Efficacy and Safety of a Furosemide Continuous Infusion Following Cardiac Surgery

CO2 Cystoscopy for Evaluation of Ureteral Patency

Gynecologic surgery is associated with various perioperative complications, especially urinary tract injuries. Intraoperative cystoscopy plays an important role in allowing assessment of the bladder to ensure the absence of injuries. Verification of the urinary jets from the ureters is a fundamental step that is not always easy to accomplish. Dyes are frequently used, but these are not always available and are associated with adverse effects. The present study aimed to demonstrate the use of CO₂ as a medium for distension during cystoscopy. A total of 47 patients underwent CO₂ cystoscopy after laparoscopic hysterectomy (n = 26) or bladder endometriosis nodule resection (n = 21). In all patients, the ureteral jets were readily identified, leaving no doubt as to their patency. The median interval between the onset of cystoscopy and the view of jetting from both ureteral ostia was 145 seconds (range, 80-300 seconds). All cystoscopies were normal, and no patient had any signs of accidental urinary tract injury in the follow-up period. Two patients experienced mild urinary tract infection. This cystoscopy technique using CO₂ is fast, easy, safe, and efficient. We recommend bladder distension with CO₂ as a reasonable alternative technique when cystoscopy is required during gynecologic procedures.

Continuous infusion of furosemide versus intermittent boluses in acute decompensated heart failure: Effect on thoracic fluid content

INTRODUCTION

The administration of loop diuretics in the management of acute decompensated heart failure (ADHF) whether IV boluses or continuous infusion is still controversial. We intended to evaluate differences between the two administration routes on the thoracic fluid content (TFC) and the renal functions.

METHODS

Sixty patients with ADHF admitted to the critical care medicine department (Cairo University, Egypt) were initially enrolled in the study. Twenty patients were excluded due to EF > 40%, myocardial infarction within 30 days, and baseline serum creatinine level > 4.0 mg/dL. Furosemide (120 mg/day) was given to the remaining 40 pts who continued the study after 1:1 randomization to either continuous infusion (group-I, 20 pts) or three equal intermittent daily doses (group-II, 20 pts). Subsequent dose titration was allowed after 24 h, but not earlier, according to patient's response. No other diuretic medications were allowed. All patients were daily evaluated for NYHA class, urine output, TFC, body weight, serum K+, and renal chemistry.

RESULTS

The median age (Q1-Q3) was 54.5 (43.8-63.8) years old with 24 (60%) males. Apart from TFC which was significantly higher in group-I, the admission demographic, clinical, laboratory and co-morbid conditions were similar in both groups. There was statistically insignificant tendency for increased urine output during the 1st and 2nd days in group-I compared to group-II (p = .08). The body weight was decreased during the 1st day by 2 (1.5-2.5) kg in group-I compared to 1.5 (1-2) kg in group-II, (p = .03). These changes became insignificant during the 2nd day (p = .4). The decrease of TFC was significantly higher in group-I than in group-II [10 (6.3-14.5) vs 7 (3.3-9.8) kΩ-1 during the first day and 8 (6-11) vs 6 (3.3-8.5) kΩ-1 during the second day in groups-I&II respectively, P = .02 for both]. There was similar NYHA class improvement in both groups (p = .7). The serum creatinine was increased by 0.2 (0.1-0.5) vs 0 (-0.1 to 0.2) mg% and the CrCl was decreased by 7.4 (4.5-12.3) vs 3.1 (0.2-8.8) ml/min in groups-I&II respectively (p = .009 and .02 respectively).

CONCLUSIONS

We concluded that continuous furosemide infusion in ADHF might cause greater weight loss and more decrease in TFC with no symptomatic improvement and possibly with more nephrotoxic effect.

Prophylactic furosemide infusion decreasing early major postoperative renal dysfunction in on-pump adult cardiac surgery: a randomized clinical trial

INTRODUCTION

Acute renal dysfunction is a common complication of cardiac surgery. Furosemide is used in prevention, or treatment, of acute renal dysfunction. This study was conducted to evaluate the protective effects of intra- and early postoperative furosemide infusion on preventing acute renal dysfunction in elective adult cardiac surgery.

METHODS

Eighty-one patients, candidates of elective cardiac surgery, were enrolled in this study in either the furosemide (n=41) or placebo (n=40) group. Furosemide (2 mg/h) or 0.9% saline was administered and continued up to 12 hours postoperatively. We measured serum creatinine (Scr) at preoperative and on the second and fifth postoperative days. Then calculated estimated glomerular filtration rate (eGFR) at these times. An increase in Scr of >0.5 mg/dL and/or >25%-50%, compared to preoperative values, was considered as acute kidney injury (AKI). In contrast, an increase in Scr by >50% and/or the need for hemodialysis was regarded as acute renal failure (ARF). At the end we compared the AKI or ARF incidence between the two groups.

