CLASSIC RCT – Does Fluid Restriction Lower ICU Mortality?
July 11, 2022
It’s IV Fluid Week on JournalFeed. Embrace Your Inner Nerd!
Written by Seth Walsh-Blackmore
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In large a multicenter RCT of patients admitted to the ICU with septic shock, there was no difference in 90-day all-cause mortality when following a restrictive IV fluid protocol vs. standard protocol.
Why does this matter?
Current Surviving Sepsis guidelines recommend, with low-level evidence, aggressive fluid resuscitation in initial septic shock management. Several studies with low-level evidence have suggested harm with this approach. This RCT aims to provide high-quality evidence regarding a ubiquitous decision point in the care of septic shock, namely fluid volume.
Shocking results?
This was an RCT from 31 sites across 8 European countries of 1,554 adult ICU patients in whom septic shock had been identified in the last 12 hours. Septic shock was defined by lactate > 2mmol with ongoing pressors, at least 1 liter of fluid in the last 24 hours, and an infectious source. Those with life-threatening bleeds, >10% burns, or shock >12 hrs were excluded. The restrictive protocol limited patients to 250-500cc isotonic boluses when demonstrating clinical signs of hypoperfusion or replacement of documented losses. Patients in the non-restrictive group essentially followed the 2016 surviving sepsis IV fluid guidelines. Neither group was orally restricted. The median total ICU IV fluid volume (excluding meds and nutrition) was 1,798mL in the restrictive and 3,811 in the standard group. Cumulative fluid balance at 90 days was only about 700mL less in the restrictive group.
The primary outcome of all-cause mortality at 90-days was 42.3% in the restrictive group and 42.1% in the standard group, with an adjusted relative risk of 1.00 (95%CI 0.89-1.13, p = 0.96). Secondary outcomes, including ischemic events, adverse reactions, and days in the ICU, were also without a significant difference or signal favoring one intervention.
Evidence doesn’t get much better than an adequately powered multi-national RCT with well-balanced characteristics, near 100% follow-up, and a clinically relevant primary outcome. A significant limitation is that it was unblinded at the clinical level, and it’s not clear if other ICU interventions differed after enrollment.
Editor’s note: I wonder if the rigorous restrictive fluid protocol cross contaminated and minimized the difference between the groups. Regardless, I don’t think any of us are going back to the days of – “You gotta swell to get well,” that I learned on my ICU rotations. ~Clay Smith
Another Spoonful
Be sure to catch EMCrit’s June/July RACC Review that covers this article and more.
Source
Restriction of Intravenous Fluid in ICU Patients with Septic Shock. N Engl J Med. 2022 Jun 17. doi: 10.1056/NEJMoa2202707. Online ahead of print.