Edward G. Clark

Comparison of standard and accelerated initiation of renal replacement therapy in acute kidney injury.

In patients with severe acute kidney injury (AKI) but no urgent indication for renal replacement therapy (RRT), the optimal time to initiate RRT remains controversial. While starting RRT preemptively may have benefits, this may expose patients to unnecessary RRT. To study this, we conducted a 12-center open-label pilot trial of critically ill adults with volume replete severe AKI. Patients were randomized to accelerated (12 h or less from eligibility) or standard RRT initiation. Outcomes were adherence to protocol-defined time windows for RRT initiation (primary), proportion of eligible patients enrolled, follow-up to 90 days, and safety in 101 fully eligible patients (57 with sepsis) with a mean age of 63 years. Median serum creatinine and urine output at enrollment were 268 micromoles/l and 356 ml per 24 h, respectively. In the accelerated arm, all patients commenced RRT and 45/48 did so within 12 h from eligibility (median 7.4 h). In the standard arm, 33 patients started RRT at a median of 31.6 h from eligibility, of which 19 did not receive RRT (6 died and 13 recovered kidney function). Clinical outcomes were available for all patients at 90 days following enrollment, with mortality 38% in the accelerated and 37% in the standard arm. Two surviving patients, both randomized to standard RRT initiation, were still RRT dependent at day 90. No safety signal was evident in either arm. Our findings can inform the design of a large-scale effectiveness randomized control trial.

A simple method to estimate renal volume from computed tomography

INTRODUCTION Renal parenchymal volume can be used clinically to estimate differential renal function. Unfortunately, conventional methods to determine renal volume from computed tomography (CT) are time-consuming or difficult due to software limitations. We evaluated the accuracy of simple renal measurements to estimate renal volume as compared with estimates made using specialized CT volumetric software. METHODS We reviewed 28 patients with contrast-enhanced abdominal CT. Using a standardized technique, one urologist and one urology resident independently measured renal length, lateral diameter and anterior-posterior diameter. Using the ellipsoid method, the products of the linear measurements were compared to 3D volume measurements made by a radiologist using specialized volumetric software. RESULTS LINEAR KIDNEY MEASUREMENTS WERE HIGHLY CONSISTENT BETWEEN THE UROLOGIST AND THE UROLOGY RESIDENT (INTRACLASS CORRELATION COEFFICIENTS: 0.97 for length, 0.96 for lateral diameter, and 0.90 for anterior-posterior diameter). Average renal volume was 170 (SD: 36) cm(3) using the ellipsoid method compared with 186 (SD 37) cm(3) using volumetric software, for a mean absolute bias of -15.2 (SD 15.0) cm(3) and a relative volume bias of -8.2% (p < 0.001). Thirty-one of 56 (55.3%) estimated volumes were within 10% of the 3D measured volume and 54 of 56 (96.4%) were within 30%. CONCLUSION Renal volume can be easily approximated from contrast-enhanced CT scans using the ellipsoid method. These findings may obviate the need for 3D volumetric software analysis in certain cases. Prospective validation is warranted.

Timing of initiation of renal replacement therapy for acute kidney injury: a survey of nephrologists and intensivists in Canada

BACKGROUND Little is known about factors that influence the timing of initiation of renal replacement therapy (RRT) for acute kidney injury (AKI). We sought to better describe these factors for Canadian physicians that prescribe RRT for AKI. METHODS A web-based survey was conducted of physicians involved in the decision to initiate RRT for critically ill patients in Canada. Participants were asked about the factors that prompt them to initiate RRT for AKI both directly and using scenario-based questions. RESULTS Surveys completed by 180 physicians at 32 different sites were included for analysis. Serum potassium level and severity of pulmonary edema were the most commonly utilized factors for deciding when RRT should be started. For all clinical and laboratory factors inquired about, there was wide variation in the minimum severity that prompted respondents to indicate that they would initiate RRT. Additional factors that influenced the timing of initiation were the time-of-day that laboratory and clinical results became available, patient age and co-morbidity, responsiveness to a diuretic challenge and the specialty of the prescribing physician. Over 90% of respondents indicated that a randomized controlled trial to assess the optimal timing of initiation of RRT for AKI is ethically justified. CONCLUSIONS These results provide insight into clinical and laboratory factors that influence the timing of initiation of RRT for AKI and may aid in the design of future trials. While most clinicians consider the degree of hyperkalemia and pulmonary edema in deciding when to initiate RRT for AKI, there is a wide range of clinical practice, uncertainty regarding the optimal timing of initiation and enthusiasm for prospective interventional studies to address this topic.

