Prolonged Daily Intermittent Renal Replacement Therapy in ICU Patients by ICU Nurses and ICU Physicians

Prolonged Intermittent Kidney Replacement Therapy

Kidney replacement therapy (KRT) is a vital, supportive treatment for patients with critical illness and severe AKI. The optimal timing, dose, and modality of KRT have been studied extensively, but gaps in knowledge remain. With respect to modalities, continuous KRT and intermittent hemodialysis are well-established options, but prolonged intermittent KRT is becoming more prevalent worldwide, particularly in emerging countries. Compared with continuous KRT, prolonged intermittent KRT offers similar hemodynamic stability and overall cost savings, and its intermittent nature allows patients time off therapy for mobilization and procedures. When compared with intermittent hemodialysis, prolonged intermittent KRT offers more hemodynamic stability, particularly in patients who remain highly vulnerable to hypotension from aggressive ultrafiltration over a shorter duration of treatment. The prescription of prolonged intermittent KRT can be tailored to patients' progression in their recovery from critical illness, and the frequency, flow rates, and duration of treatment can be modified to avert hemodynamic instability during de-escalation of care. Dosing of prolonged intermittent KRT can be extrapolated from urea kinetics used to calculate clearance for continuous KRT and intermittent hemodialysis. Practice variations across institutions with respect to terminology, prescription, and dosing of prolonged intermittent KRT create significant challenges, especially in creating specific drug dosing recommendations during prolonged intermittent KRT. During the coronavirus disease 2019 pandemic, prolonged intermittent KRT was rapidly implemented to meet the KRT demands during patient surges in some of the medical centers overwhelmed by sheer volume of patients with AKI. Ideally, implementation of prolonged intermittent KRT at any institution should be conducted in a timely manner, with judicious planning and collaboration among nephrology, critical care, dialysis and intensive care nursing, and pharmacy leadership. Future analyses and clinical trials with respect to prescription and delivery of prolonged intermittent KRT and clinical outcomes will help to guide standardization of practice.

Pediatric Continuous Renal Replacement Therapy (PCRRT) expert committee recommendation on prescribing prolonged intermittent renal replacement therapy (PIRRT) in critically ill children

INTRODUCTION

Recently, prolonged intermittent renal replacement therapies (PIRRT) have emerged as cost-effective alternatives to conventional CRRT and their use in the pediatric population has started to become more prominent. However, there is a lack of consensus guidelines on the use of PIRRT in pediatric patients in an intensive care setting.

METHODS

A literature search was performed on PubMed/Medline, Embase, and Google Scholar in conjunction with medical librarians from both India and the Cleveland Clinic hospital system to find relevant articles. The Pediatric Continuous Renal Replacement Therapy workgroup analyzed all articles for relevancy, proposed recommendations, and graded each recommendation for their strength of evidence.

RESULTS

Of the 60 studies eligible for review, the workgroup considered data from 37 studies to formulate guidelines for the use of PIRRT in children. The guidelines focused on the definition, indications, machines, and prescription of PIRRT.

CONCLUSION

Although the literature on the use of PIRRT in children is limited, the current studies give credence to their benefits and these expert recommendations are a valuable first step in the continued study of PIRRT in the pediatric population.

Prolonged intermittent renal replacement therapy in children

Wide ranges of age and weight in pediatric patients makes renal replacement therapy (RRT) in acute kidney injury (AKI) challenging, particularly in the pediatric intensive care unit (PICU), wherein children are often hemodynamically unstable. Standard hemodialysis (HD) is difficult in this group of children and continuous veno-venous hemofiltration/dialysis (CVVH/D) has been the accepted modality in the developed world. Unfortunately, due to cost constraints, CVVH/D is often not available and peritoneal dialysis (PD) remains the common mode of RRT in resource-poor facilities. Acute PD has its drawbacks, and intermittent HD (IHD) done slowly over a prolonged period has been explored as an alternative. Various modes of slow sustained IHD have been described in the literature with the recently introduced term prolonged intermittent RRT (PIRRT) serving as an umbrella terminology for all of these modes. PIRRT has been widely accepted in adults with studies showing it to be as effective as CVVH/D but with an added advantage of being more cost-effective. Pediatric data, though scanty, has been promising. In this current review, we elaborate on the practical aspects of undertaking PIRRT in children as well as summarize its current status.

