Lactated Ringer Is Associated With Reduced Mortality and Less Acute Kidney Injury in Critically Ill Patients: A Retrospective Cohort Analysis.

OBJECTIVES

To assess the impact of the percentage of fluid infused as Lactated Ringer (%LR) during the first 2 days of ICU admission in hospital mortality and occurrence of acute kidney injury.

DESIGN

Retrospective cohort.

SETTING

Analysis of a large public database (Multiparameter Intelligent Monitoring in Intensive Care-II).

PATIENTS

Adult patients with at least 2 days of ICU stay, admission creatinine lower than 5 mg/dL, and that received at least 500 mL of fluid in the first 48 hours.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

10,249 patients were included in mortality analysis and 8,085 were included in the acute kidney injury analysis. For acute kidney injury analysis, we excluded patients achieving acute kidney injury criteria in the first 2 days of ICU stay. Acute kidney injury was defined as stage 2/3 Kidney Disease: Improving Global Outcomes creatinine criteria and was assessed from days 3-7. The effects of %LR in both outcomes were assessed through logistic regression controlling for confounders. Principal component analysis was applied to assess the effect of volume of each fluid type on mortality. Higher %LR was associated with lower mortality and less acute kidney injury. %LR effect increased with total volume of fluid infused. For patients in the fourth quartile of fluid volume (> 7 L), the odds ratio for mortality for %LR equal to 75% versus %LR equal to 25% was 0.50 (95% CI, 0.32-0.79; p < 0.001). Principal component analysis suggested that volume of Lactated Ringer and 0.9% saline infused had opposite effects in outcome, favoring Lactated Ringer.

CONCLUSIONS

Higher %LR was associated with reduced hospital mortality and with less acute kidney injury from days 3-7 after ICU admission. The association between %LR and mortality was influenced by the total volume of fluids infused.