Intermittent administration of furosemide vs continuous infusion preceded by a loading dose for congestive heart failure

Continuous infusion versus bolus injection of loop diuretics for acute heart failure

BACKGROUND

Acute heart failure (AHF) is new onset of, or a sudden worsening of, chronic heart failure characterised by congestion in about 95% of cases or end-organ hypoperfusion in 5% of cases. Treatment often requires urgent escalation of diuretic therapy, mainly through hospitalisation. This Cochrane review evaluated the efficacy of intravenous loop diuretics strategies in treating AHF in individuals with New York Heart Association (NYHA) classification III or IV and fluid overload.

OBJECTIVES

To assess the effects of intravenous continuous infusion versus bolus injection of loop diuretics for the initial treatment of acute heart failure in adults.

SEARCH METHODS

We identified trials through systematic searches of bibliographic databases and in clinical trials registers including CENTRAL, MEDLINE, Embase, CPCI-S on the Web of Science, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry platform (ICTRP), and the European Union Trials register. We conducted reference checking and citation searching, and contacted study authors to identify additional studies. The latest search was performed on 29 February 2024.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving adults with AHF, NYHA classification III or IV, regardless of aetiology or ejection fraction, where trials compared intravenous continuous infusion of loop diuretics with intermittent bolus injection in AHF. We excluded trials with chronic stable heart failure, cardiogenic shock, renal artery stenosis, or end-stage renal disease. Additionally, we excluded studies combining loop diuretics with hypertonic saline, inotropes, vasoactive medications, or renal replacement therapy and trials where diuretic dosing was protocol-driven to achieve a target urine output, due to confounding factors.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened papers for inclusion and reviewed full-texts. Outcomes included weight loss, all-cause mortality, length of hospital stay, readmission following discharge, and occurrence of acute kidney injury. We performed risk of bias assessment and meta-analysis where data permitted and assessed certainty of the evidence.

MAIN RESULTS

The review included seven RCTs, spanning 32 hospitals in seven countries in North America, Europe, and Asia. Data collection ranged from eight months to six years. Following exclusion of participants in subgroups with confounding treatments and different clinical settings, 681 participants were eligible for review. These additional study characteristics, coupled with our strict inclusion and exclusion criteria, improve the applicability of the body of the evidence as they reflect real-world clinical practice. Meta-analysis was feasible for net weight loss, all-cause mortality, length of hospital stay, readmission, and acute kidney injury. Literature review and narrative analysis explored daily fluid balance; cardiovascular mortality; B-type natriuretic peptide (BNP) change; N-terminal-proBNP change; and adverse incidents such as ototoxicity, hypotension, and electrolyte imbalances. Risk of bias assessment revealed two studies with low overall risk, four with some concerns, and one with high risk. All sensitivity analyses excluded trials at high risk of bias. Only narrative analysis was conducted for 'daily fluid balance' due to diverse data presentation methods across two studies (169 participants, the evidence was very uncertain about the effect). Results of narrative analysis varied. For instance, one study reported higher daily fluid balance within the first 24 hours in the continuous infusion group compared to the bolus injection group, whereas there was no difference in fluid balance beyond this time point. Continuous intravenous infusion of loop diuretics may result in mean net weight loss of 0.86 kg more than bolus injection of loop diuretics, but the evidence is very uncertain (mean difference (MD) 0.86 kg, 95% confidence interval (CI) 0.44 to 1.28; 5 trials, 497 participants; P < 0.001, I2 = 21%; very low-certainty evidence). Importantly, sensitivity analysis excluding trials with high risk of bias showed there was insufficient evidence for a difference in bodyweight loss between groups (MD 0.70 kg, 95% CI -0.06 to 1.46; 3 trials, 378 participants; P = 0.07, I2 = 0%). There may be little to no difference in all-cause mortality between continuous infusion and bolus injection (risk ratio (RR) 1.53, 95% CI 0.81 to 2.90; 5 trials, 530 participants; P = 0.19, I2 = 4%; low-certainty evidence). Despite sensitivity analysis, the direction of the evidence remained unchanged. No trials measured cardiovascular mortality. There may be little to no difference in the length of hospital stay between continuous infusion and bolus injection of loop diuretics, but the evidence is very uncertain (MD -1.10 days, 95% CI -4.84 to 2.64; 4 trials, 211 participants; P = 0.57, I2 = 88%; very low-certainty evidence). Sensitivity analysis improved heterogeneity; however, the direction of the evidence remained unchanged. There may be little to no difference in the readmission to hospital between continuous infusion and bolus injection of loop diuretics (RR 0.85, 95% CI 0.63 to 1.16; 3 trials, 400 participants; P = 0.31, I2 = 0%; low-certainty evidence). Sensitivity analysis continued to show insufficient evidence for a difference in the readmission to hospital between groups. There may be little to no difference in the occurrence of acute kidney injury as an adverse event between continuous infusion and bolus injection of intravenous loop diuretics (RR 1.02, 95% CI 0.70 to 1.49; 3 trials, 491 participants; P = 0.92, I2 = 0%; low-certainty evidence). Sensitivity analysis continued to show that continuous infusion may make little to no difference on the occurrence of acute kidney injury as an adverse events compared to the bolus injection of intravenous loop diuretics.

AUTHORS' CONCLUSIONS

Analysis of available data comparing two delivery methods of diuretics in acute heart failure found that the current data are insufficient to show superiority of one strategy intervention over the other. Our findings were based on trials meeting stringent inclusion and exclusion criteria to ensure validity. Despite previous reviews suggesting advantages of continuous infusion over bolus injections, our review found insufficient evidence to support or refute this. However, our review, which excluded trials with clinical confounders and RCTs with high risk of bias, offers the most robust conclusion to date.

