Ringer’s Lactate vs Normal Saline in Acute Pancreatitis: A Systematic Review and Meta-Analysis

Abstract

Introduction: Acute Pancreatitis (AP) is one of the most common causes of hospitalization in the United States. Aggressive intravenous hydration with crystalloids is the first step in management, and is associated with improved survival. Guidelines are unclear regarding the choice of crystalloids. Normal saline (NS) is the most commonly used, but recent studies have shown that use of Ringer’s lactate (RL) may improve mortality rates and decrease development of systemic inflammatory response syndrome (SIRS), which is one of the markers of poor outcomes, compared to NS. Methods: A comprehensive literature review was conducted by searching the Embase, MEDLINE, PubMed, and Google Scholar databases through December 2017 to identify all studies that compared the use of NS with RL for the management of AP. Primary endpoint was to evaluate difference in mortality and secondary end point was to evaluate development of SIRS in 24 hours among two groups. Results: Five studies, three randomized controlled trials (RCTs) and two retrospective cohort studies, including 428 patients, were included in this analysis. Only 3 studies, including 127 patients, reported secondary outcome of SIRS at 24 hours. Mortality trended lower in the RL group, but was not statistically significant (pooled odds ratio 0.61 (0.28-1.29; P=0.20)). Patients in the RL group had significantly decreased odds of developing SIRS at 24 hours (pooled odds ratio 0.38 (0.15-0.98; P=0.05)). Heterogeneity among studies was low as seen by the I2 of 46% for the mortality outcome. Conclusion: In this systematic review, we demonstrated that RL is associated with decreased odds of persistent SIRS at 24 hours. This anti-inflammatory effect of RL has two possible explanations. First, RL has a slightly higher pH compared to NS. Studies show that acidosis enhances inflammation and necrosis in AP. Lactate in RL is metabolized in the liver, which results in lower metabolic acidosis and hence protective effects.Second, RL may directly decrease inflammatory response in these patients. The presence of RL in-vitro prevents activation of NF-KB, the transcription factor involved in the inflammatory process. Mortality also trended lower in RL patients, but was not statistically significant. Larger RCTs are necessary to further strengthen the association of RL with favorable outcomes in patients with AP, however, our findings may help clinicians in making decisions regarding the choice of fluid for management of AP.2_A Figure 1. Forest Plot of all studies for mortality2_B Figure 2. Forest Plot of all studies for SIRS at 24 hours2_C Figure 3. Literature review process