Ultrafiltration in Patients with Hypervolemia and Congestive Heart Failure

Development of a new miniaturized system for ultrafiltration

Acute decompensated heart failure and fluid overload are the most common causes of hospitalization in heart failure patients, and often, they contribute to disease progression. Initial treatment encompasses intravenous diuretics although there might be a percentual of patients refractory to this pharmacological approach. New technologies have been developed to perform extracorporeal ultrafiltration in fluid overloaded patients. Current equipment allows to perform ultrafiltration in most hospital and acute care settings. Extracorporeal ultrafiltration is then prescribed and conducted by specialized teams, and fluid removal is planned to restore a status of hydration close to normal. Recent clinical trials and European and North American practice guidelines suggest that ultrafiltration is indicated for patients with refractory congestion not responding to medical therapy. Close interaction between nephrologists and cardiologists may be the key to a collaborative therapeutic effort in heart failure patients. Further studies are today suggesting that wearable technologies might become available soon to treat patients in ambulatory and de-hospitalized settings. These new technologies may help to cope with the increasing demand for the care of chronic heart failure patients. Herein, we provide a state-of-the-art review on extracorporeal ultrafiltration and describe the steps in the development of a new miniaturized system for ultrafiltration, called AD1 (Artificial Diuresis).

Renal replacement therapy with net fluid removal lowers intra-abdominal pressure and volumetric indices in critically ill patients

BACKGROUND

Little is known about the effects of renal replacement therapy (RRT) with fluid removal on intra-abdominal pressure (IAP). The global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI) can easily be measured bedside by transpulmonary thermodilution (TPTD). The aim of this study is to evaluate the changes in IAP, GEDVI and EVLWI in critically ill patients receiving slow extended daily dialysis (SLEDD) or continuous venovenous haemofiltration (CVVH) with the intention of net fluid removal.

METHODS

We performed a retrospective cohort study in ICU patients who were treated with SLEDD or CVVH and in whom IAP was also measured, and RRT sessions were excluded when the dose of vasoactive medication needed to be changed between the pre- and post-dialysis TPTD measurements and when net fluid loss did not exceed 500 ml. The TPTD measurements were performed within 2 h before and after SLEDD; in case of CVVH, before and after an interval of 12 h.

RESULTS

We studied 25 consecutive dialysis sessions in nine patients with acute renal failure and cardiogenic or non-cardiogenic pulmonary oedema. The GEDVI and EVLWI values before dialysis were 877 ml/m² and 14 ml/kg, respectively. Average net ultrafiltration per session was 3.6 l, with a net fluid loss 1.9 l. The GEDVI decreased significantly during dialysis, but not more than 47.8 ml/m² (p = 0.008), as also did the EVLWI with 1 ml/kg (p = 0.03). The IAP decreased significantly from 12 to 10.5 mmHg (p < 0.0001).

CONCLUSIONS

Net fluid removal by SLEDD or CVVH in the range observed in this study decreased IAP, GEDVI and EVLWI in critically ill patients although EVLWI reduction was modest.

Efficacy and cardiovascular tolerability of continuous veno-venous hemodiafiltration in acute decompensated heart failure: a randomized comparative study

BACKGROUND AND OBJECTIVES

Recently, continuous veno-venous hemodiafiltration (CVVHDF) has received increased attention in the treatment of congestive heart failure (CHF). The aim of this study is to assess the safety and efficacy of CVVHDF compared with intravenous furosemide in patients with CHF.

METHODS

Forty patients having CHF were included in this prospective, randomized, comparative trial. We randomized patients to treatment for 72 hours with CVVHDF or intravenous furosemide. Outcomes assessed were weight loss, total fluid output, length of stay (LOS) in the intensive care unit (ICU), 30-day mortality, and cardiovascular stability.

RESULTS

Demographic data were comparable in both groups. Weight loss (P ≤ .05) and total fluid output (P ≤ .01) were greater in the CVVHDF group. Length of stay in the ICU was significantly reduced in the CVVHDF group (P ≤ .05). The mortality rates were comparable in both groups. The cardiac output and the stroke volume significantly increased, whereas the pulmonary capillary wedge pressure significantly decreased (P ≤ .05) in both groups compared with the baseline. A transient attack of hypotension occurred in 1 patient in the CVVHDF group.

CONCLUSION

In CHF, the use of CVVHDF effectively and safely produced greater weight and fluid loss and decreased LOS in the ICU more than the intravenous furosemide with no hemodynamic instability.