Effectiveness and cost-efficacy of diuretics home administration via peripherally inserted central venous catheter in patients with end-stage heart failure

BACKGROUND

End-stage heart failure (ESHF) is characterized by severe cardiac dysfunction with persistent disabling symptoms and recurrent acute decompensated heart failure (ADHF), despite guideline-directed medical therapy. The aim of this study was to evaluate the efficacy and safety of intravenous diuretics administration at home through a peripherally inserted central venous catheter (PICC) in ESHF patients.

METHODS AND RESULTS

Forty-one ESHF patients received PICC implantation for intravenous diuretic administration at home. The primary efficacy endpoint was the patient-level number of HF hospitalizations in the short (1-3 months), medium (six months), and long term (1 year), before and after PICC implantation. Pre- and post-PICC ADHF-free days were also evaluated as co-primary endpoint. Secondary endpoints comprised changes in clinical, laboratory and echocardiographic parameters, and device safety. A cost-effectiveness analysis was performed to estimate the economic impact of using PICC. For each time frame analyzed, a significant reduction in the number of hospitalizations due to ADHF was observed, resulting in a significant increase in ADHF-free days (71 ± 44 vs. 163 ± 136, p = 0.003). In matched patients' analysis, significant decrease in body weight (68 ± 16 kg vs. 63 ± 10 kg, p = 0.041) and mitral regurgitation grade 3/4 (55% vs. 18%, p < 0.001) were also observed. Freedom from PICC-related complications was observed in 61% of patients. A significant reduction in overall ADHF-hospitalizations cost was observed.

CONCLUSIONS

This proof-of-concept study demonstrates the effectiveness and safety of home administration of intravenous diuretic therapy via PICC in ESHF patients. This palliative cost-effective strategy can be taken in consideration for selected end-stage patients no longer responsive to conventional therapies.

Continuous versus intermittent use of furosemide in patients with heart failure and moderate chronic renal dysfunction

Aims

There is paucity of clinical data comparing continuous infusion (CI) with bolus injection (BI) of intravenous loop diuretics in patients with acute decompensated heart failure (ADHF) and chronic renal dysfunction. This study aimed to compare the efficacy and safety of CI versus BI intravenous furosemide administration in patients with ADHF and moderate chronic renal insufficiency.

Methods and results

Acute decompensated heart failure and moderate chronic renal insufficiency [with estimated glomerular filtration rate (eGFR) 15.0–44.9 mL/min/1.73 m²] were randomized to start intravenous furosemide by BI or by a 6 h CI. End points included freedom from congestion at 72 h, the degree of dyspnoea assessed using the 0–10 Borg's category ratio scale, net daily urine output, weight loss during the study, length of hospital stay, total urinary sodium excretion, and development of acute kidney injury or electrolyte disturbance. After 72 h of treatment, the rate of the primary endpoint of freedom from congestion in the CI group was significantly higher than that in the BI group (69.05% vs. 43.59%, P = 0.02). The modified Borg scale indicated patients in the CI group had lower dyspnoea score than those in the BI group at 48 h (4.29 ± 1.23 vs. 5.97 ± 1.56; P = 0.02) and 72 h (1.15 ± 0.35 vs. 2.66 ± 0.83; P = 0.003). There were other significant differences favouring the CI group with regard to net urine output at 72 h (5145.98 ± 621.37 mL vs. 3755.95 ± 456.93 mL; P = 0.007), the mean body weight loss (4.72 ± 1.01 kg vs. 3.53 ± 0.73 kg; P = 0.02) and the total urinary sodium excretion (385.05 ± 38.15 vs. 320.33 ± 37.67; P = 0.02). The length of hospitalization in the CI group was significantly shorter than that in the BI group (10.36 ± 4.20 days vs. 15.68 ± 6.15 days; P = 0.02). No significant differences were observed between groups in the frequency of acute kidney injury, tinnitus, electrolyte disturbance or mortality.

Conclusions

Continuous intravenous infusion of furosemide resulted in significantly greater diuresis than bolus administration of an equal dose in patients with moderate chronic renal insufficiency and ADHF, while no differences emerged in terms of side effects or mortality.

Continuous versus intermittent administration of furosemide in acute decompensated heart failure: a systematic review and meta-analysis

Diuretic therapy is important in critically ill patients because fluid overload impairs organ function and increases mortality. Compared to intermittent administration, continuous infusion of loop diuretics is theoretically superior in terms of diuresis and electrolyte balance. However, the available evidence is susceptible to carryover diuretic effects and resistance in earlier crossover trials. Consequently, we conducted a systematic review and meta-analysis of parallel-group randomized controlled trials to compare these two strategies in adults with acute decompensated heart failure. We searched Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from their inceptions to May 26, 2018. We pooled the data using a random effects model. Our primary outcomes were all-cause mortality, length of hospital stay, and body weight reduction. We analyzed 12 parallel-group randomized controlled trials involving 923 patients. Compared with intermittent administration, continuous infusion of furosemide was not associated with an improvement in all-cause mortality (risk ratio 1.19; 95% confidence interval [CI], 0.65 to 2.16), length of hospital stay (weighted mean difference [WMD] - 0.88 days; 95% CI, - 2.76 to 1.01), or 24-h urine output (WMD 489.17 mL; 95% CI, - 183.18 to 1161.51), but was significantly associated with a greater body weight reduction (WMD 0.63 kg; 95% CI, 0.23 to 1.02). No differences in hypokalemia, hyponatremia, increased serum creatinine level, and hypotension were noted. Continuous infusion of furosemide, compared to intermittent administration, is associated with a greater body weight reduction and potential increase in 24-h urine output. The limited available evidence suggests no difference in adverse events between both strategies. Trial registration: PROSPERO (CRD42017083878).