Prolonged Intermittent Renal Replacement Therapy

Prolonged intermittent renal replacement therapy (PIRRT) is becoming an increasingly popular alternative to continuous renal replacement therapy in critically ill patients with acute kidney injury. There are significant practice variations in the provision of PIRRT across institutions, with respect to prescription, technology, and delivery of therapy. Clinical trials have generally demonstrated that PIRRT is non-inferior to continuous renal replacement therapy regarding patient outcomes. PIRRT offers cost-effective renal replacement therapy along with other advantages such as early patient mobilization and decreased nursing time. However, due to lack of standardization of the procedure, PIRRT still poses significant challenges, especially pertaining to appropriate drug dosing. Future guidelines and clinical trials should work toward developing consensus definitions for PIRRT and ensure optimal delivery of therapy.

Clinical Characteristics and 30-Day Outcomes of Intermittent Hemodialysis for Acute Kidney Injury in an African Intensive Care Unit

INTRODUCTION

Acute kidney injury (AKI) is a common occurrence in the intensive care unit (ICU). Studies have looked at outcomes of renal replacement therapy using intermittent haemodialysis (IHD) in ICUs with varying results. Little is known about the outcomes of using IHD in resource-limited settings where continuous renal replacement therapy (CRRT) is limited. We sought to determine outcomes of IHD among critically ill patients admitted to a low-income country ICU.

METHODS

A retrospective review of patient records was conducted. Patients admitted to the ICU who underwent IHD for AKI were included in the study. Patients' demographic and clinical characteristics, cause of AKI, laboratory parameters, haemodialysis characteristics, and survival were interpreted and analyzed. Primary outcome was mortality.

RESULTS

Of 62 patients, 40 had complete records. Median age of patients was 38.5 years. Etiologic diagnoses associated with AKI included sepsis, malaria, and ARDS. Mortality was 52.5%. APACHE II (OR 4.550; 95% CI 1.2-17.5, p = 0.028), mechanical ventilation (OR 13.063; 95% CI 2.3-72, p = 0.003), and need for vasopressors (OR 16.8; 95% CI 3.4-82.6, p = 0.001) had statistically significant association with mortality.

CONCLUSION

IHD may be a feasible alternative for RRT in critically ill haemodynamically stable patients in low resource settings where CRRT may not be available.

Renal Replacement Therapy

During the last few years, due to medical and surgical evolution, patients with increasingly severe diseases causing multiorgan dysfunction are frequently admitted to intensive care units. Therapeutic options, when organ failure occurs, are frequently nonspecific and mostly directed towards supporting vital function. In these scenarios, the kidneys are almost always involved and, therefore, renal replacement therapies have become a common routine practice in critically ill patients with acute kidney injury. Recent technological improvement has led to the production of safe, versatile and efficient dialysis machines. In addition, emerging evidence may allow better individualization of treatment with tailored prescription depending on the patients' clinical picture (e.g. sepsis, fluid overload, pediatric). The aim of the present review is to give a general overview of current practice in renal replacement therapies for critically ill patients. The main clinical aspects, including dose prescription, modality of dialysis delivery, anticoagulation strategies and timing will be addressed. In addition, some technical issues on physical principles governing blood purification, filters characteristics, and vascular access, will be covered. Finally, a section on current standard nomenclature of renal replacement therapy is devoted to clarify the "Tower of Babel" of critical care nephrology.

Outcomes of sustained low efficiency dialysis versus continuous renal replacement therapy in critically ill adults with acute kidney injury: a cohort study

Background

Sustained low efficiency dialysis (SLED) is increasingly used as a renal replacement modality in critically ill patients with acute kidney injury (AKI) and hemodynamic instability. SLED may reduce the hemodynamic perturbations of intermittent hemodialysis, while obviating the resource demands of CRRT. Although SLED is being increasingly used, few studies have evaluated its impact on clinical outcomes.

