In this episode, I’ll discuss whether diuretics are safe to reduce fluid balance in critically ill patients.
Interest in fluid balance and the associated adverse effects in ICU patients has grown considerably over the last decade. The general practice of reducing fluid balance, sometimes referred to as deresuscitation, is associated with reduced mortality.
The safety of specific deresuscitation strategies continues to be established in literature, and a recent randomized-controlled single blind study in the journal Critical Care examined the efficacy and safety of a diuretic strategy to overcome positive fluid balance in patients on invasive mechanical ventilation.
The authors compared a practical diuretic protocol against a control group.
In the diuretic group, patients were given furosemide once or twice a day until successful extubation. The dosage was adapted by the bedside physician with the aim to reach patient’s reference weight, with a maximum daily dose set at 250 mg of furosemide to avoid kidney toxicity.
This protocol is rather vague although that did allow for adaptability of the furosemide dose to accommodate patient-specific needs.
While the primary outcome was fluid balance, secondary outcomes included numerous safety and efficacy endpoints.
There were 77 patients in the diuretic and 89 in the control group.
To the surprise of no one, fluid balance was lower in the diuretic group than the control group by about 5 liters. None of the secondary efficacy endpoints such as mortality or ICU stay were different between groups. However, there was a statistically significant difference in safety outcomes between the two groups.
While diuretics may be thought of as risky in critically ill patients due to kidney toxicity potential, the authors actually found that after randomization there was a worsening of acute kidney injury in 75.3% of the control group versus in 59.7% of the diuretic group (p = 0.03).
There was no difference between groups in hypokalemia, hypo or hypernatremia, or any of the other pre-specified safety endpoints besides worsening of acute kidney injury.
The study was extremely practical in that it used weight gain as a measure of fluid balance and a diuretic protocol that left much to the guidance of the individual physician. Critically ill patients with organ dysfunction were enrolled. The authors succeeded in their goal to validate the concept that diuretics can efficiently overcome fluid balance without major side effects. Larger studies are warranted to evaluate the effect on outcomes of such a strategy in critically ill patients.
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