Diuretic Resistance in Heart Failure

Decompensated heart failure accounts for approximately 1 million hospitalizations in the United States annually, and this number is expected to increase significantly in the near future. Diuretics provide the initial management in most patients with fluid overload. However, the development of diuretic resistance remains a significant challenge in the treatment of heart failure. Due to the lack of a standard definition, the prevalence of this phenomenon remains difficult to determine, with some estimates suggesting that 25-30% of patients with heart failure have diuretic resistance. Certain characteristics, including low systolic blood pressures, renal impairment, and atherosclerotic disease, help predict the development of diuretic resistance. The underlying pathophysiology is likely multifactorial, with pharmacokinetic alterations, hormonal dysregulation, and the cardiorenal syndrome having significant roles. The therapeutic approach to this common problem typically involves increases in the diuretic dose and/or frequency, sequential nephron blockade, and mechanical fluid movement removal with ultrafiltration or peritoneal dialysis. Paracentesis is potentially useful in patients with intra-abdominal hypertension.

Old and New Drugs for Treatment of Advanced Heart Failure

BACKGROUND

Advanced heart failure (HF) is a progressive disease with high mortality and limited medical therapeutic options. Long-term mechanical circulatory support and heart transplantation remain goldstandard treatments for these patients; however, access to these therapies is limited by the advanced age and multiple comorbidities of affected patients, as well as by the limited number of organs available.

METHODS

Traditional and new drugs available for the treatment of advanced HF have been researched.

RESULTS

To date, the cornerstone for the treatment of patients with advanced HF remains water restriction, intravenous loop diuretic therapy and inotropic support. However, many patients with advanced HF experience loop diuretics resistance and alternative therapeutic strategies to overcome this problem have been developed, including sequential nephron blockade or use of the hypertonic saline solution in combination with high-doses of furosemide. As classic inotropes augment myocardial oxygen consumption, new promising drugs have been introduced, including levosimendan, istaroxime and omecamtiv mecarbil. However, pharmacological agents still remain mainly short-term or palliative options in patients with acute decompensation or excluded from mechanical therapy.

CONCLUSION

Traditional drugs, especially when administered in combination, and new medicaments represent important therapeutic options in advanced HF. However, their impact on prognosis remains unclear. Large trials are necessary to clarify their therapeutic potential and prognostic role in these fragile patients.

Constant rate infusion vs. intermittent bolus administration of IV furosemide in 100 pets with acute left-sided congestive heart failure: A retrospective study

The aim of this study was to determine whether the addition of constant rate infusion (CRI) to intermittent intravenous bolus (IVB) administration of furosemide resulted in an improvement in medical outcomes in dogs and cats with acute left-sided congestive heart failure (L-CHF). A total of 76 client-owned dogs and 24 client-owned cats admitted with acute L-CHF were retrospectively divided between an IVB group (43 dogs and 16 cats) and a CRI group (33 dogs and 8 cats). The median furosemide dose used in dogs in the CRI group (median 0.99mg/kg/h; range 0.025-3.73mg/kg/h) was lower than the dose used in dogs in the IVB group (median 1.19mg/kg/h; range 0.027-7.14mg/kg/h; P=0.008). Respiratory rates were lower in the IVB group (P=0.005) and the CRI group (P=0.039) compared to pre-treatment values. The overall short-term mortality was 15%. A trend of longer hospitalisation in the IVB group relative to the CRI group (P=0.07) was shown. Creatinine and total plasma protein concentrations increased more in the CRI group than in the IVB group, suggestive of a higher risk of dehydration and azotaemia. There may be safety profile differences between CRI and IVB, warranting a prospective study using a larger sample size.

Management of Adult Heart Failure: Bolus versus Continuous Infusion Loop Diuretics, A Review of the Literature

In an aging population, decompensated heart failure accounts for a significant number of hospital admissions. The standard management for edema and congestion associated with heart failure is loop diuretic therapy. Traditionally, bolus-dosed furosemide has been used to manage the edema and congestion associated with heart failure. However, diuretic resistance can occur with bolus dosing, resulting in inadequate diuresis and further hemodynamic instability. Based on current literature, furosemide given by continuous infusion may now be the preferred agent and route for diuretic refractory heart failure. This article reviews the literature that compares bolus versus continuous infusion loop diuretics in adult heart failure.

A perspective on diuretic resistance in chronic congestive heart failure

Chronic congestive heart failure (CHF) is a complex disorder characterized by inability of the heart to keep up the demands on it, followed by the progressive pump failure and fluid accumulation. Although the loop diuretics are widely used in heart failure (HF) patients, both pharmacodynamic and pharmacokinetic alterations are thought to be responsible for diuretic resistance in these patients. Strategies to overcome diuretic resistance include sodium intake restriction, changes in diuretic dose and route of administration and sequential nephron diuretic therapy. In this review, we discuss the definition, prevalence, mechanism of development and management strategies of diuretic resistance in HF patients.

Treating Diuretic Resistance: An Overview

Loop diuretics are central to the management of fluid overload in acute decompensated heart failure. However, a variance in the response to loop diuretics can alter a patient's clinical course and has an adverse effect on clinical outcomes. Thus, a diminished response to loop diuretics is an important clinical issue. Factors thought to contribute to diuretic resistance include erratic oral absorption in congested states and postdiuretic sodium retention. Further contributing to diuretic resistance in patients with advanced heart failure are decreases in renal perfusion and alterations in sodium handling that occur in an attempt to maintain circulatory homeostasis. Several pharmacologic interventions have been used to improve diuretic response. Intravenous diuretic administration, increasing diuretic doses, or changing diuretic agents can potentially overcome pharmacokinetic obstacles which contribute to drug resistance. Combination diuretic therapy may be useful to overcome increased sodium retention, dopamine may improve renal perfusion, and hypertonic saline may transiently increase intravascular volume and improve sodium delivery to the tubules of the nephron. Despite the prevalence of diuretic resistance, there remains a paucity of clinical trial evidence to help guide therapy in these patients.