Cardiorenal syndrome and heart failure

PURPOSE OF REVIEW

Concomitant anemia, heart failure, and renal disease can be seen in a large proportion of patients with heart failure. The purpose of this review is to discuss the current definitions and mechanisms involved in this pathophysiological relationship, as well as the potential management and treatment options available for these patients.

RECENT FINDING

Dysfunctional heart can promote the dysfunction of the kidneys through a variety of pathophysiological mechanism, the reciprocal holds true as well. Heart failure has been considered as the most common type of cardiovascular complication seen in patients with renal failure. Central to this relationship lies anemia, which can be the result or the cause of either heart or kidney disease.

SUMMARY

Cardiorenal syndrome is a complex condition, which requires the collaboration and resources from cardiology, cardiac surgery, nephrology, and critical care. Of great importance is recognizing the presence of cardiorenal syndrome and appreciating the impact it can play on treatment options and survival.

Urea kinetics and intermittent dialysis prescription in small animals

Hemodialysis improves survival for animals with acute kidney injury beyond what would be expected with conventional management of the same animals. Clinical evidence and experience in human patients suggest a role for earlier intervention with renal replacement to avoid the morbidity of uremia and to promote better metabolic stability and recovery. For a large population of animal patients, it is the advanced standard for the management of acute and chronic uremia, life-threatening poisoning, and fluid overload for which there is no alternative therapy.

Importance of whole-body bioimpedance spectroscopy for the management of fluid balance

INTRODUCTION

Achieving normohydration remains a non-trivial issue in haemodialysis therapy. Preventing the deleterious effects of fluid overload and dehydration is difficult to achieve. Objective and clinically applicable methods for the determination of a target representing normohydration are needed.

METHODS

Whole-body bioimpedance spectroscopy (50 frequencies, 5-1,000 kHz) in combination with a physiologic tissue model can provide an objective target for normohydration based on the concept of excess extracellular volume. We review the efficacy of this approach in a number of recent clinical applications. The accuracy to determine fluid volumes (e.g. extracellular water), body composition (e.g. fat mass) and fluid overload was evaluated in more than 1,000 healthy individuals and patients against available gold standard reference methods (e.g. bromide, deuterium, dual-energy X-ray absorptiometry, air displacement plethysmography, clinical assessment).

RESULTS

The comparison with gold standard methods showed excellent accordance [e.g. R(2) (total body water) = 0.88; median +/- SD (total body water) = -0.17 +/- 2.7 litres]. Agreement with high-quality clinical assessment of fluid status was demonstrated in several hundred patients (median +/- SD = -0.23 +/- 1.5 litres). The association between ultrafiltration volume and change in fluid overload was reflected well by the method (median +/- SD = 0.015 +/- 0.8 litres). The predictive value of fluid overload on mortality underlines forcefully the clinical relevance of the normohydration target, being secondary only to the presence of diabetes. The objective normohydration target could be achieved in prevalent haemodialysis patients leading to an improvement in hypertension and reduction of adverse events.

CONCLUSION

Whole-body bioimpedance spectroscopy in combination with a physiologic tissue model provides for the first time an objective and relevant target for clinical dry weight assessment.

Cardiorenal syndrome

The term cardiorenal syndrome (CRS) increasingly has been used without a consistent or well-accepted definition. To include the vast array of interrelated derangements, and to stress the bidirectional nature of heart-kidney interactions, we present a new classification of the CRS with 5 subtypes that reflect the pathophysiology, the time-frame, and the nature of concomitant cardiac and renal dysfunction. CRS can be generally defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of 1 organ may induce acute or chronic dysfunction of the other. Type 1 CRS reflects an abrupt worsening of cardiac function (e.g., acute cardiogenic shock or decompensated congestive heart failure) leading to acute kidney injury. Type 2 CRS comprises chronic abnormalities in cardiac function (e.g., chronic congestive heart failure) causing progressive chronic kidney disease. Type 3 CRS consists of an abrupt worsening of renal function (e.g., acute kidney ischemia or glomerulonephritis) causing acute cardiac dysfunction (e.g., heart failure, arrhythmia, ischemia). Type 4 CRS describes a state of chronic kidney disease (e.g., chronic glomerular disease) contributing to decreased cardiac function, cardiac hypertrophy, and/or increased risk of adverse cardiovascular events. Type 5 CRS reflects a systemic condition (e.g., sepsis) causing both cardiac and renal dysfunction. Biomarkers can contribute to an early diagnosis of CRS and to a timely therapeutic intervention. The use of this classification can help physicians characterize groups of patients, provides the rationale for specific management strategies, and allows the design of future clinical trials with more accurate selection and stratification of the population under investigation.

