James A. Strom

Frequency of and risk factors for poor cognitive performance in hemodialysis patients

Objective: There are few detailed data on cognition in patients undergoing dialysis. We evaluated the frequency of and risk factors for poor cognitive performance using detailed neurocognitive testing. Methods: In this cross-sectional cohort study, 314 hemodialysis patients from 6 Boston-area hemodialysis units underwent detailed cognitive assessment. The neuropsychological battery assessed a broad range of functions, with established age-, sex-, and education-matched normative scores. Principal component analysis was used to derive composite scores for memory and executive function domains. Risk factors for each domain were evaluated using linear regression adjusting for age, sex, race, and education status. Analyses were repeated in those with Mini-Mental State Examination (MMSE) score ≥24. Results: Compared with population norms, patients on dialysis had significantly poorer executive function but not memory performance, a finding that persisted in the subgroup with MMSE score ≥24. In adjusted analyses, vascular risk factors and vascular disease were associated with lower executive function (p < 0.01). Conclusions: There is a high frequency of poor cognitive performance in hemodialysis patients, primarily affecting executive function. Risk factors for worse executive function include vascular risk factors as well as vascular disease. Normal performance on the MMSE does not preclude impaired cognitive function, because individuals with MMSE score ≥24 also have a high frequency of poor cognitive performance.

A Prospective, Randomized, Double-Blind Study Evaluating the Efficacy of Postoperative Continuous Local Anesthetic Infusion at the Iliac Crest Bone Graft Site After Spinal Arthrodesis

Study Design. Parallel design, prospective, double-blind, randomized, controlled trial composed of two independent groups treated with a continuous infusion catheter (saline vs. Marcaine) placed into the iliac crest bone graft (ICBG) site. Objective. To determine the effects of postoperative continuous local anesthetic agent infusion at the ICBG harvest site in reducing pain, narcotic demand and usage, and improving early postoperative function after spinal fusion. Summary of Background Data. Harvesting iliac crest bone has been shown to be a source of pain and morbidity. Long-term patient complaints may be more closely associated with the procurement of the iliac crest graft rather than the primary surgical site. Methods. Thirty-seven patients were enrolled in a prospective, randomized, double-blind parallel-designed study after informed consent and IRB approval was obtained. Twenty-eight patients had ICBG harvested for lumbar arthrodesis and nine for cervical arthrodesis. During spinal arthrodesis surgery, patients were randomly assigned to receive 96 mL (2 mL/hr × 48 hours) of either normal saline (control group, n = 22) or 0.5% Marcaine (treatment group, n = 15) delivered via a continuous infusion catheter placed at the ICBG harvest site. All patients received Dilaudid PCA after surgery. Pain scores, narcotic use/frequency, activity level, and length of stay (LOS) were recorded. Physicians, patients, nursing staff, and statisticians were blinded to the treatment. Results. Mean patient age was 60 years and similar between groups. Narcotic dosage, demand frequency, and mean VAS pain score were significantly less in the treatment (Marcaine) group at 24 and 48 hours (P < 0.05). The average LOS was 4.1 days with no difference between Marcaine or control groups. No complications were attributed to the infusion-catheter system. Conclusions. Continuous infusion of 0.5% Marcaine at the ICBG harvest site reduced postoperative parenteral narcotic usage by 50% and decreased overall pain scores. No complications were attributed to the infusion-catheter system. The use of continuous local anesthetic infusion at the iliac crest may help in alleviating acute graft-related pain, hastening patient recovery and improving short-term satisfaction.

Multidrug-resistant gram-negative bacteria among patients who require chronic hemodialysis.

BACKGROUND AND OBJECTIVES Multidrug-resistant gram-negative bacteria are rapidly spreading throughout the world. The epidemiology of multidrug-resistant gram-negative bacteria in patients who require chronic hemodialysis has not been previously studied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A prospective cohort study of an outpatient hemodialysis unit was conducted. Serial surveillance cultures for multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus were collected from patients who were undergoing chronic hemodialysis. RESULTS Nineteen (28%) of the 67 enrolled patients were colonized with one or more antimicrobial-resistant bacteria at study enrollment. Eleven (16%), nine (13%), and three (5%) patients were colonized with multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus, respectively. Independent risk factors associated with harboring multidrug-resistant gram-negative bacteria at enrollment were residence in a long-term care facility and antibiotic exposure for > or = 7 d in the previous 3 mo. Twenty-two (40%) of 55 patients who had follow-up cultures acquired at least one antimicrobial-resistant bacterium. A total of 20, 15, and 13% of patients acquired multidrug-resistant gram-negative bacteria, vancomycin-resistant enterococci, and methicillin-resistant Staphylococcus aureus, respectively. Antibiotic exposure was the only independent risk factor for multidrug-resistant gram-negative bacteria acquisition. Endogenous multidrug-resistant gram-negative bacteria acquisition was detected among 69% of acquired multidrug-resistant gram-negative bacterial strains. CONCLUSIONS The prevalence and acquisition of multidrug-resistant gram-negative bacteria surpassed that of vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus. Endogenous acquisition, as opposed to patient-to-patient spread, was the predominant mechanism of acquisition. Residence in a long-term care facility and antibiotic exposure may be important factors promoting the spread of multidrug-resistant gram-negative bacteria among this patient population.

