Remote Monitoring of Sustained Low-Efficiency Dialysis (SLED) Machines in Intensive Care Unit.

The Henry Ford Health System provides patients with a safe, improved system of continuous kidney replacement therapy using a proprietary, 24-hour sustained low-efficiency dialysis (SLED). The SLED system utilizes regional citrate anticoagulation (RCA) in conventional hemodialysis machines that have been configured to provide slow dialytic therapy. Within our hospital complex, SLED-RCA systems are deployed in intensive care units distributed over 4 floors in 2 buildings. This widespread footprint represents a spatial challenge for hemodialysis technicians. Fifteen SLED-RCA machines may be running at one time, and each deployed unit may signal an alarm for multiple reasons. Previously, audible alarms prompted intensive care unit nurses to identify the alarming machine and manually notify technicians by telephone. Technicians would then travel to resolve the alarm. To improve the process of addressing SLED-RCA machine alarms, we developed a remote alert alarm system that wirelessly notifies hemodialysis technicians of specific machine alarms. A quality improvement analysis of nearly 1,000 SLED-RCA alarms over a 1-week period revealed that the average time for alarm correction with a remote alert alarm system was approximately 5 minutes. Reducing alarm resolution time may free technicians and nurses for other critical duties.

Sentinel vascular access monitoring after endovascular intervention predicts access outcome.

BACKGROUND AND OBJECTIVES: The vascular access pressure ratio test identifies dialysis vascular access dysfunction when three consecutive vascular access pressure ratios are >0.55. We tested whether the magnitude of the decline in vascular access pressure ratio 1-week post-intervention could alert of subsequent access failure. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: The retrospective study included all vascular access procedures at one institution from March 2014 to June 2016. Data included demographics, comorbidities, vascular access features, %ΔVAPR = ((Pre-Post)/Pre] × 100% assessed within the first 2 weeks post-percutaneous transluminal balloon angioplasty, time-to-next procedure, and patency. The log-rank test compared the area under the curve, receiver operating curve, Kaplan-Meier arteriovenous graft and arteriovenous fistula survival curves. A multivariable Cox proportional hazard (CP) model was used to determine the association of %ΔVAPR with access patency. RESULTS: Analysis of 138 subjects (females 51%; Black 87%) included 64 arteriovenous fistulas with 104 angioplasties and 74 arteriovenous grafts with 134 angioplasties. The area under the receiver operating characteristic curve for fistula failure at 3 months was 0.59, with optimal screening characteristics of 33.3%, sensitivity of 56.1%, and specificity of 63.2%. Arteriovenous fistula with <33.3% decline compared to >33.3% required earlier subsequent procedure (136 vs 231 days), lower survival on Kaplan-Meier analysis (P = 0.01), and twofold greater risk of failure (P = .006). Area under the receiver operating characteristic for arteriovenous graft failure at 3 months had a sensitivity of 52.3% and specificity of 67.4%. Arteriovenous graft with a post-intervention vascular access pressure ratio decline of <28.8% also required earlier subsequent procedure (144 vs 189 days), lower survival on Kaplan-Meier (P = 0.04), and a 59% higher risk for failure. The area under the receiver operating characteristic curve for combined access failure (arteriovenous fistula + arteriovenous graft) at 3 months had an optimal cut-point value of 31.2%, a sensitivity of 54.6%, and a specificity of 63.1%. Access with a <31.2% drop had a 62% increase in the risk of failure (hazard ratio 1.62; confidence interval 1.16, 2.27; P = 0.005). CONCLUSION: The magnitude of post-intervention reduction in vascular access pressure ratio provides a novel predictive measure of access outcomes.

Intravenous iron dextran as a component of anemia management in chronic kidney disease: a report of safety and efficacy.

