Huh? Early IV Fluids Often Given With Loop Diuretics in Acute HF: Analysis

Marlene Busko

February 04, 2015

NEW HAVEN, CT — A large study reports that one in nine patients hospitalized with heart failure received not only diuretics in their first 2 days of hospitalization but also IV fluids[1]. Moreover, patients who received IV fluids were more likely to later be admitted to critical care, be intubated, have renal-replacement therapy, or die in the hospital, in this study published in the February 2015 issue of JACC: Heart Failure.

Furthermore, of the 346 hospitals in the study, some never gave HF patients IV fluids during the first 2 days of admission, whereas others gave it to 71% of such patients.

This first study to investigate use of IV fluids in this patient population showed that "the administration of fluids to patients admitted with HF is not uncommon and varies substantially across hospitals, with potential adverse consequences," Dr Behnood Bikdeli (Yale-New Haven Hospital, CT) and colleagues summarize. "This practice may occur inadvertently for many patients, warrants further investigation, and may be an opportunity for improvement."

In an accompanying editorial[2], Dr Larry A Allen (University of Colorado School of Medicine, Aurora) writes that the interhospital variation "suggests that at least some of the delivery of IV fluids among congested patients with heart failure reflects variations in the culture of care." Thus, "now that this relatively common practice is revealed, it behooves us to better understand exactly why it is happening; this understanding can then guide efforts to extinguish truly inappropriate care."

Asked to comment as an observer, Dr Randall Starling (Cleveland Clinic, OH) agreed that "sometimes the clinician has difficulty in clinically establishing the volume status of the patient." At other times, perhaps "the diuresis was too much, too fast, and the clinician is trying to play catch-up by giving the volume back."

The study highlights the importance for close and consistent clinical monitoring of these complex patients who may be receiving multiple medications, he said.

Potentially Conflicting Therapies

Hospitalized patients with HF are given early care with loop diuretics to reduce their volume overload, but hospitalized patients in general also routinely receive IV fluids, Bikdeli and colleagues write. Could some HF patients be receiving inappropriate, conflicting therapies?

To investigate this, they analyzed data from the Premier (Charlotte, NC) database, which represents about 20% of acute-care hospitalizations in the US.

They identified 131 430 patients who were 18 or older, hospitalized for HF, and treated with loop-diuretic therapy in the first 2 days of hospitalization during 2009 and 2010.

Most patients were older than 75 years (57%), female (53%) and white (63%). The diuretic therapy was almost always furosemide (91% of cases), but some patients received bumetanide, torsemide, or a combination of agents.

A total of 11% of patients received at least 500 mL of IV therapy (median 1000 mL), mostly normal saline (80% of patients) or half-normal saline (12%) and less commonly Ringer's or mixed-fluid therapy.

Among these hospitalized patients with HF who received diuretics, those who also received IV fluids had higher rates of subsequent critical-care admission (5.7% vs 3.8%; P<0.0001), late intubation (1.4% vs 1.0%; P=0.0012), renal-replacement therapy (0.6% vs 0.3%; P<0.0001), and in-hospital mortality (3.3% vs 1.8%; P<0.0001) than their peers who did not receive IV fluids.

Risk of Adverse Outcomes With IV Therapy vs None*
Outcome Odds ratio (95%CI)
Critical-care admission 1.57 (1.45–1.71)
Late intubation 1.46 (1.25–1.71)
Renal-replacement therapy 2.04 (1.62–2.55)
In-hospital death 2.20 (1.82–2.24)
*Adjusted for demographics and comorbidities

It is unlikely that the patients received IV fluids to counter detrimental effects of too much diuretic therapy, since patients in both groups received similar doses of diuretics, and, by restricting the study to the first 2 days of admission, researchers minimized the possibility of excessive diuresis, according to the authors.

The study has certain limitations, they admit. For example, the population may have included "sicker" patients with hemodynamic instability, even though they excluded patients with bleeding, sepsis, or anaphylaxis. Moreover, they lacked information about ejection fraction, blood pressure, heart rate, kidney-function biomarkers, or the reason for the IV-fluid administration.

Thus, until data from a prospective trial become available, "decisions about the use of intravenous fluids in patients with decompensated HF remain a challenge and should be made on a case-by-case basis with respect to factors such as HF status and renal function," Bikdeli and colleagues conclude.

To be "prudent," hospitals should implement strategies to minimize inadvertent IV-fluid therapy, such as a "review of standard emergency-department order sets that could routinely call for intravenous fluids, as well as use of automated reminders that could help minimize unnecessary administration of fluids to patients with decompensated HF."

According to Allen, part of the findings may be due to suboptimal communication among clinical-team members. However, these are often very complex patients. "One of the most common challenges in the delivery of inpatient care is the determination of optimal intravascular volume status: Is the patient wet or dry?" he writes.

"Specific to heart failure, we need to pay particular attention to what matters most: a thoughtful approach to the control of fluid status." For hospitalized patients in general, "we need to remember that medicine is an art: good care is grounded in physiology, guided by evidence, and tailored to the patient."

This study was supported supported by grants from the Patrick and Catherine Weldon Donaghue Medical Research Foundation and by grants from the National Center for Advancing Translational Sciences and the National Heart, Lung, and Blood Institute. Allen is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Bikdeli has no relevant financial relationships; disclosures for the coauthors are listed in the article. According to the Cleveland Clinic, Starling has reported financial relationships with Medtronic, Novartis, and Thoratec "but instructed them to donate all compensation directly to one or more nonprofit organizations."

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