Cinacalcet HCI (Sensipar/Mimpara) is an effective chronic therapy for hemodialysis patients with secondary hyperparathyroidism

AIMS This 1-year double-blind, placebo-controlled, multicenter study evaluated the long-term safety and efficacy of cinacalcet for the treatment of secondary hyperparathyroidism in patients receiving hemodialysis. METHOD Patients were randomly assigned in a 1:1 ratio to cinacalcet or control treatment groups. The initial dose of cinacalcet (or matching placebo) was 30 mg. Doses were titrated every 3 or 4 weeks based on the intact parathyroid hormone (iPTH) response and safety profile. Sequential doses included 30, 60, 90, 120 and 180 mg/d. Phosphate binders and vitamin D sterols were adjusted per protocol as needed to control levels of calcium and phosphorus. Efficacy and safety were compared between treatment groups among patients who completed the study (52 total weeks of treatment). Reasons for withdrawal are presented for patients who did not complete the study. RESULTS A total of 210 patients completed 52 weeks of double-blinded treatment with cinacalcet (n = 99) or placebo (n = 111). Over the last 6 months of the study, a greater proportion of patients in the cinacalcet group than the control group achieved an iPTH level < or = 250 pg/ml (61.6 vs. 9.9%, p < 0.001) or a > or = 30% decrease in iPTH from baseline (81.8 vs. 21.6%, p < 0.001). Mean iPTH levels decreased by -47.8% in the cinacalcet group and increased by +12.9% in the control group. Mean percentage changes in other laboratory values in the cinacalcet and control groups included the following: serum calcium -6.5 vs. +0.9% (p < 0.001), serum phosphorus -3.6 vs. -1.1% (p = 0.465), and Ca x P -9.9 vs. -0.3% (p = 0.006). The most commonly reported adverse events related to study drug by the investigators included nausea (13% cinacalcet, 5% control), investigator-reported hypocalcemia (11% cinacalcet, 1% control), vomiting (9% cinacalcet, 2% control), dyspepsia (5% cinacalcet, 4% control), and diarrhea (5% cinacalcet, 2% control). CONCLUSIONS Treatment with cinacalcet is a safe and effective therapy for long-term control of secondary hyperparathyroidism. 1-year therapy with cinacalcet was associated with sustained, clinically significant reductions in calcium, Ca x P and iPTH which allowed a greater percentage of patients to achieve NKF-KDOQI target goals for PTH and Ca x P.

Cognitive Function and All-Cause Mortality in Maintenance Hemodialysis Patients

BACKGROUND Cognitive impairment is common in hemodialysis patients and is associated with significant morbidity. Limited information exists about whether cognitive impairment is associated with survival and whether the type of cognitive impairment is important. STUDY DESIGN Longitudinal cohort. SETTING & PARTICIPANTS Cognitive function was assessed at baseline and yearly using a comprehensive battery of cognitive tests in 292 prevalent hemodialysis patients. PREDICTOR Using principal component analysis, individual test results were reduced into 2 domain scores, representing memory and executive function. By definition, each score carried a mean of 0 and SD of 1. OUTCOMES Association of each score with all-cause mortality was assessed using Cox proportional hazards models adjusted for demographics and dialysis and cardiovascular (CV) risk factors. RESULTS Mean age of participants was 63 years, 53% were men, 23% were African American, and 90% had at least a high school education. During a median follow-up of 2.1 (IQR, 1.1-3.7) years, 145 deaths occurred. Each 1-SD better executive function score was associated with a 35% lower hazard of mortality (HR, 0.65; 95% CI, 0.55-0.76). In models adjusting for demographics and dialysis-related factors, this relationship was partially attenuated but remained significant (HR, 0.81; 95% CI, 0.67-0.98), whereas adjustment for CV disease and heart failure resulted in further attenuation (HR, 0.87; 95% CI, 0.72-1.06). Use of time-dependent models showed a similar unadjusted association (HR, 0.62; 95% CI, 0.54-0.72), with the relationship remaining significant after adjustment for demographics and dialysis and CV risk factors (HR, 0.79; 95% CI, 0.66-0.94). Better memory was associated with lower mortality in univariate analysis (HR per 1 SD, 0.82; 95% CI, 0.69-0.96), but not when adjusting for demographics (HR, 1.00; 95% CI, 0.83-1.19). LIMITATIONS Patients with dementia were excluded from the full battery, perhaps underestimating the strength of the association. CONCLUSIONS Worse executive function and memory are associated with increased risk of mortality. For memory, this association is explained by patient demographics, whereas for executive function, this relationship may be explained in part by CV disease burden.