Efficacy and Safety of a Furosemide Continuous Infusion Following Cardiac Surgery

Objective:

To review the literature regarding the efficacy and safety of continuous intravenous infusion of loop diuretics following cardiac surgery.

Data Sources:

Articles were identified through a MEDLINE search (1966–March 2006) using the key words furosemide, bumetanide, torsemide, ethacrynic acid, loop diuretics, continuous infusions, intravenous infusions, surgery, cardiac surgery, cardiovascular surgery, and thoracic surgery. Search results were limited to studies in human subjects published in English. Additional references were identified through review of the bibliographies of the articles cited.

Study Selection and Data Extraction:

All clinical trials and observational reports identified that evaluated or described the efficacy and/or safety of a continuous infusion of a loop diuretic in adult or pediatric patients who had undergone cardiac surgery were included in this review.

Data Synthesis:

Loop diuretics are often used to promote diuresis following cardiac surgery. Studies in patients who have undergone cardiac surgery have demonstrated that a more consistent and sustained diuresis is produced by a continuous infusion of furosemide compared with intermittent bolus doses of furosemide. However, there does not appear to be a significant difference in total urine output or change in serum electrolyte levels when furosemide is administered as a continuous infusion compared with intermittent bolus doses.

Conclusions:

A continuous infusion of furosemide is an effective and safe method of diuresis in patients undergoing cardiac surgery.

Management of Congestion and Diuretic Resistance in Heart Failure

We present the case of a patient with heart failure and severe congestion who was responding poorly to diuretic therapy. We discuss the key problems concerning the pathophysiology and bedside therapeutic approach to congestion and fluid overload in this clinical setting, and we give practical suggestions to overcome congestion, especially in the setting of diuretic resistance and worsening renal function. We conclude that the application of key pharmacokinetic and pharmacodynamic principles of diuretic therapy, along with in-depth knowledge of the pathophysiology of heart failure, still represent the cornerstones for a correct approach to decongestive therapy in these patients.

Comparison of continuous versus intermittent furosemide administration in dogs with acute heart failure

Pulmonary oedema is a life-threatening condition which should be treated promptly in the emergency room with oxygen, cage rest, and diuretic therapy. Traditionally, bolus administration of furosemide is the treatment of choice. However, there is emerging information that continuous rate infusion might be more effective than bolus injections in relieving clinical signs and producing a lower rate of complications such as azotaemia, dehydration, and electrolyte imbalances. We tested the effect of furosemide both in bolus (4–6 mg/kg intravenously) and continuous rate infusion (1 mg/kg/h) in 30 dogs that had been presented with fulminant pulmonary oedema during 2 days of hospitalization. No differences in the selected biochemical indicators between the groups were found. There were significant differences in blood urea nitrogen in the bolus injection group and creatinine and phosphorus in the continuous rate infusion group between days 1 and 2. The results of this study showed no differences in the approach of furosemide administration in the management of pulmonary oedema. Both methods may cause renal and electrolyte complications, however, further studies with a larger number of patients are recommended.

Palliation of heart failure

Heart failure is the major cause of morbidity and mortality in the United States. Stage D heart failure has a greater mortality rate than many cancers and has equivalent symptom burden and severity. There has been a paradigm shift in our understanding of the pathophysiology of heart failure. Progressive heart failure is associated with ventricular remodeling and a maladaptive neurohumoral response. Drug classes have evolved that curtail ventricular remodeling, and blunt neurohumoral responses reduce morbidity and mortality. Despite combination drug and device therapies, the management of Stage D heart failure includes palliation. Both cardiology and palliative specialists need to learn from one another in order to palliate these highly symptomatic patients. Such collaboration will enhance care and are the basis for well-conceived research trials.

Continuous infusion or bolus injection of loop diuretics for congestive heart failure?

Loop diuretics are widely used in acute heart failure. However, there is controversy about the superiority of continuous infusion over bolus administration. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified four systematic reviews including 11 pertinent randomized controlled trials overall. We combined the evidence using meta-analysis and generated a summary of findings following the GRADE approach. We concluded continuous administration of loop diuretics probably reduces mortality and length of stay compared to intermittent administration in patients with acute heart failure.

[Hypertensive emergencies and urgencies]

Hypertension is a common disease, the most common chronic disease. Hypertensive emergency is much less frequent and only affects 1 to 2 % of all hypertensive patients. The true hypertensive emergency is characterized by the serious damage of one hypertensive target organ and requires an urgent intravenous treatment. Isolated blood pressure elevation should not be regarded as a hypertensive emergency if there is no target organ damage, even if the blood pressure is very high. These situations of "false hypertensive emergency", or hypertensive urgencies, often requires an immediate treatment, but oral. Signs of visceral pain of true hypertensive emergency often are a poor general condition, severe headache, decreased visual acuity, neurological deficit of ischemic or hemorrhagic cause, confusion, dyspnea with orthopnoea revealing heart failure, angina, chest pain revealing an aortic dissection, proteinuria, acute renal failure or eclampsia. True hypertensive emergencies include several entities, namely: severe hypertension, malignant hypertension and accelerated hypertension. If malignant hypertension is not treated, the prognosis is poor with 50 % death risk in the following year.

Loop diuretic strategies in patients with acute decompensated heart failure: a meta-analysis of randomized controlled trials

PURPOSE

The safety and efficacy of continuous infusion vs bolus injection of intravenous loop diuretics to treat acute decompensated heart failure were debated. Our aim is to compare the administration routes of diuretics in hospitalized patients with acute decompensated heart failure.

