The association of overhydration with chronic inflammation in chronic maintenance hemodiafiltration patients.

INTRODUCTION: Achieving euvolemia is one of the major challenges when treating end-stage renal disease (ESRD) patients receiving maintenance renal replacement therapy. Fluid overload is recognized as an independent predictor of mortality in ESRD, but its association with chronic inflammation is less well explored especially in chronic maintenance hemodiafiltration. METHODS: We performed a cross-sectional study of 87 prevalent ESRD patients receiving chronic maintenance hemodiafiltration (vintage 66.5 ± 57.1 months) with bioimpedance analysis to characterize the degree of percent overhydration (OH%). We also compared the levels of inflammatory markers, including C-reactive protein (CRP), serum albumin, neutrophil/lymphocyte ratio (NLR), and hemoglobin red cell distribution width (RDW) for the overhydrated (OH% ≥ 15%) versus euvolemic (OH% < 15%) groups. Linear regression analysis was performed to explore relationships between the degree of OH and inflammatory indicators. FINDINGS: The cohort represented an all-European population with a mean age of 60.9 ± 14.7 years and prevalence of diabetes mellitus of 27%. The entire cohort's OH% was 14.9% ± 5.1% (range -11.1% to 39.0%); further, the <15% group of patients' OH% was 8.0% ± 8.5% versus 20.9% ± 5.1% in the OH% ≥ 15% group (P < 0.0001). Forty-seven patients (53%) were overhydrated by traditional criteria (OH% ≥15%) and 20 patients (23%) were severely overhydrated (OH% > 20%). The euvolemic (OH% <15%) versus severely overhydrated (OH% > 20%) groups had significant differences in markers of inflammation: CRP (9.8 ± 10.6 vs. 21.5 ± 21.6 mg/L, P < 0.006), serum albumin (37.6 ± 02.9 vs. 34.5 ± 5.3 g/L, P < 0.004), and NLR (3.06 ± 1.25 vs. 3.92 ± 2.04; P < 0.004). On linear regression, significant correlations were found between OH% and CRP (r = 0.2899, P < 0.006), serum albumin (r = -0.3670; P < 0.0005), RDW (r = 0.2992; P < 0.005), and NLR (r = 0.2900; P < 0.006). DISCUSSION: In a prevalent hemodiafiltration cohort, OH was common and correlated with several inflammatory markers.

Successful Practice Transitioning Between Hemodialysis and Hemodiafiltration in Outpatient Units: Ten Key Issues for Physicians to Remember.

Hemodiafiltration (HDF) during chronic renal replacement therapy (RRT) is a relatively new practice phenomenon, emerging over the last two decades. While the technological platforms utilized during chronic RRT are in many cases similar or effectively identical to conventional hemodialysis (HD), significant differences may emerge in daily practice. Several authors of this review moved practice site between the United States and the European Union and transitioned from an HD-based practice to predominantly HDF-practicing networks. In doing so, we became keenly aware of the potential pitfalls nephrologists may be facing during such transitions. This brief review is intended to provide a succinct overview of several practical concerns and complications nephrologists may encounter in daily practice of end-stage renal disease care, including but not limited to management of electrolytes, renal anemia and treatment goals and settings during HDF.

Peritoneal dialysis: The unique features by compartmental delivery of renal replacement therapy.

Despite decades of research, the clinical efficacy of peritoneal dialysis (PD) remains enigmatic. We may wonder why the modality fail in some patients but perhaps the more proper question would be, why it works in so many? We know that the contribution of residual renal function (RRF), more so than in hemodialysis, is critically important to the well-being of many of the patients. Unique features of the modality include the relatively low volume of dialysate fluid needed to provide effective uremic control and the disproportionate tendency for both hypokalemia and hypoalbuminemia, when compared to hemodialysis. It is currently believed that most uremic toxins are generated on the interface of human and bacterial structures in the gastrointestinal tract, the intestinal biota. PD offers disproportionate removal of these toxins upon "first-pass", i.e., via PD fluid exchanges before reaching the systemic circulation beyond the gastrointestinal compartment. Studies examining the net removal gradient of protein-bound uremic toxins during PD are scarce, whereas RRF receives considerably more attention without effective interventions being developed to preserve it. We propose an alternative view on PD, emphasizing the modality's compartmental nature, both for its benefits and the limitations.

Volume-related weight gain as an independent indication for renal replacement therapy in the intensive care units.