Continuous hemofiltration for anasarca: recovery of renal function after 71 liters of net ultrafiltration

We report on a 64-year-old female presenting with anasarca secondary to volume loading in the setting of chronic liver disease, acute on chronic renal failure, circulatory failure and sepsis. Over 37 days, a net negative fluid balance of 71 L was achieved using continuous hemofiltration, with spontaneous recovery of urine output, vasopressor independence and resolution of coagulopathy. This case report underlines the pathophysiological role of tissue edema in the downward spiral of hepato-renal and cardio-renal dysfunction and illustrates that very large volumes of tissue fluid can be safely and effectively removed with continuous renal replacement therapy, thereby permitting recovery of organ function. To our knowledge, there have been no previous reports of such large volume net fluid removal by progressive ultrafiltration in the intensive care unit.

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.

Ascites and kidney transplantation: case report and critical appraisal of the literature

Ascites is an ominous finding after kidney transplantation. It occurs either as a result of technical complication of the transplant procedure or from medical reasons that include portal hypertension, graft rejection and other causes (1, 2). Here in are described a case of ascites that occurred after successful kidney transplantation. Kidney re-transplantation alone or combined heart and kidney transplantation were possible options for him. Finally, a review of published cases of ascites that occurred after kidney transplantation and treatment of putative nephrogenic ascites (NA) is presented.

Management of fluid overload in congestive heart failure: learning from a case report

A case of refractory fluid overload due to congestive heart failure and consequent renal insufficiency is reported. The case was approached multidisciplinarily, at the beginning with conservative and pharmacological therapy, subsequently with extracorporeal fluid removal in which a specific attention was payed to the maintenance of circulating blood volume and achievement of dry weight, and finally with chronic peritoneal dialysis as a maintenance therapy. The case seems to summarize the pathway of many patients seen initially in intensive care and cardiology departments and subsequently in nephrological wards.

Bigendothelin-1 (1-21) fragment during early sepsis modulates tau, p38-MAPK phosphorylation and nitric oxide synthase activation

Earlier we have demonstrated that inhibition of endothelin biosynthesis ameliorates endotoxemia-induced inducible nitric oxide synthase (iNOS) activation and phosphorylation of p38-mitogen activated protein kinase (pp38-MAPK). Therefore, in the present study, we tested the hypothesis that activation of endothelin (ET)-1 biosynthesis using bigET-1 during early sepsis would upregulate iNOS and affect myocardial function in the rat. Male Sprague-Dawley rats (350-400 g) were anesthetised using Nembutal (50 mg/kg, i.p.) and jugular vein, tail artery (Mean arterial pressure, MAP) and right carotid arteries (advanced to left ventricle, LV) were cannulated. The rats were randomly divided into saline-, bigET-1- and C-terminal fragment of bigET-1 (bigET-1(22-38))-treated groups. Sepsis was induced using i.p. injection of cecal inoculum obtained from a donor rat (200 mg/kg in 5 ml 5% sterile dextrose water, D5W). Sham animals received an i.p. injection of D5W (5 ml/kg). MAP and LVP were recorded and cardiodynamic parameters were calculated at 0, 2, 6, 12 and 24 h post sham or sepsis-induction. A significant elevation in LV isovolumic relaxation rate constant (tau), LV end diastolic pressure (LVEDP) and rate pressure product (RPP) was observed in vehicle-treated septic group at 24 h. BigET-1 significantly increased concentration of LV ET-1 both in sham and septic groups. BigET-1 elevated tau and LVEDP both in sham and septic animals as early as 12 h which persisted through 24 h. However, bigET-1(22-38) elevated LVEDP in septic group at 24 h but not in sham group. BigET-1 accentuated the levels of plasma nitric oxide byproduct (NOx) levels in both sham and septic animals at 6, 12 and 24 h. Sepsis increased myocardial iNOS at 24 h. BigET-1 significantly upregulated expression of myocardial iNOS and pp38-MAPK. The data suggest that increased substrate availability for ET-1 at the time of sepsis-induction contributes in diastolic dysfunction, iNOS activation and p38-MAPK phosphorylation.