METHODS

A systematic review and meta-analysis of randomized controlled trials was performed to evaluate the effects of continuous infusion vs bolus administration of loop diuretics in patients with acute decompensated heart failure. The primary end points were urine outputs, body weight loss, all causes of mortality, and death from cardiovascular causes. Secondary end points were electrolyte imbalance, change in creatinine levels, tinnitus or hearing loss, and days of hospitalization.

RESULTS

Ten randomized controlled trials with 518 patients were identified. Continuous infusion of diuretics was associated with a significantly greater weight loss (weighted mean difference, 0.78; 95% confidence interval, 0.03-1.54) compared with bolus injection. Urine output, the incidence of electrolyte imbalance, change in creatinine level, length of hospitalization, the incidence of ototoxicity, cardiac mortality, and all-cause mortality showed no significant differences between the 2 groups.

CONCLUSION

Meta-analysis of the existing limited studies did not confirm any significant differences in the safety and efficacy with continuous administration of loop diuretic, compared with bolus injection in patients with acute decompensated heart failure.

Clinical pharmacology of furosemide in neonates: a review

Furosemide is the diuretic most used in newborn infants. It blocks the Na⁺-K⁺-2Cl⁻ symporter in the thick ascending limb of the loop of Henle increasing urinary excretion of Na⁺ and Cl⁻. This article aimed to review the published data on the clinical pharmacology of furosemide in neonates to provide a critical, comprehensive, authoritative and, updated survey on the metabolism, pharmacokinetics, pharmacodynamics and side-effects of furosemide in neonates. The bibliographic search was performed using PubMed and EMBASE databases as search engines; January 2013 was the cutoff point. Furosemide half-life (t_1/2) is 6 to 20-fold longer, clearance (Cl) is 1.2 to 14-fold smaller and volume of distribution (Vd) is 1.3 to 6-fold larger than the adult values. t_1/2 shortens and Cl increases as the neonatal maturation proceeds. Continuous intravenous infusion of furosemide yields more controlled diuresis than the intermittent intravenous infusion. Furosemide may be administered by inhalation to infants with chronic lung disease to improve pulmonary mechanics. Furosemide stimulates prostaglandin E2 synthesis, a potent dilator of the patent ductus arteriosus, and the administration of furosemide to any preterm infants should be carefully weighed against the risk of precipitation of a symptomatic patent ductus arteriosus. Infants with low birthweight treated with chronic furosemide are at risk for the development of intra-renal calcifications.

Clinical effects and safety of different strategies for administering intravenous diuretics in acutely decompensated heart failure: a randomised clinical trial

BACKGROUND

The mainstay of treatment for acutely decompensated heart failure (ADHF) is intravenous diuretic therapy either as a bolus or via continuous infusion.

OBJECTIVES

We evaluated the clinical effects and safety of three strategies of intravenous furosemide administration used in emergency departments (EDs) for ADHF.

METHODS

We performed a multicentre, randomised, parallel-group study. Patients with ADHF were randomised within 2 h of ED arrival to receive furosemide by continuous infusion (10 mg/h, group 1) or boluses (20 mg/6 h, group 2; or 20 mg/8 h, group 3). The primary end point was total diuresis, and secondary end points were dyspnoea, orthopnoea, extension of rales and peripheral oedema, blood pressure, respiratory and heart rates, and pulse oximetry, which were measured at arrival and 3, 6, 12 and 24 h after treatment onset. We also measured serum creatinine, sodium and potassium levels at arrival and after 24 h.

RESULTS

Group 1 patients (n=36) showed greater 24 h diuresis (3705 mL) than those in groups 2 (n=37) and 3 (n=36) (3093 and 2670 mL, respectively; p<0.01), and this greater diuretic effect was observed earlier. However, no differences were observed among groups in the nine secondary clinical end points evaluated. Creatinine deterioration developed in 15.6% of patients, hyponatraemia in 9.2%, and hypokalaemia in 19.3%, with the only difference among groups observed in hypokalaemia (group 1, 36.3%; group 2, 13.5%; group 3, 8.3%; p<0.01).

CONCLUSIONS

In patients with ADHF attending the ED, boluses of furosemide have a smaller diuretic effect but provide similar clinical relief, similar preservation of renal function, and a lower incidence of hypokalaemia than continuous infusion.

TRIAL REGISTRATION NUMBER

This randomised trial was registered in the European Clinical Trial Database (EudraCT) with the reference number 2008-004488-20.

A meta-analysis of continuous vs intermittent infusion of loop diuretics in hospitalized patients

BACKGROUND

Several studies have examined the potential benefits of continuous vs intermittent (bolus) intravenous loop diuretic administration in hospitalized patients with conflicting results. We conducted a meta-analysis to compare the efficacy of these 2 strategies in hospitalized adults and children with extracellular fluid volume expansion.

METHODS

We searched MEDLINE (through October 2012) and prior meta-analyses for randomized controlled trials comparing the efficacy of continuous vs intermittent infusion of loop diuretics. Random-effects model meta-analyses were performed to examine several outcomes, including net change in urine output and body weight.

RESULTS

We identified 7 crossover and 11 parallel-arm randomized controlled trials (936 patients) of adults and children. In the 15 studies of adults, continuous loop diuretic infusion resulted in a nonsignificant net increase in daily urine output of 334 mL (95% confidence interval [CI], -74 to 742; P = .11) relative to the bolus infusion. In the 8 studies that used a loading dose, continuous loop diuretic infusion resulted in a significant net increase in daily urine output of 294 mL (95% CI, 31-557; P = .03) relative to the intermittent infusion. There was also a significant net decrease in body weight of 0.78 kg (95% CI, -1.54 to -0.03; P = .04) in the continuous relative to the intermittent loop diuretic infusion. In the 3 studies of children, there was no demonstrable effect on daily urine output or body weight.

