STUDY PROTOCOL Open Access Efficacy and safety of rapid intermittent correction compared with slow continuous correction with hypertonic saline in patients with moderately severe or severe symptomatic hyponatremia: study protocol for a randomized controlled trial (SALSA trial) Anna Lee 1 , You Hwan Jo 2 , Kyuseok Kim 2 , Soyeon Ahn 3 , Yun Kyu Oh 4 , Huijai Lee 5 , Jonghwan Shin 5 , Ho Jun Chin 1 , Ki Young Na 1 , Jung Bok Lee 6 , Seon Ha Baek 1,7* and Sejoong Kim 1* Abstract Background: Hyponatremia is the most common electrolyte imbalance encountered in clinical practice, associated with increased mortality and length of hospital stay. However, no high-quality evidence regarding whether hypertonic saline is best administered as a continuous infusion or a bolus injection has been found to date. Therefore, in the current study, we will evaluate the efficacy and safety of rapid intermittent correction compared with slow continuous correction with hypertonic saline in patients with moderately severe or severe symptomatic hyponatremia. Methods/design: This is a prospective, investigator-initiated, multicenter, open-label, randomized controlled study with two experimental therapy groups. A total of 178 patients with severe symptomatic hyponatremia will be enrolled and randomly assigned to receive either rapid intermittent bolus or slow continuous infusion management with hypertonic saline. The primary outcome is the incidence of overcorrection at any given period over 2 days. The secondary outcomes will include the efficacy and safety of two other approaches to the treatment of hyponatremia with 3% hypertonic saline. Discussion: This is the first clinical trial to investigate the efficacy and safety of rapid intermittent correction compared with slow continuous correction with hypertonic saline in patients with moderately severe or severe hyponatremia. Trial registration: ClinicalTrials.gov, identifier number: NCT02887469. Registered on 1 August 2016. Keywords: Hyponatremia, Hypertonic saline, Treatment, Osmotic demyelination syndrome Background Hyponatremia is the most common electrolyte imbalance encountered in clinical practice, and is associated with increased mortality and length of hospital stay [1]. The symptoms related to hyponatremia span a broad range from moderately severe (cognitive test abnormalities, gait impairment) to severe or life-threatening (hypoxemia, coma, and epilepsy) [2–5]. Treatment strategies for hyponatremia differ according to the severity of clinical symptoms and duration of hyponatremia [6]. The extent and rate of increase in serum sodium (sNa) levels during treatment are crucial. Overcorrection of chronic hypona- tremia may result in osmotic demyelination syndrome (ODS), whereas undercorrection may be insufficient to prevent its life-threatening manifestations [6–9]. Several methods for continuous infusion of hypertonic saline have been used to guide the rate of fluid * Correspondence: seonhabaek@hallym.or.kr; haya2001@hanmail.net; sejoong@snubh.org 1 Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea Full list of author information is available at the end of the article © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Lee et al. Trials (2017) 18:147 DOI 10.1186/s13063-017-1865-z