Base Excess and Beyond: Evolving Concepts in Acid-base Analysis.

Area of Science:

• Critical Care Medicine
• Biochemistry
• Renal Medicine

Background:

• Base excess (BE) is a crucial marker for metabolic acid-base disturbances and mortality prediction in critically ill patients.
• Traditional BE assessment relied on the Henderson-Hasselbalch model.
• The Stewart approach offers a more mechanistic evaluation but involves complex calculations.

Purpose of the Study:

• To review the evolution of the Base excess concept.
• To highlight simplified formulas for integrating BE with the Stewart approach for bedside assessment.
• To introduce and explain the concept of 'alactic BE'.

Main Methods:

• Review of the historical development of Base excess calculations.
• Discussion of the integration of the Stewart approach with BE.
• Explanation of simplified mathematical formulations for bedside use.
• Definition and application of 'alactic BE'.

Main Results:

• Simplified BE formulas enable more reliable, detailed, and rapid bedside evaluations.
• The integration with the Stewart approach provides a more comprehensive mechanistic understanding.
• 'Alactic BE' distinguishes between fixed acid retention and lactic acidosis, particularly in renal failure.

Conclusions:

• The evolution of Base excess has led to more practical and informative clinical tools.
• Simplified BE calculations integrated with the Stewart approach improve bedside assessment of acid-base disturbances.
• The 'alactic BE' concept enhances diagnostic accuracy in patients with renal impairment.