Intermittent venovenous hemofiltration as a chronic treatment for refractory and intractable heart failure

Continuous Renal Replacement Therapy (CRRT) in the Intensive Care Unit

This review is specifically designed to address the topic of CRRT based on the needs and interests of intensivists. Some of the materials, concepts, and formulas presented in this review have been drawn from a previous chapter authored by myself and intended for individuals whose primary interest is specifically dialysis[1]. Since this previous chapter was authored in 1994, similar material presented in this review has been updated in order to present the most current information.

Ultrafiltration in Heart Failure

Managing volume overload is essential for the treatment of symptomatic heart failure. Traditionally, it is achieved with oral and intravenous diuretics. Alternatively, the excess fluid can be removed via ultrafiltration. Modern technology has made this latter option more feasible than before for routine clinical practice. In this article we review the existing literature on the use of ultrafiltration for treating volume overload states in patients with heart failure.

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.

Reviews: The Current State of Nonuremic Applications for Extracorporeal Blood Purification

Despite the commonly accepted indications for hemodialysis and extracorporeal depuritive techniques, some clinicians have come to rely on blood purification for clinical states where the targeted substance for removal differs from uremic waste products. Over the last decade, a number of studies have emerged to help define the application of extracorporeal blood purification (ECBP) to these "nonuremic" indications. This review describes the application of extracorporeal blood purification in clinical states including sepsis, rhabdomyolysis, congestive heart failure, hepatic failure, tumor lysis syndrome, adult respiratory distress syndrome, intravenous contrast exposure, and lactic acidosis. Additional comments are provided to review existing literature on thermoregulation and osmoregulation, including acute brain injury.

Management of diuretic-refractory, volume-overloaded patients with acutely decompensated heart failure

Fluid overload is a common presentation for decompensated heart failure, yet management strategies are poorly defined because of relatively few randomized clinical trials that delineate an optimal strategy. Patients refractory to diuretic therapy may be considered for treatment with inotropes or vasodilators, and others may be considered for venovenous ultrafiltration. The rationale for use of each therapy is reviewed.

Congestive heart failure in patients with chronic kidney disease and on dialysis

CHF is highly prevalent in ESRD and is a leading cause of death in such patients. Hypertension, renal anemia, and comorbid conditions such as coronary artery disease are particularly important risk factors for CHF in ESRD. Dialysis hypotension may be a marker of poor prognosis in such persons. Recent studies suggest that lipid peroxidation and L-carnitine deficiency may contribute to CHF in some patients with ESRD. All forms of renal replacement therapy are capable of ameliorating symptoms of CHF, but their effect on cardiovascular mortality has not been firmly established. Drug therapy, particularly angiotensin-converting enzyme inhibitors and beta-adrenergic receptor blockers, is under-used in patients with ESRD and CHF. Heart/kidney transplantation may be a viable option for some patients with advanced CHF and ESRD.

The Acute Dialysis Quality Initiative--part II: patient selection for CRRT

The delivery of optimal acute dialytic support requires that the correct patients be selected for such treatment in a timely fashion and that such treatment be delivered at the appropriate dose, for an appropriate length of time, and for the appropriate indications. The Acute Dialysis Quality Initiative sought to address these issues through an expert-enhanced review of the literature. This article represents a condensation of its findings with regard to patients selection for CRRT, indications for initiation of treatment, transition to other treatments, cessation of treatment, and availability of continuous therapy. The article offers recommendations for clinical practice based on the findings of the expert group. It also offers suggestions and sets priorities for future research in this important area of critical care nephrology.

Renal replacement therapies

Slow continuous renal replacement therapy is more hemodynamically stabilizing and is replacing conventional hemodialysis as the therapy of choice for acute renal failure in the intensive care unit. This article presents practical information, including basic terminology, basic physiology, technical aspects, and indications for and application of this technique.

Non-renal indications for continuous renal replacement therapy

While there is clear support for the use of continuous renal replacement therapy (CRRT) in critically ill acute renal failure patients, there are other illnesses without renal involvement where CRRT might be of value. These include sepsis and other inflammatory syndromes such as acute respiratory distress syndrome (ARDS) and cardiopulmonary bypass where removal of inflammatory mediators by hemofiltration is hypothesized to improve outcome. Adsorption appears to be the predominant mechanism of mediator elimination. However, the observed hemodynamic improvement can, at least partially, be attributed to a reduction of body temperature or to fluid removal, and the evidence for a clinically important removal of proinflammatory cytokines remains limited. Continuous and therefore smooth fluid removal may improve organ function in ARDS, after surgery with cardiopulmonary bypass, and in patients with refractory congestive heart failure. Continuous removal of endogenous toxins, eventually combined with intermittent hemodialysis, is probably beneficial in inborn errors of metabolism, severe lactic acidosis, or tumor lysis syndrome.