Objective. We aimed to demonstrate safety and efficacy of intravenous (IV) low molecular weight iron dextran (LMWID) during treatment of anemic stage 3 and 4 chronic kidney disease (CKD) patients. Methods. Efficacy data was obtained by retrospective chart review of 150 consecutively enrolled patients. Patients were assigned per protocol to oral or IV iron, with IV iron given to those with lower iron stores and/or hemoglobin. Iron and darbepoetin were administered to achieve and maintain hemoglobin at 10-12 g/dL. Efficacy endpoints were mean hemoglobin and change in iron indices approximately 30 and 60 days after enrollment. Safety data was obtained by retrospective review of reported adverse drug events (ADEs) following 1699 infusions of LMWID (0.5-1.0 g). Results. Mean hemoglobin, iron saturation, and ferritin increased significantly from baseline to 60 days in patients assigned to LMWID (hemoglobin: 11.3 versus 9.4 g/dL; iron saturation: 24% versus 12.9%; ferritin: 294.7 versus 134.7 ng/mL; all P values < 0.0001). Iron stores and hemoglobin were maintained in the group assigned to oral iron. Of 1699 iron dextran infusions, three ADEs occurred. Conclusions. Treatment of anemia in CKD stages 3 and 4 with LMWID and darbepoetin is efficacious. The serious ADE rate was 0.06% per infusion.

Automated intravascular access pressure surveillance reduces thrombosis rates.

Although monitoring of vascular accesses by physical examination is nearly as sensitive as surveillance measurements by vascular access pressure when performed by examiners, the frequency of examinations is limited by time. We developed intravascular access pressure surveillance as a surrogate to physical examination. Using real-time data from hemodialysis machines, we derived intravascular access pressure ratios for each dialytic procedure. An automated, noninvasive surveillance algorithm that generated a "warning" list of patients at risk for thrombosis was formulated. We hypothesized that this algorithm would reduce access thrombosis frequency. We designed a study comparing thrombosis rates during a baseline 6-month interval to three subsequent 6-month periods of active surveillance. Referrals for interventions during this 18-month period were based on persistently abnormal elevated vascular access pressure ratio tests (VAPRT) >0.55. Thrombosis rates declined progressively for arteriovenous grafts (AVG) during the intervention period compared with the baseline period. Arteriovenous fistula (AVF) thrombosis rates decreased during postintervention months 13-18 during employment of the VAPRT. We conclude that use of VAPRT can reduce thrombosis rates in vascular accesses, and the magnitude of the effect is larger and more consistent in arteriovenous grafts (AVGs) than autologous AVFs.

Hemoglobin variability and hyporesponsiveness: much ado about something or nothing?

Hemoglobin (Hb) variability is considered a discrete clinical entity that when present may presage poor clinical outcomes. However, Hb variability is an intrinsic property of biological systems and is present in all patients, those with and without the anemia of chronic kidney disease. Taken together, variability actually represents the integration of multiple influences at multiple levels in the life of a red cell, namely the summation of positive and negative influences on erythropoiesis. Thus, Hb variability may be interpreted as a mathematic function of time and is the result of a host of influences including definition of the normal Hb range, native erythron responsiveness/hyporesponsiveness, temporal changes in endogenous and exogenous erythropoiesis-stimulating agent (ESA) levels, the algorithms used to dose ESAs and their duration of action, the presence of biologically available iron, red cell turnover, and recyclable and non-recyclable blood loss and gain. When viewed within this construct of matrixed determinants, the source of hemoglobin variability is more readily identified. When variability is present but the etiology is not easily discerned, erythropoietic hyporesponsiveness must be considered and evaluated. Finally, integration of all of these concepts is possible within the context of an anemia management protocol.

Automation, decision support, and expert systems in nephrology.