Attempts to identify specific therapies to reverse acute kidney injury (AKI) have been unsuccessful in the past; only modifying risk profile or addressing the underlying disease processes leading to AKI proved efficacious. The current thinking on recognizing AKI is compromised by a "kidney function percent-centered" viewpoint, a paradigm further reinforced by the emergence of serum creatinine-based automated glomerular filtration reporting over the last two decades. Such thinking is, however, grossly corrupted for AKI and poorly applicable in critically ill patients in general. Conventional indications for renal replacement therapy (RRT) may have limited applicability in critically ill patients and there has been a relative lack of progress on RRT modalities in these patients. AKI in critically ill patients is a highly complex syndrome and it may be counterproductive to produce complex clinical practice guidelines, which are labor and resource-intensive to maintain, difficult to memorize or may not be immediately available in all settings all over the world. Additionally, despite attempts to develop reliable and reproducible biomarkers to replace serum creatinine as a guide to therapy such biomarkers failed to materialize. Under such circumstances, there is an ongoing need to reassess the practical value of simple measures, such as volume-related weight gain (VRWG) and urine output, both for prognostic markers and clinical indicators for the need for RRT. This current paper reviews the practical utility of VRWG as an independent indication for RRT in face of reduced urine output and hemodynamic instability.

Bedside Tunneled Dialysis Catheter Removal-A Lesson Learned From Nephrology Trainees.

Semi-permanent dual-lumen tunneled (or tunneled-cuffed) hemodialysis catheters (TDC) are increasingly utilized during renal replacement therapy, while awaiting permanent access maturation or renal recovery. Although there is a wealth of literature focused on placement, infection prevention, and maintenance of catheter patency, circumstances and indications for TDC removal are less well understood. Timely removal of these catheters is an important management decision, with the length of TDC duration representing the largest cumulative risk factor for catheter-associated blood stream infections. Waiting for assistance from surgical or radiological services-which may not be available in all hospitals-may result in delays in services and potential harm to the patients. Imparting and maintaining procedural skills to remove infected TDC may be very valuable for training programs in clinical nephrology. In this article the current literature on bedside TDC removal, including potential anticipated complications during removal, are reviewed. To date, the authors have documented successful implementation of bedside TDC removal in training programs from two different settings, including both in- and outpatients and with trainee involvement. In summary, training general nephrologists for bedside TDC removal will afford immediate removal of infected hardware in ill patients and avoid potential delays in outpatient setting.

Clinical Utility of Potassium-Sparing Diuretics to Maintain Normal Serum Potassium in Peritoneal Dialysis Patients.

♦ BACKGROUND: Hypokalemia is a vexing problem in end-stage renal disease patients on peritoneal dialysis (PD), and oral potassium supplements (OPS) have limited palatability. Potassium-sparing diuretics (KSD) (spironolactone, amiloride) may be effective in these patients. ♦ METHODS: We performed a cross-sectional review of 75 current or past (vintage > 6 months) PD patients with regard to serum potassium (K+), OPS, and KSD utilization. We reviewed charts for multiple clinical and laboratory variables, including dialysis adequacy, residual renal function, nutritional status and co-existing medical therapy. ♦ RESULTS: The cohort was middle-aged with a mean age of 49.2 years (standard deviation [SD] = 14.7) and overweight with a body mass index of 29.5 (6.7) kg/m2. Of all the participants, 57.3% were female, 73.3% African-American, and 48% diabetic with an overall PD vintage of 28.2 (24.3) months at the time of enrollment. Weekly Kt/V was 2.12 (0.43), creatinine clearance was 73.5 (33.6) L/week/1.73 m2 with total daily exchange volume of 10.8 (2.7) L. Residual urine output (RUO) measured at 440 (494) mL (anuric 30.6%). Three-month averaged serum K+ measured at 4 (0.5) mmol/L with 36% of the participants receiving K+ supplements (median: 20 [0;20] mmol/day) and 41.3% KSD (spironolactone dose: 25 - 200 mg/day; amiloride dose: 5 - 10 mg/day). Serum K+ correlated positively with weekly Kt/V (r = 0.239; p = 0.039), PD vintage (r = 0.272; p = 0.018) but not with PD modality, daily exchange volume, RUO, or KSD use. However, KSD use was associated with decreased use of OPS (r = -0.646; p < 0.0001). ♦ CONCLUSIONS: Potassium-sparing diuretics were effective in this cohort of PD patients and decreased the need for OPS utilization.

Inflammatory Markers and Outcomes in Kidney Transplant Recipients.

