Mary Gellens

Achieving K/DOQI Laboratory Target Values for Bone and Mineral Metabolism: An Uphill Battle

Background: The National Kidney Foundation has recently published the Kidney Disease Outcomes Quality Initiative (K/DOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease (CKD). According to these guidelines, in patients with stage 5 CKD, the adjusted calcium level should be 8.4– 9.5 mg/dl, the serum phosphate should be 3.5–5.5 mg/dl, the calcium phosphorous product should be <55 mg2/dl2 and the intact parathyroid hormone (PTH) level should be 150–300 pg/ml. Methods: In order to evaluate our ability to meet these targets, we reviewed laboratory parameters of bone and mineral metabolism of 140 patients over a 6-month period in an inner city hemodialysis unit. Serum calcium and phosphate levels were determined using standard assays and PTH levels were determined using the Nichols Intact PTH assay. Results: We found that the levels of serum calcium and serum phosphorus fell within the range recommended by the K/DOQI guidelines 49 and 36% of the time respectively. 57% of the determinations for calcium × phosphorus product were <55 mg2/dl2. PTH levels were within the recommended values in 20% of the determinations. Only 7% of the determinations met all four criteria simultaneously in spite of meeting other K/DOQI targets such as hematocrit and dialysis adequacy. Conclusion: These data indicate that current practice for the management of bone and mineral metabolism in hemodialysis falls far short of meeting the K/DOQI guidelines.

Complications associated with insertion of jugular venous catheters for hemodialysis: The value of postprocedural radiograph☆☆☆

It is routine in hemodialysis units to require a chest radiograph after the insertion of an internal jugular line for venous access before dialysis is commenced. There are two principal reasons for this: (1) to ensure that no procedural complications have occurred and (2) to verify correct catheter placement. Knowledge of the time delay involved may prompt nephrologists to opt for femoral access (with increased hemodialysis recirculation and need for repeated line placement). The benefit of the postprocedural chest radiograph has never been evaluated in the hemodialysis population. We retrospectively reviewed the data on internal jugular access placement from two large nephrology training centers. Over a 36-month period, 460 internal jugular dialysis catheters were placed in 312 patients. Wherever possible, 15-cm lines were used for the left internal jugular vein and 12-cm lines for the right internal jugular vein. Ultrasound guidance was used in 105 cases (22.8%). There were a total of 90 (19.6%) clinical complications in 62 patients (13.5%). These consisted of carotid artery puncture (n = 35, 7.6%) and hematoma (n = 55, 12%). All of these patients had a normal post-internal jugular chest radiograph. Carotid artery puncture did not occur if ultrasound guidance was used. There was no case of associated pneumothorax. Of the 370 line insertions in 250 patients in whom it was believed clinically that no complication had occurred, the chest radiograph only showed unsuspected line malposition in four cases (1.08%). Routine chest radiographs rarely contribute to the diagnosis of any procedural complications and are of little value after internal jugular access placement, especially if it is believed clinically that no complication occurred.

Routine Replacement of Tunneled, Cuffed, Hemodialysis Catheters Eliminates Paraspinal/Vertebral Infections in Patients with Catheter-Associated Bacteremia

Background: Management of tunneled, cuffed, central venous catheters in hemodialysis (HD) patients with bacteremia remains a challenge. Attempts to salvage the catheter with systemic antibiotics alone have been associated with increased risk of metastatic infectious complications. Methods: Retrospective case series of patients with infectious complications in a chronic dialysis unit, affiliated with a tertiary care university hospital. Results: Between 1996 and 1999, when we treated HD catheter-associated bacteremia with systemic antibiotics alone, we encountered a clustering of 8 cases of paraspinal/vertebral infections in a population of 162 patients. After changing our protocol, i.e., routine catheter exchange over a guide wire at ∼48 h, while on systemic antibiotic therapy, we did not encounter any new cases of paraspinal/vertebral infections over a 15-month period. Conclusion: Our experience suggests that routine exchange of tunneled, cuffed catheters over a guide wire in HD patients presenting with bacteremia may significantly reduce serious infectious complications, e.g., epidural abscess/vertebral osteomyelitis.

Successful treatment of normeperidine neurotoxicity by hemodialysis.

Normeperidine, a major metabolite of meperidine, is half as potent as meperidine as an analgesic but two to three times more potent as a convulsant. Renal failure significantly increases the plasma half-life of normeperidine. The intensity of the central nervous system excitation is highly correlated with the plasma concentration of normeperidine. Moreover, normeperidine toxicity is not reversed by naloxone, which may exacerbate it. We report a patient with end-stage renal disease undergoing maintenance continuous cycler peritoneal dialysis who had been receiving meperidine for pain control. The patient subsequently developed myoclonic contractions and a grand mal seizure. The patient was successfully treated with hemodialysis (using an F8 dialyzer) for presumed normeperidine-induced seizure. During hemodialysis, normeperidine average blood clearance was 73 mL/min, average plasma clearance was 50 mL/min, and average percentage of plasma extraction was 24%. There also was a 26% reduction in plasma concentration of normeperidine over 3 hours of hemodialysis. In conclusion, our findings suggest that hemodialysis may be used effectively for treating patients with suspected normeperidine-induced neurotoxicity.

Lack of reaction to ferric gluconate in hemodialysis patients with a history of severe reaction to iron dextran.