Increasing data suggest that errors in medicine occur frequently and result in substantial harm to the patient. The Institute of Medicine report described the magnitude of the problem, and public interest in this issue, which was already large, has grown. The traditional approach in medicine has been to identify the persons making the errors and recommend corrective strategies. However, it has become increasingly clear that it is more productive to focus on the systems and processes through which care is provided. If these systems are set up in ways that would both make errors less likely and identify those that do occur and, at the same time, improve efficiency, then safety and productivity would be substantially improved. Clinical decision support systems (CDSSs) are active knowledge systems that use 2 or more items of patient data to generate case specific recommendations. CDSSs are typically designed to integrate a medical knowledge base, patient data, and an inference engine to generate case specific advice. This article describes how automation, templating, and CDSS improve efficiency, patient care, and safety by reducing the frequency and consequences of medical errors in nephrology. We discuss practical applications of these in 3 settings: a computerized anemia-management program (CAMP, Henry Ford Health System, Detroit, MI), vascular access surveillance systems, and monthly capitation notes in the hemodialysis unit.

Dynamic venous access pressure ratio test for hemodialysis access monitoring.

BACKGROUND: Early recognition of arteriovenous graft (AVG) dysfunction in hemodialysis (HD) patients followed by prompt corrective procedures reduces AVG thrombosis rates and lengthens access survival. We developed a method to prospectively monitor AVGs that uses an algorithm to calculate venous access pressure (VAP) during HD from the venous drip chamber pressure (VDP). METHODS: Sham HD with blood was performed using standard blood tubing and a 1-in. 15-G needle. The pressure needed to overcome circuit resistance at an intra-access pressure of zero (VDP(0)) was recorded at blood flow rates (Q(b)s) from 0 to 600 mL/min and hematocrits varied in steps from 38.4% to 18.2%. An equation for VDP(0) was developed. VAP in patients was calculated as VAP = VDP - VDP(0). VAP ratio (VAPR) was defined as VAP/mean arterial pressure (MAP). VAPR was calculated only if MAP was greater than 75 mm Hg, Q(b) was greater than 200 mL/min, and VDP was greater than 20 mm Hg. A positive VAPR test (VAPRT) result was defined as three consecutive treatments with VAPR exceeding 0.55 during a given month. Sensitivity and specificity of VAPRT to predict a graft event, defined by AVG occlusion or requirement for angioplasty, were calculated. RESULTS: During a 3-month interval, 120 HD patients with AVGs underwent 359 VAPRTs while access outcomes were monitored for 6 months. After 3 months, sensitivity and specificity for detection of a graft event were 70% +/- 8% and 88% +/- 2% and increased to 74% +/- 5% and 92% +/- 3% at 6 months, respectively. CONCLUSION: The VAPRT is a valuable tool to prospectively monitor for adverse AVG events.

Race is a major determinant of secondary hyperparathyroidism in uremic patients.

In the general population, blacks have higher parathyroid gland mass and circulating parathyroid hormone (PTH) levels than whites. This may predispose black patients to more severe parathyroid disease when renal failure develops. Therefore, racial differences in the severity of uremic hyperparathyroidism were examined in a population of patients with end-stage renal disease (ESRD). Among ESRD patients receiving hemodialysis or peritoneal dialysis, two or more values of intact PTH (immunoradiometric assay, pg/ml) obtained at least 90 d apart were available in 1270 prevalent cases (61.1% blacks, 51% males, and 31.1% diabetic), including 466 incident cases with onset of ESRD after 1993. Maximum PTH levels were analyzed as a function of race, gender, age, diabetic status, and levels of serum calcium, phosphorus, alkaline phosphatase, and aluminum. Using a stepwise multiple regression model, the determinants of maximum PTH in the order of their importance were black race, serum phosphorus, absence of diabetes, younger age, serum calcium, and female gender. The maximum PTH levels averaged 641.7 in blacks and 346.0 in whites after adjusting for age, gender, diabetic status, serum calcium, and phosphorus (P < 0.0001). In blacks compared with whites, the odds ratio (95% confidence interval) for adynamic bone disease (maximum PTH <150 pg/ml) was 0.26 (0.17 to 0.41), whereas the odds ratio for hyperparathyroid bone disease (mean PTH >500 pg/ml) was 4.4 (2.10 to 9.25). Race is a major independent determinant of uremic secondary hyperparathyroidism. Among ESRD patients, blacks may be at an increased risk for hyperparathyroid bone disease and whites for adynamic bone disease.