RESULTS

On the second and fifth postoperative days, Scr was lower, and the eGFR was higher in the furosemide group. AKI incidence was similar in the two groups (11 vs 12 cases; P-value 0.622); however, ARF rate was lower in furosemide group (1 vs 6 cases; P-value 0.044). During the study period, Scr was more stable in the furosemide group, however in the placebo group, Scr initially increased and then decreased to its preoperative value after a few days.

CONCLUSION

This study showed that intra- and early postoperative furosemide infusion has a renal protective effect in adult cardiac surgery with cardiopulmonary bypass. Although this protective effect cannot be discovered in mild renal dysfunctions, it apparently reduces the rate of the more severe renal dysfunctions. A more multidisciplinary strategy may be needed in reducing the milder renal damage.

Goal-directed diuresis: A case - control study of continuous furosemide infusion in critically ill trauma patients

BACKGROUND

Excessive crystalloid administration is common and associated with negative outcomes in critically ill trauma patients. Continuous furosemide infusion (CFI) to remove excessive fluid has not been previously described in this population. We hypothesized that a goal-directed CFI is more effective for fluid removal than intermittent bolus injection (IBI) diuresis without excess incidence of hypokalemia or renal failure.

MATERIALS AND METHODS

CFI cases were prospectively enrolled between November 2011 and August 2012, and matched to historic IBI controls by age, gender, Injury Severity Score (ISS), and net fluid balance (NFB) at diuresis initiation. Paired and unpaired analyses were performed to compare groups. The primary endpoints were net fluid balance, potassium and creatinine levels. Secondary endpoints included intensive care unit (ICU) and hospital length of stay (LOS), ventilator-free days (VFD), and mortality.

RESULTS

55 patients were included, with 19 cases and 36 matched controls. Mean age was 54 years, mean ISS was 32.7, and mean initial NFB was +7.7 L. After one day of diuresis with CFI vs. IBI, net 24 h fluid balance was negative (-0.55 L vs. +0.43 L, P = 0.026) only for the CFI group, and there was no difference in potassium and creatinine levels. Cumulative furosemide dose (59.4mg vs. 25.4mg, P < 0.001) and urine output (4.2 L vs. 2.8 L, P < 0.001) were also significantly increased with CFI vs. IBI. There were no statistically significant differences in ICU LOS, hospital LOS, VFD, or mortality.

CONCLUSIONS

Compared to IBI, goal-directed diuresis by CFI is more successful in achieving net negative fluid balance in patients with fluid overload with no detrimental side effects on renal function or patient outcome.

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.

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.

Continuous renal replacement therapy versus furosemide for management of kidney impairment in heart transplant recipients with volume overload

OBJECTIVES

It is unknown whether continuous renal replacement therapy or furosemide therapy is superior in heart transplant recipients who are in postoperative kidney insufficiency and volume overload. This prospective non-randomized, controlled trial investigated the efficacy of the two methods after transplantation.

METHODS

We assigned heart transplant recipients 18 years of age or older who were oliguric (urine output < 400 ml/day); had volume overload and estimated glomerular filtration rate <60 ml/min/1.73 m(2) of body surface area calculated with the use of the Modification of Diet in Renal Disease equation, to designed initiation of intervention. We followed 30 patients for up to 30 days. The primary outcome was estimated glomerular filtration rate status after intervention.

RESULTS

Between January 2010 and April 2012, a total of 30 adults (mean age: 37 years; 18 men and 12 women) were assessed for entry in this trial. Continuous renal replacement therapy, when compared with furosemide, was associated with a significant increase in estimated glomerular filtration rate of patients after intervention 61 ± 4.5 vs 55 ± 8.5l ml/min/1.73 m(2) (P = 0.02). Moreover, the mean glomerular filtration rate at discharge time for the continuous renal replacement therapy group was 72 ± 7.3 and 58 ± 7.4 ml/min/1.73 m(2) for the furosemide group (P < 0.001). During the follow-up period, 6 of 15 patients in the continuous renal replacement therapy group (40%) and 4 of 15 in the furosemide group (26.6%) died (P = 0.43).

CONCLUSIONS

In this study, continuous renal replacement therapy in heart transplant recipients with reduced kidney function was associated with an improvement in estimated glomerular filtration rate status in comparison with furosemide.

