Association between normal saline infusion volume in the emergency department and acute kidney injury in heat stroke patients: a multicenter retrospective study

Abstract

Background

Previous studies have shown that intravenous normal saline (NS) may be associated with the incidence of acute kidney injury (AKI). This study aimed to evaluate the association between the volume of NS infusion and AKI in heat stroke (HS) patients.

Methods

This multicenter retrospective cohort study included 138 patients with HS. The primary outcome was the incidence of AKI. Secondary outcomes included the need for continuous renal replacement therapy (CRRT), admission to the intensive care unit (ICU), length of stay in the ICU and hospital, and in-hospital mortality. Multivariate regression models, random forest imputation, and genetic and propensity score matching were used to explore the relationship between NS infusion and outcomes.

Results

The mean volume of NS infusion in the emergency department (ED) was 3.02 ± 1.45 L. During hospitalization, 33 patients (23.91%) suffered from AKI. In the multivariate model, as a continuous variable (per 1 L), the volume of NS infusion was associated with the incidence of AKI (OR, 2.51; 95% CI, 1.43–4.40; p = .001), admission to the ICU (OR, 3.46; 95% CI 1.58–7.54; p = .002), and length of stay in the ICU (β, 1.00 days; 95% CI, 0.44–1.56; p < .001) and hospital (β, 1.41 days; 95% CI, 0.37–2.45; p = .008). These relationships also existed in the forest imputation cohort and matching cohort. There were no differences in the use of CRRT or in-hospital mortality.

Conclusions

The volume of NS infusion was associated with a significant increase in the incidence of AKI, admission to the ICU, and length of stay in the ICU and hospital among patients with HS.

Keywords:

• Normal saline
• acute kidney injury
• serum chloride
• heat stroke
• emergency department

Author contributions

Lan Chen: conceptualization, visualization, formal analysis, writing – original draft, writing – review and editing; Junlu Zhao: data curation; Liyun Lu: data curation; Zhumei Gong: data curation; Shuying Xu: data curation; Xiaoling Yang: data curation; Yuping Zhang: conceptualization and methodology; Xiuqin Feng: conceptualization, methodology, validation, writing – review and editing, supervision, and project administration. The authors read and approved the final manuscript.

Ethical approval

This study was approved by the Ethics Committee of the Second Affiliated Hospital of Zhejiang University School of Medicine (approval number: 2022-0913), and the requirement for informed consent was waived.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.