Iron deficiency is the most common cause of a poor response to recombinant human erythropoietin (rHuEPO) in patients receiving long-term dialysis, who are known to absorb oral iron preparations poorly. This retrospective case series reports our preliminary observation of five patients receiving long-term dialysis in a tertiary care university hospital who had responded poorly to rHuEPO because of iron deficiency. These patients also had a history of severe, potentially life-threatening reaction to intravenous iron dextran preparation, but they tolerated the newly available ferric gluconate complex in sucrose with no untoward effects. These results suggest that the parenteral administration of ferric gluconate can be safe for those who require iron therapy and who have had a severe reaction to iron dextran.

Comparison of Blood Loss with Different High-Flux and High-Efficiency Hemodialysis Membranes

Iron deficiency is a common problem in patients on chronic HD. Earlier studies have shown significant blood loss per HD session. To identify whether the new more biocompatible high-flux or high-efficiency membranes are also responsible for significant blood loss during HD, we quantitated the amount of blood loss associated with 4 commonly used membranes (F-50, F-80, CA-210, and CT-190). The residual blood in each compartment of extracorporeal circuit was quantitated after total lysis of the red blood cells (RBC), hemoglobin assay, and calculation of the RBC volume using the patient’s hemoglobin and hematocrit concentrations just prior to the study. The average residual RBC volume in different membranes was 0.2–0.3 ml. The residual RBC volume in the dialysis lines (arterial or venous) was 0.1–0.2 ml and did not correlate with the residual RBC volume in the dialysis membranes. The residual RBC volume in the whole extracorporeal circuit (HD membrane, arterial and venous lines) ranged from 0.5 to 0.6 ml. It was significantly higher with F-50 vs. CA-210. The residual RBC volume in the dialysis membrane was significantly higher in the F-80 vs. CA-210 and CT-190 dialyzers. There was also significant difference in the residual RBC volume in the arterial lines of F-50 vs. CT-190, and F-50 vs. F-80 dialyzers. Conclusion: Our results demonstrate for the first time that the total RBC loss per HD session is minimal in chronic HD patients.

Serum β2-Microglobulin Levels in Patients Chronically Dialyzed with CA-210 versus CT-190 Dialysis Membranes

β2-Microglobulin (B2M) amyloidosis (dialysis-related amyloidosis), manifested primarily by carpal tunnel syndrome and destructive osteoarthropathy, is a major sequel of long-term dialysis. Previous investigators have shown that high-flux biocompatible synthetic membranes (e.g., polyacrylonitrile) lower β2M levels when compared to cellulosic membranes (e.g., cuprophane). To date, however, no study has compared β2M levels of patients dialyzed with the two more biocompatible cellulosic membranes CA-210 (cellulose acetate) and CT-190 (cellulose triacetate; high flux, more biocompatible). We retrospectively compared the serum β2M levels in two chronic hemodialysis populations: 22 patients on CT-190 and 21 patients on CA-210. There was no difference between the two groups with regard to age, sex, or duration of dialysis. The patients on the CA-210 membrane had significantly higher serum β2M levels (mean ± SE; 53.6 ± 4.7 vs. 36.8 ± 2.6 mg/l, CA-210 vs. CT-190, respectively, p = 0.003). Subsequently we switched 13 patients dialyzed with a CA-210 membrane to a CT-190 membrane and followed serum β2M levels for 14 months. We found a significant decrease in serum β2M levels within 1 month which was maintained over 14 months of follow-up (47.4 ± 4.4 vs. 62.8 ± 6.7 mg/l, CT-190 at 14 months vs. CA-210 at baseline, respectively, p < 0.01).

Comparative Effectiveness of Dialyzers: A Longitudinal, Propensity Score-matched Study of Incident Hemodialysis Patients.

Differences in dialyzer design may have consequences for patient outcomes. We evaluated the comparative effectiveness of commonly used dialyzers with respect to measures of dialysis treatment, anemia management, inflammation, and dialyzer clotting. Patients receiving hemodialysis between January 1, 2009, and December 31, 2013, and using polyarylethersulfone–polyvinylpyrrolidone (PAS-PVP; Polyflux Revaclear) or polysulfone (PS; Optiflux 160 or Optiflux 180) dialyzers were followed for 1 year or until end of study or censoring for dialyzer switch, modality change, or loss to follow-up. For each comparison, eligible patients were propensity score-matched 1:1 on a range of baseline characteristics. Outcomes were assessed using generalized linear mixed models. Dialysis adequacy was similar in both dialyzer groups. Erythropoiesis-stimulating agent (ESA) doses were lower for patients using PAS-PVP versus patients using PS-160 (difference range: 75–589 units/treatment; statistically significant in months 1–5 and 7) and for patients using PAS-PVP versus patients using PS-180 (difference range: 27–591 unit/treatment; statistically significant in months 1–9). Intravenous iron doses trended lower for patients using PAS-PVP versus patients using PS, but hemoglobin concentrations were equivalent. In conclusion, use of PAS-PVP versus PS dialyzers was associated with equivalent dialysis adequacy, lower ESA doses, modestly lower Intravenous iron doses, and equivalent hemoglobin concentrations.

Cimetidine-Induced Climacteric Symptoms in a Young Man Maintained on Chronic Hemodialysis

We present the case of a young man on maintenance hemodialysis who developed frequent episodes of ‘fluttering, racing heartbeats’, hot flashes, profuse sweating, anxiety, dizziness, and shortness of breath. These symptoms started approximately 1 month after taking cimetidine 400 mg/day with an occasional extra dose. His workup included a total of 72 h of cardiac monitoring, two-dimensional echocardiogram, and thyroid function tests, all of which were essentially unremarkable. When the drug cimetidine was temporarily discontinued, and on another occasion after the drug was totally withdrawn, the patient noticed marked improvement in his symptoms at 48 h with total resolution on the 5th day after discontinuation. This is the 2nd such case reported in the literature.