and performed once or twice daily until the platelet count normalized. During each plasma exchange procedure, 1-1.5 plasma volumes (3606 +/- 991 mL) were replaced with fresh frozen plasma. In 37 females and 19 males (44 +/- 21 years), 1066 plasma exchange procedures were performed. The average duration of treatment was 23 +/- 17 days. The average number of plasma exchanges was 19 +/- 17 per patient. Renal impairment was detected in 36% of patients. At the initiation of plasma exchange treatment, the average platelet count was 31 +/- 30 x 10(9)/L and reached 199 +/- 95 x 10(9)/L thereafter. Fifty-two of 56 (93%) patients demonstrated an excellent response to plasma exchange therapy, of whom 48 patients (86%) attained complete remission with a platelet count of more than 100 x 10(9)/L. Four patients died soon after the initiation of plasma exchange therapy, when only 1-3 procedures had been performed. During the follow-up period, six patients with complete remission had 1-5 subsequent relapses each year. One of them died of acute hemolytic reaction during the tapering of plasma exchange procedures. Three patients underwent additional splenectomy. Our experience with primary TTP supports the plasma exchange treatment with fresh frozen plasma as a mandatory, up-to-date therapy. Close monitoring during all 1066 procedures showed no serious side-effects.

Hemodialysis catheters with citrate locking in critically ill patients with acute kidney injury treated with intermittent online hemofiltration or hemodialysis.

The purpose of the study was to compare the long-term catheter-related complications associated with temporary untunneled hemodialysis catheters, locked with citrate in the interdialysis period, inserted in critically ill patients with acute kidney injury, between different catheter insertion sites (femoral vs. jugular and subclavian) and catheter types (single-lumen [SL] vs. double-lumen [DL]). In a retrospective clinical study, the long-term catheter-related complications in 290 critically ill patients treated with intermittent high-volume online hemofiltration or hemodialysis between December 2004 and January 2008 were analyzed. Among 534 inserted catheters, 493 (92.3%) were femoral, 29 (5.4%) jugular, and 12 (2.3%) subclavian; 304 (56.9%) were SL and 230 (43.1%) were DL. There were 125 (20.3/1000 catheter days [c.d.]) thrombotic complications, while infectious complications were exceptionally rare, that is, only 13 (2.1/1000 c.d.), of which 10 (1.6/1000 c.d.) were possible catheter-related bloodstream infections and 3 (0.5/1000 c.d.) exit-site infections. The incidence rate of all thrombotic complications was significantly lower in all jugular and subclavian vs. all femoral catheters (7.7/1000 c.d. vs. 21.8/1000 c.d., P = 0.01), and in all SL vs. DL catheters (11.4/1000 c.d. vs. 32.2/1000 c.d., P < 0.001). The incidence rate of any possible catheter-related bloodstream and exit-site infections was not significantly different in all jugular and subclavian vs. all femoral catheters, neither in femoral SL vs. DL catheters. The major long-term catheter-related complications were thrombotic, and significantly more frequent in DL vs. SL catheters. Infectious complications were exceptionally rare, most probably due to the strict catheter care protocol, as well as the routine use of a citrate catheter lock and antibiotic ointment at the catheter exit-site.

Subcutaneous compared with intravenous epoetin treatment in patients on hemodialysis: one center study.

The use of epoetin has, in Europe, been restricted to the intravenous (i.v.) route in patients on hemodialysis. This study is aimed at investigating impacts of this change in policy. We retrospectively compared 45 hemodialysis patients treated with epoetin (alpha, beta) subcutaneously (subcutaneous [s.c.] period) for 12 months before and 12 months after changing the route from s.c. to i.v., and 38 patients of the i.v. period who underwent long-term, i.v. low-dose iron therapy (i.v. iron period) for 6 months. During the study period, the dose of epoetin increased in the i.v. period compared to the s.c. period by 6.4% (7379 +/- 3556 IU/week [median 7846] vs 6907 +/- 3842 IU/week [median 5846], respectively [NS]). During the i.v. iron period, patients began to receive regular i.v. iron. The postiron epoetin dose was 5923 +/- 4779 IU/week (median 4500). The dose was decreased in comparison with the s.c. and i.v. periods by 14.2% and 19.7%, respectively. Hemoglobin decreased in the i.v. period compared to the s.c. period (120.4 +/- 8.0 g/L vs 123.5 +/- 6.7 g/L [P < 0.01]), and increased in the i.v. iron period compared to the s.c. and i.v. periods ([126.5 +/- 9.9 g/L vs 123.5 +/- 6.7 [P < 0.01]), and vs 120.4 +/- 8.0 (P < 0.01)]. Changing the route of administration of epoetin required an insignificant increase in dosage. Regular low-dose iron improves the response to epoetin and lowers the dose of epoetin, even in cases when the intravenously administration route is used.