Fig. 3.

Restricted cubic spline analysis of 30-day mortality with positive (a) and negative (b) fluctuations in Cl⁻ within 72 h according to dyschloremia upon ICU admission. Normochloremia: 97–110 mmol L^− 1, Hyperchloremia: > 110 mmol L^− 1, Hypochloremia: < 97 mmol L^− 1. Positive fluctuation in Cl⁻: Maximum Cl⁻ level within 72 h after ICU admission – Cl⁻ level upon ICU admission. Negative fluctuation in Cl⁻: Cl⁻ level upon ICU admission – minimum Cl⁻ level within 72 h after ICU admission