Clinical pharmacology of the loop diuretics furosemide and bumetanide in neonates and infants

The loop diuretics furosemide and bumetanide are used widely for the management of fluid overload in both acute and chronic disease states. To date, most pharmacokinetic studies in neonates have been conducted with furosemide and little is known about bumetanide. The aim of this article was to review the published data on the pharmacology of furosemide and bumetanide in neonates and infants in order to provide a critical analysis of the literature, and a useful tool for physicians. The bibliographic search was performed electronically using PubMed and EMBASE databases as search engines and March 2011 was the cutoff point. The half-life (t(½)) of both furosemide and bumetanide is considerably longer in neonates than in adults and consequently the clearance (CL) of these drugs is reduced at birth. In healthy volunteers, plasma t(½) of furosemide ranges from 33 to 100 minutes, whereas in neonates it ranges from 8 to 27 hours. The volume of distribution (V(d)) of furosemide undergoes little variation during neonate maturation. The dose of furosemide, administered by intermittent intravenous infusion, is 1 mg/kg and may increase to a maximum of 2 mg/kg every 24 hours in premature infants and every 12 hours in full-term infants. Comparison of continuous infusion versus intermittent infusion of furosemide showed that the diuresis is more controlled with fewer hemodynamic and electrolytic variations during continuous infusion. The appropriate infusion rate of furosemide ranges from 0.1 to 0.2 mg/kg/h and when the diuresis is <1 mL/kg/h the infusion rate may be increased to 0.4 mg/kg/h. Treatment with theophylline before administration of furosemide results in a significant increase of urine flow rate. Bumetanide is more potent than furosemide and its dose after intermittent intravenous infusion ranges from 0.005 to 0.1 mg/kg every 24 hours. The t(½) of bumetanide in neonates ranges from 1.74 to 7.0 hours. Up to now, no data are available on the continuous infusion of bumetanide. Extracorporeal membrane oxygenation (ECMO) is used for a variety of indications including sepsis, persistent pulmonary hypertension, meconium aspiration syndrome, cardiac defects and congenital diaphragmatic hernia. There are two studies of furosemide in neonates undergoing ECMO and only one on the pharmacokinetics of bumetanide under ECMO. When ECMO was conducted for 72 hours, the total amount of furosemide administered was 7.0 mg/kg, and the urine production in the 3 days of treatment was about 6 mL/kg/h, which is the target value. The t(½) of bumetanide in neonates during ECMO was extremely variable. CL, t(½), and V(d) were 0.63 mL/min/kg, 13.2 hours, and 0.45 L/kg, respectively. Furosemide may be administered by inhalation and inhibits the bronco-constrictive effect of exercise, cold air ventilation and antigen challenge. However, inhaled furosemide is not active in infants with viral bronchiolitis and its effect on broncho-pulmonary dysplasia is still uncertain. Furosemide does not significantly increase the risk of failure of patent ductus arteriosus closure when indomethacin or ibuprofen have been co-administered. Infants with low birth weight treated long-term with furosemide are at risk for the development of intra-renal calcification. Furosemide therapy above 10 mg/kg bodyweight cumulative dose had a 48-fold increased risk of nephrocalcinosis. The use of furosemide in combination with indomethacin increased the incidence of acute renal failure. The maturation of the kidney governs the pharmacokinetics of furosemide and bumetanide in the infant. CL and t(½) are influenced by development, and this must be taken into consideration when planning a dosage regimen with these drugs.

Does perioperative furosemide usage reduce the need for renal replacement therapy in cardiac surgery patients?

A best evidence topic was constructed according to a structured protocol. The question addressed was 'Does perioperative furosemide usage reduce the need for renal replacement therapy in cardiac surgery patients?' Forty-seven papers were found using the reported search, of which 10 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Current best available evidence to resolve the issue includes a systematic review and nine randomized controlled trials (RCTs). The systematic review of seven RCTs and one observational study has demonstrated that in patients who have undergone cardiac surgery, 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 the total urine output or a change in serum electrolyte levels when furosemide is administered as a continuous infusion compared with intermittent bolus doses. Three RCTs recruiting neonatal and paediatric patients after open heart surgery also validated the safety and efficacy of furosemide infusion as well as intermittent bolus doses. Two of the five RCTS in adult cardiac surgery patients showed that furosemide infusion was associated with a reduced need for renal replacement therapy (RRT), while two RCTs failed to show any benefit and one reported an increased incidence of renal impairment. We conclude that continuous furosemide infusion in the perioperative period promotes a gentle and sustained diuresis in cardiac surgery patients. The evidence supporting the benefit of this strategy in terms of reducing the need for RRT is weak. At the same time, current best available evidence, albeit from small RCTs, suggests that the timely introduction of continuous furosemide infusion does not increase the incidence of renal impairment after cardiac surgery.