A primer on continuous renal replacement therapy for critically ill patients

OBJECTIVES

To characterize the multiple continuous renal replacement therapy (CRRT) techniques available for the management of critically ill adults, and to review the indications for and complications of use, principles of drug removal during CRRT, drug dosage individualization guidelines, and the influence of CRRT on patient outcomes.

DATA SOURCES

MEDLINE (January 1981-December 1996) was searched for appropriate publications by using terms such as hemofiltration, ultrafiltration, hemodialysis, hemodiafiltration, medications, and pharmacokinetics; selected articles were cross-referenced.

STUDY SELECTION

References selected were those considered to enhance the reader's knowledge of the principles of CRRT, and to provide adequate therapies on drug disposition.

DATA SYNTHESIS

CRRTs use filtration/convection and in some cases diffusion to treat hemodynamically unstable patients with fluid overload and/or acute renal failure. Recent data suggest that positive outcomes may also be attained in patients with other medical conditions such as septic shock, multiple organ dysfunction syndrome, and hepatic failure. Age, ventilator support, inotropic support, reduced urine volume, and elevated serum bilirubin concentrations have been associated with poor outcomes. Complications associated with CRRT include bleeding due to excessive anticoagulation and line disconnections, fluid and electrolyte imbalance, and filter and venous clotting. CRRT can complicate the medication regimens of patients for whom it is important to maintain drug plasma concentrations within a narrow therapeutic range. Since the physicochemical characteristics of a drug and procedure-specific factors can alter drug removal, a thorough assessment of all factors needs to be considered before dosage regimens are revised. In addition, an algorithm for drug dosing considerations based on drug and CRRT characteristics, as well as standard pharmacokinetic equations, is proposed.

CONCLUSIONS

The use of CRRT has expanded to encompass the treatment of disease states other than just acute renal failure. Since there is great variability among treatment centers, it is premature to conclude that there is enhanced survival in CRRT-treated patients compared with those who received conventional hemodialysis. This primer may help clinicians understand the need to individualize these therapies and to prospectively optimize the pharmacotherapy of their patients receiving CRRT.

Outcome predictors of ultrafiltration in patients with refractory congestive heart failure and renal failure

This study is an attempt to identify predictors of outcome from the use of ultrafiltration (UF) in patients with refractory congestive heart failure (CHF) and renal failure. The authors studied 30 patients in NYHA functional class IV in whom UF was utilized in the management of refractory CHF. Patients were retrospectively divided into two groups according to their outcome. Group A included 12 patients who improved and survived hospital admission, and group B included 18 patients who did not respond and died shortly after UF. Clinical, hemodynamic, and laboratory data before UF were fairly comparable between both groups. Renal function and hemodynamic parameters were compared and analyzed within the same group and between both groups before and after UF. The mean age in group A was sixty-three +/- thirteen years while in group B it was seventy +/- eleven years (P < 0.005). A mean of 9.6 liters of fluid were removed from group A and 3.2 liters from group B (P < 0.001). Group A showed greater reduction in the mean values of right atrial pressure (P < 0.005) and pulmonary capillary wedge pressure (P < 0.05) after UF. Additionally, group A showed a significant decrease in their blood urea nitrogen (P < 0.05) and serum creatinine values (P < 0.05), in contradistinction to group B patients who showed a major increase in those values after UF. There was no significant change in the mean values of cardiac index, systemic vascular resistance, and pulmonary vascular resistance after UF. These findings suggest that younger age groups, greater fluid removal, as well as significant decreases in blood urea nitrogen, serum creatinine, and right atrial and pulmonary wedge pressures after UF, are associated with favorable outcome. Conversely, older age groups, less fluid removal, and rising blood urea nitrogen and serum creatinine levels after UF were associated with poor outcome.

Chronic intermittent haemofiltration and haemodialysis in end stage chronic heart failure with oedema refractory to high dose frusemide

OBJECTIVE

To assess the benefits and problems of chronic intermittent treatment with haemofiltration or haemodialysis or both in patients with severe chronic heart failure (New York Heart Association class III or IV) and oedema refractory to pharmacological treatment.

DESIGN AND SETTING

A retrospective case-cohort study. A general hospital in The Netherlands.

PATIENTS

The results of chronic intermittent treatment with haemofiltration (n = 10) or haemodialysis (n = 2) were analysed in patients with severe chronic heart failure, predominantly due to coronary heart disease, and oedema refractory to a pharmacological regimen including high dose frusemide.

INTERVENTION

Patients had an average of 25 (SD 38) treatments.

RESULTS

There was improvement of NYHA class IV to III in seven patients. However, this was not reflected in a decrease in hospital admission: only two patients could be managed as outpatients. The median survival after start of the treatment was 24 days (varying from 0 to 393 days). In four patients the treatment was discontinued after discussion with the patient and family.

CONCLUSIONS

The use of chronic intermittent haemofiltration and haemodialysis is of limited value in end stage chronic heart failure with oedema, refractory to maximal conventional treatment.