Journal Feed Weekly Wrap-Up

We always work hard, but we may not have time to read through a bunch of journals. It’s time to learn smarter. 
Originally published at JournalFeed, a site that provides daily or weekly literature updates. 
Follow Dr. Clay Smith at @spoonfedEM, and sign up for email updates here.

#1: How Fast Should I be Giving Fluids to My Sick Patient? – The BaSICS RCT Part 1

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There was no difference in 90-day mortality in critically ill ICU patients randomized to receive IV fluid at a slow versus rapid infusion rate.

Why does this matter?

In patients with poor perfusion, fluids are a mainstay of treatment. While boluses of fluid are normally given to these patients, there is little literature to guide how fast the fluid should be delivered. If there is a difference in outcomes based on rate of infusion, this would be a simple step to take to better serve our patients.

‘Slow and Steady’ or ‘The Need for Speed?’

The Balanced Solutions in Intensive Care Study (BaSICS) was a double-blind, randomized clinical trial in 75 ICUs in Brazil with over 10,000 adult patients participating. The two intervention arms were looking at both fluid infusion speed (333ml/hr and 999ml/hr) and fluid type (PlasmaLyte vs NS), which we will cover tomorrow. The primary outcome, 90-day mortality, was 26.6% in the slower infusion rate and 27.0% in the faster infusion rate group (aHR, 1.03; 95% CI, 0.96-1.11; P=.46). A secondary outcome, need for renal replacement therapy within 90 days or doubling of the creatine, was also not statistically significant (27.8% balanced crystalloids vs 28.9% NS, 95% CI, 0.86-1.04). There was no association with type of fluid and rate on any patient outcome.

There has been a lot of attention of late in the literature on type of fluid given, but there are other variables to giving fluids than just the type: volume, temperature, and timing of administration could all play a roll. This study, in some part, sought to answer the question of whether fluid rate made a difference, and for their population it did not. While this study is ICU based and I practice in the pre-hospital and ED setting, it is reassuring for my current practice – which is in patients without adequate perfusion to get the fluids in as fast as possible.

Source

Effect of Slower vs Faster Intravenous Fluid Bolus Rates on Mortality in Critically Ill Patients: The BaSICS Randomized Clinical Trial. JAMA. Published online August 10, 2021. doi:10.1001/jama.2021.11444


#2: Are Balanced Crystalloids Still Better? – The BaSICS RCT Part 2

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A large RCT in Brazilian ICUs found no difference in 90-day mortality between patients who received balanced crystalloids versus normal saline (NS).

Why does this matter?

Two large studies, SMART and SALT-ED, both showed that patients who received balanced crystalloids had better outcomes than those who received NS. This large ICU RCT did not show a statistically significant difference in mortality between the two. Does this minimize the impact of SMART and SALT-ED, or is there more to unpack from BaSICS?

Back to BaSICS or a changing of the times?

Yesterday we covered the first intervention arm of BaSICS which look at mortality in relation to fluid administration rate. This double-blind, randomized clinical trial in 75 Brazilian ICUs, with over 10,000 adult patients enrolled, also set out to measure 90-day mortality in patients randomized to either PlasmaLyte or NS. There was no significant mortality difference between PlasmaLyte (26.4%) and NS (27.2%) (aHR 0.97, CI 0.90-1.05, P=.47). A secondary outcome showed no significant difference in need for renal replacement therapy or doubled creatinine in balanced crystalloid group (27.8%) versus NS group (28.9%) (95% CI, 0.86-1.04). Although the primary and secondary outcomes measured differed slightly, this study contrasts with both SMART and SALT-ED, which showed decreased likelihood of a major adverse kidney event and decreased in-hospital mortality at 30 days. So, what gives? Does this study mean what fluid we use doesn’t matter?

You could read the abstract and conclude that there is no difference between balanced crystalloids and NS – but that’s not how we do things around here! There are several key points to unpack when comparing this trial with the two major RCTs that came before it.

The overall signal from the study still leans towards balanced crystalloids. While you do need to prove statistical significance to be practice changing (or not), BaSICS had ~4,300 fewer patients than SMART, and only looked at 90-day mortality as their primary outcome. If outcomes were similar to SMART and SALT-ED, perhaps with more patients, things might look different. Additionally, this study only looked at patients after they arrived in the ICU, and fluids patients received prior to this were NOT controlled or considered, which could be a huge factor in interpreting these results.

In the end, my big takeaway from this is there is no one-size-fits-all fluid. One subgroup from BaSICS showed statistically significant decrease in 90-day mortality in patients with TBI who received NS (21.1%) instead of PlasmaLyte (31.3%) (HR 1.48, 95% CI 1.03-2.12, P=0.02). LR is better for patients with DKA and sepsis, but it seems that NS is preferred in some other clinical scenarios. This is a vital topic to medical practice, and I am glad to see so many high-quality studies being put forward and can’t wait to see what’s next.

Source

Effect of Intravenous Fluid Treatment With a Balanced Solution vs 0.9% Saline Solution on Mortality in Critically Ill Patients: The BaSICS Randomized Clinical Trial. JAMA. 2021 Aug 10;e2111684. doi: 10.1001/jama.2021.11684. Online ahead of print.

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There was no difference in acute kidney injury (AKI) on ICU day 3 or other longer-term outcomes after a single PICU switched from normal saline (NS) to balanced fluid.

Why does this matter?

NS has 154 meq/L of chloride. Hyperchloremia is associated with metabolic acidosis, decreased renal blood flow, and acute kidney injury. When this PICU changed from NS to balanced fluids, did it reduce the rate of AKI on ICU day 3 in these children?

A balanced perspective

  • Design: This was a single center before and after study in a PICU setting that switched from NS to balanced fluid.

  • Results: There were ~1,400 children before and after (total N = 2,863) included, with no major differences in the before/after cohorts except PlasmaLyte became the dominant bolus fluid and LR the dominant maintenance fluid instead of NS. For the primary outcome of AKI on day 3, there was no difference. For secondary outcomes after the switch, there was a lower rate of hyperchloremia. There was also lower hyperkalemia with balanced fluid. On the downside, there was a higher rate of hypokalemia after the switch. There was no difference in need for renal replacement therapy, length of stay, ventilator-free days, or in-hospital mortality after the switch.

  • Implications: Balanced fluids alone appeared to have little or no short or long term benefit in a PICU population. These data are so messy, it will take a well designed RCT to sort this out.

  • Limitations: After the switch to balanced fluid, children were statistically more likely to have >10% fluid overload on day 3. In other words, they not only changed fluid, they gave more than before. This could confound results, as fluid overload is associated with adverse outcomes. We also have no idea what fluid or what volume patients received prior to arrival in the PICU, which could significantly confound outcomes.

Source

Association between the use of balanced fluids and outcomes in critically ill children: a before and after study. Crit Care. 2021 Jul 29;25(1):266. doi: 10.1186/s13054-021-03705-3.

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