Challenges and pitfalls when implementing renal replacement therapy in the ICU

Indications for and Timing of Initiation of KRT

KRT is considered for patients with severe AKI and associated complications. The exact indications for initiating KRT have been debated for decades. There is a general consensus that KRT should be considered in patients with AKI and medically refractory complications ("urgent indications"). "Relative indications" are more common but defined with less precision. In this review, we summarize the latest evidence from recent landmark clinical trials, discuss strategies to anticipate the need for KRT in individual patients, and propose an algorithm for decision making. We emphasize that the decision to consider KRT should be made in conjunction with other forms of organ support therapies and important nonkidney factors, including the patient's preferences and overall goals of care. We also suggest future research to differentiate patients who benefit from timely initiation of KRT from those with imminent recovery of kidney function. Until then, efforts are needed to optimize the initiation and delivery of KRT in routine clinical practice, to minimize nonessential variation, and to ensure that patients with persistent AKI or progressive organ failure affected by AKI receive KRT in a timely manner.

Patients with Severe Lactic Acidosis in the Intensive Care Unit: A Retrospective Study of Contributing Factors and Impact of Renal Replacement Therapy

INTRODUCTION

Hyperlactatemia is a regular condition in the intensive care unit, which is often associated with adverse outcomes. Control of the triggering condition is the most effective treatment of hyperlactatemia, but since this is mostly not readily possible, extracorporeal renal replacement therapy (RRT) is often tried as a last resort. The present study aims to evaluate the factors that may contribute to the decision whether to start RRT or not and the potential impact of the start of RRT on the outcome in patients with severe lactic acidosis (SLA) (lactate ≥5 mmol/L).

MATERIALS AND METHODS

We conducted a retrospective single-center cohort analysis over a 3-year period including all patients with a lactate level ≥5 mmol/L. Patients were considered as treated with RRT because of SLA if RRT was started within 24 h after reaching a lactate level ≥5 mmol/L.

RESULTS

Overall, 90-day mortality in patients with SLA was 34.5%. Of the 1,203 patients who matched inclusion/exclusion criteria, 11% (n = 133) were dialyzed within 24 h. The propensity to receive RRT was related to the lactate level and to the SOFA renal and cardio score. The most frequently used modality was continuous RRT. Patients who were started on RRT versus those who did not have 2.3 higher odds of mortality, even after adjustment for the propensity to start RRT.

CONCLUSIONS

Our analysis confirms the high mortality rate of patients with SLA. It adds that odds for mortality is even higher in patients who were started on RRT versus not. We suggest keeping an open mind to the factors that may influence the decision to start dialysis and bear in mind that without being a bridge to correction of the underlying condition, dialysis is unlikely to affect the outcome.

Acute Renal Replacement Therapy in Intensive Care Units versus Outside Intensive Care Units: Are They Different?

Introduction

Acute renal replacement therapy (RRT) is indicated when metabolic and fluid demands exceed total kidney capacity, and demand for kidney function is determined by non-renal comorbidities, severity of acute disease and solute and fluid burden; therefore, the criteria for commencing RRT and dialysis in intensive care units (ICUs) may be different to those outside ICUs.

Objective

We investigated whether criteria for commencing acute RRT and dialysis outside ICU were different to those in ICU and whether these differences affected patient mortality in either setting.

Methods

We performed a retrospective observational study evaluating acute kidney injury (AKI), Kidney Disease Improving Global Outcome 3 (KDIGO3) in adult patients undergoing RRT “in and outside” ICU from 2012 to 2018, in a Brazilian teaching hospital.

Results

We evaluated 913 adults with AKI KDIGO3 undergoing RRT; 629 (68.9%) outside ICU and 284 (31.1%) in ICU. Infections were the main cause of hospitalisation (34.4%). Septic and ischaemic AKI were the main aetiologies of AKI (50.8% and 32.9%, respectively), metabolic and fluid demand to capacity imbalance were the main indications for dialysis (69.7%), and intermittent haemodialysis (IHD) was the primary dialysis method (59.2%). The general mortality rate after 30 days was 59%. There were no differences in gender, age and main diagnosis between groups. Both groups were different in acute tubular necrosis index specific scores (ATN-ISS), AKI aetiology, elderly population, indications for dialysis, dialysis methods and mortality rates. In ICU, patients older than 65 years old, with septic AKI were more prevalent (49.1 versus 41.4%, and 55.1 versus 37.5%, respectively), while ischaemic and nephrotoxic AKI were less frequent (24.3 versus 37 and 10.2 versus 16.3%, respectively), and ATN-ISS was higher (0.74 ± 0.31 versus 0.58 ± 0.16). Similarly, metabolic and fluid demand to capacity imbalance as an indication for acute RRT, prolonged intermittent haemodialysis (PIRRT) and continuous renal replacement therapy (CRRT) were more frequent, while peritoneal dialysis (PD) was less frequent (74.6 versus 69.7%, 31.6 versus 22.4%, and 5.3 versus 17.8%, respectively), and mortality was higher (69 versus 54.7%, respectively). Logistic regression revealed that age, septic AKI and being “in” ICU were factors associated with death.

Conclusion

The criteria for commencing RRT and dialysis in ICU were different to those outside ICU; however, they did not impact on patient outcomes.

The future of critical care: renal support in 2027

Since its inception four decades ago, both the clinical and technologic aspects of continuous renal replacement therapy (CRRT) have evolved substantially. Devices now specifically designed for critically ill patients with acute kidney injury are widely available and the clinical challenges associated with treating this complex patient population continue to be addressed. However, several important questions remain unanswered, leaving doubts in the minds of many clinicians about therapy prescription/delivery and patient management. Specifically, questions surrounding therapy dosing, timing of initiation and termination, fluid management, anticoagulation, drug dosing, and data analytics may lead to inconsistent delivery of CRRT and even reluctance to prescribe it. In this review, we discuss current limitations of CRRT and potential solutions over the next decade from both a patient management and a technology perspective. We also address the issue of sustainability for CRRT and related therapies beyond 2027 and raise several points for consideration.