Prognostic impact of hypernatremia for septic shock patients in the intensive care unit

Hypernatremia represents a significant electrolyte imbalance associated with numerous adverse outcomes, particularly in cases of intensive care unit (ICU)-acquired hypernatremia (IAH). Nevertheless, its relevance in patients with septic shock remains uncertain.

To identify independent risk factors and their predictive efficacy for IAH to improve outcomes in patients with septic shock.

In the present retrospective single-center study, a cohort of 157 septic shock patients with concurrent hypernatremia in the ICU at The First Affiliated Hospital of Soochow University, between August 1, 2018, and May 31, 2023, were analyzed. Patients were categorized based on the timing of hypernatremia occurrence into the IAH group (n = 62), the non-IAH group (n = 41), and the normonatremia group (n = 54).

In the present study, there was a significant association between the high serum sodium concentrations, excessive persistent inflammation, immunosuppression and catabolism syndrome and chronic critical illness, while rapid recovery had an apparent association with normonatremia. Moreover, multivariable analyses revealed the following independent risk factors for IAH: Total urinary output over the preceding three days [odds ratio (OR) = 1.09; 95%CI: 1.02-1.17; P = 0.014], enteral nutrition (EN) sodium content of 500 mg (OR = 2.93; 95%CI: 1.13-7.60; P = 0.027), and EN sodium content of 670 mg (OR = 6.19; 95%CI: 1.75-21.98; P = 0.005) were positively correlated with the development of IAH. Notably, the area under the curve for total urinary output over the preceding three days was 0.800 (95%CI: 0.678-0.922, P = 0.001). Furthermore, maximum serum sodium levels, the duration of hypernatremia, and varying sodium correction rates were significantly associated with 28-day in-hospital mortality in septic shock patients (P < 0.05).

The present findings illustrate that elevated serum sodium level was significantly associated with a poor prognosis in septic shock patients in the ICU. It is highly recommended that hypernatremia be considered a potentially important prognostic indicator for the outcome of septic shock.