Patients in the intensive care unit frequently receive IV fluid. Two basic types of IV fluid exist: saline (which contains more chloride than human blood) and balanced crystalloids (which contains about the same amount of chloride as human blood). No large trials had previously evaluated which fluid resulted in the best outcomes for patients. In preparation for a large trial examining this question, the SALT pilot trial aimed to determine whether software tools in the hospital’s electronic health record would produce balanced study groups and divide study participants to either receive balanced crystalloids or saline in a separate and equal way. Results of the study showed that this approach can produce well-balanced study groups and separate the receipt of saline or balanced crystalloids in an effective way. These findings suggest that electronic health records may be used to efficiently conduct trials comparing treatments commonly used in clinical care.
Rationale: Saline is the intravenous fluid most commonly administered to critically ill adults, but it may be associated with acute kidney injury and death. Whether use of balanced crystalloids rather than saline affects patient outcomes remains unknown.
Objectives: To pilot a cluster-randomized, multiple-crossover trial using software tools within the electronic health record to compare saline to balanced crystalloids.
Methods: This was a cluster-randomized, multiple-crossover trial among 974 adults admitted to a tertiary medical intensive care unit from February 3, 2015 to May 31, 2015. The intravenous crystalloid used in the unit alternated monthly between saline (0.9% sodium chloride) and balanced crystalloids (lactated Ringer’s solution or Plasma-Lyte A). Enrollment, fluid delivery, and data collection were performed using software tools within the electronic health record. The primary outcome was the difference between study groups in the proportion of isotonic crystalloid administered that was saline. The secondary outcome was major adverse kidney events within 30 days (MAKE30), a composite of death, dialysis, or persistent renal dysfunction.
Measurements and main results: Patients assigned to saline (n = 454) and balanced crystalloids (n = 520) were similar at baseline and received similar volumes of crystalloid by 30 days (median [interquartile range]: 1,424 ml [500-3,377] vs. 1,617 ml [500-3,628]; P = 0.40). Saline made up a larger proportion of the isotonic crystalloid given in the saline group than in the balanced crystalloid group (91% vs. 21%; P < 0.001). MAKE30 did not differ between groups (24.7% vs. 24.6%; P = 0.98).
Conclusions: An electronic health record-embedded, cluster-randomized, multiple-crossover trial comparing saline with balanced crystalloids can produce well-balanced study groups and separation in crystalloid receipt. Clinical trial registered with www.clinicaltrials.gov (NCT 02345486).
Trial registration: ClinicalTrials.gov NCT02345486.
Keywords: acute kidney injury; critical illness; crystalloid; intravenous fluid; saline.
Manuscript Title: “Balanced Crystalloids versus Saline in the Intensive Care Unit. The SALT Randomized Trial.”
Journal: American Journal of Respiratory and Critical Care Medicine