Hypernatremia Due to Repeated Doses of Charcoal-Sorbitol

Hypernatremic dehydration due to unreplaced stool water losses often complicates the use of the osmotic cathartic lactulose in the treatment of hepatic encephalopathy. Sorbitol, another osmotic cathartic commonly used in the treatment of drug intoxications, has been reported in the pediatric literature to induce severe hypernatremia, but there is only a rare case report in an adult. We report a dramatic case of severe hypernatremia secondary to repetitive administration of activated charcoal-sorbitol suspension for the treatment of phenobarbital intoxication in an adult. Based on our experience with this case, several recommendations are provided regarding management of drug intoxications with charcoal-sorbitol suspension, including meticulous attention to fluid-electrolyte balance, type of replacement fluid, and dosing of the suspension.

Antimicrobial use in outpatient hemodialysis units.

OBJECTIVE To quantify and characterize overall antimicrobial use, including appropriateness of indication, among patients receiving chronic hemodialysis. DESIGN Retrospective and prospective observational study. SETTING Two outpatient hemodialysis units. PATIENTS All patients receiving chronic hemodialysis. METHODS The rate of parenteral antimicrobial use (number of doses per 100 patient-months) was calculated retrospectively from September 2008 through July 2011. Indication and appropriateness of antimicrobial doses were characterized prospectively from August 2010 through July 2011. Inappropriate administration was defined as occasions when criteria for infection based on national guidelines were not met, failure to choose a more narrow-spectrum antimicrobial on the basis of culture data, or occasions when indications for surgical prophylaxis were not met. RESULTS Over the 35-month retrospective study period, the rate of parenteral antimicrobial use was 32.9 doses per 100 patient-months. Vancomycin was the most commonly prescribed antimicrobial, followed by cefazolin and third- or fourth-generation cephalosporins. Over the 12-month prospective study, 1,003 antimicrobial doses were prescribed. Among the 926 (92.3%) doses for which an indication for administration was available, 276 (29.8%) were classified as inappropriate. Of these, a total of 146 (52.9%) did not meet criteria for infection, 74 (26.8%) represented failure to choose a more narrow-spectrum antimicrobial, and 56 (20.3%) did not meet criteria for surgical prophylaxis. The most common inappropriately prescribed antimicrobials were vancomycin and third- or fourth- generation cephalosporins. CONCLUSIONS Parenteral antimicrobial use was extensive, and as much as one-third was categorized as inappropriate. The findings of this study provide novel information toward minimizing inappropriate antimicrobial use.

Infections associated with use of the LifeSite hemodialysis Access system

We observed infection rates associated with the LifeSite Hemodialysis Access System, a novel dialysis device consisting of 2 subcutaneously implanted valves accessed by repeated use of fibrous tissue tracts, of 4.8 total infections and 8.1 first episodes per 1000 patient-days. These rates are higher than those observed elsewhere, which may be related to use of the device in a population of chronically ill patients, to the learning curve associated with use of the device, or to inherent qualities of the device.

Intradialytic Parenteral Nutrition: Evolution and Current Concepts

A historical review of nutrition supplementation of the renal patient documents the evolution of nutritional support as an accepted mode of therapy. The purpose of this study was to examine the role of intradialytic parenteral nutrition (IDPN) as it exists today as well as to offer patient selection criteria, clarification of administration, and patient monitoring guidelines. The pilot study results and established IDPN protocol offer an opportunity to assess individual patient requirements and administer appropriate nutritional support when indicated. Clinical indices for IDPN patient selection are discussed along with suggested solutions for common problems encountered with IDPN.

Spurious assessment of acid-base status due to dilutional effect of heparin

A patient was encountered in whom clinically significant spurious hypocapnia and hypobicarbonatemia were diagnosed resulting from the dilutional effect of excessive amounts of sodium heparin solution in the blood sample. This report presents the relevant data in this patient, summarizes the effects of heparin on the determination of the acid-base status, and provides suggestions for avoiding this important pitfall in clinical practice.