CONCLUSION

Continuous infusion of loop diuretics preceded by a loading dose results in greater diuresis in hospitalized adults with extracellular fluid volume expansion compared with intermittent dosing regimens. Further studies are required to examine whether these benefits translate into improved clinical outcomes.

Comparison of bumetanide- and metolazone-based diuretic regimens to furosemide in acute heart failure

INTRODUCTION

Limited data exist comparing the efficacy and safety of bumetanide- or metolazone-based diuretic regimens to furosemide in acute heart failure (HF). Our purpose was to evaluate the comparative effect on urine output (UO) and renal function between these regimens.

METHODS

A retrospective study of hospitalized HF patients treated with continuous infusion furosemide (CIF), combination furosemide plus metolazone (F + M), or continuous infusion bumetanide (CIB). Primary end points were between regimen comparisons for change in mean hourly UO versus baseline and incidence of worsening renal function.

RESULTS

Data on 242 patients with acute HF (age 58 ± 12 years, 63% male, left ventricular ejection fraction 38% ± 17%) were analyzed (160 CIF, 42 F + M, 40 CIB). The mean duration of diuretic regimens was 41 ± 32 hours. Compared to baseline, all regimens increased mean hourly UO (P < .0001 for all), with greater increases with F + M (109 ± 171 mL) and CIB (90 ± 90 mL) compared to CIF (48 ± 103 mL; P = .009). Incidence of worsening renal function was not different between regimens; however, blood urea nitrogen (BUN) tended to increase more with F + M (4.4 ± 9.8 mg/dL) and CIB (4.3 ± 9.7 mg/dL) than CIF (1.8 ± 10.8 mg/dL), P = .09. The incidence of hyponatremia was higher with F + M and CIB. Differences in UO, BUN, and hyponatremia were retained in the subgroup analysis limited to patients with baseline serum creatinine <1.5 mg/dL, where renal function between the groups was not different.

CONCLUSION

Compared to CIF, F + M or CIB was associated with greater increases in UO. No difference in the incidence of worsening renal function was found; however, electrolyte abnormalities may be more prevalent when furosemide is combined with metolazone or when bumetanide is used. These therapeutic differences warrant prospective study.

Diagnostic accuracy of early urinary index changes in differentiating transient from persistent acute kidney injury in critically ill patients: multicenter cohort study

INTRODUCTION

Urinary indices have limited effectiveness in separating transient acute kidney injury (AKI) from persistent AKI in ICU patients. Their time-course may vary with the mechanism of AKI. The primary objective of this study was to evaluate the diagnostic value of changes over time of the usual urinary indices in separating transient AKI from persistent AKI.

METHODS

An observational prospective multicenter study was performed in six ICUs involving 244 consecutive patients, including 97 without AKI, 54 with transient AKI, and 93 with persistent AKI. Urinary sodium, urea and creatinine were measured at ICU admission (H0) and on 6-hour urine samples during the first 24 ICU hours (H6, H12, H18, and H24). Transient AKI was defined as AKI with a cause for renal hypoperfusion and reversal within 3 days.

RESULTS

Significant increases from H0 to H24 were noted in fractional excretion of urea (median, 31% (22 to 41%) and 39% (29 to 48%) at H24, P<0.0001), urinary urea/plasma urea ratio (15 (7 to 28) and 20 (9 to 40), P<0.0001), and urinary creatinine/plasma creatinine ratio (50 (24 to 101) and 57 (29 to 104), P=0.01). Fractional excretion of sodium did not change significantly during the first 24 hours in the ICU (P=0.13). Neither urinary index values at ICU admission nor changes in urinary indices between H0 and H24 performed sufficiently well to recommend their use in clinical setting (area under the receiver-operating characteristic curve≤0.65).

CONCLUSION

Although urinary indices at H24 performed slightly better than those at H0 in differentiating transient AKI from persistent AKI, they remain insufficiently reliable to be clinically relevant.

The management of acute heart failure and diuretic therapy

One million patients are hospitalized each year with acute decompensated heart failure, and up to 20% of these patients are rehospitalized within a month after the acute presentation. Acute heart failure (AHF) accounts for 50,000 deaths annually and is the most frequent reason for hospital admissions in the United States. This article reviews the therapeutic options and the results of recent clinical trials in the treatment of AHF. Most patients can be effectively managed by use of diuretic agents or diuretics in combinations with nitrates, IV nitroglycerin, IV nitroprusside, and possibly IV nesiritide. Ultrafiltration is a promising technique that can be very helpful in the resistant patient. However, given the ease of initiation of diuretic therapy, it is unlikely that ultrafiltration would supplant diuretic use in acutely symptomatic patients. Patients in acute distress with AHF almost invariably respond to diuretics or a vasodilator combined with diuretic therapy. The loop diuretics are the most effective diuretics and thus most frequently used agents in treating AHF. Currently, there are 4 loop diuretics in the US market: furosemide, bumetanide, torsemide, and ethacrynic acid. IV furosemide and ethacrynic acid have a prompt venous dilatory effect, consequently decrease left ventricular filling pressure and immediately relieve symptoms of pulmonary congestion, before a diuresis can occur. Furosemide is more often used than ethacrynic acid due to its reduced ototoxic potential. However, ethacrynic acid should be used in sulfa-sensitive patients because ethacrynic acid is the only loop diuretic, which does not contain a sulfa moiety.

