Authors: Semler MW et al. N Engl J Med 2018 Mar 1.
Acutely hospitalized patients had better outcomes with lactated Ringer’s solution than with normal saline.
What is the right crystalloid for fluid resuscitation? Because limited data guide this decision, choices traditionally have been driven by culture: saline in medical units, and lactated Ringer’s solution for surgical patients. With emerging evidence showing that the hyperchloremia associated with administration of normal saline might cause harm, interest in the effects of various crystalloids has increased.
During 2 years in two parallel studies, investigators at Vanderbilt University assigned patients to receive either normal saline or a more-balanced crystalloid solution (i.e., lactated Ringer’s or Plasma-Lyte). One cohort comprised 15,802 patients who were admitted to the intensive care unit (ICU), and the other cohort comprised 13,347 patients admitted from the emergency department (ED) to non-ICU acute care. The study design was unique: For each month of the trials, the ED and ICU were assigned to use either saline or a balanced crystalloid, and computer order entry systems directed providers to use the assigned fluid. The unassigned fluid also was available, but few patients received it. Most patients who received balanced crystalloid solutions were given lactated Ringer’s.
In the ICU trial, significantly more patients in the saline group (15% vs. 14%) suffered major adverse kidney events (a composite of death, renal replacement therapy, or a doubling of creatinine at discharge). This effect was most pronounced in patients with sepsis and in those who received larger volumes of fluid. The primary outcome (hospital-free days) in the ED trial was similar in the two groups; however, major adverse kidney events were also significantly higher for the ED saline group (6% vs. 5%).
These data suggest the benefit of balanced crystalloid solution is greatest in septic patients and in those who require large volume resuscitation; these might be the populations where grabbing lactated Ringer’s makes the most sense.