Impact of intravenous fluid composition on outcomes in patients with systemic inflammatory response syndrome
Introduction: Intravenous (IV) fluids may be associated with complications not often attributed to fluid type. Fluids with high chloride concentrations such as 0.9 % saline have been associated with adverse outcomes in surgery and critical care. Understanding the association between fluid type and outcomes in general hospitalized patients may inform selection of fluid type in clinical practice. We sought to determine if the type of IV fluid administered to patients with systemic inflammatory response syndrome (SIRS) is associated with outcome.
Methods: This was a propensity-matched cohort study in hospitalized patients receiving at least 500 mL IV crystalloid within 48 hours of SIRS. Patient data was extracted from a large multi-hospital electronic health record database between January 1, 2009, and March 31, 2013. The primary outcome was in-hospital mortality. Secondary outcomes included length of stay, readmission, and complications measured by ICD-9 coding and clinical definitions. Outcomes were adjusted for illness severity using the Acute Physiology Score. Of the 91,069 patients meeting inclusion criteria, 89,363 (98%) received 0.9% saline whereas 1706 (2%) received a calcium-free balanced solution as the primary fluid.
Results: There were 3116 well-matched patients, 1558 in each cohort. In comparison with the calcium-free balanced cohort, the saline cohort experienced greater in-hospital mortality (3.27% vs. 1.03%, P <0.001), length of stay (4.87 vs. 4.38 days, P = 0.016), frequency of readmission at 60 (13.54 vs. 10.91, P = 0.025) and 90 days (16.56 vs. 12.58, P = 0.002) and frequency of cardiac, infectious, and coagulopathy complications (all P < 0.002). Outcomes were defined by administrative coding and clinically were internally consistent. Patients in the saline cohort received more chloride and had electrolyte abnormalities requiring replacement more frequently (P < 0.001). No differences were found in acute renal failure.
Conclusions: In this large electronic health record, the predominant use of 0.9% saline in patients with SIRS was associated with significantly greater morbidity and mortality compared with predominant use of balanced fluids. The signal is consistent with that reported previously in perioperative and critical care patients. Given the large population of hospitalized patients receiving IV fluids, these differences may confer treatment implications and warrant corroboration via large clinical trials.
Trial registration: NCT02083198 clinicaltrials.gov; March 5, 2014.