Administration of intravascular (IV) fluid is the most common emergency department (ED) procedure. IV fluids are integral to increasing effective blood volume and ensuring organ perfusion in patients with volume depletion and dehydration. There are many options of IV fluids providers can use when treating ED patients. Surveys show physicians do not cite an evidence-based reason for selecting the crystalloid IV fluid used; the decision was likely to be influenced by type and location of practice. A gap exists in the current literature, as there is no evidence for the optimal IV fluid choice for the ED patient requiring IV fluid before discharge.

Normal saline (NS) is commonly used as an IV fluid replacement in ED patients. However, NS has been associated with increased risk of acidosis and acute kidney injury. This study will use a novel approach of a patient-centered outcome in a non-critically ill population to ascertain the optimal IV fluid for patient quality of recovery. The results of this study will inform provider's IV fluid decisions between NS and LR. More importantly, the results of this study will have the power to improve patient's quality of recovery following IV fluid administration and subsequent ED discharge.

ED patients will be recruited, and participants will be randomized to receive one of two IV solutions (Lactated ringer's or normal saline). Participants will answer a survey before and after the intervention to assess their quality of recovery. The post-survey will be administered by phone after ED discharge. Participants will also be contacted by text message one week following their ED visit to gather information on their healthcare utilization.

This is a single-center randomized, single-blinded, controlled clinical trial testing superiority of LR compared to NS in patients receiving IV fluid before discharge.

The study site is the University of Iowa Emergency Department (annual patient volume is 60,000 patients/year).

The study population will include adult ED patients presenting with chief complaints associated with volume depletion. Figure 1 outlines the enrollment flowchart for the study with inclusion and exclusion criteria. Research assistants (RAs) are available in the ED from 9am - 10pm every day, and an automated paging system will alert the team when patients qualify, as the study team has done previously. All participants will receive 2 liters of blinded IV fluid as part of the study. The intervention group will receive lactated ringer's, and the control group will receive normal saline (0.9% sodium chloride). Nursing staff will establish the peripheral IV access, and subjects will be blinded to group.

The primary outcome, Quality of Recovery-40, will be analyzed using a t-test (if parametric) or Mann Whitney U Test (non-parametric) in an intention-to-treat (ITT) analysis. Normality will be assessed with a Kolmogorov-Smirnov (K-S) and visualization of data. Due to the nature of time-critical emergency department research, an additional analysis will be done by treatment received and compared to the primary ITT analysis as a sensitivity analysis. Secondary outcomes will be reported as a relative risk with 95%CI in an ITT analysis. A safety analysis of secondary outcomes will be performed by treatment received (see page 37). Baseline characteristics will be reported with summary statistics as appropriate (mean, SD, median, IQR) and differences in characteristics will be conducted using a t-test and chi-square test, as appropriate. The following variables will also be assessed: actual fluid administered(mL), pre-intervention QoR-40 score, and time from intervention to primary outcome. If differences in these characteristics exist between the control and intervention groups, multivariate linear regression and multivariate logistic regression (primary and secondary outcomes, respectively) will be used.

Inclusion Criteria:

• Emergency department patient
• Chief complaint of nausea, vomiting or emesis, diarrhea, abdominal pain, dehydration, heat stroke or exhaustion
• ED provider approves administration of two liters of fluid
• ED provider states patient is likely to be discharged
• Patient has followed up with PCP in the last two years
• Patient has access to phone for next two days following ED discharge

Exclusion Criteria:

• Prisoners
• Children
• Women known to be pregnant
• Jaundice
• Current chemotherapy

Participants could be assessed for adverse events at the phone call 24-48 hours following study enrollment and/or at the text message seven days following study enrollment.

Participants responding to the 24-hour phone call and/or the seven-day text could be assessed for adverse events. Therefore, the total of participants in the LR group is 42 (one participant did not respond to the primary outcome, but did respond to the seven-day text to assess secondary outcomes).

Fluid being administered to participants will be covered by an opaque bag. The investigator calling the participant for follow-up does not know how the participant was allocated.