A randomized hospital trial in Canada found similar mortality and readmission rates at 90 days when hospitals used lactated Ringer’s solution instead of normal saline for intravenous therapy. The composite primary outcome of death or readmission within 90 days occurred in 20% of patients who received lactated Ringer’s and 21% who received saline. Mortality occurred in 7% of the lactated Ringer’s group and 8% of the saline group. Readmissions occurred in about 15% of both groups. Other measured outcomes, including emergency department visits, dialysis initiation, length of stay, and discharge to a facility other than home, were also similar between groups. Subgroup analyses by age, sex, admission type, comorbidity burden, ICU admission, trauma, and infection were consistent with the overall findings. Smaller groups, such as patients with sepsis or traumatic brain injury, showed no differences, though these analyses were limited by sample size.
The study was conducted at 7 academic and community hospitals in Ontario between 2016 and 2020, though they planned to enroll 16. The trial ended early due to COVID-19–related challenges, which reduced the ability to detect small differences. "Small differences," lead author Lauralyn McIntyre, MD, of the Ottawa Hospital Research Institute and the University of Ottawa in Canada wrote with colleagues, "could have major effects at the level of the hospital or health care system."
Each hospital used one fluid for 12 weeks, followed by a washout period, then switched to the other fluid for another 12 weeks. All patients with an index admission during these periods were included. In total, 22,017 patients were in the lactated Ringer’s group and 21,609 were in the saline group. Patients' average age was about 58 years, and slightly more than half were women. Adherence to assigned fluid was 78% for lactated Ringer’s and 94% for saline. Individual fluid exposure could not be confirmed.
The authors concluded that "this trial adds to the growing body of evidence about the influence of crystalloid fluids on patient outcomes. Our findings align with those of recent meta-analyses of randomized, controlled trials that suggest a small but clinically relevant reduction in mortality with balanced crystalloids as compared with normal saline."
Full disclosures can be found in the published study.