Methods

We conducted a cohort study comparing SLED (target 8 h/session, blood flow 200 mL/min, predominantly without anticoagulation) to CRRT in four ICUs at an academic medical centre. The primary outcome was mortality 30 days after RRT initiation, adjusted for demographics, comorbidity, baseline kidney function, and Sequential Organ Failure Assessment score. Secondary outcomes were persistent RRT dependence at 30 days and early clinical deterioration, defined as a rise in SOFA score or death 48 h after starting RRT.

Results

We identified 158 patients who initiated treatment with CRRT and 74 with SLED. Mortality at 30 days was 54 % and 61 % among SLED- and CRRT-treated patients, respectively [adjusted odds ratio (OR) 1.07, 95 % CI 0.56–2.03, as compared with CRRT]. Among SLED recipients, the risk of RRT dependence at 30 days (adjusted OR 1.36, 95 % CI 0.51–3.57) and early clinical deterioration (adjusted OR 0.73, 95 % CI 0.40–1.34) were not different as compared to patients who initiated CRRT.

Conclusions

Notwithstanding the limitations of this small non-randomized study, we found similar clinical outcomes for patients treated with SLED and CRRT. While we await the completion of a trial that will definitively assess the non-inferiority of SLED as compared to CRRT, SLED appears to be an acceptable alternative form of renal support in hemodynamically unstable patients with AKI.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0123-4) contains supplementary material, which is available to authorized users.

A new machine for continuous renal replacement therapy: from development to clinical testing

A new continuous renal replacement therapy machine has been designed to fulfill the expectations of nephrologists and intensivists operating in the common ground of critical care nephrology. The new equipment is called Prismaflex and it is the natural evolution of the PRISMA machine that has been utilized worldwide for continuous renal replacement therapy in the last 10 years. The authors performed a preliminary alpha-trial to establish the usability, flexibility and reliability of the new device. Accuracy was also tested by recording various operational parameters during different intermittent and continuous renal replacement modalities during 62 treatments. This article will describe our first experience with this new device and touch upon the historic and technologic background leading to its development.

Comparison of outcomes by modality for critically ill patients requiring renal replacement therapy: a single-centre cohort study adjusting for time-varying illness severity and modality exposure

Prolonged intermittent renal replacement therapy (PIRRT) is a recently defined acute modality for critically ill patients, and in theory combines the superior detoxification and haemodynamic stability of continuous renal replacement therapy (CRRT) with the operational convenience and low cost of intermittent haemodialysis (iHD). We performed a retrospective cohort study for all critically ill adults treated with renal replacement therapy at our centre in Auckland, New Zealand from 1 January 2002 to 31 December 2008. The exposure of interest was modality (PIRRT, CRRT, iHD). Primary and secondary outcomes were patient mortality determined at hospital discharge and 90 days post renal replacement therapy inception, respectively. Co-variates included co-morbidity and baseline illness severity measured by Acute Physiology and Chronic Health Evaluation IV and Sepsis-Related Organ Failure Assessment (SOFA) and time-varying illness severity measured by daily SOFA scores. We used Marginal Structural Modelling to estimate mortality risk adjusting for both time-varying illness severity and modality exposure. A total of 146 patients with 633 treatment-days had sufficient data for modelling. With PIRRT as the reference, the adjusted hazard ratios for patient hospital mortality were 1.31 (0.60 to 2.90) for CRRT and 1.22 (0.21 to 2.29) for iHD. Corresponding estimates for mortality at 90 days were 0.96 (0.39 to 2.36) and 2.22 (0.49 to 10.11), respectively, reflecting the poorer longer-term prognosis of patients still on iHD at hospital discharge with delayed or non-recovery of acute kidney injury. Our study supports the recent increased use of PIRRT, which within limits can be regarded as safe and effective.