Clinical Experience With Low-Dose Continuous Infusion of Furosemide in Acute Heart Failure

Introduction:

Clinical data are scarce for furosemide administered as a low-dose (<160 mg/24 hours) continuous intravenous infusion in acute heart failure (HF). Our purpose was to evaluate the efficacy and safety of low-dose continuous infusion of furosemide on diuretic response, renal function, and patient outcomes.

Methods:

A retrospective study of patients with acute HF who received furosemide administered as a continuous infusion after initial therapy with intermittent boluses (usually 40-80 mg every 12 hours). End points included mean hourly urine output, incidence of acute renal injury, and outcome disparities of patients who developed acute renal injury. Comparison of patients with preserved and reduced left ventricular ejection fraction (LVEF) was also performed.

Results:

The study included 150 patients (age 57 ± 13 years, male gender 61%, admission weight 87 ± 32 kg, LVEF 37 ± 15%, 28% preserved LVEF). Mean initial and maximum furosemide doses were 5.1 ± 1.1 mg/h and 6.2 ± 2.2 mg/h, respectively. Mean duration of therapy was 51.4 ± 67.5 hours. Continuous infusion of furosemide was associated with a significant increase in mean hourly urine output compared to baseline (150 ± 77 mL/h vs 116 ± 69 mL/h, P < .001). Acute renal injury developed in 19% of patients, with 70% of those occurring within the first 48 hours of therapy. Mean serum creatinine (baseline 1.55 ± 1.50 mg/dL vs at discharge 1.64 ± 1.61 mg/dL, P = .20) and estimated glomerular filtration rate (baseline 67 ± 39 mL/min vs at discharge 67 ± 43 mL/min, P = .89) did not significantly change over the course of the hospitalization. Development of acute renal injury was associated with poorer outcomes, higher furosemide dose, and longer duration of furosemide therapy. Diuretic response and safety were not different between patients with preserved or reduced LVEF.

Conclusions:

In patients with acute HF, furosemide administered as a low-dose continuous infusion was effective in achieving diuresis and was not associated with a detectable effect on renal function. This diuretic approach appeared to be similarly effective and safe in patients with preserved LVEF.

Update in diuretic therapy: clinical pharmacology

All diuretics except spironolactone exert their effects from the lumen of the nephron. Thus, to exert an effect, they must reach the urine. Pharmacokinetics (PK) describes this access. Different edematous disorders can affect access to this site of action and therein affect response to a diuretic. In addition, once a diuretic reaches the site of action, a response ensues. The characteristics of this response that can be affected by a patient's clinical condition are described by the pharmacodynamics (PD) of a diuretic. To understand the mechanisms of abnormal response to a diuretic one must dissect its PK and PD in different edematous disorders. For example, in patients with renal insufficiency, the mechanism of poor diuretic response is PK. In contrast, in patients with cirrhosis or in those with congestive heart failure, it is PD. In patients with nephrotic syndrome, both PK and PD are operative. These different mechanisms mandate differences in therapeutic strategy, as explained in this article.

Pharmacologic management of myxomatous mitral valve disease in dogs

Myxomatous mitral valve disease (MMVD) causing mitral regurgitation is the most important disease of the heart in small animal cardiovascular medicine. Because MMVD is an example of a chronic disease that progresses from mild to severe over years, treatment strategies change with the stage of the disease. In this review the treatment options are compared and contrasted as they are discussed relative to the recently published ACVIM consensus statement regarding the treatment of MMVD. Results from clinical trials and evidence-based medicine are likely to provide significant improvements in the management of MMVD in the coming decades.

Continuous infusion versus intermittent bolus furosemide in ADHF: an updated meta-analysis of randomized control trials

OBJECTIVE

Administering intermittent boluses of furosemide to patients with acute decompensated heart failure (ADHF) often leads to unfavorable hemodynamic changes. Continuous infusion may induce similar or greater diuresis without adverse hemodynamic consequences. We conducted a systemic review and meta-analysis of randomized clinical trials that compared the effects of continuous infusion and intermittent bolus of furosemide in patients hospitalized with ADHF.

METHODS

We searched PubMed, EMBASE, and The Cochrane Central Register of Controlled Trials databases from their inception until March 2011. Two investigators independently abstracted data on study characteristics, quality, and selected outcomes. Differences between investigators were resolved by mutual consensus. Comparisons were reported as the weighted mean difference (WMDs).

RESULTS

Ten trials involving a total of 564 patients were included. When administered as a continuous infusion, furosemide resulted in greater diuresis (WMD, -240.54 mL/24 hours/100 mg furosemide; 95% confidence interval [CI], -462.42 to -18.66) and reduction in total body weight (WMD, -0.78 kg; 95% CI, -1.54 to -0.03), than when administered in intermittent boluses. Urinary sodium excretion (WMD, -20.26 mmol/24 hours; 95% CI, -60.48 to 19.96) and duration of hospital stay (WMD, 0.99 days; 95% CI, -2.08 to 4.06) were not different between the 2 groups.

CONCLUSION

This meta-analysis showed statistical support for administering furosemide as a continuous infusion for greater diuresis and reduction in total body weight in patients hospitalized with ADHF. With the exception of greater diuresis, available data are homogenous for the reported outcomes but lack information on clinical endpoints. Larger studies are needed to provide robust recommendations for clinical practice.

Recent Insights into Dosing Diuretics for Acute Decompensated Heart Failure

Acute decompensated heart failure (ADHF) is a major problem among the elderly requiring frequent hospitalizations. Although the vast majority of patients with ADHF require loop diuretic therapy to control symptoms, guidelines for their use have been driven primarily by small nonrandomized trials and observational studies. Ongoing debate has centered on the risks of adverse effects including renal dysfunction and the most appropriate method of administration to minimize these risks. Recently, a large prospective randomized trial, the Diuretic Optimization Strategies Evaluation (DOSE), addressed these issues. This article will review the findings of this trial and the implications for clinical practice.