Temporary Hemodialysis Catheter Placement by Nephrology Fellows: Implications for Nephrology Training

The insertion of temporary hemodialysis catheters is considered to be a core competency of nephrology fellowship training. Little is known about the adequacy of training for this procedure and the extent to which evidence-based techniques to reduce complications have been adopted. We conducted a web-based survey of Canadian nephrology trainees regarding the insertion of temporary hemodialysis catheters. Responses were received from 45 of 68 (66%) eligible trainees. The median number of temporary hemodialysis catheters inserted during the prior 6 months of training was 5 (IQR, 2-11), with 9 (20%) trainees reporting they had inserted none. More than one-third of respondents indicated that they were not adequately trained to competently insert temporary hemodialysis catheters at both the femoral and internal jugular sites. These findings are relevant to a discussion of the current adequacy of procedural skills training during nephrology fellowship. With respect to temporary hemodialysis catheter placement, there is an opportunity for increased use of simulation-based teaching by training programs. Certain infection control techniques and use of real-time ultrasound should be more widely adopted. Consideration should be given to the establishment of minimum procedural training requirements at the level of both individual training programs and nationwide certification authorities.

Unnecessary Renal Replacement Therapy for Acute Kidney Injury is Harmful for Renal Recovery

The use of renal replacement therapy (RRT) for severe acute kidney injury (AKI) is frequently necessary in the face of life‐threatening complications; however, there is wide practice variation with respect to triggers for RRT initiation. Recent evidence suggests that RRT may be independently associated with impaired recovery following AKI. There are plausible mechanistic reasons why RRT may be harmful and this concept is supported by ancillary evidence in the form of studies that have assessed the impact of different modalities of RRT for AKI as well as some of the literature pertaining to initiation of chronic hemodialysis in end‐stage kidney disease patients (ESKD). As such, avoiding unnecessary RRT (URRT) is a desirable goal. There is emerging evidence of strategies that may be effective to help limit URRT. These strategies primarily involve early identification of AKI and limiting iatrogenic harm once AKI is established. Further research into defining and preventing URRT may help improve the consistently poor outcomes following severe AKI with respect to development of chronic kidney disease and ESKD.

Health-related quality-of-life among survivors of acute kidney injury in the intensive care unit: a systematic review.

PurposeTo summarize evidence on long-term health-related quality-of-life (HRQL) among survivors of acute kidney injury (AKI) in the intensive care unit (ICU).MethodsWe performed a comprehensive search of the literature for studies reporting original data describing HRQL utilizing validated instruments. Search, study selection and data abstraction were performed in duplicate. Study quality was appraised. Due to study heterogeneity, data are primarily summarized qualitatively.Results Our search yielded 2193 articles of which 18 were selected for detailed analysis. The quality of these 18 studies was generally good. Numerous HRQL instruments were utilized, and assessment occurred at variable follow-up duration (range 2 months to 14.5 years). HRQL among AKI survivors was reduced when compared to age/sex-matched populations. HRQL among survivors with and without AKI was generally described as similar beyond 6 months. Physical component domains were consistently more impaired than mental component domains. Survivors had considerable limitations in activities of daily living, implying newly acquired disability, with few returning to work. Despite diminished HRQL, patients’ HRQL was generally perceived as satisfactory, and the majority would receive similar treatment again, including renal replacement therapy in the ICU, if necessary.ConclusionsAmong survivors of critical illness complicated by AKI, HRQL was impaired when referenced to population norms, but it was not significantly different from that of survivors without AKI. Physical limitations and disabilities were more commonly exhibited by AKI patients. Importantly, the impaired HRQL was generally perceived as acceptable to patients, most of whom expressed willingness to undergo similar treatment in the future.

Venous thromboembolism in chronic kidney disease: epidemiology, the role of proteinuria, CKD severity and therapeutics

The worldwide prevalence of chronic kidney disease is 10–15 % of the adult population, is rising and increases susceptibility to venous thromboembolism (VTE). In this narrative review we discuss the underlying evidence behind the association of VTE/CKD and examine the role of worsening CKD stage, proteinuria, and the risk of recurrent VTE. As CKD may alter therapeutic options we discuss the role of emerging therapies, the non-vitamin K oral anticoagulants (NOAC), in the treatment of VTE.

Hemodialysis Tunneled Catheter-Related Infections

Catheter-related bloodstream infections, exit-site infections, and tunnel infections are common complications related to hemodialysis central venous catheter use. The various definitions of catheter-related infections are reviewed, and various preventive strategies are discussed. Treatment options, for both empiric and definitive infections, including antibiotic locks and systemic antibiotics, are reviewed.

Arteriovenous Access Infection, Neuropathy, and Other Complications

Complications of vascular access lead to morbidity and may reduce quality of life. In this module, we review both infectious and noninfectious arteriovenous access complications including neuropathy, aneurysm, and high-output access. For the challenging patients who have developed many complications and are now nearing their last vascular access, we highlight some potentially novel approaches.

Practical Aspects of Nontunneled and Tunneled Hemodialysis Catheters

Nontunneled hemodialysis catheters (NTHCs) are typically used when vascular access is required for urgent renal replacement therapy. The preferred site for NTHC insertion in acute kidney injury is the right internal jugular vein followed by the femoral vein. When aided by real-time ultrasound, mechanical complications related to NTHC insertion are significantly reduced. The preferred site for tunneled hemodialysis catheters placement is the right internal jugular vein followed by the left internal jugular vein. Ideally, the catheter should be inserted on the opposite side of a maturing or planned fistula/graft. Several dual-lumen, large-diameter catheters are available with multiple catheter tip designs, but no one catheter has shown significant superior performance.