February 12th, 2015
Insights About the Use of IV Fluids in Patients Hospitalized for Heart Failure
The CardioExchange Editors interview Behnood Bikdeli, lead author of a retrospective cohort study of the use of intravenous fluids, within 2 days after admission, among patients hospitalized with acute decompensated heart failure and treated with loop diuretics at 346 hospitals in 2009 and 2010. Larry A. Allen, who wrote the editorial about the study, answers the same questions. Both articles are published in JACC: Heart Failure.
Of more than 130,000 patients hospitalized for heart failure, 11% were treated with IV fluids during the first 2 days after admission. Patients who received IV fluids had significantly higher rates of subsequent critical care admission (5.7% vs. 3.8%;), intubation (1.4% vs. 1.0%), renal replacement therapy (0.6% vs. 0.3%), and in-hospital death (3.3% vs. 1.8%) than patients who received only diuretics. Hospitals varied widely in the proportion of hospitalized HF patients who received IV fluids (range: 0% to 71%; median: 12.5%).
CardioExchange Editors: How do you think administration of IV fluids affects outcomes among patients hospitalized with congestive heart failure?
Bikdeli: This is an excellent question. There are multiple potential explanations. First, let me take a step back. We studied the early phase after admission (the first 48 hours of the inpatient stay). So it is less likely that patients in our study received IV fluids in response to excessive diuresis, although we cannot exclude that possibility. Another possibility is that — despite our exclusion criteria (people with sepsis, bleeding, or anaphylaxis, and those undergoing cardiac procedures) — some of these patients did require IV fluids for legitimate medical conditions and that use of IV fluids is a marker (rather than a cause) of higher risk and worse outcomes. Yet another possibility is that IV fluids were used inadvertently for some patients, and this might have contributed to worse outcomes. The wide variations in the risk-standardized utilization of IV fluids make me wonder whether this third hypothesis is important. I should clarify again, though, that our findings should not be interpreted as demonstrating causation at this stage.
Allen: Certainly administration of IV fluids to patients who actually need decongestion is counter to therapeutic goals. This may directly worsen a patient’s status or at least slow improvement, thereby unnecessarily prolonging symptoms and the hospital stay. Perhaps more important, simultaneous administration of IV fluids and IV diuretics may be a marker of poorly defined therapeutic goals or inadequately coordinated care.
Note that the use of both IV fluids and IV diuretics within the first 48 hours after hospitalization for heart failure may occur for a variety of reasons: reflexive connection of IV fluids in the emergency setting, carrier fluid for other IV medications, confusion over hemodynamic status, development of worsening renal function or hypotension with diuresis, development of sepsis physiology on top of heart failure, and so on. Administrative data have limits in elucidating the actual clinical decision-making rationale (or the lack of it). However, the significant variation among hospitals in IV fluid administration for these patients suggests that the reasons are not necessarily standard responses to physiology or accepted guidelines.
CardioExchange Editors: How should physicians and health care systems address this problem?
Bikdeli: There are multiple implications. At the patient level, we need to better identify the people who receive both diuretics and fluids within a short time span. Using more granular data, we also must determine whether or not the use of IV fluids is the main cause of these patients’ worse outcomes.
At the level of health-system pharmacists, it might be prudent to help promote initiatives that aim to minimize the amounts of IV fluids required for administration of other necessary medications (e.g., antibiotics) in patients with heart failure.
At the policy-making level, it might be helpful for hospital administrators to promote strategies that would reduce the chances of inadvertent IV fluid use in patients with decompensated heart failure. These might include (1) reminders/ alerts when a provider tries to add IV fluids for someone with HF, with the flexibility to override the alert if the patient’s clinical profile warrants it; (2) EMR-related strategies that would minimize routine use of IV fluids when patients present to the emergency department; and (3) better hand-offs when the level of care changes.
Allen: For clinicians treating individual patients, this study raises many questions. Most important, what are the reasons behind IV fluid administration? How can we improve rapid, accurate assessment of volume status and then implement care consistent with optimizing hemodynamics? In the face of worsening renal function during heart failure hospitalization, how can we know better when cardiorenal syndrome is due to persistent venous congestion, overdiuresis, or something else?
Health systems also need to understand the reasons behind IV fluid administration. With that knowledge, systems can then work to ensure that automated responses are consistent with clinical realities and that all ordered therapies reflect individualized, high-quality care.
JOIN THE DISCUSSION
Should these insights from Drs. Bikdeli and Allen influence how your institution approaches the use of IV fluids in hospitalized patients with heart failure?