Continuous versus intermittent infusion of furosemide in acute decompensated heart failure

BACKGROUND

Despite advances in the treatment of chronic ambulatory heart failure, hospitalization rates for acute decompensated heart failure (ADHF) remain high. Although loop diuretics are used in nearly all patients with ADHF to relieve congestive symptoms, optimal dosing strategies remain poorly defined.

METHODS AND RESULTS

This was a prospective, randomized, parallel-group study comparing the effectiveness of continuous intravenous (cIV) with intermittent intravenous (iIV) infusion of furosemide in 56 patients with ADHF. The dose and duration of furosemide as well as concomitant medications to treat ADHF were determined by physician preference. The primary end point of the study was net urine output (nUOP)/24 hours. Safety measures including electrolyte loss and hemodynamic instability were also assessed. Twenty-six patients received cIV and 30 patients received iIV dosing. The mean nUOP/24 hours was 2098+/-1132 mL in patients receiving cIV versus 1575+/-1100 mL in the iIV group (P=.086). The cIV group had significantly greater total urine output (tUOP) with 3726+/-1121 mL/24 hours versus 2955+/-1267 mL/24 hours in the iIV group (P=.019) and tUOP/mg furosemide with 38.0+/-31.0 mL/mg versus 22.2+/-12.5 mL/mg (P=.021). Mean weight loss was not significantly different between the groups. The cIV group experienced a shorter length of hospital stay (6.9+/-3.7 versus 10.9+/-8.3 days, P=.006). There were no differences in safety measures between the groups.

CONCLUSIONS

The cIV of furosemide was well tolerated and significantly more effective than iIV for tUOP. In addition, continuous infusion appears to provide more efficient diuresis.

Managing acute renal failure in patients with acute decompensated heart failure: the cardiorenal syndrome

In patients with acute decompensated heart failure, worsening renal function during conventional decongestive therapy (cardiorenal syndrome) affects prognosis and the initiation of therapies with known benefit in chronic heart failure. Potential strategies for decongestion in patients who develop cardiorenal syndrome include invasive hemodynamic monitoring to guide therapy, use of continuous diuretic infusions, ultrafiltration, or novel therapy with adenosine or vasopressin receptor antagonists. Clinical trials by the National Heart, Lung, and Blood Institute's Heart Failure Network are currently underway to validate such therapies in patients with acute decompensated heart failure with worsening renal function and to establish novel biomarkers for the early identification of patients who develop cardiorenal syndrome.

Management of loop diuretic resistance in the intensive care unit

PURPOSE

The management of loop diuretic resistance in the intensive care unit (ICU) is reviewed.

SUMMARY

Volume overload, a common complication of fluid resuscitation, is frequently encountered in the ICU and is associated with numerous adverse effects, including pulmonary and peripheral edema, acute lung injury, and pleural effusions. Loop diuretics are used to treat volume overload and acute renal failure and to ameliorate their associated complications. When administered intravenously, these drugs induce vigorous and prompt diuresis, which may result in negative fluid balance. This may also result in significant adverse effects, including electrolyte imbalance, ototoxicity, and volume contraction. Prolonged use of loop diuretics may lead to loop diuretic resistance, a frequent observation in the ICU. Three general mechanisms are used to explain loop diuretic resistance: rebound sodium retention, postdiuretic effect, and diuretic braking. While very few agents have joined the armamentarium and no new strategies have been developed to deal with this phenomenon, several options are available to clinicians for managing loop diuretic resistance, including salt restriction, administration of i.v. loop diuretics, continuous infusion of loop diuretics, and combination therapy using loop diuretics and thiazides.

CONCLUSION

Loop diuretic resistance presents a challenge for clinicians in the ICU setting. Strategies to improve patients' responsiveness to these agents include fluid and salt restriction, switching from oral to i.v. loop diuretics, increasing diuretic dose, continuous infusion, and combination therapy with thiazides. Several of these strategies may be used concurrently to combat diuretic resistance and promote symptomatic relief of edema in the critically ill patient.

The benefit of low-dose dopamine during vigorous diuresis for congestive heart failure associated with renal insufficiency: does it protect renal function?

BACKGROUND

Low-dose dopamine, a renal vasodilator, has been used empirically to improve renal function or outcome in critically ill patients with oliguria or acute renal failure.

HYPOTHESIS

This study was designed to investigate the efficacy of low-dose dopamine (2 micrograms/kg/min) as a renal-protective agent during vigorous diuresis for congestive heart failure (CHF) associated with mild or moderate renal insufficiency.

METHODS

Of 20 study patients (mean age 74.3 +/- 15 years) with severe CHF, 10 (Group A) were randomized to a treatment strategy of intravenous bumetanide (1 mg b.i.d.) alone and another 10 (Group B) to low-dose dopamine and a similar diuretic regimen for a duration of 5 days or less if clinical edema remitted.

RESULTS

Group B patients showed a significant improvement in renal function and urinary output: serum blood urea nitrogen 48.9 +/- 10.3 to 32.1 +/- 14.4 mg/dl (p < 0.05); serum creatinine 1.97 +/- 0.24 to 1.49 +/- 0.39 mg/dl (p < 0.05); creatinine clearance 35.6 +/- 11.6 to 48.8 +/- 12.3 ml/min (p < 0.05); and indexed urinary output 0.56 +/- 0.16 to 2.02 +/- 0.72 ml/kg/h (p < 0.05). Group A patients showed a significant increase in urinary output but nonsignificant renal functional deterioration.

CONCLUSION

The renal-protective effect of low-dose dopamine in the setting of CHF and vigorous diuresis is supported by this study.