Non-lactate strong ion difference: a clearer picture.

Area of Science:

• Critical Care Medicine
• Biochemistry
• Medical Diagnostics

Background:

• The non-lactate strong ion difference (SIDnl) is crucial for understanding acid-base balance, particularly in hyperchloremic conditions.
• Previous studies established a link between HCO3 (-) and SIDnl in hyperchloremic patients.

Purpose of the Study:

• To investigate the relationship between SIDnl, apparent strong ion difference (SIDa), and mortality in intensive care unit (ICU) patients.
• To determine if SIDnl serves as a prognostic indicator for ICU mortality.

Main Methods:

• A retrospective analysis of 2691 ICU admissions, including 1069 critically ill patients, across two centers.
• Patients were categorized into low (<38 mmol L(-1)), normal (38-40 mmol L(-1)), and high (>40 mmol L(-1)) SIDnl groups upon ICU admission.
• Data collected included patient demographics, diagnoses, blood gas values, ICU stay length, and mortality, analyzed using multivariate logistic regression.

Main Results:

• No significant difference in lactate levels was observed among the SIDnl groups (p = 0.635).
• Low SIDnl (<38 mmol L(-1)) was independently associated with a 2.55-fold increased likelihood of mortality (p = 0.049).
• APACHE II score and lactate level ≥2 mmol L(-) also significantly increased mortality risk.

Conclusions:

• SIDnl effectively quantifies the impact of non-lactate strong ions on acid-base balance and SIDa.
• A low SIDnl upon ICU admission is a valuable prognostic marker for predicting patient mortality.