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: = 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.