BACKGROUND: Increased levels of TNF-α and IL6 are associated with inflammation and cardiovascular disease among patients with normal kidney function. However, little is known about their association with outcomes in kidney transplant recipients. METHODS: We collected sociodemographic, clinical and laboratory parameters, medical and transplant history from 977 prevalent kidney transplant recipients enrolled in the Malnutrition-Inflammation in Transplant-Hungary study. Serum cytokine levels were measured at baseline. Associations between serum TNF-α and IL6 values and death with a functioning graft over a 6-year follow-up period were examined in unadjusted and adjusted models. RESULTS: The mean ± SD age of the study population was 51 ± 13 years, 57% were men, 21% were diabetics. Median serum TNF-α and IL6 concentrations were significantly higher in patients who died with a functioning graft as compared with those who did not die during the follow-up period (TNF-α: median, 1.92 pg/mL; interquartile range [IQR], 1.43-2.67 pg/mL vs median, 2.25 pg/mL; IQR, 1.63-3.08 pg/mL, P < 0.001; and for IL6: median, 1.91 pg/mL; IQR, 1.21-3.02 pg/mL vs median, 2.81 pg/mL; IQR, 1.65-4.97 pg/mL, P < 0.001). Higher serum TNF-α and IL6 levels were associated with higher mortality risk in both unadjusted and fully adjusted models: TNF-α: hazard ratios (HRs)(1 pg/ml increments), 1.24; 95% confidence interval (CI), 1.13-1.36 and HRs(1 pg/ml increments), 1.19; 95% CI, 1.08-1.32; IL6: HRs(1 pg/ml increments), 1.06; 95% CI, 1.03-1.09 and HRs(1 pg/ml increments), 1.03; 95% CI, 0.99-1.06, respectively. Compared with patients whose serum TNF-α or IL6 levels were in the lowest tertile, those in the middle tertile had similar mortality risk (TNF-α: HR, 1.09; 95% CI, 0.74-1.61; IL6: HR, 1.05; 95% CI, 0.68-1.62), but patients in the highest tertile reported higher risk of mortality: TNF-α: HR, 1.45; 95% CI, 1.01-2.09; IL6: HR, 1.55; 95% CI, 1.04-2.32 in multivariable adjusted models. CONCLUSIONS: In prevalent kidney transplant recipients, serum TNF-α and IL6 were independently associated with death with a functioning graft.

Outpatient removal of tunneled dialysis catheters by nephrology fellows in training at a Veterans Affairs Medical Center.

BACKGROUND: Removal of tunneled dialysis catheters (TDC) usually occurs in dedicated procedure suites and is performed relatively rarely at the bedside. Scarce evidence exists in the literature to assess the safety and success of this procedure when performed during supervised academic training. PATIENTS AND METHODS: We conducted a retrospective chart review of all TDC removals performed on an outpatient basis by nephrology fellows under faculty supervision during a 5-year period at an academic Veterans Affairs Medical Center. Data were collected regarding patient demographics, basic laboratory studies, pertinent clinical information and procedure-related variables. We evaluated the safety, success and complication rate of this procedure. RESULTS: We identified 72 TDC removals that met the above criteria. Mean age was 63 ± 10 years. All patients were male and hypertensive, 68% were diabetic and 69% were African-American. Overall, 88% of procedures were performed in end-stage renal disease (ESRD) patients, while the rest had needed temporary dialysis for acute kidney injury. Notably, 49 patients (68%) were taking one or more of aspirin, clopidogrel or warfarin at the time of TDC removal. Overall complication rate was low (<2%). There was no increase in risk of bleeding, even in subjects receiving anti-platelet therapy; only one of the 49 patients (2%) had a minor bleeding complication. CONCLUSIONS: Outpatient TDC removal by trainees was successful and safe in the vast majority of cases (99%). We propose that TDC removal skills should be actively pursued and acquired by all nephrology fellows. This would expand the scope of practice for future general nephrologists and facilitate timely patient care.

The effect of ambient temperature and humidity on interdialytic weight gains in end-stage renal disease patients on maintenance hemodialysis.