Diuretic therapy in heart failure: current controversies and new approaches for fluid removal

Hospitalization for heart failure is a major health problem with high in-hospital and postdischarge mortality and morbidity. Non-potassium-sparing diuretics (NPSDs) still remain the cornerstone of therapy for fluid management in heart failure despite the lack of large randomized trials evaluating their safety and optimal dosing regimens in both the acute and chronic setting. Recent retrospective data suggest increased mortality and re-hospitalization rates in a wide spectrum of heart failure patients receiving NPSDs, particularly at high doses. Electrolyte abnormalities, hypotension, activation of neurohormones, and worsening renal function may all be responsible for the observed poor outcomes. Although NPSD will continue to be important agents to promptly resolve signs and symptoms of heart failure, alternative therapies such as vasopressine antagonists and adenosine blocking agents or techniques like veno-venous ultrafiltration have been developed in an effort to reduce NPSD exposure and minimize their side effects. Until other new agents become available, it is probably prudent to combine NPSD with aldosterone blocking agents that are known to improve outcomes.

Continuous versus bolus dosing of Furosemide for patients hospitalized for heart failure

Intravenous diuretics are the cornerstone of management for patients hospitalized for heart failure. Physiologic data suggest that intermittent high-dose furosemide promotes neurohormonal activation, which a slow continuous infusion might remediate. However, the limited clinical data comparing dosing schemes are confounded. This study was a randomized, open-label, single-center trial of twice-daily bolus injection versus continuous infusion furosemide in patients hospitalized with heart failure and volume overload. The primary outcome was change in creatinine from admission to hospital day 3 or discharge. Twenty-one patients were randomized to bolus injection and 20 patients to continuous infusion. Baseline characteristics were balanced between study arms except for gender, with a mean age of 60 +/- 15 years, a mean ejection fraction of 35 +/- 19%, and a mean creatinine level of 1.9 +/- 1.2 mg/dl. The mean doses of furosemide were similar between arms over the first 48 hours (162 +/- 48 and 162 +/- 52 mg/24 hours). None of the outcomes differed significantly between bolus and continuous dosing from admission to hospital day 3 or discharge (mean change in creatinine -0.02 vs 0.13 mg/dl, p = 0.18; urine output 5,113 vs 4,894 ml, p = 0.78; length of stay 8.8 vs 9.9 days, p = 0.69). All patients survived to discharge. In conclusion, there were no substantial differences between bolus injection and continuous infusion of equal doses of furosemide for the treatment of patients hospitalized with heart failure. Given the high prevalence of heart failure hospitalization and the disparate results of small studies regarding optimal dosing of loop diuretics to treat these patients, larger multicenter blinded studies are needed.

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.

Canadian Cardiovascular Society Consensus Conference recommendations on heart failure update 2007: Prevention, management during intercurrent illness or acute decompensation, and use of biomarkers

Heart failure is common, yet it is difficult to treat. It presents in many different guises and circumstances in which therapy needs to be individualized. The Canadian Cardiovascular Society published a comprehensive set of recommendations in January 2006 on the diagnosis and management of heart failure, and the present update builds on those core recommendations. Based on feedback obtained through a national program of heart failure workshops during 2006, several topics were identified as priorities because of the challenges they pose to health care professionals. New evidence-based recommendations were developed using the structured approach for the review and assessment of evidence adopted and previously described by the Society. Specific recommendations and practical tips were written for the prevention of heart failure, the management of heart failure during intercurrent illness, the treatment of acute heart failure, and the current and future roles of biomarkers in heart failure care. Specific clinical questions that are addressed include: which patients should be identified as being at high risk of developing heart failure and which interventions should be used? What complications can occur in heart failure patients during an intercurrent illness, how should these patients be monitored and which medications may require a dose adjustment or discontinuation? What are the best therapeutic, both drug and nondrug, strategies for patients with acute heart failure? How can new biomarkers help in the treatment of heart failure, and when and how should BNP be measured in heart failure patients? The goals of the present update are to translate best evidence into practice, to apply clinical wisdom where evidence for specific strategies is weaker, and to aid physicians and other health care providers to optimally treat heart failure patients to result in a measurable impact on patient health and clinical outcomes in Canada.