Chloride

Chloride is an equally critical but largely overlooked component of salt compared to sodium. High potassium intake without proportional salt can deplete chloride and sodium and cause salt cravings. The change in chloride was calculated as the 48-hour chloride value minus the admission chloride value. The study measured chloride at ICU admission and again 48 hours after admission. Chloride is an important extracellular anion involved in fluid tension, homeostasis, electrolyte balance, and acid-base physiology. Chloride is required to manufacture hydrochloric acid in the stomach. Each 1 mmol/L increase in chloride at 48 hours was associated with an 11% higher risk of all-cause in-hospital mortality. A restricted cubic spline analysis found a U-shaped relationship between chloride at 48 hours and in-hospital mortality. Chloride is lost through sweat and fluid loss and must be replenished. Chloride serves immune defense both through hypochlorite production and through enabling stomach acid formation.