Dose and efficiency of renal replacement therapy: continuous renal replacement therapy versus intermittent hemodialysis versus slow extended daily dialysis

Acute kidney injury represents an independent risk of death in the intensive care unit and significantly contributes to in-hospital mortality. The only accepted treatment of severe acute kidney injury so far is renal replacement therapy, which is not a causative therapy but rather a life-support treatment. Renal replacement therapy can be performed by several different techniques: intermittent hemodialysis, slow extended daily dialysis, peritoneal dialysis, or continuous renal replacement therapy. There is controversy about which technique should be used, which dosage should be selected for each therapy, and whether the technique and/or the dose of renal replacement therapy may impact survival in critically ill patients. After a careful review of the recent literature, definitive conclusions cannot be drawn: Trials are in most cases underpowered and conducted over many years, in which significant changes in the practice of acute dialytic techniques have taken place. Other studies have described therapeutic modalities requiring a high level of specific expertise in the field and generally not easily reproducible in the routine practice. While practitioners are waiting for the ultimate trial to be published, we think it is worth reporting some broad concepts and few suggestions for renal replacement therapy prescription derived from current evidence and from the available experience.

The future of extracorporeal support

Extracorporeal therapy has expanded significantly over the past few decades from solely artificial renal replacement therapy. In patients with multiple organ dysfunction syndrome, it becomes necessary to provide multiple organ support therapy. Technological advances have opened the door to a multifaceted intervention directed at supporting the function of multiple organs through the treatment of blood. Indications for "old" therapies such as hemofiltration and adsorption have been expanded, and using these therapies in combination further enhances blood detoxification capabilities. Furthermore, new devices are constantly in development. Nanotechnology allows us to refine membrane characteristics and design innovative monitoring/biofeedback devices. Miniaturization is leading down the path of wearable/implantable devices. With the incorporation of viable cells within medical devices, these instruments become capable not only of detoxification but synthetic functions as well, bringing us closer to the holy grail of complete replacement of organ function. This article provides a brief overview of current and future direction in extracorporeal support in the critical care setting.

Current status of dosing and quantification of acute renal replacement therapy. Part 1: mechanisms and consequences of therapy under-delivery

The dosing and quantification of acute renal replacement therapy has emerged as one of the most pressing issues in the management of critically-ill patients with acute kidney injury. Although there is ongoing debate as to the best marker of uraemic injury in this setting, several landmark studies have identified clearance-related expressions of acute renal replacement therapy dose as important determinants of survival. Part 1 of this review examines the factors affecting delivery of prescribed acute renal replacement therapy dose. The review continues in Part 2 and examines the implications of recent advances in this area for clinical practice.

Technology Insight: treatment of renal failure in the intensive care unit with extended dialysis

Sustained low-efficiency dialysis (SLED) is an increasingly popular extracorporeal renal replacement therapy for patients with renal failure in the intensive care unit (ICU). Several centers across the world employ this 'hybrid' technique, which has advantages of both intermittent and continuous methods. The goal of these centers is to provide an easy-to-perform treatment with reduced solute clearances for prolonged periods. Many centers use standard, sophisticated dialysis equipment for SLED. An increasing number of hospitals in Europe and South America employ a single-pass batch dialysis system, the procedural simplicity of which makes it an ideal modality for SLED in the ICU. All systems offer the advantages of flexible timing of treatment and reduced costs; their ease of handling means that SLED is readily accepted by ICU staff. Prospective controlled studies have shown that SLED clears small solutes with an efficacy comparable to that of intermittent hemodialysis and continuous venovenous hemofiltration (even when the latter employs high rates of fluid substitution). Cardiovascular tolerability associated with SLED is similar to that associated with continuous renal replacement therapy, even in severely ill patients. Nocturnal dialysis -- a special form of SLED -- has all the advantages outlined above, with the added benefit of unrestricted physician access to the patient during the day, minimizing the interference of renal replacement therapy with other ICU activities.

Renal replacement II: dialysis dose

Improved survival of critically ill acute renal failure patients can be correlated with therapy dose. The overall solute elimination can be measured by the product of clearance and time (Kt), which is usually normalized for the volume of distribution (V) of the solute as "Kt/V." Setting a Kt/V threshold of 1.4 can guide clinicians toward adequate treatment. This is a slightly higher prescription than the current value for chronic dialysis. However, the true uraemic toxins probably diffuse among body compartments less readily than urea and, as such, the frequency of renal replacement therapy should be more important to its efficiency, and should be optimal with continuous therapy. In the absence of an optimal dialysis dose, it can only be recommended that the prescription should exceed that calculated to be "adequate."