PURPOSE: Interdialytic weight gain (IDWG) is both a measure of dietary compliance and a well-established predictor of future adverse outcomes in dialysis patients. The impact of environmental conditions on IDWG in end-stage renal disease is little studied to date. METHODS: We retrospectively reviewed IDWG for 100 consenting chronic end-stage renal disease patients undergoing thrice weekly in-center hemodiafiltration under three different climatic conditions in a Central European city: Weekend_1 was humid (93 %) and warm (24 °C); Weekend_2 was dry (38 %) and hot (33 °C); and Weekend_3 was dry (30 %) and warm (24 °C). RESULTS: The cohort's mean age was 60.9 ± 14.7 years, all were Eastern European, and 56 % were men. Residual urine output measured 100 [25-75 % quartiles: 0, 612] mL/day, single-pool Kt/V 1.4 ± 0.25, and albumin 40.1 ± 3.9 g/L. Mean IDWGs measured as follows: Weekend_1 ("humid-warm"): 2973 ± 1386 mL; Weekend_2 ("dry-hot"): 2685 ± 1368 mL and Weekend_3 ("dry-warm"): 2926 ± 1311 mL. Paired-samples testing for difference showed higher fluid gains on the humid-warm (239 mL; 95 % CI 21-458 mL; p = 0.032) and on the dry-warm weekends (222 mL; 95 % CI -8 to 453 mL, p = 0.059), when compared to the dry-hot weekend. Under the latter, dry-hot climatic condition, residual urine output lost its significance to impact IDWG during multiple regression analysis. CONCLUSION: While excess temperature may impact IDWG to a small degree, air humidity does not; the least weight gains occurred on the dry-hot weekend. However, the effects of both were minimal under continental summer conditions and are unlikely to explain large excesses of individual session-to-session variations.

Tunneled Hemodialysis Catheter Removals by Non-Interventional Nephrologists: The University of Mississippi Experience.

Bedside removal of tunneled hemodialysis catheters (TDC) by noninterventional Nephrologists has not been frequently performed or studied. We performed a retrospective review of bedside TDC removal at the University of Mississippi Medical Center between January, 2010 and June, 2013. We collected data on multiple patients and procedure-related variables, success, and complications rates. Of the 138 subjects, mean age was 50 (±15.9) years, 49.3% were female, 88.2% African American and 41% diabetics. Site of removal was the right internal jugular (IJ) in 76.8%, the left IJ in 15.2%, and the femoral vein in 8% of patients. Exactly 44.9% of removals took place in the outpatient setting. Main indications for the removal were proven bacteremia in 30.4%, sepsis or clinical concerns for infection in 15.2% of the cases, while TDC was no longer necessary in 52.2% of patients. All removals were technically successful and well tolerated, but we observed Dacron "cuff" separation and subcutaneous retention in 6.5% of the cases. There was a significant association between outpatient removal and cuff retention (p = 0.007), but not with the site of removal or operator experience. In this relatively large mixed cohort of inpatients and outpatients, bedside TDC removal was well tolerated with a minimal complication rate.

Which fluid space is affected by ultrafiltration during hemodiafiltration?

Ultrafiltration (UF) is a common procedure performed during almost all dialysis sessions. During UF, several liters of fluid are removed; however, what proportion of this fluid is removed from which fluid space could not be clinically measured easily until now; we designed this study to evaluate the fluid spaces most affected by UF. This is a prospective cohort study of 40 prevalent chronic hemodialysis patients receiving thrice weekly hemodiafiltration (HDF). We measured the patients' fluid spaces using a whole-body bioimpedance apparatus to evaluate the changes of fluid spaces before and immediately after the HDF sessions. We recorded the data on fluid spaces, UF volume, and blood pressures. The cohort consisted of 40 prevalent HDF patients, aged 60.0 ± 5.2 years (37.5% men; 27.5% people with diabetes), and body weight 71.03 ± 15.48 kg. Achieved UF was 2.38 ± 0.98 L on HDF (measured fluid overload: 2.35 ± 1.44 L). The extracellular fluid (EC) volume decreased from 16.84 ± 3.52 to 14.89 ± 3.06 L (P < 0.0001) and intracellular fluid (IC) volume from 16.88 ± 4.40 to 16.55 ± 4.48 L (P = 0.45). Although urea volume of distribution remained effectively unchanged (31.38 ± 7.28 vs. 30.70 ± 7.32 L; P = 0.45), the degree of EC volume overload decreased from 13.60% ± 7.30% to 3.83% ± 8.32% (P < 0.0001). The mean arterial pressure also decreased from 122.95 ± 19.02 to 108.50 ± 13.91 mmHg (P < 0.0001). We conclude that source of net fluid loss by ultrafiltration is almost exclusively the EC fluid space. The intracellular fluid space is not significantly affected immediately after HDF.